Commit Graph

282 Commits

Author SHA1 Message Date
Linus Torvalds
3871d93b82 Perf events updates for v6.1:
- PMU driver updates:
 
      - Add AMD Last Branch Record Extension Version 2 (LbrExtV2)
        feature support for Zen 4 processors.
 
      - Extend the perf ABI to provide branch speculation information,
        if available, and use this on CPUs that have it (eg. LbrExtV2).
 
      - Improve Intel PEBS TSC timestamp handling & integration.
 
      - Add Intel Raptor Lake S CPU support.
 
      - Add 'perf mem' and 'perf c2c' memory profiling support on
        AMD CPUs by utilizing IBS tagged load/store samples.
 
      - Clean up & optimize various x86 PMU details.
 
  - HW breakpoints:
 
      - Big rework to optimize the code for systems with hundreds of CPUs and
        thousands of breakpoints:
 
         - Replace the nr_bp_mutex global mutex with the bp_cpuinfo_sem
 	  per-CPU rwsem that is read-locked during most of the key operations.
 
 	- Improve the O(#cpus * #tasks) logic in toggle_bp_slot()
 	  and fetch_bp_busy_slots().
 
 	- Apply micro-optimizations & cleanups.
 
   - Misc cleanups & enhancements.
 
 Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'perf-core-2022-10-07' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull perf events updates from Ingo Molnar:
 "PMU driver updates:

   - Add AMD Last Branch Record Extension Version 2 (LbrExtV2) feature
     support for Zen 4 processors.

   - Extend the perf ABI to provide branch speculation information, if
     available, and use this on CPUs that have it (eg. LbrExtV2).

   - Improve Intel PEBS TSC timestamp handling & integration.

   - Add Intel Raptor Lake S CPU support.

   - Add 'perf mem' and 'perf c2c' memory profiling support on AMD CPUs
     by utilizing IBS tagged load/store samples.

   - Clean up & optimize various x86 PMU details.

  HW breakpoints:

   - Big rework to optimize the code for systems with hundreds of CPUs
     and thousands of breakpoints:

      - Replace the nr_bp_mutex global mutex with the bp_cpuinfo_sem
        per-CPU rwsem that is read-locked during most of the key
        operations.

      - Improve the O(#cpus * #tasks) logic in toggle_bp_slot() and
        fetch_bp_busy_slots().

      - Apply micro-optimizations & cleanups.

  - Misc cleanups & enhancements"

* tag 'perf-core-2022-10-07' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (75 commits)
  perf/hw_breakpoint: Annotate tsk->perf_event_mutex vs ctx->mutex
  perf: Fix pmu_filter_match()
  perf: Fix lockdep_assert_event_ctx()
  perf/x86/amd/lbr: Adjust LBR regardless of filtering
  perf/x86/utils: Fix uninitialized var in get_branch_type()
  perf/uapi: Define PERF_MEM_SNOOPX_PEER in kernel header file
  perf/x86/amd: Support PERF_SAMPLE_PHY_ADDR
  perf/x86/amd: Support PERF_SAMPLE_ADDR
  perf/x86/amd: Support PERF_SAMPLE_{WEIGHT|WEIGHT_STRUCT}
  perf/x86/amd: Support PERF_SAMPLE_DATA_SRC
  perf/x86/amd: Add IBS OP_DATA2 DataSrc bit definitions
  perf/mem: Introduce PERF_MEM_LVLNUM_{EXTN_MEM|IO}
  perf/x86/uncore: Add new Raptor Lake S support
  perf/x86/cstate: Add new Raptor Lake S support
  perf/x86/msr: Add new Raptor Lake S support
  perf/x86: Add new Raptor Lake S support
  bpf: Check flags for branch stack in bpf_read_branch_records helper
  perf, hw_breakpoint: Fix use-after-free if perf_event_open() fails
  perf: Use sample_flags for raw_data
  perf: Use sample_flags for addr
  ...
2022-10-10 09:27:46 -07:00
Jiri Olsa
cce6a2d7e0 bpf: Check flags for branch stack in bpf_read_branch_records helper
Recent commit [1] changed branch stack data indication from
br_stack pointer to sample_flags in perf_sample_data struct.

We need to check sample_flags for PERF_SAMPLE_BRANCH_STACK
bit for valid branch stack data.

[1] a9a931e266 ("perf: Use sample_flags for branch stack")

Fixes: a9a931e266 ("perf: Use sample_flags for branch stack")
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Kan Liang <kan.liang@linux.intel.com>
Link: https://lore.kernel.org/r/20220927203259.590950-1-jolsa@kernel.org
2022-09-27 22:50:25 +02:00
Jiri Olsa
0e253f7e55 bpf: Return value in kprobe get_func_ip only for entry address
Changing return value of kprobe's version of bpf_get_func_ip
to return zero if the attach address is not on the function's
entry point.

For kprobes attached in the middle of the function we can't easily
get to the function address especially now with the CONFIG_X86_KERNEL_IBT
support.

If user cares about current IP for kprobes attached within the
function body, they can get it with PT_REGS_IP(ctx).

Suggested-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Martynas Pumputis <m@lambda.lt>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20220926153340.1621984-6-jolsa@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-09-26 20:30:40 -07:00
Jiri Olsa
c09eb2e578 bpf: Adjust kprobe_multi entry_ip for CONFIG_X86_KERNEL_IBT
Martynas reported bpf_get_func_ip returning +4 address when
CONFIG_X86_KERNEL_IBT option is enabled.

When CONFIG_X86_KERNEL_IBT is enabled we'll have endbr instruction
at the function entry, which screws return value of bpf_get_func_ip()
helper that should return the function address.

There's short term workaround for kprobe_multi bpf program made by
Alexei [1], but we need this fixup also for bpf_get_attach_cookie,
that returns cookie based on the entry_ip value.

Moving the fixup in the fprobe handler, so both bpf_get_func_ip
and bpf_get_attach_cookie get expected function address when
CONFIG_X86_KERNEL_IBT option is enabled.

Also renaming kprobe_multi_link_handler entry_ip argument to fentry_ip
so it's clearer this is an ftrace __fentry__ ip.

[1] commit 7f0059b58f ("selftests/bpf: Fix kprobe_multi test.")

Cc: Peter Zijlstra <peterz@infradead.org>
Reported-by: Martynas Pumputis <m@lambda.lt>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20220926153340.1621984-5-jolsa@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-09-26 20:30:39 -07:00
Jiri Olsa
05b24ff9b2 bpf: Prevent bpf program recursion for raw tracepoint probes
We got report from sysbot [1] about warnings that were caused by
bpf program attached to contention_begin raw tracepoint triggering
the same tracepoint by using bpf_trace_printk helper that takes
trace_printk_lock lock.

 Call Trace:
  <TASK>
  ? trace_event_raw_event_bpf_trace_printk+0x5f/0x90
  bpf_trace_printk+0x2b/0xe0
  bpf_prog_a9aec6167c091eef_prog+0x1f/0x24
  bpf_trace_run2+0x26/0x90
  native_queued_spin_lock_slowpath+0x1c6/0x2b0
  _raw_spin_lock_irqsave+0x44/0x50
  bpf_trace_printk+0x3f/0xe0
  bpf_prog_a9aec6167c091eef_prog+0x1f/0x24
  bpf_trace_run2+0x26/0x90
  native_queued_spin_lock_slowpath+0x1c6/0x2b0
  _raw_spin_lock_irqsave+0x44/0x50
  bpf_trace_printk+0x3f/0xe0
  bpf_prog_a9aec6167c091eef_prog+0x1f/0x24
  bpf_trace_run2+0x26/0x90
  native_queued_spin_lock_slowpath+0x1c6/0x2b0
  _raw_spin_lock_irqsave+0x44/0x50
  bpf_trace_printk+0x3f/0xe0
  bpf_prog_a9aec6167c091eef_prog+0x1f/0x24
  bpf_trace_run2+0x26/0x90
  native_queued_spin_lock_slowpath+0x1c6/0x2b0
  _raw_spin_lock_irqsave+0x44/0x50
  __unfreeze_partials+0x5b/0x160
  ...

The can be reproduced by attaching bpf program as raw tracepoint on
contention_begin tracepoint. The bpf prog calls bpf_trace_printk
helper. Then by running perf bench the spin lock code is forced to
take slow path and call contention_begin tracepoint.

Fixing this by skipping execution of the bpf program if it's
already running, Using bpf prog 'active' field, which is being
currently used by trampoline programs for the same reason.

Moving bpf_prog_inc_misses_counter to syscall.c because
trampoline.c is compiled in just for CONFIG_BPF_JIT option.

Reviewed-by: Stanislav Fomichev <sdf@google.com>
Reported-by: syzbot+2251879aa068ad9c960d@syzkaller.appspotmail.com
[1] https://lore.kernel.org/bpf/YxhFe3EwqchC%2FfYf@krava/T/#t
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20220916071914.7156-1-jolsa@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-09-21 18:05:44 -07:00
Roberto Sassu
865b0566d8 bpf: Add bpf_verify_pkcs7_signature() kfunc
Add the bpf_verify_pkcs7_signature() kfunc, to give eBPF security modules
the ability to check the validity of a signature against supplied data, by
using user-provided or system-provided keys as trust anchor.

The new kfunc makes it possible to enforce mandatory policies, as eBPF
programs might be allowed to make security decisions only based on data
sources the system administrator approves.

The caller should provide the data to be verified and the signature as eBPF
dynamic pointers (to minimize the number of parameters) and a bpf_key
structure containing a reference to the keyring with keys trusted for
signature verification, obtained from bpf_lookup_user_key() or
bpf_lookup_system_key().

