Commit Graph

42297 Commits

Author SHA1 Message Date
YiFei Zhu
d1a02358d4 bpf: Non-atomically allocate freelist during prefill
In internal testing of test_maps, we sometimes observed failures like:
  test_maps: test_maps.c:173: void test_hashmap_percpu(unsigned int, void *):
    Assertion `bpf_map_update_elem(fd, &key, value, BPF_ANY) == 0' failed.
where the errno is ENOMEM. After some troubleshooting and enabling
the warnings, we saw:
  [   91.304708] percpu: allocation failed, size=8 align=8 atomic=1, atomic alloc failed, no space left
  [   91.304716] CPU: 51 PID: 24145 Comm: test_maps Kdump: loaded Tainted: G                 N 6.1.38-smp-DEV #7
  [   91.304719] Hardware name: Google Astoria/astoria, BIOS 0.20230627.0-0 06/27/2023
  [   91.304721] Call Trace:
  [   91.304724]  <TASK>
  [   91.304730]  [<ffffffffa7ef83b9>] dump_stack_lvl+0x59/0x88
  [   91.304737]  [<ffffffffa7ef83f8>] dump_stack+0x10/0x18
  [   91.304738]  [<ffffffffa75caa0c>] pcpu_alloc+0x6fc/0x870
  [   91.304741]  [<ffffffffa75ca302>] __alloc_percpu_gfp+0x12/0x20
  [   91.304743]  [<ffffffffa756785e>] alloc_bulk+0xde/0x1e0
  [   91.304746]  [<ffffffffa7566c02>] bpf_mem_alloc_init+0xd2/0x2f0
  [   91.304747]  [<ffffffffa7547c69>] htab_map_alloc+0x479/0x650
  [   91.304750]  [<ffffffffa751d6e0>] map_create+0x140/0x2e0
  [   91.304752]  [<ffffffffa751d413>] __sys_bpf+0x5a3/0x6c0
  [   91.304753]  [<ffffffffa751c3ec>] __x64_sys_bpf+0x1c/0x30
  [   91.304754]  [<ffffffffa7ef847a>] do_syscall_64+0x5a/0x80
  [   91.304756]  [<ffffffffa800009b>] entry_SYSCALL_64_after_hwframe+0x63/0xcd

This makes sense, because in atomic context, percpu allocation would
not create new chunks; it would only create in non-atomic contexts.
And if during prefill all precpu chunks are full, -ENOMEM would
happen immediately upon next unit_alloc.

Prefill phase does not actually run in atomic context, so we can
use this fact to allocate non-atomically with GFP_KERNEL instead
of GFP_NOWAIT. This avoids the immediate -ENOMEM.

GFP_NOWAIT has to be used in unit_alloc when bpf program runs
in atomic context. Even if bpf program runs in non-atomic context,
in most cases, rcu read lock is enabled for the program so
GFP_NOWAIT is still needed. This is often also the case for
BPF_MAP_UPDATE_ELEM syscalls.

Signed-off-by: YiFei Zhu <zhuyifei@google.com>
Acked-by: Yonghong Song <yonghong.song@linux.dev>
Acked-by: Hou Tao <houtao1@huawei.com>
Link: https://lore.kernel.org/r/20230728043359.3324347-1-zhuyifei@google.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-07-28 09:41:10 -07:00
Yonghong Song
09fedc7318 bpf: Fix compilation warning with -Wparentheses
The kernel test robot reported compilation warnings when -Wparentheses is
added to KBUILD_CFLAGS with gcc compiler. The following is the error message:

  .../bpf-next/kernel/bpf/verifier.c: In function ‘coerce_reg_to_size_sx’:
  .../bpf-next/kernel/bpf/verifier.c:5901:14:
    error: suggest parentheses around comparison in operand of ‘==’ [-Werror=parentheses]
    if (s64_max >= 0 == s64_min >= 0) {
        ~~~~~~~~^~~~
  .../bpf-next/kernel/bpf/verifier.c: In function ‘coerce_subreg_to_size_sx’:
  .../bpf-next/kernel/bpf/verifier.c:5965:14:
    error: suggest parentheses around comparison in operand of ‘==’ [-Werror=parentheses]
    if (s32_min >= 0 == s32_max >= 0) {
        ~~~~~~~~^~~~

To fix the issue, add proper parentheses for the above '>=' condition
to silence the warning/error.

I tried a few clang compilers like clang16 and clang18 and they do not emit
such warnings with -Wparentheses.

Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202307281133.wi0c4SqG-lkp@intel.com/
Signed-off-by: Yonghong Song <yonghong.song@linux.dev>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20230728055740.2284534-1-yonghong.song@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-07-28 08:54:04 -07:00
Yonghong Song
f835bb6222 bpf: Add kernel/bpftool asm support for new instructions
Add asm support for new instructions so kernel verifier and bpftool
xlated insn dumps can have proper asm syntax for new instructions.

Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Acked-by: Quentin Monnet <quentin@isovalent.com>
Signed-off-by: Yonghong Song <yonghong.song@linux.dev>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-07-27 18:54:02 -07:00
Yonghong Song
4cd58e9af8 bpf: Support new 32bit offset jmp instruction
Add interpreter/jit/verifier support for 32bit offset jmp instruction.
If a conditional jmp instruction needs more than 16bit offset,
it can be simulated with a conditional jmp + a 32bit jmp insn.

Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/r/20230728011231.3716103-1-yonghong.song@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-07-27 18:52:33 -07:00
Yonghong Song
7058e3a31e bpf: Fix jit blinding with new sdiv/smov insns
Handle new insns properly in bpf_jit_blind_insn() function.

Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/r/20230728011225.3715812-1-yonghong.song@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-07-27 18:52:33 -07:00
Yonghong Song
ec0e2da95f bpf: Support new signed div/mod instructions.
Add interpreter/jit support for new signed div/mod insns.
The new signed div/mod instructions are encoded with
unsigned div/mod instructions plus insn->off == 1.
Also add basic verifier support to ensure new insns get
accepted.

Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/r/20230728011219.3714605-1-yonghong.song@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-07-27 18:52:33 -07:00
Yonghong Song
0845c3db7b bpf: Support new unconditional bswap instruction
The existing 'be' and 'le' insns will do conditional bswap
depends on host endianness. This patch implements
unconditional bswap insns.

Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/r/20230728011213.3712808-1-yonghong.song@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-07-27 18:52:33 -07:00
Yonghong Song
1f1e864b65 bpf: Handle sign-extenstin ctx member accesses
Currently, if user accesses a ctx member with signed types,
the compiler will generate an unsigned load followed by
necessary left and right shifts.

With the introduction of sign-extension load, compiler may
just emit a ldsx insn instead. Let us do a final movsx sign
extension to the final unsigned ctx load result to
satisfy original sign extension requirement.

Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/r/20230728011207.3712528-1-yonghong.song@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-07-27 18:52:33 -07:00
Yonghong Song
8100928c88 bpf: Support new sign-extension mov insns
Add interpreter/jit support for new sign-extension mov insns.
The original 'MOV' insn is extended to support reg-to-reg
signed version for both ALU and ALU64 operations. For ALU mode,
the insn->off value of 8 or 16 indicates sign-extension
from 8- or 16-bit value to 32-bit value. For ALU64 mode,
the insn->off value of 8/16/32 indicates sign-extension
from 8-, 16- or 32-bit value to 64-bit value.

Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/r/20230728011202.3712300-1-yonghong.song@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-07-27 18:52:33 -07:00
Yonghong Song
1f9a1ea821 bpf: Support new sign-extension load insns
Add interpreter/jit support for new sign-extension load insns
which adds a new mode (BPF_MEMSX).
Also add verifier support to recognize these insns and to
do proper verification with new insns. In verifier, besides
to deduce proper bounds for the dst_reg, probed memory access
is also properly handled.

Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/r/20230728011156.3711870-1-yonghong.song@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-07-27 18:52:33 -07:00
Arnd Bergmann
63e2da3b7f bpf: work around -Wuninitialized warning
Splitting these out into separate helper functions means that we
actually pass an uninitialized variable into another function call
if dec_active() happens to not be inlined, and CONFIG_PREEMPT_RT
is disabled:

kernel/bpf/memalloc.c: In function 'add_obj_to_free_list':
kernel/bpf/memalloc.c:200:9: error: 'flags' is used uninitialized [-Werror=uninitialized]
  200 |         dec_active(c, flags);

Avoid this by passing the flags by reference, so they either get
initialized and dereferenced through a pointer, or the pointer never
gets accessed at all.

Fixes: 18e027b1c7 ("bpf: Factor out inc/dec of active flag into helpers.")
Suggested-by: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/r/20230725202653.2905259-1-arnd@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-07-25 17:14:18 -07:00
Jakub Kicinski
59be3baa8d Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
Cross-merge networking fixes after downstream PR.

