wait_for_kprobe_optimizer() seems largely broken. It uses
optimizer_comp which is never re-initialized, so
wait_for_kprobe_optimizer() will never wait for anything once
kprobe_optimizer() finishes all pending jobs for the first time.
Also, aside from completion, delayed_work_pending() is %false once
kprobe_optimizer() starts execution and wait_for_kprobe_optimizer()
won't wait for it.
Reimplement it so that it flushes optimizing_work until
[un]optimizing_lists are empty. Note that this also makes
optimizing_work execute immediately if someone's waiting for it, which
is the nicer behavior.
Only compile tested.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Cc: "David S. Miller" <davem@davemloft.net>
* Drop unnesssary delayd_work_pending() tests.
* Unify scan_event_{now|later} by using mod_delayed_work() w/ 0 delay
for scan_event_now.
* Make ipw2200 scan_event handling match ipw2100 - use
mod_delayed_work() w/ 0 delay for immediate scanning.
Only compile tested.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Stanislav Yakovlev <stas.yakovlev@gmail.com>
Cc: linux-wireless@vger.kernel.org
1) Lockdep thinks all nouveau subdevs belong to the same class and can be
locked in arbitrary order, which is not true (at least in general case).
Tell it to distinguish subdevs by (o)class type.
2) DRM client can be locked under user client lock - tell lockdep to put
DRM client lock in a separate class.
Reported-by: Arend van Spriel <arend@broadcom.com>
Reported-by: Peter Hurley <peter@hurleysoftware.com>
Reported-by: Maarten Lankhorst <maarten.lankhorst@canonical.com>
Reported-by: Daniel J Blueman <daniel@quora.org>
Signed-off-by: Marcin Slusarz <marcin.slusarz@gmail.com>
Cc: stable@vger.kernel.org [3.7, but needs s/const ofuncs/ofuncs/ to build]
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
At init time, if the system time is "warped" forward in warp_clock()
it will differ from the hardware clock by sys_tz.tz_minuteswest. This time
difference is not taken into account when ntp updates the hardware clock,
and this causes the system time to jump forward by this offset every reboot.
The kernel must take this offset into account when writing the system time
to the hardware clock in the ntp code. This patch adds
persistent_clock_is_local which indicates that an offset has been applied
in warp_clock() and accounts for the "warp" before writing the hardware
clock.
x86 does not have this problem as rtc writes are software limited to a
+/-15 minute window relative to the current rtc time. Other arches, such
as powerpc, however do a full synchronization of the system time to the
rtc and will see this problem.
[v2]: generated against tip/timers/core
Signed-off-by: Prarit Bhargava <prarit@redhat.com>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: John Stultz <john.stultz@linaro.org>
This reverts commit d64ec84151.
Jörg Otte reported his 8168evl to increase boot time link detection
from 1.6 to 10 s.
Hayes suggests reverting it for the time being.
Signed-off-by: Francois Romieu <romieu@fr.zoreil.com>
Cc: Hayes Wang <hayeswang@realtek.com>
Cc: Jörg Otte <jrg.otte@gmail.com>
This reverts commit e0c0755779.
Jörg Otte reported his 8168evl to fail boot time link detection.
Hayes suggests reverting it for the time being.
Signed-off-by: Francois Romieu <romieu@fr.zoreil.com>
Cc: Hayes Wang <hayeswang@realtek.com>
Cc: Jörg Otte <jrg.otte@gmail.com>
Pull ARM fixes from Russell King:
"I was going to hold these off until v3.8 was out, and send them with a
stable tag, but as everyone else is pushing much bigger fixes which
Linus is accepting, let's save people from the hastle of having to
patch v3.8 back into working or use a stable kernel.
Looking at the diffstat, this really is high value for its size; this
is miniscule compared to how the -rc6 to tip diffstat currently looks.
So, four patches in this set:
- Punit Agrawal reports that the kernel no longer boots on MPCore due
to a new assumption made in the GIC code which isn't true of
earlier GIC designs. This is the biggest change in this set.