For bpf_key structures obtained from the former lookup function,
bpf_verify_pkcs7_signature() completes the permission check deferred by
that function by calling key_validate(). key_task_permission() is already
called by the PKCS#7 code.

Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Acked-by: KP Singh <kpsingh@kernel.org>
Acked-by: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/r/20220920075951.929132-9-roberto.sassu@huaweicloud.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-09-21 17:32:49 -07:00
Roberto Sassu
f3cf4134c5 bpf: Add bpf_lookup_*_key() and bpf_key_put() kfuncs
Add the bpf_lookup_user_key(), bpf_lookup_system_key() and bpf_key_put()
kfuncs, to respectively search a key with a given key handle serial number
and flags, obtain a key from a pre-determined ID defined in
include/linux/verification.h, and cleanup.

Introduce system_keyring_id_check() to validate the keyring ID parameter of
bpf_lookup_system_key().

Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Acked-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Acked-by: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/r/20220920075951.929132-8-roberto.sassu@huaweicloud.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-09-21 17:32:49 -07:00
Jakub Kicinski
93817be8b6 Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
No conflicts.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-06-23 12:33:24 -07:00
Jakub Kicinski
9fb424c4c2 Merge https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next
Daniel Borkmann says:

====================
pull-request: bpf-next 2022-06-17

We've added 72 non-merge commits during the last 15 day(s) which contain
a total of 92 files changed, 4582 insertions(+), 834 deletions(-).

The main changes are:

1) Add 64 bit enum value support to BTF, from Yonghong Song.

2) Implement support for sleepable BPF uprobe programs, from Delyan Kratunov.

3) Add new BPF helpers to issue and check TCP SYN cookies without binding to a
   socket especially useful in synproxy scenarios, from Maxim Mikityanskiy.

4) Fix libbpf's internal USDT address translation logic for shared libraries as
   well as uprobe's symbol file offset calculation, from Andrii Nakryiko.

5) Extend libbpf to provide an API for textual representation of the various
   map/prog/attach/link types and use it in bpftool, from Daniel Müller.

6) Provide BTF line info for RV64 and RV32 JITs, and fix a put_user bug in the
   core seen in 32 bit when storing BPF function addresses, from Pu Lehui.

7) Fix libbpf's BTF pointer size guessing by adding a list of various aliases
   for 'long' types, from Douglas Raillard.

8) Fix bpftool to readd setting rlimit since probing for memcg-based accounting
   has been unreliable and caused a regression on COS, from Quentin Monnet.

9) Fix UAF in BPF cgroup's effective program computation triggered upon BPF link
   detachment, from Tadeusz Struk.

10) Fix bpftool build bootstrapping during cross compilation which was pointing
    to the wrong AR process, from Shahab Vahedi.

11) Fix logic bug in libbpf's is_pow_of_2 implementation, from Yuze Chi.

12) BPF hash map optimization to avoid grabbing spinlocks of all CPUs when there
    is no free element. Also add a benchmark as reproducer, from Feng Zhou.

13) Fix bpftool's codegen to bail out when there's no BTF, from Michael Mullin.

14) Various minor cleanup and improvements all over the place.

* https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (72 commits)
  bpf: Fix bpf_skc_lookup comment wrt. return type
  bpf: Fix non-static bpf_func_proto struct definitions
  selftests/bpf: Don't force lld on non-x86 architectures
  selftests/bpf: Add selftests for raw syncookie helpers in TC mode
  bpf: Allow the new syncookie helpers to work with SKBs
  selftests/bpf: Add selftests for raw syncookie helpers
  bpf: Add helpers to issue and check SYN cookies in XDP
  bpf: Allow helpers to accept pointers with a fixed size
  bpf: Fix documentation of th_len in bpf_tcp_{gen,check}_syncookie
  selftests/bpf: add tests for sleepable (uk)probes
  libbpf: add support for sleepable uprobe programs
  bpf: allow sleepable uprobe programs to attach
  bpf: implement sleepable uprobes by chaining gps
  bpf: move bpf_prog to bpf.h
  libbpf: Fix internal USDT address translation logic for shared libraries
  samples/bpf: Check detach prog exist or not in xdp_fwd
  selftests/bpf: Avoid skipping certain subtests
  selftests/bpf: Fix test_varlen verification failure with latest llvm
  bpftool: Do not check return value from libbpf_set_strict_mode()
  Revert "bpftool: Use libbpf 1.0 API mode instead of RLIMIT_MEMLOCK"
  ...
====================

Link: https://lore.kernel.org/r/20220617220836.7373-1-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-06-17 19:35:19 -07:00
Jiri Olsa
eb5fb03256 bpf: Force cookies array to follow symbols sorting
When user specifies symbols and cookies for kprobe_multi link
interface it's very likely the cookies will be misplaced and
returned to wrong functions (via get_attach_cookie helper).

The reason is that to resolve the provided functions we sort
them before passing them to ftrace_lookup_symbols, but we do
not do the same sort on the cookie values.

Fixing this by using sort_r function with custom swap callback
that swaps cookie values as well.

Fixes: 0236fec57a ("bpf: Resolve symbols with ftrace_lookup_symbols for kprobe multi link")
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20220615112118.497303-4-jolsa@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-06-16 19:42:21 -07:00
Delyan Kratunov
8c7dcb84e3 bpf: implement sleepable uprobes by chaining gps
uprobes work by raising a trap, setting a task flag from within the
interrupt handler, and processing the actual work for the uprobe on the
way back to userspace. As a result, uprobe handlers already execute in a
might_fault/_sleep context. The primary obstacle to sleepable bpf uprobe
programs is therefore on the bpf side.

Namely, the bpf_prog_array attached to the uprobe is protected by normal
rcu. In order for uprobe bpf programs to become sleepable, it has to be
protected by the tasks_trace rcu flavor instead (and kfree() called after
a corresponding grace period).

Therefore, the free path for bpf_prog_array now chains a tasks_trace and
normal grace periods one after the other.

Users who iterate under tasks_trace read section would
be safe, as would users who iterate under normal read sections (from
non-sleepable locations).

The downside is that the tasks_trace latency affects all perf_event-attached
bpf programs (and not just uprobe ones). This is deemed safe given the
possible attach rates for kprobe/uprobe/tp programs.

Separately, non-sleepable programs need access to dynamically sized
rcu-protected maps, so bpf_run_prog_array_sleepables now conditionally takes
an rcu read section, in addition to the overarching tasks_trace section.

Signed-off-by: Delyan Kratunov <delyank@fb.com>
Link: https://lore.kernel.org/r/ce844d62a2fd0443b08c5ab02e95bc7149f9aeb1.1655248076.git.delyank@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-06-16 19:27:29 -07:00
Dan Carpenter
fd58f7df24 bpf: Use safer kvmalloc_array() where possible
The kvmalloc_array() function is safer because it has a check for
integer overflows.  These sizes come from the user and I was not
able to see any bounds checking so an integer overflow seems like a
realistic concern.

Fixes: 0dcac27254 ("bpf: Add multi kprobe link")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/Yo9VRVMeHbALyjUH@kili
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-06-07 10:40:53 -07:00
Geliang Tang
3bc253c2e6 bpf: Add bpf_skc_to_mptcp_sock_proto
This patch implements a new struct bpf_func_proto, named
bpf_skc_to_mptcp_sock_proto. Define a new bpf_id BTF_SOCK_TYPE_MPTCP,
and a new helper bpf_skc_to_mptcp_sock(), which invokes another new
helper bpf_mptcp_sock_from_subflow() in net/mptcp/bpf.c to get struct
mptcp_sock from a given subflow socket.

v2: Emit BTF type, add func_id checks in verifier.c and bpf_trace.c,
remove build check for CONFIG_BPF_JIT
v5: Drop EXPORT_SYMBOL (Martin)

Co-developed-by: Nicolas Rybowski <nicolas.rybowski@tessares.net>
Co-developed-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: Nicolas Rybowski <nicolas.rybowski@tessares.net>
Signed-off-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: Geliang Tang <geliang.tang@suse.com>
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220519233016.105670-2-mathew.j.martineau@linux.intel.com
2022-05-20 15:29:00 -07:00
Feng Zhou
07343110b2 bpf: add bpf_map_lookup_percpu_elem for percpu map
Add new ebpf helpers bpf_map_lookup_percpu_elem.

The implementation method is relatively simple, refer to the implementation
method of map_lookup_elem of percpu map, increase the parameters of cpu, and
obtain it according to the specified cpu.

Signed-off-by: Feng Zhou <zhoufeng.zf@bytedance.com>
Link: https://lore.kernel.org/r/20220511093854.411-2-zhoufeng.zf@bytedance.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-05-11 18:16:54 -07:00
Kui-Feng Lee
2fcc82411e bpf, x86: Attach a cookie to fentry/fexit/fmod_ret/lsm.
Pass a cookie along with BPF_LINK_CREATE requests.

Add a bpf_cookie field to struct bpf_tracing_link to attach a cookie.
The cookie of a bpf_tracing_link is available by calling
bpf_get_attach_cookie when running the BPF program of the attached
link.

The value of a cookie will be set at bpf_tramp_run_ctx by the
trampoline of the link.

Signed-off-by: Kui-Feng Lee <kuifeng@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220510205923.3206889-4-kuifeng@fb.com
2022-05-10 21:58:31 -07:00
Jiri Olsa
0236fec57a bpf: Resolve symbols with ftrace_lookup_symbols for kprobe multi link
Using kallsyms_lookup_names function to speed up symbols lookup in
kprobe multi link attachment and replacing with it the current
kprobe_multi_resolve_syms function.