No conflicts or adjacent changes.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2023-07-20 15:52:55 -07:00
Linus Torvalds
57f1f9dd3a Including fixes from BPF, netfilter, bluetooth and CAN.
Current release - regressions:
 
  - eth: r8169: multiple fixes for PCIe ASPM-related problems
 
  - vrf: fix RCU lockdep splat in output path
 
 Previous releases - regressions:
 
  - gso: fall back to SW segmenting with GSO_UDP_L4 dodgy bit set
 
  - dsa: mv88e6xxx: do a final check before timing out when polling
 
  - nf_tables: fix sleep in atomic in nft_chain_validate
 
 Previous releases - always broken:
 
  - sched: fix undoing tcf_bind_filter() in multiple classifiers
 
  - bpf, arm64: fix BTI type used for freplace attached functions
 
  - can: gs_usb: fix time stamp counter initialization
 
  - nft_set_pipapo: fix improper element removal (leading to UAF)
 
 Misc:
 
  - net: support STP on bridge in non-root netns, STP prevents
    packet loops so not supporting it results in freezing systems
    of unsuspecting users, and in turn very upset noises being made
 
  - fix kdoc warnings
 
  - annotate various bits of TCP state to prevent data races
 
 Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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Merge tag 'net-6.5-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net

Pull networking fixes from Jakub Kicinski:
 "Including fixes from BPF, netfilter, bluetooth and CAN.

  Current release - regressions:

   - eth: r8169: multiple fixes for PCIe ASPM-related problems

   - vrf: fix RCU lockdep splat in output path

  Previous releases - regressions:

   - gso: fall back to SW segmenting with GSO_UDP_L4 dodgy bit set

   - dsa: mv88e6xxx: do a final check before timing out when polling

   - nf_tables: fix sleep in atomic in nft_chain_validate

  Previous releases - always broken:

   - sched: fix undoing tcf_bind_filter() in multiple classifiers

   - bpf, arm64: fix BTI type used for freplace attached functions

   - can: gs_usb: fix time stamp counter initialization

   - nft_set_pipapo: fix improper element removal (leading to UAF)

  Misc:

   - net: support STP on bridge in non-root netns, STP prevents packet
     loops so not supporting it results in freezing systems of
     unsuspecting users, and in turn very upset noises being made

   - fix kdoc warnings

   - annotate various bits of TCP state to prevent data races"

* tag 'net-6.5-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (95 commits)
  net: phy: prevent stale pointer dereference in phy_init()
  tcp: annotate data-races around fastopenq.max_qlen
  tcp: annotate data-races around icsk->icsk_user_timeout
  tcp: annotate data-races around tp->notsent_lowat
  tcp: annotate data-races around rskq_defer_accept
  tcp: annotate data-races around tp->linger2
  tcp: annotate data-races around icsk->icsk_syn_retries
  tcp: annotate data-races around tp->keepalive_probes
  tcp: annotate data-races around tp->keepalive_intvl
  tcp: annotate data-races around tp->keepalive_time
  tcp: annotate data-races around tp->tsoffset
  tcp: annotate data-races around tp->tcp_tx_delay
  Bluetooth: MGMT: Use correct address for memcpy()
  Bluetooth: btusb: Fix bluetooth on Intel Macbook 2014
  Bluetooth: SCO: fix sco_conn related locking and validity issues
  Bluetooth: hci_conn: return ERR_PTR instead of NULL when there is no link
  Bluetooth: hci_sync: Avoid use-after-free in dbg for hci_remove_adv_monitor()
  Bluetooth: coredump: fix building with coredump disabled
  Bluetooth: ISO: fix iso_conn related locking and validity issues
  Bluetooth: hci_event: call disconnect callback before deleting conn
  ...
2023-07-20 14:46:39 -07:00
Alexei Starovoitov
6f5a630d7c bpf, net: Introduce skb_pointer_if_linear().
Network drivers always call skb_header_pointer() with non-null buffer.
Remove !buffer check to prevent accidental misuse of skb_header_pointer().
Introduce skb_pointer_if_linear() instead.

Reported-by: Jakub Kicinski <kuba@kernel.org>
Acked-by: Jakub Kicinski <kuba@kernel.org>
Link: https://lore.kernel.org/r/20230718234021.43640-1-alexei.starovoitov@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-07-19 10:27:33 -07:00
Daniel Borkmann
e420bed025 bpf: Add fd-based tcx multi-prog infra with link support
This work refactors and adds a lightweight extension ("tcx") to the tc BPF
ingress and egress data path side for allowing BPF program management based
on fds via bpf() syscall through the newly added generic multi-prog API.
The main goal behind this work which we also presented at LPC [0] last year
and a recent update at LSF/MM/BPF this year [3] is to support long-awaited
BPF link functionality for tc BPF programs, which allows for a model of safe
ownership and program detachment.

Given the rise in tc BPF users in cloud native environments, this becomes
necessary to avoid hard to debug incidents either through stale leftover
programs or 3rd party applications accidentally stepping on each others toes.
As a recap, a BPF link represents the attachment of a BPF program to a BPF
hook point. The BPF link holds a single reference to keep BPF program alive.
Moreover, hook points do not reference a BPF link, only the application's
fd or pinning does. A BPF link holds meta-data specific to attachment and
implements operations for link creation, (atomic) BPF program update,
detachment and introspection. The motivation for BPF links for tc BPF programs
is multi-fold, for example:

  - From Meta: "It's especially important for applications that are deployed
    fleet-wide and that don't "control" hosts they are deployed to. If such
    application crashes and no one notices and does anything about that, BPF
    program will keep running draining resources or even just, say, dropping
    packets. We at FB had outages due to such permanent BPF attachment
    semantics. With fd-based BPF link we are getting a framework, which allows
    safe, auto-detachable behavior by default, unless application explicitly
    opts in by pinning the BPF link." [1]

  - From Cilium-side the tc BPF programs we attach to host-facing veth devices
    and phys devices build the core datapath for Kubernetes Pods, and they
    implement forwarding, load-balancing, policy, EDT-management, etc, within
    BPF. Currently there is no concept of 'safe' ownership, e.g. we've recently
    experienced hard-to-debug issues in a user's staging environment where
    another Kubernetes application using tc BPF attached to the same prio/handle
    of cls_bpf, accidentally wiping all Cilium-based BPF programs from underneath
    it. The goal is to establish a clear/safe ownership model via links which
    cannot accidentally be overridden. [0,2]

BPF links for tc can co-exist with non-link attachments, and the semantics are
in line also with XDP links: BPF links cannot replace other BPF links, BPF
links cannot replace non-BPF links, non-BPF links cannot replace BPF links and
lastly only non-BPF links can replace non-BPF links. In case of Cilium, this
would solve mentioned issue of safe ownership model as 3rd party applications
would not be able to accidentally wipe Cilium programs, even if they are not
BPF link aware.

Earlier attempts [4] have tried to integrate BPF links into core tc machinery
to solve cls_bpf, which has been intrusive to the generic tc kernel API with
extensions only specific to cls_bpf and suboptimal/complex since cls_bpf could
be wiped from the qdisc also. Locking a tc BPF program in place this way, is
getting into layering hacks given the two object models are vastly different.

We instead implemented the tcx (tc 'express') layer which is an fd-based tc BPF
attach API, so that the BPF link implementation blends in naturally similar to
other link types which are fd-based and without the need for changing core tc
internal APIs. BPF programs for tc can then be successively migrated from classic
cls_bpf to the new tc BPF link without needing to change the program's source
code, just the BPF loader mechanics for attaching is sufficient.

For the current tc framework, there is no change in behavior with this change
and neither does this change touch on tc core kernel APIs. The gist of this
patch is that the ingress and egress hook have a lightweight, qdisc-less
extension for BPF to attach its tc BPF programs, in other words, a minimal
entry point for tc BPF. The name tcx has been suggested from discussion of
earlier revisions of this work as a good fit, and to more easily differ between
the classic cls_bpf attachment and the fd-based one.

For the ingress and egress tcx points, the device holds a cache-friendly array
with program pointers which is separated from control plane (slow-path) data.
Earlier versions of this work used priority to determine ordering and expression
of dependencies similar as with classic tc, but it was challenged that for
something more future-proof a better user experience is required. Hence this
resulted in the design and development of the generic attach/detach/query API
for multi-progs. See prior patch with its discussion on the API design. tcx is
the first user and later we plan to integrate also others, for example, one
candidate is multi-prog support for XDP which would benefit and have the same
'look and feel' from API perspective.

The goal with tcx is to have maximum compatibility to existing tc BPF programs,
so they don't need to be rewritten specifically. Compatibility to call into
classic tcf_classify() is also provided in order to allow successive migration
or both to cleanly co-exist where needed given its all one logical tc layer and
the tcx plus classic tc cls/act build one logical overall processing pipeline.

tcx supports the simplified return codes TCX_NEXT which is non-terminating (go
to next program) and terminating ones with TCX_PASS, TCX_DROP, TCX_REDIRECT.
The fd-based API is behind a static key, so that when unused the code is also
not entered. The struct tcx_entry's program array is currently static, but
could be made dynamic if necessary at a point in future. The a/b pair swap
design has been chosen so that for detachment there are no allocations which
otherwise could fail.

The work has been tested with tc-testing selftest suite which all passes, as
well as the tc BPF tests from the BPF CI, and also with Cilium's L4LB.

Thanks also to Nikolay Aleksandrov and Martin Lau for in-depth early reviews
of this work.