- Punit's boot log also revealed a bunch of WARN_ON() dumps caused by
the DT-ification of the GIC support without fixing up non-DT
Realview - which now sees a greater number of interrupts than it
did before.
- A fix for the DMA coherent code from Marek which uses the wrong
check for atomic allocations; this can result in spinlock lockups
or other nasty effects.
- A fix from Will, which will affect all Android based platforms if
not applied (which use the 2G:2G VM split) - this causes
particularly 'make' to misbehave unless this bug is fixed."
* 'fixes' of git://git.linaro.org/people/rmk/linux-arm:
ARM: 7641/1: memory: fix broken mmap by ensuring TASK_UNMAPPED_BASE is aligned
ARM: DMA mapping: fix bad atomic test
ARM: realview: ensure that we have sufficient IRQs available
ARM: GIC: fix GIC cpumask initialization
Pull networking fixes from David Miller:
1) Revert iwlwifi reclaimed packet tracking, it causes problems for a
bunch of folks. From Emmanuel Grumbach.
2) Work limiting code in brcmsmac wifi driver can clear tx status
without processing the event. From Arend van Spriel.
3) rtlwifi USB driver processes wrong SKB, fix from Larry Finger.
4) l2tp tunnel delete can race with close, fix from Tom Parkin.
5) pktgen_add_device() failures are not checked at all, fix from Cong
Wang.
6) Fix unintentional removal of carrier off from tun_detach(),
otherwise we confuse userspace, from Michael S. Tsirkin.
7) Don't leak socket reference counts and ubufs in vhost-net driver,
from Jason Wang.
8) vmxnet3 driver gets it's initial carrier state wrong, fix from Neil
Horman.
9) Protect against USB networking devices which spam the host with 0
length frames, from Bjørn Mork.
10) Prevent neighbour overflows in ipv6 for locally destined routes,
from Marcelo Ricardo. This is the best short-term fix for this, a
longer term fix has been implemented in net-next.
11) L2TP uses ipv4 datagram routines in it's ipv6 code, whoops. This
mistake is largely because the ipv6 functions don't even have some
kind of prefix in their names to suggest they are ipv6 specific.
From Tom Parkin.
12) Check SYN packet drops properly in tcp_rcv_fastopen_synack(), from
Yuchung Cheng.
13) Fix races and TX skb freeing bugs in via-rhine's NAPI support, from
Francois Romieu and your's truly.
14) Fix infinite loops and divides by zero in TCP congestion window
handling, from Eric Dumazet, Neal Cardwell, and Ilpo Järvinen.
15) AF_PACKET tx ring handling can leak kernel memory to userspace, fix
from Phil Sutter.
16) Fix error handling in ipv6 GRE tunnel transmit, from Tommi Rantala.
17) Protect XEN netback driver against hostile frontend putting garbage
into the rings, don't leak pages in TX GOP checking, and add proper
resource releasing in error path of xen_netbk_get_requests(). From
Ian Campbell.
18) SCTP authentication keys should be cleared out and released with
kzfree(), from Daniel Borkmann.
19) L2TP is a bit too clever trying to maintain skb->truesize, and ends
up corrupting socket memory accounting to the point where packet
sending is halted indefinitely. Just remove the adjustments
entirely, they aren't really needed. From Eric Dumazet.
20) ATM Iphase driver uses a data type with the same name as the S390
headers, rename to fix the build. From Heiko Carstens.
21) Fix a typo in copying the inner network header offset from one SKB
to another, from Pravin B Shelar.