This speeds up bpftrace kprobe attachment:

  # perf stat -r 5 -e cycles ./src/bpftrace -e 'kprobe:x* {  } i:ms:1 { exit(); }'
  ...
  6.5681 +- 0.0225 seconds time elapsed  ( +-  0.34% )

After:

  # perf stat -r 5 -e cycles ./src/bpftrace -e 'kprobe:x* {  } i:ms:1 { exit(); }'
  ...
  0.5661 +- 0.0275 seconds time elapsed  ( +-  4.85% )

Acked-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20220510122616.2652285-5-jolsa@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-05-10 14:42:06 -07:00
Stanislav Fomichev
055eb95533 bpf: Move rcu lock management out of BPF_PROG_RUN routines
Commit 7d08c2c911 ("bpf: Refactor BPF_PROG_RUN_ARRAY family of macros
into functions") switched a bunch of BPF_PROG_RUN macros to inline
routines. This changed the semantic a bit. Due to arguments expansion
of macros, it used to be:

	rcu_read_lock();
	array = rcu_dereference(cgrp->bpf.effective[atype]);
	...

Now, with with inline routines, we have:
	array_rcu = rcu_dereference(cgrp->bpf.effective[atype]);
	/* array_rcu can be kfree'd here */
	rcu_read_lock();
	array = rcu_dereference(array_rcu);

I'm assuming in practice rcu subsystem isn't fast enough to trigger
this but let's use rcu API properly.

Also, rename to lower caps to not confuse with macros. Additionally,
drop and expand BPF_PROG_CGROUP_INET_EGRESS_RUN_ARRAY.

See [1] for more context.

  [1] https://lore.kernel.org/bpf/CAKH8qBs60fOinFdxiiQikK_q0EcVxGvNTQoWvHLEUGbgcj1UYg@mail.gmail.com/T/#u

v2
- keep rcu locks inside by passing cgroup_bpf

Fixes: 7d08c2c911 ("bpf: Refactor BPF_PROG_RUN_ARRAY family of macros into functions")
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20220414161233.170780-1-sdf@google.com
2022-04-19 09:45:47 -07:00
Jakub Kicinski
34ba23b44c Merge https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next
Daniel Borkmann says:

====================
pull-request: bpf-next 2022-04-09

We've added 63 non-merge commits during the last 9 day(s) which contain
a total of 68 files changed, 4852 insertions(+), 619 deletions(-).

The main changes are:

1) Add libbpf support for USDT (User Statically-Defined Tracing) probes.
   USDTs are an abstraction built on top of uprobes, critical for tracing
   and BPF, and widely used in production applications, from Andrii Nakryiko.

2) While Andrii was adding support for x86{-64}-specific logic of parsing
   USDT argument specification, Ilya followed-up with USDT support for s390
   architecture, from Ilya Leoshkevich.

3) Support name-based attaching for uprobe BPF programs in libbpf. The format
   supported is `u[ret]probe/binary_path:[raw_offset|function[+offset]]`, e.g.
   attaching to libc malloc can be done in BPF via SEC("uprobe/libc.so.6:malloc")
   now, from Alan Maguire.

4) Various load/store optimizations for the arm64 JIT to shrink the image
   size by using arm64 str/ldr immediate instructions. Also enable pointer
   authentication to verify return address for JITed code, from Xu Kuohai.

5) BPF verifier fixes for write access checks to helper functions, e.g.
   rd-only memory from bpf_*_cpu_ptr() must not be passed to helpers that
   write into passed buffers, from Kumar Kartikeya Dwivedi.

6) Fix overly excessive stack map allocation for its base map structure and
   buckets which slipped-in from cleanups during the rlimit accounting removal
   back then, from Yuntao Wang.

7) Extend the unstable CT lookup helpers for XDP and tc/BPF to report netfilter
   connection tracking tuple direction, from Lorenzo Bianconi.

8) Improve bpftool dump to show BPF program/link type names, Milan Landaverde.

9) Minor cleanups all over the place from various others.

* https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (63 commits)
  bpf: Fix excessive memory allocation in stack_map_alloc()
  selftests/bpf: Fix return value checks in perf_event_stackmap test
  selftests/bpf: Add CO-RE relos into linked_funcs selftests
  libbpf: Use weak hidden modifier for USDT BPF-side API functions
  libbpf: Don't error out on CO-RE relos for overriden weak subprogs
  samples, bpf: Move routes monitor in xdp_router_ipv4 in a dedicated thread
  libbpf: Allow WEAK and GLOBAL bindings during BTF fixup
  libbpf: Use strlcpy() in path resolution fallback logic
  libbpf: Add s390-specific USDT arg spec parsing logic
  libbpf: Make BPF-side of USDT support work on big-endian machines
  libbpf: Minor style improvements in USDT code
  libbpf: Fix use #ifdef instead of #if to avoid compiler warning
  libbpf: Potential NULL dereference in usdt_manager_attach_usdt()
  selftests/bpf: Uprobe tests should verify param/return values
  libbpf: Improve string parsing for uprobe auto-attach
  libbpf: Improve library identification for uprobe binary path resolution
  selftests/bpf: Test for writes to map key from BPF helpers
  selftests/bpf: Test passing rdonly mem to global func
  bpf: Reject writes for PTR_TO_MAP_KEY in check_helper_mem_access
  bpf: Check PTR_TO_MEM | MEM_RDONLY in check_helper_mem_access
  ...
====================

Link: https://lore.kernel.org/r/20220408231741.19116-1-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-04-08 17:07:29 -07:00
Jiapeng Chong
11e17ae423 bpf: Use swap() instead of open coding it
Clean the following coccicheck warning:

./kernel/trace/bpf_trace.c:2263:34-35: WARNING opportunity for swap().
./kernel/trace/bpf_trace.c:2264:40-41: WARNING opportunity for swap().

Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20220322062149.109180-1-jiapeng.chong@linux.alibaba.com
2022-04-01 22:27:07 +02:00
Jiri Olsa
d31e0386a2 bpf: Fix sparse warnings in kprobe_multi_resolve_syms
Adding missing __user tags to fix sparse warnings:

kernel/trace/bpf_trace.c:2370:34: warning: incorrect type in argument 2 (different address spaces)
kernel/trace/bpf_trace.c:2370:34:    expected void const [noderef] __user *from
kernel/trace/bpf_trace.c:2370:34:    got void const *usyms
kernel/trace/bpf_trace.c:2376:51: warning: incorrect type in argument 2 (different address spaces)
kernel/trace/bpf_trace.c:2376:51:    expected char const [noderef] __user *src
kernel/trace/bpf_trace.c:2376:51:    got char const *
kernel/trace/bpf_trace.c:2443:49: warning: incorrect type in argument 1 (different address spaces)
kernel/trace/bpf_trace.c:2443:49:    expected void const *usyms
kernel/trace/bpf_trace.c:2443:49:    got void [noderef] __user *[assigned] usyms

Fixes: 0dcac27254 ("bpf: Add multi kprobe link")
Reported-by: Alexei Starovoitov <ast@kernel.org>
Reported-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20220330110510.398558-1-jolsa@kernel.org
2022-03-30 14:10:06 +02:00
Linus Torvalds
169e77764a Networking changes for 5.18.
Core
 ----
 
  - Introduce XDP multi-buffer support, allowing the use of XDP with
    jumbo frame MTUs and combination with Rx coalescing offloads (LRO).
 
  - Speed up netns dismantling (5x) and lower the memory cost a little.
    Remove unnecessary per-netns sockets. Scope some lists to a netns.
    Cut down RCU syncing. Use batch methods. Allow netdev registration
    to complete out of order.
 
  - Support distinguishing timestamp types (ingress vs egress) and
    maintaining them across packet scrubbing points (e.g. redirect).
 
  - Continue the work of annotating packet drop reasons throughout
    the stack.
 
  - Switch netdev error counters from an atomic to dynamically
    allocated per-CPU counters.
 
  - Rework a few preempt_disable(), local_irq_save() and busy waiting
    sections problematic on PREEMPT_RT.
 
  - Extend the ref_tracker to allow catching use-after-free bugs.
 
 BPF
 ---
 
  - Introduce "packing allocator" for BPF JIT images. JITed code is
    marked read only, and used to be allocated at page granularity.
    Custom allocator allows for more efficient memory use, lower
    iTLB pressure and prevents identity mapping huge pages from
    getting split.
 
  - Make use of BTF type annotations (e.g. __user, __percpu) to enforce
    the correct probe read access method, add appropriate helpers.
 
  - Convert the BPF preload to use light skeleton and drop
    the user-mode-driver dependency.
 
  - Allow XDP BPF_PROG_RUN test infra to send real packets, enabling
    its use as a packet generator.
 
  - Allow local storage memory to be allocated with GFP_KERNEL if called
    from a hook allowed to sleep.
 
  - Introduce fprobe (multi kprobe) to speed up mass attachment (arch
    bits to come later).
 
  - Add unstable conntrack lookup helpers for BPF by using the BPF
    kfunc infra.
 
  - Allow cgroup BPF progs to return custom errors to user space.
 
  - Add support for AF_UNIX iterator batching.
 
  - Allow iterator programs to use sleepable helpers.
 
  - Support JIT of add, and, or, xor and xchg atomic ops on arm64.
 
  - Add BTFGen support to bpftool which allows to use CO-RE in kernels
    without BTF info.
 