  [0] https://lpc.events/event/16/contributions/1353/
  [1] https://lore.kernel.org/bpf/CAEf4BzbokCJN33Nw_kg82sO=xppXnKWEncGTWCTB9vGCmLB6pw@mail.gmail.com
  [2] https://colocatedeventseu2023.sched.com/event/1Jo6O/tales-from-an-ebpf-programs-murder-mystery-hemanth-malla-guillaume-fournier-datadog
  [3] http://vger.kernel.org/bpfconf2023_material/tcx_meta_netdev_borkmann.pdf
  [4] https://lore.kernel.org/bpf/20210604063116.234316-1-memxor@gmail.com

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Jakub Kicinski <kuba@kernel.org>
Link: https://lore.kernel.org/r/20230719140858.13224-3-daniel@iogearbox.net
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-07-19 10:07:27 -07:00
Daniel Borkmann
053c8e1f23 bpf: Add generic attach/detach/query API for multi-progs
This adds a generic layer called bpf_mprog which can be reused by different
attachment layers to enable multi-program attachment and dependency resolution.
In-kernel users of the bpf_mprog don't need to care about the dependency
resolution internals, they can just consume it with few API calls.

The initial idea of having a generic API sparked out of discussion [0] from an
earlier revision of this work where tc's priority was reused and exposed via
BPF uapi as a way to coordinate dependencies among tc BPF programs, similar
as-is for classic tc BPF. The feedback was that priority provides a bad user
experience and is hard to use [1], e.g.:

  I cannot help but feel that priority logic copy-paste from old tc, netfilter
  and friends is done because "that's how things were done in the past". [...]
  Priority gets exposed everywhere in uapi all the way to bpftool when it's
  right there for users to understand. And that's the main problem with it.

  The user don't want to and don't need to be aware of it, but uapi forces them
  to pick the priority. [...] Your cover letter [0] example proves that in
  real life different service pick the same priority. They simply don't know
  any better. Priority is an unnecessary magic that apps _have_ to pick, so
  they just copy-paste and everyone ends up using the same.

The course of the discussion showed more and more the need for a generic,
reusable API where the "same look and feel" can be applied for various other
program types beyond just tc BPF, for example XDP today does not have multi-
program support in kernel, but also there was interest around this API for
improving management of cgroup program types. Such common multi-program
management concept is useful for BPF management daemons or user space BPF
applications coordinating internally about their attachments.

Both from Cilium and Meta side [2], we've collected the following requirements
for a generic attach/detach/query API for multi-progs which has been implemented
as part of this work:

  - Support prog-based attach/detach and link API
  - Dependency directives (can also be combined):
    - BPF_F_{BEFORE,AFTER} with relative_{fd,id} which can be {prog,link,none}
      - BPF_F_ID flag as {fd,id} toggle; the rationale for id is so that user
        space application does not need CAP_SYS_ADMIN to retrieve foreign fds
        via bpf_*_get_fd_by_id()
      - BPF_F_LINK flag as {prog,link} toggle
      - If relative_{fd,id} is none, then BPF_F_BEFORE will just prepend, and
        BPF_F_AFTER will just append for attaching
      - Enforced only at attach time
    - BPF_F_REPLACE with replace_bpf_fd which can be prog, links have their
      own infra for replacing their internal prog
    - If no flags are set, then it's default append behavior for attaching
  - Internal revision counter and optionally being able to pass expected_revision
  - User space application can query current state with revision, and pass it
    along for attachment to assert current state before doing updates
  - Query also gets extension for link_ids array and link_attach_flags:
    - prog_ids are always filled with program IDs
    - link_ids are filled with link IDs when link was used, otherwise 0
    - {prog,link}_attach_flags for holding {prog,link}-specific flags
  - Must be easy to integrate/reuse for in-kernel users

The uapi-side changes needed for supporting bpf_mprog are rather minimal,
consisting of the additions of the attachment flags, revision counter, and
expanding existing union with relative_{fd,id} member.

The bpf_mprog framework consists of an bpf_mprog_entry object which holds
an array of bpf_mprog_fp (fast-path structure). The bpf_mprog_cp (control-path
structure) is part of bpf_mprog_bundle. Both have been separated, so that
fast-path gets efficient packing of bpf_prog pointers for maximum cache
efficiency. Also, array has been chosen instead of linked list or other
structures to remove unnecessary indirections for a fast point-to-entry in
tc for BPF.

The bpf_mprog_entry comes as a pair via bpf_mprog_bundle so that in case of
updates the peer bpf_mprog_entry is populated and then just swapped which
avoids additional allocations that could otherwise fail, for example, in
detach case. bpf_mprog_{fp,cp} arrays are currently static, but they could
be converted to dynamic allocation if necessary at a point in future.
Locking is deferred to the in-kernel user of bpf_mprog, for example, in case
of tcx which uses this API in the next patch, it piggybacks on rtnl.

An extensive test suite for checking all aspects of this API for prog-based
attach/detach and link API comes as BPF selftests in this series.

Thanks also to Andrii Nakryiko for early API discussions wrt Meta's BPF prog
management.

  [0] https://lore.kernel.org/bpf/20221004231143.19190-1-daniel@iogearbox.net
  [1] https://lore.kernel.org/bpf/CAADnVQ+gEY3FjCR=+DmjDR4gp5bOYZUFJQXj4agKFHT9CQPZBw@mail.gmail.com
  [2] http://vger.kernel.org/bpfconf2023_material/tcx_meta_netdev_borkmann.pdf

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/r/20230719140858.13224-2-daniel@iogearbox.net
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-07-19 10:07:27 -07:00
Anton Protopopov
72829b1c1f bpf: allow any program to use the bpf_map_sum_elem_count kfunc
Register the bpf_map_sum_elem_count func for all programs, and update the
map_ptr subtest of the test_progs test to test the new functionality.

The usage is allowed as long as the pointer to the map is trusted (when
using tracing programs) or is a const pointer to map, as in the following
example:

    struct {
            __uint(type, BPF_MAP_TYPE_HASH);
            ...
    } hash SEC(".maps");

    ...

    static inline int some_bpf_prog(void)
    {
            struct bpf_map *map = (struct bpf_map *)&hash;
            __s64 count;

            count = bpf_map_sum_elem_count(map);

            ...
    }

Signed-off-by: Anton Protopopov <aspsk@isovalent.com>
Link: https://lore.kernel.org/r/20230719092952.41202-5-aspsk@isovalent.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-07-19 09:48:53 -07:00
Anton Protopopov
9c29804961 bpf: make an argument const in the bpf_map_sum_elem_count kfunc
We use the map pointer only to read the counter values, no locking
involved, so mark the argument as const.

Signed-off-by: Anton Protopopov <aspsk@isovalent.com>
Link: https://lore.kernel.org/r/20230719092952.41202-4-aspsk@isovalent.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-07-19 09:48:52 -07:00
Anton Protopopov
5ba190c29c bpf: consider CONST_PTR_TO_MAP as trusted pointer to struct bpf_map
Add the BTF id of struct bpf_map to the reg2btf_ids array. This makes the
values of the CONST_PTR_TO_MAP type to be considered as trusted by kfuncs.
This, in turn, allows users to execute trusted kfuncs which accept `struct
bpf_map *` arguments from non-tracing programs.

While exporting the btf_bpf_map_id variable, save some bytes by defining
it as BTF_ID_LIST_GLOBAL_SINGLE (which is u32[1]) and not as BTF_ID_LIST
(which is u32[64]).

Signed-off-by: Anton Protopopov <aspsk@isovalent.com>
Link: https://lore.kernel.org/r/20230719092952.41202-3-aspsk@isovalent.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-07-19 09:48:52 -07:00
Anton Protopopov
831deb2976 bpf: consider types listed in reg2btf_ids as trusted
The reg2btf_ids array contains a list of types for which we can (and need)
to find a corresponding static BTF id. All the types in the list can be
considered as trusted for purposes of kfuncs.

Signed-off-by: Anton Protopopov <aspsk@isovalent.com>
Link: https://lore.kernel.org/r/20230719092952.41202-2-aspsk@isovalent.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-07-19 09:48:52 -07:00
Dave Marchevsky
c3c510ce43 bpf: Add 'owner' field to bpf_{list,rb}_node
As described by Kumar in [0], in shared ownership scenarios it is
necessary to do runtime tracking of {rb,list} node ownership - and
synchronize updates using this ownership information - in order to
prevent races. This patch adds an 'owner' field to struct bpf_list_node
and bpf_rb_node to implement such runtime tracking.

The owner field is a void * that describes the ownership state of a
node. It can have the following values:

  NULL           - the node is not owned by any data structure
  BPF_PTR_POISON - the node is in the process of being added to a data
                   structure
  ptr_to_root    - the pointee is a data structure 'root'
                   (bpf_rb_root / bpf_list_head) which owns this node

The field is initially NULL (set by bpf_obj_init_field default behavior)
and transitions states in the following sequence:

  Insertion: NULL -> BPF_PTR_POISON -> ptr_to_root
  Removal:   ptr_to_root -> NULL

Before a node has been successfully inserted, it is not protected by any
root's lock, and therefore two programs can attempt to add the same node
to different roots simultaneously. For this reason the intermediate
BPF_PTR_POISON state is necessary. For removal, the node is protected
by some root's lock so this intermediate hop isn't necessary.

Note that bpf_list_pop_{front,back} helpers don't need to check owner
before removing as the node-to-be-removed is not passed in as input and
is instead taken directly from the list. Do the check anyways and
WARN_ON_ONCE in this unexpected scenario.

Selftest changes in this patch are entirely mechanical: some BTF
tests have hardcoded struct sizes for structs that contain
bpf_{list,rb}_node fields, those were adjusted to account for the new
sizes. Selftest additions to validate the owner field are added in a
further patch in the series.