  - Large number of libbpf API improvements, cleanups and deprecations.
 
 Protocols
 ---------
 
  - Micro-optimize UDPv6 Tx, gaining up to 5% in test on dummy netdev.
 
  - Adjust TSO packet sizes based on min_rtt, allowing very low latency
    links (data centers) to always send full-sized TSO super-frames.
 
  - Make IPv6 flow label changes (AKA hash rethink) more configurable,
    via sysctl and setsockopt. Distinguish between server and client
    behavior.
 
  - VxLAN support to "collect metadata" devices to terminate only
    configured VNIs. This is similar to VLAN filtering in the bridge.
 
  - Support inserting IPv6 IOAM information to a fraction of frames.
 
  - Add protocol attribute to IP addresses to allow identifying where
    given address comes from (kernel-generated, DHCP etc.)
 
  - Support setting socket and IPv6 options via cmsg on ping6 sockets.
 
  - Reject mis-use of ECN bits in IP headers as part of DSCP/TOS.
    Define dscp_t and stop taking ECN bits into account in fib-rules.
 
  - Add support for locked bridge ports (for 802.1X).
 
  - tun: support NAPI for packets received from batched XDP buffs,
    doubling the performance in some scenarios.
 
  - IPv6 extension header handling in Open vSwitch.
 
  - Support IPv6 control message load balancing in bonding, prevent
    neighbor solicitation and advertisement from using the wrong port.
    Support NS/NA monitor selection similar to existing ARP monitor.
 
  - SMC
    - improve performance with TCP_CORK and sendfile()
    - support auto-corking
    - support TCP_NODELAY
 
  - MCTP (Management Component Transport Protocol)
    - add user space tag control interface
    - I2C binding driver (as specified by DMTF DSP0237)
 
  - Multi-BSSID beacon handling in AP mode for WiFi.
 
  - Bluetooth:
    - handle MSFT Monitor Device Event
    - add MGMT Adv Monitor Device Found/Lost events
 
  - Multi-Path TCP:
    - add support for the SO_SNDTIMEO socket option
    - lots of selftest cleanups and improvements
 
  - Increase the max PDU size in CAN ISOTP to 64 kB.
 
 Driver API
 ----------
 
  - Add HW counters for SW netdevs, a mechanism for devices which
    offload packet forwarding to report packet statistics back to
    software interfaces such as tunnels.
 
  - Select the default NIC queue count as a fraction of number of
    physical CPU cores, instead of hard-coding to 8.
 
  - Expose devlink instance locks to drivers. Allow device layer of
    drivers to use that lock directly instead of creating their own
    which always runs into ordering issues in devlink callbacks.
 
  - Add header/data split indication to guide user space enabling
    of TCP zero-copy Rx.
 
  - Allow configuring completion queue event size.
 
  - Refactor page_pool to enable fragmenting after allocation.
 
  - Add allocation and page reuse statistics to page_pool.
 
  - Improve Multiple Spanning Trees support in the bridge to allow
    reuse of topologies across VLANs, saving HW resources in switches.
 
  - DSA (Distributed Switch Architecture):
    - replay and offload of host VLAN entries
    - offload of static and local FDB entries on LAG interfaces
    - FDB isolation and unicast filtering
 
 New hardware / drivers
 ----------------------
 
  - Ethernet:
    - LAN937x T1 PHYs
    - Davicom DM9051 SPI NIC driver
    - Realtek RTL8367S, RTL8367RB-VB switch and MDIO
    - Microchip ksz8563 switches
    - Netronome NFP3800 SmartNICs
    - Fungible SmartNICs
    - MediaTek MT8195 switches
 
  - WiFi:
    - mt76: MediaTek mt7916
    - mt76: MediaTek mt7921u USB adapters
    - brcmfmac: Broadcom BCM43454/6
 
  - Mobile:
    - iosm: Intel M.2 7360 WWAN card
 
 Drivers
 -------
 
  - Convert many drivers to the new phylink API built for split PCS
    designs but also simplifying other cases.
 
  - Intel Ethernet NICs:
    - add TTY for GNSS module for E810T device
    - improve AF_XDP performance
    - GTP-C and GTP-U filter offload
    - QinQ VLAN support
 
  - Mellanox Ethernet NICs (mlx5):
    - support xdp->data_meta
    - multi-buffer XDP
    - offload tc push_eth and pop_eth actions
 
  - Netronome Ethernet NICs (nfp):
    - flow-independent tc action hardware offload (police / meter)
    - AF_XDP
 
  - Other Ethernet NICs:
    - at803x: fiber and SFP support
    - xgmac: mdio: preamble suppression and custom MDC frequencies
    - r8169: enable ASPM L1.2 if system vendor flags it as safe
    - macb/gem: ZynqMP SGMII
    - hns3: add TX push mode
    - dpaa2-eth: software TSO
    - lan743x: multi-queue, mdio, SGMII, PTP
    - axienet: NAPI and GRO support
 
  - Mellanox Ethernet switches (mlxsw):
    - source and dest IP address rewrites
    - RJ45 ports
 
  - Marvell Ethernet switches (prestera):
    - basic routing offload
    - multi-chain TC ACL offload
 
  - NXP embedded Ethernet switches (ocelot & felix):
    - PTP over UDP with the ocelot-8021q DSA tagging protocol
    - basic QoS classification on Felix DSA switch using dcbnl
    - port mirroring for ocelot switches
 
  - Microchip high-speed industrial Ethernet (sparx5):
    - offloading of bridge port flooding flags
    - PTP Hardware Clock
 
  - Other embedded switches:
    - lan966x: PTP Hardward Clock
    - qca8k: mdio read/write operations via crafted Ethernet packets
 
  - Qualcomm 802.11ax WiFi (ath11k):
    - add LDPC FEC type and 802.11ax High Efficiency data in radiotap
    - enable RX PPDU stats in monitor co-exist mode
 
  - Intel WiFi (iwlwifi):
    - UHB TAS enablement via BIOS
    - band disablement via BIOS
    - channel switch offload
    - 32 Rx AMPDU sessions in newer devices
 
  - MediaTek WiFi (mt76):
    - background radar detection
    - thermal management improvements on mt7915
    - SAR support for more mt76 platforms
    - MBSSID and 6 GHz band on mt7915
 
  - RealTek WiFi:
    - rtw89: AP mode
    - rtw89: 160 MHz channels and 6 GHz band
    - rtw89: hardware scan
 
  - Bluetooth:
    - mt7921s: wake on Bluetooth, SCO over I2S, wide-band-speed (WBS)
 
  - Microchip CAN (mcp251xfd):
    - multiple RX-FIFOs and runtime configurable RX/TX rings
    - internal PLL, runtime PM handling simplification
    - improve chip detection and error handling after wakeup
 
 Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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Merge tag 'net-next-5.18' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next

Pull networking updates from Jakub Kicinski:
 "The sprinkling of SPI drivers is because we added a new one and Mark
  sent us a SPI driver interface conversion pull request.

  Core
  ----

   - Introduce XDP multi-buffer support, allowing the use of XDP with
     jumbo frame MTUs and combination with Rx coalescing offloads (LRO).

   - Speed up netns dismantling (5x) and lower the memory cost a little.
     Remove unnecessary per-netns sockets. Scope some lists to a netns.
     Cut down RCU syncing. Use batch methods. Allow netdev registration
     to complete out of order.

   - Support distinguishing timestamp types (ingress vs egress) and
     maintaining them across packet scrubbing points (e.g. redirect).

   - Continue the work of annotating packet drop reasons throughout the
     stack.

   - Switch netdev error counters from an atomic to dynamically
     allocated per-CPU counters.

   - Rework a few preempt_disable(), local_irq_save() and busy waiting
     sections problematic on PREEMPT_RT.

   - Extend the ref_tracker to allow catching use-after-free bugs.

  BPF
  ---

   - Introduce "packing allocator" for BPF JIT images. JITed code is
     marked read only, and used to be allocated at page granularity.
     Custom allocator allows for more efficient memory use, lower iTLB
     pressure and prevents identity mapping huge pages from getting
     split.

   - Make use of BTF type annotations (e.g. __user, __percpu) to enforce
     the correct probe read access method, add appropriate helpers.

   - Convert the BPF preload to use light skeleton and drop the
     user-mode-driver dependency.

   - Allow XDP BPF_PROG_RUN test infra to send real packets, enabling
     its use as a packet generator.

   - Allow local storage memory to be allocated with GFP_KERNEL if
     called from a hook allowed to sleep.

   - Introduce fprobe (multi kprobe) to speed up mass attachment (arch
     bits to come later).

   - Add unstable conntrack lookup helpers for BPF by using the BPF
     kfunc infra.

   - Allow cgroup BPF progs to return custom errors to user space.

   - Add support for AF_UNIX iterator batching.

   - Allow iterator programs to use sleepable helpers.

   - Support JIT of add, and, or, xor and xchg atomic ops on arm64.

   - Add BTFGen support to bpftool which allows to use CO-RE in kernels
     without BTF info.

   - Large number of libbpf API improvements, cleanups and deprecations.

  Protocols
  ---------

   - Micro-optimize UDPv6 Tx, gaining up to 5% in test on dummy netdev.

   - Adjust TSO packet sizes based on min_rtt, allowing very low latency
     links (data centers) to always send full-sized TSO super-frames.

   - Make IPv6 flow label changes (AKA hash rethink) more configurable,
     via sysctl and setsockopt. Distinguish between server and client
     behavior.

   - VxLAN support to "collect metadata" devices to terminate only
     configured VNIs. This is similar to VLAN filtering in the bridge.

   - Support inserting IPv6 IOAM information to a fraction of frames.

   - Add protocol attribute to IP addresses to allow identifying where
     given address comes from (kernel-generated, DHCP etc.)

   - Support setting socket and IPv6 options via cmsg on ping6 sockets.

   - Reject mis-use of ECN bits in IP headers as part of DSCP/TOS.
     Define dscp_t and stop taking ECN bits into account in fib-rules.

   - Add support for locked bridge ports (for 802.1X).

   - tun: support NAPI for packets received from batched XDP buffs,
     doubling the performance in some scenarios.

   - IPv6 extension header handling in Open vSwitch.

   - Support IPv6 control message load balancing in bonding, prevent
     neighbor solicitation and advertisement from using the wrong port.
     Support NS/NA monitor selection similar to existing ARP monitor.

   - SMC
      - improve performance with TCP_CORK and sendfile()
      - support auto-corking
      - support TCP_NODELAY

   - MCTP (Management Component Transport Protocol)
      - add user space tag control interface
      - I2C binding driver (as specified by DMTF DSP0237)

   - Multi-BSSID beacon handling in AP mode for WiFi.

   - Bluetooth:
      - handle MSFT Monitor Device Event
      - add MGMT Adv Monitor Device Found/Lost events

   - Multi-Path TCP:
      - add support for the SO_SNDTIMEO socket option
      - lots of selftest cleanups and improvements

   - Increase the max PDU size in CAN ISOTP to 64 kB.

  Driver API
  ----------

   - Add HW counters for SW netdevs, a mechanism for devices which
     offload packet forwarding to report packet statistics back to
     software interfaces such as tunnels.

   - Select the default NIC queue count as a fraction of number of
     physical CPU cores, instead of hard-coding to 8.

   - Expose devlink instance locks to drivers. Allow device layer of
     drivers to use that lock directly instead of creating their own
     which always runs into ordering issues in devlink callbacks.

   - Add header/data split indication to guide user space enabling of
     TCP zero-copy Rx.

   - Allow configuring completion queue event size.

   - Refactor page_pool to enable fragmenting after allocation.

   - Add allocation and page reuse statistics to page_pool.

   - Improve Multiple Spanning Trees support in the bridge to allow
     reuse of topologies across VLANs, saving HW resources in switches.

   - DSA (Distributed Switch Architecture):
      - replay and offload of host VLAN entries
      - offload of static and local FDB entries on LAG interfaces
      - FDB isolation and unicast filtering

  New hardware / drivers
  ----------------------

   - Ethernet:
      - LAN937x T1 PHYs
      - Davicom DM9051 SPI NIC driver
      - Realtek RTL8367S, RTL8367RB-VB switch and MDIO
      - Microchip ksz8563 switches
      - Netronome NFP3800 SmartNICs
      - Fungible SmartNICs
      - MediaTek MT8195 switches

   - WiFi:
      - mt76: MediaTek mt7916
      - mt76: MediaTek mt7921u USB adapters
      - brcmfmac: Broadcom BCM43454/6

   - Mobile:
      - iosm: Intel M.2 7360 WWAN card

  Drivers
  -------

   - Convert many drivers to the new phylink API built for split PCS
     designs but also simplifying other cases.

   - Intel Ethernet NICs:
      - add TTY for GNSS module for E810T device
      - improve AF_XDP performance
      - GTP-C and GTP-U filter offload
      - QinQ VLAN support

   - Mellanox Ethernet NICs (mlx5):
      - support xdp->data_meta
      - multi-buffer XDP
      - offload tc push_eth and pop_eth actions

   - Netronome Ethernet NICs (nfp):
      - flow-independent tc action hardware offload (police / meter)
      - AF_XDP

   - Other Ethernet NICs:
      - at803x: fiber and SFP support
      - xgmac: mdio: preamble suppression and custom MDC frequencies
      - r8169: enable ASPM L1.2 if system vendor flags it as safe
      - macb/gem: ZynqMP SGMII
      - hns3: add TX push mode
      - dpaa2-eth: software TSO
      - lan743x: multi-queue, mdio, SGMII, PTP
      - axienet: NAPI and GRO support

   - Mellanox Ethernet switches (mlxsw):
      - source and dest IP address rewrites
      - RJ45 ports

   - Marvell Ethernet switches (prestera):
      - basic routing offload
      - multi-chain TC ACL offload

   - NXP embedded Ethernet switches (ocelot & felix):
      - PTP over UDP with the ocelot-8021q DSA tagging protocol
      - basic QoS classification on Felix DSA switch using dcbnl
      - port mirroring for ocelot switches

   - Microchip high-speed industrial Ethernet (sparx5):
      - offloading of bridge port flooding flags
      - PTP Hardware Clock

   - Other embedded switches:
      - lan966x: PTP Hardward Clock
      - qca8k: mdio read/write operations via crafted Ethernet packets

   - Qualcomm 802.11ax WiFi (ath11k):
      - add LDPC FEC type and 802.11ax High Efficiency data in radiotap
      - enable RX PPDU stats in monitor co-exist mode

   - Intel WiFi (iwlwifi):
      - UHB TAS enablement via BIOS
      - band disablement via BIOS
      - channel switch offload
      - 32 Rx AMPDU sessions in newer devices

   - MediaTek WiFi (mt76):
      - background radar detection
      - thermal management improvements on mt7915
      - SAR support for more mt76 platforms
      - MBSSID and 6 GHz band on mt7915

   - RealTek WiFi:
      - rtw89: AP mode
      - rtw89: 160 MHz channels and 6 GHz band
      - rtw89: hardware scan

   - Bluetooth:
      - mt7921s: wake on Bluetooth, SCO over I2S, wide-band-speed (WBS)

   - Microchip CAN (mcp251xfd):
      - multiple RX-FIFOs and runtime configurable RX/TX rings
      - internal PLL, runtime PM handling simplification
      - improve chip detection and error handling after wakeup"

* tag 'net-next-5.18' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (2521 commits)
  llc: fix netdevice reference leaks in llc_ui_bind()
  drivers: ethernet: cpsw: fix panic when interrupt coaleceing is set via ethtool
  ice: don't allow to run ice_send_event_to_aux() in atomic ctx
  ice: fix 'scheduling while atomic' on aux critical err interrupt
  net/sched: fix incorrect vlan_push_eth dest field
  net: bridge: mst: Restrict info size queries to bridge ports
  net: marvell: prestera: add missing destroy_workqueue() in prestera_module_init()
  drivers: net: xgene: Fix regression in CRC stripping
  net: geneve: add missing netlink policy and size for IFLA_GENEVE_INNER_PROTO_INHERIT
  net: dsa: fix missing host-filtered multicast addresses
  net/mlx5e: Fix build warning, detected write beyond size of field
  iwlwifi: mvm: Don't fail if PPAG isn't supported
  selftests/bpf: Fix kprobe_multi test.
  Revert "rethook: x86: Add rethook x86 implementation"
  Revert "arm64: rethook: Add arm64 rethook implementation"
  Revert "powerpc: Add rethook support"
  Revert "ARM: rethook: Add rethook arm implementation"
  netdevice: add missing dm_private kdoc
  net: bridge: mst: prevent NULL deref in br_mst_info_size()
  selftests: forwarding: Use same VRF for port and VLAN upper
  ...
2022-03-24 13:13:26 -07:00
Jiri Olsa
f70986902c bpf: Fix kprobe_multi return probe backtrace
Andrii reported that backtraces from kprobe_multi program attached
as return probes are not complete and showing just initial entry [1].

It's caused by changing registers to have original function ip address
as instruction pointer even for return probe, which will screw backtrace
from return probe.

This change keeps registers intact and store original entry ip and
link address on the stack in bpf_kprobe_multi_run_ctx struct, where
bpf_get_func_ip and bpf_get_attach_cookie helpers for kprobe_multi
programs can find it.

[1] https://lore.kernel.org/bpf/CAEf4BzZDDqK24rSKwXNp7XL3ErGD4bZa1M6c_c4EvDSt3jrZcg@mail.gmail.com/T/#m8d1301c0ea0892ddf9dc6fba57a57b8cf11b8c51

Fixes: ca74823c6e ("bpf: Add cookie support to programs attached with kprobe multi link")
Reported-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220321070113.1449167-3-jolsa@kernel.org
2022-03-21 14:54:15 +01:00
Jiri Olsa
f705ec764b Revert "bpf: Add support to inline bpf_get_func_ip helper on x86"
This reverts commit 97ee4d20ee.

Following change is adding more complexity to bpf_get_func_ip
helper for kprobe_multi programs, which can't be inlined easily.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20220321070113.1449167-2-jolsa@kernel.org
2022-03-21 14:53:42 +01:00
Jiri Olsa
ca74823c6e bpf: Add cookie support to programs attached with kprobe multi link
Adding support to call bpf_get_attach_cookie helper from
kprobe programs attached with kprobe multi link.

The cookie is provided by array of u64 values, where each
value is paired with provided function address or symbol
with the same array index.

When cookie array is provided it's sorted together with
addresses (check bpf_kprobe_multi_cookie_swap). This way
we can find cookie based on the address in
bpf_get_attach_cookie helper.