  [0]: https://lore.kernel.org/bpf/d7hyspcow5wtjcmw4fugdgyp3fwhljwuscp3xyut5qnwivyeru@ysdq543otzv2

Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
Suggested-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20230718083813.3416104-4-davemarchevsky@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-07-18 17:23:10 -07:00
Dave Marchevsky
0a1f7bfe35 bpf: Introduce internal definitions for UAPI-opaque bpf_{rb,list}_node
Structs bpf_rb_node and bpf_list_node are opaquely defined in
uapi/linux/bpf.h, as BPF program writers are not expected to touch their
fields - nor does the verifier allow them to do so.

Currently these structs are simple wrappers around structs rb_node and
list_head and linked_list / rbtree implementation just casts and passes
to library functions for those data structures. Later patches in this
series, though, will add an "owner" field to bpf_{rb,list}_node, such
that they're not just wrapping an underlying node type. Moreover, the
bpf linked_list and rbtree implementations will deal with these owner
pointers directly in a few different places.

To avoid having to do

  void *owner = (void*)bpf_list_node + sizeof(struct list_head)

with opaque UAPI node types, add bpf_{list,rb}_node_kern struct
definitions to internal headers and modify linked_list and rbtree to use
the internal types where appropriate.

Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
Link: https://lore.kernel.org/r/20230718083813.3416104-3-davemarchevsky@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-07-18 17:23:10 -07:00
Kumar Kartikeya Dwivedi
b5e9ad522c bpf: Repeat check_max_stack_depth for async callbacks
While the check_max_stack_depth function explores call chains emanating
from the main prog, which is typically enough to cover all possible call
chains, it doesn't explore those rooted at async callbacks unless the
async callback will have been directly called, since unlike non-async
callbacks it skips their instruction exploration as they don't
contribute to stack depth.

It could be the case that the async callback leads to a callchain which
exceeds the stack depth, but this is never reachable while only
exploring the entry point from main subprog. Hence, repeat the check for
the main subprog *and* all async callbacks marked by the symbolic
execution pass of the verifier, as execution of the program may begin at
any of them.

Consider functions with following stack depths:
main: 256
async: 256
foo: 256

main:
    rX = async
    bpf_timer_set_callback(...)

async:
    foo()

Here, async is not descended as it does not contribute to stack depth of
main (since it is referenced using bpf_pseudo_func and not
bpf_pseudo_call). However, when async is invoked asynchronously, it will
end up breaching the MAX_BPF_STACK limit by calling foo.

Hence, in addition to main, we also need to explore call chains
beginning at all async callback subprogs in a program.

Fixes: 7ddc80a476 ("bpf: Teach stack depth check about async callbacks.")
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20230717161530.1238-3-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-07-18 15:21:09 -07:00
Kumar Kartikeya Dwivedi
ba7b3e7d5f bpf: Fix subprog idx logic in check_max_stack_depth
The assignment to idx in check_max_stack_depth happens once we see a
bpf_pseudo_call or bpf_pseudo_func. This is not an issue as the rest of
the code performs a few checks and then pushes the frame to the frame
stack, except the case of async callbacks. If the async callback case
causes the loop iteration to be skipped, the idx assignment will be
incorrect on the next iteration of the loop. The value stored in the
frame stack (as the subprogno of the current subprog) will be incorrect.

This leads to incorrect checks and incorrect tail_call_reachable
marking. Save the target subprog in a new variable and only assign to
idx once we are done with the is_async_cb check which may skip pushing
of frame to the frame stack and subsequent stack depth checks and tail
call markings.

Fixes: 7ddc80a476 ("bpf: Teach stack depth check about async callbacks.")
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20230717161530.1238-2-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-07-18 15:21:09 -07:00
Linus Torvalds
4806364acf Seven hotfixes, six of which are cc:stable and one of which addresses a
post-6.5 issue.
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Merge tag 'mm-hotfixes-stable-2023-07-18-12-28' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull hotfixes from Andrew Morton:
 "Seven hotfixes, six of which are cc:stable and one of which addresses
  a post-6.5 issue"

* tag 'mm-hotfixes-stable-2023-07-18-12-28' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm:
  maple_tree: fix node allocation testing on 32 bit
  maple_tree: fix 32 bit mas_next testing
  selftests/mm: mkdirty: fix incorrect position of #endif
  maple_tree: set the node limit when creating a new root node
  mm/mlock: fix vma iterator conversion of apply_vma_lock_flags()
  prctl: move PR_GET_AUXV out of PR_MCE_KILL
  selftests/mm: give scripts execute permission
2023-07-18 14:19:42 -07:00
Miguel Ojeda
636e348353 prctl: move PR_GET_AUXV out of PR_MCE_KILL
Somehow PR_GET_AUXV got added into PR_MCE_KILL's switch when the patch was
applied [1].

Thus move it out of the switch, to the place the patch added it.

In the recently released v6.4 kernel some user could, in principle, be
already using this feature by mapping the right page and passing the
PR_GET_AUXV constant as a pointer:

    prctl(PR_MCE_KILL, PR_GET_AUXV, ...)

So this does change the behavior for users.  We could keep the bug since
the other subcases in PR_MCE_KILL (PR_MCE_KILL_CLEAR and PR_MCE_KILL_SET)
do not overlap.

However, v6.4 may be recent enough (2 weeks old) that moving the lines
(rather than just adding a new case) does not break anybody?  Moreover,
the documentation in man-pages was just committed today [2].

Link: https://lkml.kernel.org/r/20230708233344.361854-1-ojeda@kernel.org
Fixes: ddc65971bb ("prctl: add PR_GET_AUXV to copy auxv to userspace")
Link: https://lore.kernel.org/all/d81864a7f7f43bca6afa2a09fc2e850e4050ab42.1680611394.git.josh@joshtriplett.org/ [1]
Link: https://git.kernel.org/pub/scm/docs/man-pages/man-pages.git/commit/?id=8cf0c06bfd3c2b219b044d4151c96f0da50af9ad [2]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-07-17 12:53:21 -07:00
Linus Torvalds
f61a89ca11 - Remove a cgroup from under a polling process properly
- Fix the idle sibling selection
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Merge tag 'sched_urgent_for_v6.5_rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull scheduler fixes from Borislav Petkov:

 - Remove a cgroup from under a polling process properly

 - Fix the idle sibling selection

* tag 'sched_urgent_for_v6.5_rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched/psi: use kernfs polling functions for PSI trigger polling
  sched/fair: Use recent_used_cpu to test p->cpus_ptr
2023-07-16 13:22:08 -07:00
Linus Torvalds
6eede0686f hardening fixes for v6.5-rc2
- Remove LTO-only suffixes from promoted global function symbols (Yonghong Song)
 
 - Remove unused .text..refcount section from vmlinux.lds.h (Petr Pavlu)
 
 - Add missing __always_inline to sparc __arch_xchg() (Arnd Bergmann)
 
 - Claim maintainership of string routines
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Merge tag 'hardening-v6.5-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux

Pull hardening fixes from Kees Cook:

 - Remove LTO-only suffixes from promoted global function symbols
   (Yonghong Song)

 - Remove unused .text..refcount section from vmlinux.lds.h (Petr Pavlu)

 - Add missing __always_inline to sparc __arch_xchg() (Arnd Bergmann)

 - Claim maintainership of string routines

* tag 'hardening-v6.5-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  sparc: mark __arch_xchg() as __always_inline
  MAINTAINERS: Foolishly claim maintainership of string routines
  kallsyms: strip LTO-only suffixes from promoted global functions
  vmlinux.lds.h: Remove a reference to no longer used sections .text..refcount
2023-07-16 12:18:18 -07:00
Linus Torvalds
4b4eef57e6 Probe fixes for 6.5-rc1, the 2nd set:
- fprobe: Add a comment why fprobe will be skipped if another kprobe is
    running in fprobe_kprobe_handler().
 
  - probe-events: Fix some issues related to fetch-argument
   . Fix double counting of the string length for user-string and symstr.
     This will require longer buffer in the array case.
   . Fix not to count error code (minus value) for the total used length
     in array argument. This makes the total used length shorter.
   . Fix to update dynamic used data size counter only if fetcharg uses
     the dynamic size data. This may mis-count the used dynamic data
     size and corrupt data.
   . Revert "tracing: Add "(fault)" name injection to kernel probes"
     because that did not work correctly with a bug, and we agreed the
     current '(fault)' output (instead of '"(fault)"' like a string)
     explains what happened more clearly.
   . Fix to record 0-length (means fault access) data_loc data in fetch
     function itself, instead of store_trace_args(). If we record an
     array of string, this will fix to save fault access data on each
     entry of the array correctly.
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Merge tag 'probes-fixes-v6.5-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

Pull probe fixes from Masami Hiramatsu:

 - fprobe: Add a comment why fprobe will be skipped if another kprobe is
   running in fprobe_kprobe_handler().

 - probe-events: Fix some issues related to fetch-arguments:

    - Fix double counting of the string length for user-string and
      symstr. This will require longer buffer in the array case.

    - Fix not to count error code (minus value) for the total used
      length in array argument. This makes the total used length
      shorter.

    - Fix to update dynamic used data size counter only if fetcharg uses
      the dynamic size data. This may mis-count the used dynamic data
      size and corrupt data.

    - Revert "tracing: Add "(fault)" name injection to kernel probes"
      because that did not work correctly with a bug, and we agreed the
      current '(fault)' output (instead of '"(fault)"' like a string)
      explains what happened more clearly.