Suggested-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220316122419.933957-7-jolsa@kernel.org
2022-03-17 20:17:19 -07:00
Jiri Olsa
97ee4d20ee bpf: Add support to inline bpf_get_func_ip helper on x86
Adding support to inline it on x86, because it's single
load instruction.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220316122419.933957-6-jolsa@kernel.org
2022-03-17 20:17:19 -07:00
Jiri Olsa
42a5712094 bpf: Add bpf_get_func_ip kprobe helper for multi kprobe link
Adding support to call bpf_get_func_ip helper from kprobe
programs attached by multi kprobe link.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220316122419.933957-5-jolsa@kernel.org
2022-03-17 20:17:19 -07:00
Jiri Olsa
0dcac27254 bpf: Add multi kprobe link
Adding new link type BPF_LINK_TYPE_KPROBE_MULTI that attaches kprobe
program through fprobe API.

The fprobe API allows to attach probe on multiple functions at once
very fast, because it works on top of ftrace. On the other hand this
limits the probe point to the function entry or return.

The kprobe program gets the same pt_regs input ctx as when it's attached
through the perf API.

Adding new attach type BPF_TRACE_KPROBE_MULTI that allows attachment
kprobe to multiple function with new link.

User provides array of addresses or symbols with count to attach the
kprobe program to. The new link_create uapi interface looks like:

  struct {
          __u32           flags;
          __u32           cnt;
          __aligned_u64   syms;
          __aligned_u64   addrs;
  } kprobe_multi;

The flags field allows single BPF_TRACE_KPROBE_MULTI bit to create
return multi kprobe.

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220316122419.933957-4-jolsa@kernel.org
2022-03-17 20:17:18 -07:00
Arnd Bergmann
967747bbc0 uaccess: remove CONFIG_SET_FS
There are no remaining callers of set_fs(), so CONFIG_SET_FS
can be removed globally, along with the thread_info field and
any references to it.

This turns access_ok() into a cheaper check against TASK_SIZE_MAX.

As CONFIG_SET_FS is now gone, drop all remaining references to
set_fs()/get_fs(), mm_segment_t, user_addr_max() and uaccess_kernel().

Acked-by: Sam Ravnborg <sam@ravnborg.org> # for sparc32 changes
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Tested-by: Sergey Matyukevich <sergey.matyukevich@synopsys.com> # for arc changes
Acked-by: Stafford Horne <shorne@gmail.com> # [openrisc, asm-generic]
Acked-by: Dinh Nguyen <dinguyen@kernel.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
2022-02-25 09:36:06 +01:00
Kenny Yu
376040e473 bpf: Add bpf_copy_from_user_task() helper
This adds a helper for bpf programs to read the memory of other
tasks.

As an example use case at Meta, we are using a bpf task iterator program
and this new helper to print C++ async stack traces for all threads of
a given process.

Signed-off-by: Kenny Yu <kennyyu@fb.com>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20220124185403.468466-3-kennyyu@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-01-24 19:59:27 -08:00
Eelco Chaudron
d99173027d bpf: add frags support to xdp copy helpers
This patch adds support for frags for the following helpers:
  - bpf_xdp_output()
  - bpf_perf_event_output()

Acked-by: Toke Hoiland-Jorgensen <toke@redhat.com>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Acked-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Eelco Chaudron <echaudro@redhat.com>
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Link: https://lore.kernel.org/r/340b4a99cdc24337b40eaf8bb597f9f9e7b0373e.1642758637.git.lorenzo@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-01-21 14:14:02 -08:00
Hao Luo
216e3cd2f2 bpf: Add MEM_RDONLY for helper args that are pointers to rdonly mem.
Some helper functions may modify its arguments, for example,
bpf_d_path, bpf_get_stack etc. Previously, their argument types
were marked as ARG_PTR_TO_MEM, which is compatible with read-only
mem types, such as PTR_TO_RDONLY_BUF. Therefore it's legitimate,
but technically incorrect, to modify a read-only memory by passing
it into one of such helper functions.

This patch tags the bpf_args compatible with immutable memory with
MEM_RDONLY flag. The arguments that don't have this flag will be
only compatible with mutable memory types, preventing the helper
from modifying a read-only memory. The bpf_args that have
MEM_RDONLY are compatible with both mutable memory and immutable
memory.

Signed-off-by: Hao Luo <haoluo@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20211217003152.48334-9-haoluo@google.com
2021-12-18 13:27:41 -08:00
Jiri Olsa
f92c1e1836 bpf: Add get_func_[arg|ret|arg_cnt] helpers
Adding following helpers for tracing programs:

Get n-th argument of the traced function:
  long bpf_get_func_arg(void *ctx, u32 n, u64 *value)

Get return value of the traced function:
  long bpf_get_func_ret(void *ctx, u64 *value)

Get arguments count of the traced function:
  long bpf_get_func_arg_cnt(void *ctx)

The trampoline now stores number of arguments on ctx-8
address, so it's easy to verify argument index and find
return value argument's position.

Moving function ip address on the trampoline stack behind
the number of functions arguments, so it's now stored on
ctx-16 address if it's needed.

All helpers above are inlined by verifier.

Also bit unrelated small change - using newly added function
bpf_prog_has_trampoline in check_get_func_ip.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20211208193245.172141-5-jolsa@kernel.org
2021-12-13 09:25:59 -08:00
Jakub Kicinski
be3158290d Merge https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next
Andrii Nakryiko says:

====================
bpf-next 2021-12-10 v2

We've added 115 non-merge commits during the last 26 day(s) which contain
a total of 182 files changed, 5747 insertions(+), 2564 deletions(-).

The main changes are:

1) Various samples fixes, from Alexander Lobakin.

2) BPF CO-RE support in kernel and light skeleton, from Alexei Starovoitov.

3) A batch of new unified APIs for libbpf, logging improvements, version
   querying, etc. Also a batch of old deprecations for old APIs and various
   bug fixes, in preparation for libbpf 1.0, from Andrii Nakryiko.

4) BPF documentation reorganization and improvements, from Christoph Hellwig
   and Dave Tucker.

5) Support for declarative initialization of BPF_MAP_TYPE_PROG_ARRAY in
   libbpf, from Hengqi Chen.

6) Verifier log fixes, from Hou Tao.

7) Runtime-bounded loops support with bpf_loop() helper, from Joanne Koong.

8) Extend branch record capturing to all platforms that support it,
   from Kajol Jain.

9) Light skeleton codegen improvements, from Kumar Kartikeya Dwivedi.

10) bpftool doc-generating script improvements, from Quentin Monnet.

11) Two libbpf v0.6 bug fixes, from Shuyi Cheng and Vincent Minet.

12) Deprecation warning fix for perf/bpf_counter, from Song Liu.

13) MAX_TAIL_CALL_CNT unification and MIPS build fix for libbpf,
    from Tiezhu Yang.

14) BTF_KING_TYPE_TAG follow-up fixes, from Yonghong Song.

15) Selftests fixes and improvements, from Ilya Leoshkevich, Jean-Philippe
    Brucker, Jiri Olsa, Maxim Mikityanskiy, Tirthendu Sarkar, Yucong Sun,
    and others.

* https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (115 commits)
  libbpf: Add "bool skipped" to struct bpf_map
  libbpf: Fix typo in btf__dedup@LIBBPF_0.0.2 definition
  bpftool: Switch bpf_object__load_xattr() to bpf_object__load()
  selftests/bpf: Remove the only use of deprecated bpf_object__load_xattr()
  selftests/bpf: Add test for libbpf's custom log_buf behavior
  selftests/bpf: Replace all uses of bpf_load_btf() with bpf_btf_load()
  libbpf: Deprecate bpf_object__load_xattr()
  libbpf: Add per-program log buffer setter and getter
  libbpf: Preserve kernel error code and remove kprobe prog type guessing
  libbpf: Improve logging around BPF program loading
  libbpf: Allow passing user log setting through bpf_object_open_opts
  libbpf: Allow passing preallocated log_buf when loading BTF into kernel
  libbpf: Add OPTS-based bpf_btf_load() API
  libbpf: Fix bpf_prog_load() log_buf logic for log_level 0
  samples/bpf: Remove unneeded variable
  bpf: Remove redundant assignment to pointer t
  selftests/bpf: Fix a compilation warning
  perf/bpf_counter: Use bpf_map_create instead of bpf_create_map
  samples: bpf: Fix 'unknown warning group' build warning on Clang
  samples: bpf: Fix xdp_sample_user.o linking with Clang
  ...
====================

Link: https://lore.kernel.org/r/20211210234746.2100561-1-andrii@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2021-12-10 15:56:13 -08:00
Kajol Jain
db52f57211 bpf: Remove config check to enable bpf support for branch records
Branch data available to BPF programs can be very useful to get stack traces
out of userspace application.

Commit fff7b64355 ("bpf: Add bpf_read_branch_records() helper") added BPF
support to capture branch records in x86. Enable this feature also for other
architectures as well by removing checks specific to x86.

If an architecture doesn't support branch records, bpf_read_branch_records()
still has appropriate checks and it will return an -EINVAL in that scenario.
Based on UAPI helper doc in include/uapi/linux/bpf.h, unsupported architectures
should return -ENOENT in such case. Hence, update the appropriate check to
return -ENOENT instead.