    - Fix to record 0-length (means fault access) data_loc data in fetch
      function itself, instead of store_trace_args(). If we record an
      array of string, this will fix to save fault access data on each
      entry of the array correctly.

* tag 'probes-fixes-v6.5-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  tracing/probes: Fix to record 0-length data_loc in fetch_store_string*() if fails
  Revert "tracing: Add "(fault)" name injection to kernel probes"
  tracing/probes: Fix to update dynamic data counter if fetcharg uses it
  tracing/probes: Fix not to count error code to total length
  tracing/probes: Fix to avoid double count of the string length on the array
  fprobes: Add a comment why fprobe_kprobe_handler exits if kprobe is running
2023-07-16 12:13:51 -07:00
Linus Torvalds
bde7f15027 Power management fixes for 6.5-rc2
- Unbreak the /sys/power/resume interface after recent changes (Azat
    Khuzhin).
 
  - Allow PM_QOS_DEFAULT_VALUE to be used with frequency QoS (Chungkai
    Yang).
 
  - Remove __init from cpufreq callbacks in the sparc driver, because
    they may be called after initialization too (Viresh Kumar).
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Merge tag 'pm-6.5-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

Pull power management fixes from Rafael Wysocki:
 "These fix hibernation (after recent changes), frequency QoS and the
  sparc cpufreq driver.

  Specifics:

   - Unbreak the /sys/power/resume interface after recent changes (Azat
     Khuzhin).

   - Allow PM_QOS_DEFAULT_VALUE to be used with frequency QoS (Chungkai
     Yang).

   - Remove __init from cpufreq callbacks in the sparc driver, because
     they may be called after initialization too (Viresh Kumar)"

* tag 'pm-6.5-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  cpufreq: sparc: Don't mark cpufreq callbacks with __init
  PM: QoS: Restore support for default value on frequency QoS
  PM: hibernate: Fix writing maj:min to /sys/power/resume
2023-07-14 11:07:04 -07:00
Rafael J. Wysocki
d121758da6 Merge branches 'pm-sleep' and 'pm-qos'
Merge a PM QoS fix and a hibernation fix for 6.5-rc2.

 - Unbreak the /sys/power/resume interface after recent changes (Azat
   Khuzhin).

 - Allow PM_QOS_DEFAULT_VALUE to be used with frequency QoS (Chungkai
   Yang).

* pm-sleep:
  PM: hibernate: Fix writing maj:min to /sys/power/resume

* pm-qos:
  PM: QoS: Restore support for default value on frequency QoS
2023-07-14 19:13:21 +02:00
Masami Hiramatsu (Google)
797311bce5 tracing/probes: Fix to record 0-length data_loc in fetch_store_string*() if fails
Fix to record 0-length data to data_loc in fetch_store_string*() if it fails
to get the string data.
Currently those expect that the data_loc is updated by store_trace_args() if
it returns the error code. However, that does not work correctly if the
argument is an array of strings. In that case, store_trace_args() only clears
the first entry of the array (which may have no error) and leaves other
entries. So it should be cleared by fetch_store_string*() itself.
Also, 'dyndata' and 'maxlen' in store_trace_args() should be updated
only if it is used (ret > 0 and argument is a dynamic data.)

Link: https://lore.kernel.org/all/168908496683.123124.4761206188794205601.stgit@devnote2/

Fixes: 40b53b7718 ("tracing: probeevent: Add array type support")
Cc: stable@vger.kernel.org
Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
2023-07-14 17:04:58 +09:00
Jakub Kicinski
d2afa89f66 for-netdev
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Merge tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next

Alexei Starovoitov says:

====================
pull-request: bpf-next 2023-07-13

We've added 67 non-merge commits during the last 15 day(s) which contain
a total of 106 files changed, 4444 insertions(+), 619 deletions(-).

The main changes are:

1) Fix bpftool build in presence of stale vmlinux.h,
   from Alexander Lobakin.

2) Introduce bpf_me_mcache_free_rcu() and fix OOM under stress,
   from Alexei Starovoitov.

3) Teach verifier actual bounds of bpf_get_smp_processor_id()
   and fix perf+libbpf issue related to custom section handling,
   from Andrii Nakryiko.

4) Introduce bpf map element count, from Anton Protopopov.

5) Check skb ownership against full socket, from Kui-Feng Lee.

6) Support for up to 12 arguments in BPF trampoline, from Menglong Dong.

7) Export rcu_request_urgent_qs_task, from Paul E. McKenney.

8) Fix BTF walking of unions, from Yafang Shao.

9) Extend link_info for kprobe_multi and perf_event links,
   from Yafang Shao.

* tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (67 commits)
  selftests/bpf: Add selftest for PTR_UNTRUSTED
  bpf: Fix an error in verifying a field in a union
  selftests/bpf: Add selftests for nested_trust
  bpf: Fix an error around PTR_UNTRUSTED
  selftests/bpf: add testcase for TRACING with 6+ arguments
  bpf, x86: allow function arguments up to 12 for TRACING
  bpf, x86: save/restore regs with BPF_DW size
  bpftool: Use "fallthrough;" keyword instead of comments
  bpf: Add object leak check.
  bpf: Convert bpf_cpumask to bpf_mem_cache_free_rcu.
  bpf: Introduce bpf_mem_free_rcu() similar to kfree_rcu().
  selftests/bpf: Improve test coverage of bpf_mem_alloc.
  rcu: Export rcu_request_urgent_qs_task()
  bpf: Allow reuse from waiting_for_gp_ttrace list.
  bpf: Add a hint to allocated objects.
  bpf: Change bpf_mem_cache draining process.
  bpf: Further refactor alloc_bulk().
  bpf: Factor out inc/dec of active flag into helpers.
  bpf: Refactor alloc_bulk().
  bpf: Let free_all() return the number of freed elements.
  ...
====================

Link: https://lore.kernel.org/r/20230714020910.80794-1-alexei.starovoitov@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2023-07-13 19:13:24 -07:00
Yafang Shao
33937607ef bpf: Fix an error in verifying a field in a union
We are utilizing BPF LSM to monitor BPF operations within our container
environment. When we add support for raw_tracepoint, it hits below
error.

; (const void *)attr->raw_tracepoint.name);
27: (79) r3 = *(u64 *)(r2 +0)
access beyond the end of member map_type (mend:4) in struct (anon) with off 0 size 8

It can be reproduced with below BPF prog.

SEC("lsm/bpf")
int BPF_PROG(bpf_audit, int cmd, union bpf_attr *attr, unsigned int size)
{
	switch (cmd) {
	case BPF_RAW_TRACEPOINT_OPEN:
		bpf_printk("raw_tracepoint is %s", attr->raw_tracepoint.name);
		break;
	default:
		break;
	}
	return 0;
}

The reason is that when accessing a field in a union, such as bpf_attr,
if the field is located within a nested struct that is not the first
member of the union, it can result in incorrect field verification.

  union bpf_attr {
      struct {
          __u32 map_type; <<<< Actually it will find that field.
          __u32 key_size;
          __u32 value_size;
         ...
      };
      ...
      struct {
          __u64 name;    <<<< We want to verify this field.
          __u32 prog_fd;
      } raw_tracepoint;
  };

Considering the potential deep nesting levels, finding a perfect
solution to address this issue has proven challenging. Therefore, I
propose a solution where we simply skip the verification process if the
field in question is located within a union.

Fixes: 7e3617a72d ("bpf: Add array support to btf_struct_access")
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Link: https://lore.kernel.org/r/20230713025642.27477-4-laoar.shao@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-07-13 16:24:29 -07:00
Yafang Shao
7ce4dc3e4a bpf: Fix an error around PTR_UNTRUSTED
Per discussion with Alexei, the PTR_UNTRUSTED flag should not been
cleared when we start to walk a new struct, because the struct in
question may be a struct nested in a union. We should also check and set
this flag before we walk its each member, in case itself is a union.
We will clear this flag if the field is BTF_TYPE_SAFE_RCU_OR_NULL.

Fixes: 6fcd486b3a ("bpf: Refactor RCU enforcement in the verifier.")
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Link: https://lore.kernel.org/r/20230713025642.27477-2-laoar.shao@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-07-13 16:24:29 -07:00
Linus Torvalds
b1983d427a Networking fixes for 6.5-rc2, including fixes from netfilter,
wireless and ebpf
 
 Current release - regressions:
 
   - netfilter: conntrack: gre: don't set assured flag for clash entries
 
   - wifi: iwlwifi: remove 'use_tfh' config to fix crash
 
 Previous releases - regressions:
 
   - ipv6: fix a potential refcount underflow for idev
 
   - icmp6: ifix null-ptr-deref of ip6_null_entry->rt6i_idev in icmp6_dev()
 
   - bpf: fix max stack depth check for async callbacks
 
   - eth: mlx5e:
     - check for NOT_READY flag state after locking
     - fix page_pool page fragment tracking for XDP
 
   - eth: igc:
     - fix tx hang issue when QBV gate is closed
     - fix corner cases for TSN offload
 
   - eth: octeontx2-af: Move validation of ptp pointer before its usage
 
   - eth: ena: fix shift-out-of-bounds in exponential backoff
 
 Previous releases - always broken:
 
   - core: prevent skb corruption on frag list segmentation
 
   - sched:
     - cls_fw: fix improper refcount update leads to use-after-free
     - sch_qfq: account for stab overhead in qfq_enqueue
 
   - netfilter:
     - report use refcount overflow
     - prevent OOB access in nft_byteorder_eval
 
   - wifi: mt7921e: fix init command fail with enabled device
 
   - eth: ocelot: fix oversize frame dropping for preemptible TCs
 
   - eth: fec: recycle pages for transmitted XDP frames
 
 Signed-off-by: Paolo Abeni <pabeni@redhat.com>
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Merge tag 'net-6.5-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net

Pull networking fixes from Paolo Abeni:
 "Including fixes from netfilter, wireless and ebpf.