Selftest 'perf_branches' result on power9 machine which has the branch stacks
support:

 - Before this patch:

  [command]# ./test_progs -t perf_branches
   #88/1 perf_branches/perf_branches_hw:FAIL
   #88/2 perf_branches/perf_branches_no_hw:OK
   #88 perf_branches:FAIL
  Summary: 0/1 PASSED, 0 SKIPPED, 1 FAILED

 - After this patch:

  [command]# ./test_progs -t perf_branches
   #88/1 perf_branches/perf_branches_hw:OK
   #88/2 perf_branches/perf_branches_no_hw:OK
   #88 perf_branches:OK
  Summary: 1/2 PASSED, 0 SKIPPED, 0 FAILED

Selftest 'perf_branches' result on power9 machine which doesn't have branch
stack report:

 - After this patch:

  [command]# ./test_progs -t perf_branches
   #88/1 perf_branches/perf_branches_hw:SKIP
   #88/2 perf_branches/perf_branches_no_hw:OK
   #88 perf_branches:OK
  Summary: 1/1 PASSED, 1 SKIPPED, 0 FAILED

Fixes: fff7b64355 ("bpf: Add bpf_read_branch_records() helper")
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Kajol Jain <kjain@linux.ibm.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20211206073315.77432-1-kjain@linux.ibm.com
2021-12-06 15:21:15 +01:00
Jakub Kicinski
50fc24944a Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2021-11-18 13:13:16 -08:00
Dmitrii Banshchikov
5e0bc3082e bpf: Forbid bpf_ktime_get_coarse_ns and bpf_timer_* in tracing progs
Use of bpf_ktime_get_coarse_ns() and bpf_timer_* helpers in tracing
progs may result in locking issues.

bpf_ktime_get_coarse_ns() uses ktime_get_coarse_ns() time accessor that
isn't safe for any context:
======================================================
WARNING: possible circular locking dependency detected
5.15.0-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor.4/14877 is trying to acquire lock:
ffffffff8cb30008 (tk_core.seq.seqcount){----}-{0:0}, at: ktime_get_coarse_ts64+0x25/0x110 kernel/time/timekeeping.c:2255

but task is already holding lock:
ffffffff90dbf200 (&obj_hash[i].lock){-.-.}-{2:2}, at: debug_object_deactivate+0x61/0x400 lib/debugobjects.c:735

which lock already depends on the new lock.

the existing dependency chain (in reverse order) is:

-> #1 (&obj_hash[i].lock){-.-.}-{2:2}:
       lock_acquire+0x19f/0x4d0 kernel/locking/lockdep.c:5625
       __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
       _raw_spin_lock_irqsave+0xd1/0x120 kernel/locking/spinlock.c:162
       __debug_object_init+0xd9/0x1860 lib/debugobjects.c:569
       debug_hrtimer_init kernel/time/hrtimer.c:414 [inline]
       debug_init kernel/time/hrtimer.c:468 [inline]
       hrtimer_init+0x20/0x40 kernel/time/hrtimer.c:1592
       ntp_init_cmos_sync kernel/time/ntp.c:676 [inline]
       ntp_init+0xa1/0xad kernel/time/ntp.c:1095
       timekeeping_init+0x512/0x6bf kernel/time/timekeeping.c:1639
       start_kernel+0x267/0x56e init/main.c:1030
       secondary_startup_64_no_verify+0xb1/0xbb

-> #0 (tk_core.seq.seqcount){----}-{0:0}:
       check_prev_add kernel/locking/lockdep.c:3051 [inline]
       check_prevs_add kernel/locking/lockdep.c:3174 [inline]
       validate_chain+0x1dfb/0x8240 kernel/locking/lockdep.c:3789
       __lock_acquire+0x1382/0x2b00 kernel/locking/lockdep.c:5015
       lock_acquire+0x19f/0x4d0 kernel/locking/lockdep.c:5625
       seqcount_lockdep_reader_access+0xfe/0x230 include/linux/seqlock.h:103
       ktime_get_coarse_ts64+0x25/0x110 kernel/time/timekeeping.c:2255
       ktime_get_coarse include/linux/timekeeping.h:120 [inline]
       ktime_get_coarse_ns include/linux/timekeeping.h:126 [inline]
       ____bpf_ktime_get_coarse_ns kernel/bpf/helpers.c:173 [inline]
       bpf_ktime_get_coarse_ns+0x7e/0x130 kernel/bpf/helpers.c:171
       bpf_prog_a99735ebafdda2f1+0x10/0xb50
       bpf_dispatcher_nop_func include/linux/bpf.h:721 [inline]
       __bpf_prog_run include/linux/filter.h:626 [inline]
       bpf_prog_run include/linux/filter.h:633 [inline]
       BPF_PROG_RUN_ARRAY include/linux/bpf.h:1294 [inline]
       trace_call_bpf+0x2cf/0x5d0 kernel/trace/bpf_trace.c:127
       perf_trace_run_bpf_submit+0x7b/0x1d0 kernel/events/core.c:9708
       perf_trace_lock+0x37c/0x440 include/trace/events/lock.h:39
       trace_lock_release+0x128/0x150 include/trace/events/lock.h:58
       lock_release+0x82/0x810 kernel/locking/lockdep.c:5636
       __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:149 [inline]
       _raw_spin_unlock_irqrestore+0x75/0x130 kernel/locking/spinlock.c:194
       debug_hrtimer_deactivate kernel/time/hrtimer.c:425 [inline]
       debug_deactivate kernel/time/hrtimer.c:481 [inline]
       __run_hrtimer kernel/time/hrtimer.c:1653 [inline]
       __hrtimer_run_queues+0x2f9/0xa60 kernel/time/hrtimer.c:1749
       hrtimer_interrupt+0x3b3/0x1040 kernel/time/hrtimer.c:1811
       local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1086 [inline]
       __sysvec_apic_timer_interrupt+0xf9/0x270 arch/x86/kernel/apic/apic.c:1103
       sysvec_apic_timer_interrupt+0x8c/0xb0 arch/x86/kernel/apic/apic.c:1097
       asm_sysvec_apic_timer_interrupt+0x12/0x20
       __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline]
       _raw_spin_unlock_irqrestore+0xd4/0x130 kernel/locking/spinlock.c:194
       try_to_wake_up+0x702/0xd20 kernel/sched/core.c:4118
       wake_up_process kernel/sched/core.c:4200 [inline]
       wake_up_q+0x9a/0xf0 kernel/sched/core.c:953
       futex_wake+0x50f/0x5b0 kernel/futex/waitwake.c:184
       do_futex+0x367/0x560 kernel/futex/syscalls.c:127
       __do_sys_futex kernel/futex/syscalls.c:199 [inline]
       __se_sys_futex+0x401/0x4b0 kernel/futex/syscalls.c:180
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x44/0xae

There is a possible deadlock with bpf_timer_* set of helpers:
hrtimer_start()
  lock_base();
  trace_hrtimer...()
    perf_event()
      bpf_run()
        bpf_timer_start()
          hrtimer_start()
            lock_base()         <- DEADLOCK

Forbid use of bpf_ktime_get_coarse_ns() and bpf_timer_* helpers in
BPF_PROG_TYPE_KPROBE, BPF_PROG_TYPE_TRACEPOINT, BPF_PROG_TYPE_PERF_EVENT
and BPF_PROG_TYPE_RAW_TRACEPOINT prog types.

Fixes: d055126180 ("bpf: Add bpf_ktime_get_coarse_ns helper")
Fixes: b00628b1c7 ("bpf: Introduce bpf timers.")
Reported-by: syzbot+43fd005b5a1b4d10781e@syzkaller.appspotmail.com
Signed-off-by: Dmitrii Banshchikov <me@ubique.spb.ru>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20211113142227.566439-2-me@ubique.spb.ru
2021-11-15 20:35:58 -08:00
Song Liu
d19ddb476a bpf: Introduce btf_tracing_ids
Similar to btf_sock_ids, btf_tracing_ids provides btf ID for task_struct,
file, and vm_area_struct via easy to understand format like
btf_tracing_ids[BTF_TRACING_TYPE_[TASK|file|VMA]].

Suggested-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20211112150243.1270987-3-songliubraving@fb.com
2021-11-12 10:19:09 -08:00
Song Liu
7c7e3d31e7 bpf: Introduce helper bpf_find_vma
In some profiler use cases, it is necessary to map an address to the
backing file, e.g., a shared library. bpf_find_vma helper provides a
flexible way to achieve this. bpf_find_vma maps an address of a task to
the vma (vm_area_struct) for this address, and feed the vma to an callback
BPF function. The callback function is necessary here, as we need to
ensure mmap_sem is unlocked.

It is necessary to lock mmap_sem for find_vma. To lock and unlock mmap_sem
safely when irqs are disable, we use the same mechanism as stackmap with
build_id. Specifically, when irqs are disabled, the unlocked is postponed
in an irq_work. Refactor stackmap.c so that the irq_work is shared among
bpf_find_vma and stackmap helpers.

Signed-off-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Tested-by: Hengqi Chen <hengqi.chen@gmail.com>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20211105232330.1936330-2-songliubraving@fb.com
2021-11-07 11:54:51 -08:00
Hou Tao
35346ab641 bpf: Factor out helpers for ctx access checking
Factor out two helpers to check the read access of ctx for raw tp
and BTF function. bpf_tracing_ctx_access() is used to check
the read access to argument is valid, and bpf_tracing_btf_ctx_access()
checks whether the btf type of argument is valid besides the checking
of argument read. bpf_tracing_btf_ctx_access() will be used by the
following patch.

Signed-off-by: Hou Tao <houtao1@huawei.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20211025064025.2567443-3-houtao1@huawei.com
2021-11-01 14:10:00 -07:00
Hengqi Chen
9eeb3aa33a bpf: Add bpf_skc_to_unix_sock() helper
The helper is used in tracing programs to cast a socket
pointer to a unix_sock pointer.
The return value could be NULL if the casting is illegal.