  Current release - regressions:

   - netfilter: conntrack: gre: don't set assured flag for clash entries

   - wifi: iwlwifi: remove 'use_tfh' config to fix crash

  Previous releases - regressions:

   - ipv6: fix a potential refcount underflow for idev

   - icmp6: ifix null-ptr-deref of ip6_null_entry->rt6i_idev in
     icmp6_dev()

   - bpf: fix max stack depth check for async callbacks

   - eth: mlx5e:
      - check for NOT_READY flag state after locking
      - fix page_pool page fragment tracking for XDP

   - eth: igc:
      - fix tx hang issue when QBV gate is closed
      - fix corner cases for TSN offload

   - eth: octeontx2-af: Move validation of ptp pointer before its usage

   - eth: ena: fix shift-out-of-bounds in exponential backoff

  Previous releases - always broken:

   - core: prevent skb corruption on frag list segmentation

   - sched:
      - cls_fw: fix improper refcount update leads to use-after-free
      - sch_qfq: account for stab overhead in qfq_enqueue

   - netfilter:
      - report use refcount overflow
      - prevent OOB access in nft_byteorder_eval

   - wifi: mt7921e: fix init command fail with enabled device

   - eth: ocelot: fix oversize frame dropping for preemptible TCs

   - eth: fec: recycle pages for transmitted XDP frames"

* tag 'net-6.5-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (79 commits)
  selftests: tc-testing: add test for qfq with stab overhead
  net/sched: sch_qfq: account for stab overhead in qfq_enqueue
  selftests: tc-testing: add tests for qfq mtu sanity check
  net/sched: sch_qfq: reintroduce lmax bound check for MTU
  wifi: cfg80211: fix receiving mesh packets without RFC1042 header
  wifi: rtw89: debug: fix error code in rtw89_debug_priv_send_h2c_set()
  net: txgbe: fix eeprom calculation error
  net/sched: make psched_mtu() RTNL-less safe
  net: ena: fix shift-out-of-bounds in exponential backoff
  netdevsim: fix uninitialized data in nsim_dev_trap_fa_cookie_write()
  net/sched: flower: Ensure both minimum and maximum ports are specified
  MAINTAINERS: Add another mailing list for QUALCOMM ETHQOS ETHERNET DRIVER
  docs: netdev: update the URL of the status page
  wifi: iwlwifi: remove 'use_tfh' config to fix crash
  xdp: use trusted arguments in XDP hints kfuncs
  bpf: cpumap: Fix memory leak in cpu_map_update_elem
  wifi: airo: avoid uninitialized warning in airo_get_rate()
  octeontx2-pf: Add additional check for MCAM rules
  net: dsa: Removed unneeded of_node_put in felix_parse_ports_node
  net: fec: use netdev_err_once() instead of netdev_err()
  ...
2023-07-13 14:21:22 -07:00
Linus Torvalds
ebc27aacee Tracing fixes and clean ups:
- Fix some missing-prototype warnings
 
 - Fix user events struct args (did not include size of struct)
   When creating a user event, the "struct" keyword is to denote
   that the size of the field will be passed in. But the parsing
   failed to handle this case.
 
 - Add selftest to struct sizes for user events
 
 - Fix sample code for direct trampolines.
   The sample code for direct trampolines attached to handle_mm_fault().
   But the prototype changed and the direct trampoline sample code
   was not updated. Direct trampolines needs to have the arguments correct
   otherwise it can fail or crash the system.
 
 - Remove unused ftrace_regs_caller_ret() prototype.
 
 - Quiet false positive of FORTIFY_SOURCE
   Due to backward compatibility, the structure used to save stack traces
   in the kernel had a fixed size of 8. This structure is exported to
   user space via the tracing format file. A change was made to allow
   more than 8 functions to be recorded, and user space now uses the
   size field to know how many functions are actually in the stack.
   But the structure still has size of 8 (even though it points into
   the ring buffer that has the required amount allocated to hold a
   full stack. This was fine until the fortifier noticed that the
   memcpy(&entry->caller, stack, size) was greater than the 8 functions
   and would complain at runtime about it. Hide this by using a pointer
   to the stack location on the ring buffer instead of using the address
   of the entry structure caller field.
 
 - Fix a deadloop in reading trace_pipe that was caused by a mismatch
   between ring_buffer_empty() returning false which then asked to
   read the data, but the read code uses rb_num_of_entries() that
   returned zero, and causing a infinite "retry".
 
 - Fix a warning caused by not using all pages allocated to store
   ftrace functions, where this can happen if the linker inserts a bunch of
   "NULL" entries, causing the accounting of how many pages needed
   to be off.
 
 - Fix histogram synthetic event crashing when the start event is
   removed and the end event is still using a variable from it.
 
 - Fix memory leak in freeing iter->temp in tracing_release_pipe()
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Merge tag 'trace-v6.5-rc1-3' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

Pull tracing fixes from Steven Rostedt:

 - Fix some missing-prototype warnings

 - Fix user events struct args (did not include size of struct)

   When creating a user event, the "struct" keyword is to denote that
   the size of the field will be passed in. But the parsing failed to
   handle this case.

 - Add selftest to struct sizes for user events

 - Fix sample code for direct trampolines.

   The sample code for direct trampolines attached to handle_mm_fault().
   But the prototype changed and the direct trampoline sample code was
   not updated. Direct trampolines needs to have the arguments correct
   otherwise it can fail or crash the system.

 - Remove unused ftrace_regs_caller_ret() prototype.

 - Quiet false positive of FORTIFY_SOURCE

   Due to backward compatibility, the structure used to save stack
   traces in the kernel had a fixed size of 8. This structure is
   exported to user space via the tracing format file. A change was made
   to allow more than 8 functions to be recorded, and user space now
   uses the size field to know how many functions are actually in the
   stack.

   But the structure still has size of 8 (even though it points into the
   ring buffer that has the required amount allocated to hold a full
   stack.

   This was fine until the fortifier noticed that the
   memcpy(&entry->caller, stack, size) was greater than the 8 functions
   and would complain at runtime about it.

   Hide this by using a pointer to the stack location on the ring buffer
   instead of using the address of the entry structure caller field.

 - Fix a deadloop in reading trace_pipe that was caused by a mismatch
   between ring_buffer_empty() returning false which then asked to read
   the data, but the read code uses rb_num_of_entries() that returned
   zero, and causing a infinite "retry".

 - Fix a warning caused by not using all pages allocated to store ftrace
   functions, where this can happen if the linker inserts a bunch of
   "NULL" entries, causing the accounting of how many pages needed to be
   off.

 - Fix histogram synthetic event crashing when the start event is
   removed and the end event is still using a variable from it

 - Fix memory leak in freeing iter->temp in tracing_release_pipe()

* tag 'trace-v6.5-rc1-3' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  tracing: Fix memory leak of iter->temp when reading trace_pipe
  tracing/histograms: Add histograms to hist_vars if they have referenced variables
  tracing: Stop FORTIFY_SOURCE complaining about stack trace caller
  ftrace: Fix possible warning on checking all pages used in ftrace_process_locs()
  ring-buffer: Fix deadloop issue on reading trace_pipe
  tracing: arm64: Avoid missing-prototype warnings
  selftests/user_events: Test struct size match cases
  tracing/user_events: Fix struct arg size match check
  x86/ftrace: Remove unsued extern declaration ftrace_regs_caller_ret()
  arm64: ftrace: Add direct call trampoline samples support
  samples: ftrace: Save required argument registers in sample trampolines
2023-07-13 13:44:28 -07:00
Masami Hiramatsu (Google)
4ed8f337de Revert "tracing: Add "(fault)" name injection to kernel probes"
This reverts commit 2e9906f84f.

It was turned out that commit 2e9906f84f ("tracing: Add "(fault)"
name injection to kernel probes") did not work correctly and probe
events still show just '(fault)' (instead of '"(fault)"'). Also,
current '(fault)' is more explicit that it faulted.

This also moves FAULT_STRING macro to trace.h so that synthetic
event can keep using it, and uses it in trace_probe.c too.

Link: https://lore.kernel.org/all/168908495772.123124.1250788051922100079.stgit@devnote2/
Link: https://lore.kernel.org/all/20230706230642.3793a593@rorschach.local.home/

Cc: stable@vger.kernel.org
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Tom Zanussi <zanussi@kernel.org>
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-07-14 00:37:43 +09:00
Masami Hiramatsu (Google)
e38e2c6a9e tracing/probes: Fix to update dynamic data counter if fetcharg uses it
Fix to update dynamic data counter ('dyndata') and max length ('maxlen')
only if the fetcharg uses the dynamic data. Also get out arg->dynamic
from unlikely(). This makes dynamic data address wrong if
process_fetch_insn() returns error on !arg->dynamic case.

Link: https://lore.kernel.org/all/168908494781.123124.8160245359962103684.stgit@devnote2/

Suggested-by: Steven Rostedt <rostedt@goodmis.org>
Link: https://lore.kernel.org/all/20230710233400.5aaf024e@gandalf.local.home/
Fixes: 9178412ddf ("tracing: probeevent: Return consumed bytes of dynamic area")
Cc: stable@vger.kernel.org
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-07-14 00:37:00 +09:00
Masami Hiramatsu (Google)
b41326b5e0 tracing/probes: Fix not to count error code to total length
Fix not to count the error code (which is minus value) to the total
used length of array, because it can mess up the return code of
process_fetch_insn_bottom(). Also clear the 'ret' value because it
will be used for calculating next data_loc entry.

Link: https://lore.kernel.org/all/168908493827.123124.2175257289106364229.stgit@devnote2/

Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Closes: https://lore.kernel.org/all/8819b154-2ba1-43c3-98a2-cbde20892023@moroto.mountain/
Fixes: 9b960a3883 ("tracing: probeevent: Unify fetch_insn processing common part")
Cc: stable@vger.kernel.org
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-07-14 00:36:28 +09:00
Masami Hiramatsu (Google)
66bcf65d6c tracing/probes: Fix to avoid double count of the string length on the array
If an array is specified with the ustring or symstr, the length of the
strings are accumlated on both of 'ret' and 'total', which means the
length is double counted.
Just set the length to the 'ret' value for avoiding double counting.

Link: https://lore.kernel.org/all/168908492917.123124.15076463491122036025.stgit@devnote2/

Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Closes: https://lore.kernel.org/all/8819b154-2ba1-43c3-98a2-cbde20892023@moroto.mountain/
Fixes: 88903c4643 ("tracing/probe: Add ustring type for user-space string")
Cc: stable@vger.kernel.org
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-07-14 00:35:53 +09:00
Masami Hiramatsu (Google)
d5f28bb1ce fprobes: Add a comment why fprobe_kprobe_handler exits if kprobe is running
Add a comment the reason why fprobe_kprobe_handler() exits if any other
kprobe is running.

Link: https://lore.kernel.org/all/168874788299.159442.2485957441413653858.stgit@devnote2/

Suggested-by: Steven Rostedt <rostedt@goodmis.org>
Link: https://lore.kernel.org/all/20230706120916.3c6abf15@gandalf.local.home/
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-07-14 00:24:00 +09:00
Zheng Yejian
d5a8218963 tracing: Fix memory leak of iter->temp when reading trace_pipe
kmemleak reports:
  unreferenced object 0xffff88814d14e200 (size 256):
    comm "cat", pid 336, jiffies 4294871818 (age 779.490s)
    hex dump (first 32 bytes):
      04 00 01 03 00 00 00 00 08 00 00 00 00 00 00 00  ................
      0c d8 c8 9b ff ff ff ff 04 5a ca 9b ff ff ff ff  .........Z......
    backtrace:
      [<ffffffff9bdff18f>] __kmalloc+0x4f/0x140
      [<ffffffff9bc9238b>] trace_find_next_entry+0xbb/0x1d0
      [<ffffffff9bc9caef>] trace_print_lat_context+0xaf/0x4e0
      [<ffffffff9bc94490>] print_trace_line+0x3e0/0x950
      [<ffffffff9bc95499>] tracing_read_pipe+0x2d9/0x5a0
      [<ffffffff9bf03a43>] vfs_read+0x143/0x520
      [<ffffffff9bf04c2d>] ksys_read+0xbd/0x160
      [<ffffffff9d0f0edf>] do_syscall_64+0x3f/0x90
      [<ffffffff9d2000aa>] entry_SYSCALL_64_after_hwframe+0x6e/0xd8

when reading file 'trace_pipe', 'iter->temp' is allocated or relocated
in trace_find_next_entry() but not freed before 'trace_pipe' is closed.

To fix it, free 'iter->temp' in tracing_release_pipe().

Link: https://lore.kernel.org/linux-trace-kernel/20230713141435.1133021-1-zhengyejian1@huawei.com

Cc: stable@vger.kernel.org
Fixes: ff895103a8 ("tracing: Save off entry when peeking at next entry")
Signed-off-by: Zheng Yejian <zhengyejian1@huawei.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-07-13 10:48:36 -04:00
Mohamed Khalfella
6018b585e8 tracing/histograms: Add histograms to hist_vars if they have referenced variables
Hist triggers can have referenced variables without having direct
variables fields. This can be the case if referenced variables are added
for trigger actions. In this case the newly added references will not
have field variables. Not taking such referenced variables into
consideration can result in a bug where it would be possible to remove
hist trigger with variables being refenced. This will result in a bug
that is easily reproducable like so

$ cd /sys/kernel/tracing
$ echo 'synthetic_sys_enter char[] comm; long id' >> synthetic_events
$ echo 'hist:keys=common_pid.execname,id.syscall:vals=hitcount:comm=common_pid.execname' >> events/raw_syscalls/sys_enter/trigger
$ echo 'hist:keys=common_pid.execname,id.syscall:onmatch(raw_syscalls.sys_enter).synthetic_sys_enter($comm, id)' >> events/raw_syscalls/sys_enter/trigger
$ echo '!hist:keys=common_pid.execname,id.syscall:vals=hitcount:comm=common_pid.execname' >> events/raw_syscalls/sys_enter/trigger

[  100.263533] ==================================================================
[  100.264634] BUG: KASAN: slab-use-after-free in resolve_var_refs+0xc7/0x180
[  100.265520] Read of size 8 at addr ffff88810375d0f0 by task bash/439
[  100.266320]
[  100.266533] CPU: 2 PID: 439 Comm: bash Not tainted 6.5.0-rc1 #4
[  100.267277] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.0-20220807_005459-localhost 04/01/2014
[  100.268561] Call Trace:
[  100.268902]  <TASK>
[  100.269189]  dump_stack_lvl+0x4c/0x70
[  100.269680]  print_report+0xc5/0x600
[  100.270165]  ? resolve_var_refs+0xc7/0x180
[  100.270697]  ? kasan_complete_mode_report_info+0x80/0x1f0
[  100.271389]  ? resolve_var_refs+0xc7/0x180
[  100.271913]  kasan_report+0xbd/0x100
[  100.272380]  ? resolve_var_refs+0xc7/0x180
[  100.272920]  __asan_load8+0x71/0xa0
[  100.273377]  resolve_var_refs+0xc7/0x180
[  100.273888]  event_hist_trigger+0x749/0x860
[  100.274505]  ? kasan_save_stack+0x2a/0x50
[  100.275024]  ? kasan_set_track+0x29/0x40
[  100.275536]  ? __pfx_event_hist_trigger+0x10/0x10
[  100.276138]  ? ksys_write+0xd1/0x170
[  100.276607]  ? do_syscall_64+0x3c/0x90
[  100.277099]  ? entry_SYSCALL_64_after_hwframe+0x6e/0xd8
[  100.277771]  ? destroy_hist_data+0x446/0x470
[  100.278324]  ? event_hist_trigger_parse+0xa6c/0x3860
[  100.278962]  ? __pfx_event_hist_trigger_parse+0x10/0x10
[  100.279627]  ? __kasan_check_write+0x18/0x20
[  100.280177]  ? mutex_unlock+0x85/0xd0
[  100.280660]  ? __pfx_mutex_unlock+0x10/0x10
[  100.281200]  ? kfree+0x7b/0x120
[  100.281619]  ? ____kasan_slab_free+0x15d/0x1d0
[  100.282197]  ? event_trigger_write+0xac/0x100
[  100.282764]  ? __kasan_slab_free+0x16/0x20
[  100.283293]  ? __kmem_cache_free+0x153/0x2f0
[  100.283844]  ? sched_mm_cid_remote_clear+0xb1/0x250
[  100.284550]  ? __pfx_sched_mm_cid_remote_clear+0x10/0x10
[  100.285221]  ? event_trigger_write+0xbc/0x100
[  100.285781]  ? __kasan_check_read+0x15/0x20
[  100.286321]  ? __bitmap_weight+0x66/0xa0
[  100.286833]  ? _find_next_bit+0x46/0xe0
[  100.287334]  ? task_mm_cid_work+0x37f/0x450
[  100.287872]  event_triggers_call+0x84/0x150
[  100.288408]  trace_event_buffer_commit+0x339/0x430
[  100.289073]  ? ring_buffer_event_data+0x3f/0x60
[  100.292189]  trace_event_raw_event_sys_enter+0x8b/0xe0
[  100.295434]  syscall_trace_enter.constprop.0+0x18f/0x1b0
[  100.298653]  syscall_enter_from_user_mode+0x32/0x40
[  100.301808]  do_syscall_64+0x1a/0x90
[  100.304748]  entry_SYSCALL_64_after_hwframe+0x6e/0xd8
[  100.307775] RIP: 0033:0x7f686c75c1cb
[  100.310617] Code: 73 01 c3 48 8b 0d 65 3c 10 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa b8 21 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 35 3c 10 00 f7 d8 64 89 01 48
[  100.317847] RSP: 002b:00007ffc60137a38 EFLAGS: 00000246 ORIG_RAX: 0000000000000021
[  100.321200] RAX: ffffffffffffffda RBX: 000055f566469ea0 RCX: 00007f686c75c1cb
[  100.324631] RDX: 0000000000000001 RSI: 0000000000000001 RDI: 000000000000000a
[  100.328104] RBP: 00007ffc60137ac0 R08: 00007f686c818460 R09: 000000000000000a
[  100.331509] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000009
[  100.334992] R13: 0000000000000007 R14: 000000000000000a R15: 0000000000000007
[  100.338381]  </TASK>

We hit the bug because when second hist trigger has was created
has_hist_vars() returned false because hist trigger did not have
variables. As a result of that save_hist_vars() was not called to add
the trigger to trace_array->hist_vars. Later on when we attempted to
remove the first histogram find_any_var_ref() failed to detect it is
being used because it did not find the second trigger in hist_vars list.