Suggested-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Hengqi Chen <hengqi.chen@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Song Liu <songliubraving@fb.com>
Link: https://lore.kernel.org/bpf/20211021134752.1223426-2-hengqi.chen@gmail.com
2021-10-21 15:11:06 -07:00
Dave Marchevsky
10aceb629e bpf: Add bpf_trace_vprintk helper
This helper is meant to be "bpf_trace_printk, but with proper vararg
support". Follow bpf_snprintf's example and take a u64 pseudo-vararg
array. Write to /sys/kernel/debug/tracing/trace_pipe using the same
mechanism as bpf_trace_printk. The functionality of this helper was
requested in the libbpf issue tracker [0].

[0] Closes: https://github.com/libbpf/libbpf/issues/315

Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210917182911.2426606-4-davemarchevsky@fb.com
2021-09-17 14:02:05 -07:00
Dave Marchevsky
335ff4990c bpf: Merge printk and seq_printf VARARG max macros
MAX_SNPRINTF_VARARGS and MAX_SEQ_PRINTF_VARARGS are used by bpf helpers
bpf_snprintf and bpf_seq_printf to limit their varargs. Both call into
bpf_bprintf_prepare for print formatting logic and have convenience
macros in libbpf (BPF_SNPRINTF, BPF_SEQ_PRINTF) which use the same
helper macros to convert varargs to a byte array.

Changing shared functionality to support more varargs for either bpf
helper would affect the other as well, so let's combine the _VARARGS
macros to make this more obvious.

Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210917182911.2426606-2-davemarchevsky@fb.com
2021-09-17 14:02:05 -07:00
Song Liu
856c02dbce bpf: Introduce helper bpf_get_branch_snapshot
Introduce bpf_get_branch_snapshot(), which allows tracing pogram to get
branch trace from hardware (e.g. Intel LBR). To use the feature, the
user need to create perf_event with proper branch_record filtering
on each cpu, and then calls bpf_get_branch_snapshot in the bpf function.
On Intel CPUs, VLBR event (raw event 0x1b00) can be use for this.

Signed-off-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210910183352.3151445-3-songliubraving@fb.com
2021-09-13 10:53:50 -07:00
Daniel Xu
eb529c5b10 bpf: Fix bpf-next builds without CONFIG_BPF_EVENTS
This commit fixes linker errors along the lines of:

    s390-linux-ld: task_iter.c:(.init.text+0xa4): undefined reference to `btf_task_struct_ids'`

Fix by defining btf_task_struct_ids unconditionally in kernel/bpf/btf.c
since there exists code that unconditionally uses btf_task_struct_ids.

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Daniel Xu <dxu@dxuuu.xyz>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/05d94748d9f4b3eecedc4fddd6875418a396e23c.1629942444.git.dxu@dxuuu.xyz
2021-08-25 19:41:39 -07:00
Daniel Xu
dd6e10fbd9 bpf: Add bpf_task_pt_regs() helper
The motivation behind this helper is to access userspace pt_regs in a
kprobe handler.

uprobe's ctx is the userspace pt_regs. kprobe's ctx is the kernelspace
pt_regs. bpf_task_pt_regs() allows accessing userspace pt_regs in a
kprobe handler. The final case (kernelspace pt_regs in uprobe) is
pretty rare (usermode helper) so I think that can be solved later if
necessary.

More concretely, this helper is useful in doing BPF-based DWARF stack
unwinding. Currently the kernel can only do framepointer based stack
unwinds for userspace code. This is because the DWARF state machines are
too fragile to be computed in kernelspace [0]. The idea behind
DWARF-based stack unwinds w/ BPF is to copy a chunk of the userspace
stack (while in prog context) and send it up to userspace for unwinding
(probably with libunwind) [1]. This would effectively enable profiling
applications with -fomit-frame-pointer using kprobes and uprobes.

[0]: https://lkml.org/lkml/2012/2/10/356
[1]: https://github.com/danobi/bpf-dwarf-walk

Signed-off-by: Daniel Xu <dxu@dxuuu.xyz>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/e2718ced2d51ef4268590ab8562962438ab82815.1629772842.git.dxu@dxuuu.xyz
2021-08-25 10:37:05 -07:00
Daniel Xu
a396eda551 bpf: Extend bpf_base_func_proto helpers with bpf_get_current_task_btf()
bpf_get_current_task() is already supported so it's natural to also
include the _btf() variant for btf-powered helpers.

This is required for non-tracing progs to use bpf_task_pt_regs() in the
next commit.

Signed-off-by: Daniel Xu <dxu@dxuuu.xyz>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/f99870ed5f834c9803d73b3476f8272b1bb987c0.1629772842.git.dxu@dxuuu.xyz
2021-08-25 10:37:05 -07:00
Daniel Xu
33c5cb3601 bpf: Consolidate task_struct BTF_ID declarations
No need to have it defined 5 times. Once is enough.

Signed-off-by: Daniel Xu <dxu@dxuuu.xyz>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/6dcefa5bed26fe1226f26683f36819bb53ec19a2.1629772842.git.dxu@dxuuu.xyz
2021-08-25 10:37:05 -07:00
Andrii Nakryiko
7adfc6c9b3 bpf: Add bpf_get_attach_cookie() BPF helper to access bpf_cookie value
Add new BPF helper, bpf_get_attach_cookie(), which can be used by BPF programs
to get access to a user-provided bpf_cookie value, specified during BPF
program attachment (BPF link creation) time.

Naming is hard, though. With the concept being named "BPF cookie", I've
considered calling the helper:
  - bpf_get_cookie() -- seems too unspecific and easily mistaken with socket
    cookie;
  - bpf_get_bpf_cookie() -- too much tautology;
  - bpf_get_link_cookie() -- would be ok, but while we create a BPF link to
    attach BPF program to BPF hook, it's still an "attachment" and the
    bpf_cookie is associated with BPF program attachment to a hook, not a BPF
    link itself. Technically, we could support bpf_cookie with old-style
    cgroup programs.So I ultimately rejected it in favor of
    bpf_get_attach_cookie().

Currently all perf_event-backed BPF program types support
bpf_get_attach_cookie() helper. Follow-up patches will add support for
fentry/fexit programs as well.

While at it, mark bpf_tracing_func_proto() as static to make it obvious that
it's only used from within the kernel/trace/bpf_trace.c.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20210815070609.987780-7-andrii@kernel.org
2021-08-17 00:45:07 +02:00
Andrii Nakryiko
82e6b1eee6 bpf: Allow to specify user-provided bpf_cookie for BPF perf links
Add ability for users to specify custom u64 value (bpf_cookie) when creating
BPF link for perf_event-backed BPF programs (kprobe/uprobe, perf_event,
tracepoints).

This is useful for cases when the same BPF program is used for attaching and
processing invocation of different tracepoints/kprobes/uprobes in a generic
fashion, but such that each invocation is distinguished from each other (e.g.,
BPF program can look up additional information associated with a specific
kernel function without having to rely on function IP lookups). This enables
new use cases to be implemented simply and efficiently that previously were
possible only through code generation (and thus multiple instances of almost
identical BPF program) or compilation at runtime (BCC-style) on target hosts
(even more expensive resource-wise). For uprobes it is not even possible in
some cases to know function IP before hand (e.g., when attaching to shared
library without PID filtering, in which case base load address is not known
for a library).

This is done by storing u64 bpf_cookie in struct bpf_prog_array_item,
corresponding to each attached and run BPF program. Given cgroup BPF programs
already use two 8-byte pointers for their needs and cgroup BPF programs don't
have (yet?) support for bpf_cookie, reuse that space through union of
cgroup_storage and new bpf_cookie field.

Make it available to kprobe/tracepoint BPF programs through bpf_trace_run_ctx.
This is set by BPF_PROG_RUN_ARRAY, used by kprobe/uprobe/tracepoint BPF
program execution code, which luckily is now also split from
BPF_PROG_RUN_ARRAY_CG. This run context will be utilized by a new BPF helper
giving access to this user-provided cookie value from inside a BPF program.
Generic perf_event BPF programs will access this value from perf_event itself
through passed in BPF program context.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Yonghong Song <yhs@fb.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/bpf/20210815070609.987780-6-andrii@kernel.org
2021-08-17 00:45:07 +02:00
Andrii Nakryiko
7d08c2c911 bpf: Refactor BPF_PROG_RUN_ARRAY family of macros into functions
Similar to BPF_PROG_RUN, turn BPF_PROG_RUN_ARRAY macros into proper functions
with all the same readability and maintainability benefits. Making them into
functions required shuffling around bpf_set_run_ctx/bpf_reset_run_ctx
functions. Also, explicitly specifying the type of the BPF prog run callback
required adjusting __bpf_prog_run_save_cb() to accept const void *, casted
internally to const struct sk_buff.

Further, split out a cgroup-specific BPF_PROG_RUN_ARRAY_CG and
BPF_PROG_RUN_ARRAY_CG_FLAGS from the more generic BPF_PROG_RUN_ARRAY due to
the differences in bpf_run_ctx used for those two different use cases.

I think BPF_PROG_RUN_ARRAY_CG would benefit from further refactoring to accept
struct cgroup and enum bpf_attach_type instead of bpf_prog_array, fetching
cgrp->bpf.effective[type] and RCU-dereferencing it internally. But that
required including include/linux/cgroup-defs.h, which I wasn't sure is ok with
everyone.

The remaining generic BPF_PROG_RUN_ARRAY function will be extended to
pass-through user-provided context value in the next patch.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20210815070609.987780-3-andrii@kernel.org
2021-08-17 00:45:07 +02:00