With this change we wait until trigger actions are created so we can take
into consideration if hist trigger has variable references. Also, now we
check the return value of save_hist_vars() and fail trigger creation if
save_hist_vars() fails.

Link: https://lore.kernel.org/linux-trace-kernel/20230712223021.636335-1-mkhalfella@purestorage.com

Cc: stable@vger.kernel.org
Fixes: 067fe038e7 ("tracing: Add variable reference handling to hist triggers")
Signed-off-by: Mohamed Khalfella <mkhalfella@purestorage.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-07-12 19:08:56 -04:00
Yonghong Song
8cc32a9bbf kallsyms: strip LTO-only suffixes from promoted global functions
Commit 6eb4bd92c1 ("kallsyms: strip LTO suffixes from static functions")
stripped all function/variable suffixes started with '.' regardless
of whether those suffixes are generated at LTO mode or not. In fact,
as far as I know, in LTO mode, when a static function/variable is
promoted to the global scope, '.llvm.<...>' suffix is added.

The existing mechanism breaks live patch for a LTO kernel even if
no <symbol>.llvm.<...> symbols are involved. For example, for the following
kernel symbols:
  $ grep bpf_verifier_vlog /proc/kallsyms
  ffffffff81549f60 t bpf_verifier_vlog
  ffffffff8268b430 d bpf_verifier_vlog._entry
  ffffffff8282a958 d bpf_verifier_vlog._entry_ptr
  ffffffff82e12a1f d bpf_verifier_vlog.__already_done
'bpf_verifier_vlog' is a static function. '_entry', '_entry_ptr' and
'__already_done' are static variables used inside 'bpf_verifier_vlog',
so llvm promotes them to file-level static with prefix 'bpf_verifier_vlog.'.
Note that the func-level to file-level static function promotion also
happens without LTO.

Given a symbol name 'bpf_verifier_vlog', with LTO kernel, current mechanism will
return 4 symbols to live patch subsystem which current live patching
subsystem cannot handle it. With non-LTO kernel, only one symbol
is returned.

In [1], we have a lengthy discussion, the suggestion is to separate two
cases:
  (1). new symbols with suffix which are generated regardless of whether
       LTO is enabled or not, and
  (2). new symbols with suffix generated only when LTO is enabled.

The cleanup_symbol_name() should only remove suffixes for case (2).
Case (1) should not be changed so it can work uniformly with or without LTO.

This patch removed LTO-only suffix '.llvm.<...>' so live patching and
tracing should work the same way for non-LTO kernel.
The cleanup_symbol_name() in scripts/kallsyms.c is also changed to have the same
filtering pattern so both kernel and kallsyms tool have the same
expectation on the order of symbols.

 [1] https://lore.kernel.org/live-patching/20230615170048.2382735-1-song@kernel.org/T/#u

Fixes: 6eb4bd92c1 ("kallsyms: strip LTO suffixes from static functions")
Reported-by: Song Liu <song@kernel.org>
Signed-off-by: Yonghong Song <yhs@fb.com>
Reviewed-by: Zhen Lei <thunder.leizhen@huawei.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Acked-by: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/r/20230628181926.4102448-1-yhs@fb.com
Signed-off-by: Kees Cook <keescook@chromium.org>
2023-07-12 15:39:34 -07:00
Steven Rostedt (Google)
bec3c25c24 tracing: Stop FORTIFY_SOURCE complaining about stack trace caller
The stack_trace event is an event created by the tracing subsystem to
store stack traces. It originally just contained a hard coded array of 8
words to hold the stack, and a "size" to know how many entries are there.
This is exported to user space as:

name: kernel_stack
ID: 4
format:
	field:unsigned short common_type;	offset:0;	size:2;	signed:0;
	field:unsigned char common_flags;	offset:2;	size:1;	signed:0;
	field:unsigned char common_preempt_count;	offset:3;	size:1;	signed:0;
	field:int common_pid;	offset:4;	size:4;	signed:1;

	field:int size;	offset:8;	size:4;	signed:1;
	field:unsigned long caller[8];	offset:16;	size:64;	signed:0;

print fmt: "\t=> %ps\n\t=> %ps\n\t=> %ps\n" "\t=> %ps\n\t=> %ps\n\t=> %ps\n" "\t=> %ps\n\t=> %ps\n",i
 (void *)REC->caller[0], (void *)REC->caller[1], (void *)REC->caller[2],
 (void *)REC->caller[3], (void *)REC->caller[4], (void *)REC->caller[5],
 (void *)REC->caller[6], (void *)REC->caller[7]

Where the user space tracers could parse the stack. The library was
updated for this specific event to only look at the size, and not the
array. But some older users still look at the array (note, the older code
still checks to make sure the array fits inside the event that it read.
That is, if only 4 words were saved, the parser would not read the fifth
word because it will see that it was outside of the event size).

This event was changed a while ago to be more dynamic, and would save a
full stack even if it was greater than 8 words. It does this by simply
allocating more ring buffer to hold the extra words. Then it copies in the
stack via:

	memcpy(&entry->caller, fstack->calls, size);

As the entry is struct stack_entry, that is created by a macro to both
create the structure and export this to user space, it still had the caller
field of entry defined as: unsigned long caller[8].

When the stack is greater than 8, the FORTIFY_SOURCE code notices that the
amount being copied is greater than the source array and complains about
it. It has no idea that the source is pointing to the ring buffer with the
required allocation.

To hide this from the FORTIFY_SOURCE logic, pointer arithmetic is used:

	ptr = ring_buffer_event_data(event);
	entry = ptr;
	ptr += offsetof(typeof(*entry), caller);
	memcpy(ptr, fstack->calls, size);

Link: https://lore.kernel.org/all/20230612160748.4082850-1-svens@linux.ibm.com/
Link: https://lore.kernel.org/linux-trace-kernel/20230712105235.5fc441aa@gandalf.local.home

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Reported-by: Sven Schnelle <svens@linux.ibm.com>
Tested-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-07-12 17:47:49 -04:00
Zheng Yejian
26efd79c46 ftrace: Fix possible warning on checking all pages used in ftrace_process_locs()
As comments in ftrace_process_locs(), there may be NULL pointers in
mcount_loc section:
 > Some architecture linkers will pad between
 > the different mcount_loc sections of different
 > object files to satisfy alignments.
 > Skip any NULL pointers.

After commit 20e5227e9f ("ftrace: allow NULL pointers in mcount_loc"),
NULL pointers will be accounted when allocating ftrace pages but skipped
before adding into ftrace pages, this may result in some pages not being
used. Then after commit 706c81f87f ("ftrace: Remove extra helper
functions"), warning may occur at:
  WARN_ON(pg->next);

To fix it, only warn for case that no pointers skipped but pages not used
up, then free those unused pages after releasing ftrace_lock.

Link: https://lore.kernel.org/linux-trace-kernel/20230712060452.3175675-1-zhengyejian1@huawei.com

Cc: stable@vger.kernel.org
Fixes: 706c81f87f ("ftrace: Remove extra helper functions")
Suggested-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Zheng Yejian <zhengyejian1@huawei.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-07-12 17:47:37 -04:00
Hou Tao
4ed8b5bcfa bpf: Add object leak check.
The object leak check is cheap. Do it unconditionally to spot difficult races
in bpf_mem_alloc.

Signed-off-by: Hou Tao <houtao1@huawei.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20230706033447.54696-15-alexei.starovoitov@gmail.com
2023-07-12 23:45:23 +02:00
Alexei Starovoitov
8e07bb9ebc bpf: Convert bpf_cpumask to bpf_mem_cache_free_rcu.
Convert bpf_cpumask to bpf_mem_cache_free_rcu.
Note that migrate_disable() in bpf_cpumask_release() is still necessary, since
bpf_cpumask_release() is a dtor. bpf_obj_free_fields() can be converted to do
migrate_disable() there in a follow up.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/bpf/20230706033447.54696-14-alexei.starovoitov@gmail.com
2023-07-12 23:45:23 +02:00
Alexei Starovoitov
5af6807bdb bpf: Introduce bpf_mem_free_rcu() similar to kfree_rcu().
Introduce bpf_mem_[cache_]free_rcu() similar to kfree_rcu().
Unlike bpf_mem_[cache_]free() that links objects for immediate reuse into
per-cpu free list the _rcu() flavor waits for RCU grace period and then moves
objects into free_by_rcu_ttrace list where they are waiting for RCU
task trace grace period to be freed into slab.

The life cycle of objects:
alloc: dequeue free_llist
free: enqeueu free_llist
free_rcu: enqueue free_by_rcu -> waiting_for_gp
free_llist above high watermark -> free_by_rcu_ttrace
after RCU GP waiting_for_gp -> free_by_rcu_ttrace
free_by_rcu_ttrace -> waiting_for_gp_ttrace -> slab

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Hou Tao <houtao1@huawei.com>
Link: https://lore.kernel.org/bpf/20230706033447.54696-13-alexei.starovoitov@gmail.com
2023-07-12 23:45:23 +02:00