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (56 commits)
net: sctp: sctp_endpoint_free: zero out secret key data
net: sctp: sctp_setsockopt_auth_key: use kzfree instead of kfree
atm/iphase: rename fregt_t -> ffreg_t
net: usb: fix regression from FLAG_NOARP code
l2tp: dont play with skb->truesize
net: sctp: sctp_auth_key_put: use kzfree instead of kfree
netback: correct netbk_tx_err to handle wrap around.
xen/netback: free already allocated memory on failure in xen_netbk_get_requests
xen/netback: don't leak pages on failure in xen_netbk_tx_check_gop.
xen/netback: shutdown the ring if it contains garbage.
net: qmi_wwan: add more Huawei devices, including E320
net: cdc_ncm: add another Huawei vendor specific device
ipv6/ip6_gre: fix error case handling in ip6gre_tunnel_xmit()
tcp: fix for zero packets_in_flight was too broad
brcmsmac: rework of mac80211 .flush() callback operation
ssb: unregister gpios before unloading ssb
bcma: unregister gpios before unloading bcma
rtlwifi: Fix scheduling while atomic bug
net: usbnet: fix tx_dropped statistics
tcp: ipv6: Update MIB counters for drops
...
Daniel Borkmann says:
====================
Cryptographically used keys should be zeroed out when our session
ends resp. memory is freed, thus do not leave them somewhere in the
memory.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
On sctp_endpoint_destroy, previously used sensitive keying material
should be zeroed out before the memory is returned, as we already do
with e.g. auth keys when released.
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Acked-by: Vlad Yasevich <vyasevic@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
In sctp_setsockopt_auth_key, we create a temporary copy of the user
passed shared auth key for the endpoint or association and after
internal setup, we free it right away. Since it's sensitive data, we
should zero out the key before returning the memory back to the
allocator. Thus, use kzfree instead of kfree, just as we do in
sctp_auth_key_put().
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
automount-support is broken on the parisc architecture, because the existing
#if list does not include a check for defined(__hppa__). The HPPA (parisc)
architecture is similiar to other 64bit Linux targets where we have to define
autofs_wqt_t (which is passed back and forth to user space) as int type which
has a size of 32bit across 32 and 64bit kernels.
During the discussion on the mailing list, H. Peter Anvin suggested to invert
the #if list since only specific platforms (specifically those who do not have
a 32bit userspace, like IA64 and Alpha) should have autofs_wqt_t as unsigned
long type.
This suggestion is probably the best way to go, since Arm64 (and maybe others?)
seems to have a non-working automounter. So in the long run even for other new
upcoming architectures this inverted check seem to be the best solution, since
it will not require them to change this #if again (unless they are 64bit only).
Signed-off-by: Helge Deller <deller@gmx.de>
Acked-by: H. Peter Anvin <hpa@zytor.com>
Acked-by: Ian Kent <raven@themaw.net>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
CC: James Bottomley <James.Bottomley@HansenPartnership.com>
CC: Rolf Eike Beer <eike-kernel@sf-tec.de>
We have conflicting type qualifiers for "freg_t" in s390's ptrace.h and the
iphase atm device driver, which causes the compile error below.
Unfortunately the s390 typedef can't be renamed, since it's a user visible api,
nor can I change the include order in s390 code to avoid the conflict.
So simply rename the iphase typedef to a new name. Fixes this compile error:
In file included from drivers/atm/iphase.c:66:0:
drivers/atm/iphase.h:639:25: error: conflicting type qualifiers for 'freg_t'
In file included from next/arch/s390/include/asm/ptrace.h:9:0,
from next/arch/s390/include/asm/lowcore.h:12,
from next/arch/s390/include/asm/thread_info.h:30,
from include/linux/thread_info.h:54,
from include/linux/preempt.h:9,
from include/linux/spinlock.h:50,
from include/linux/seqlock.h:29,
from include/linux/time.h:5,
from include/linux/stat.h:18,
from include/linux/module.h:10,
from drivers/atm/iphase.c:43:
next/arch/s390/include/uapi/asm/ptrace.h:197:3: note: previous declaration of 'freg_t' was here
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Acked-by: chas williams - CONTRACTOR <chas@cmf.nrl.navy.mil>
Signed-off-by: David S. Miller <davem@davemloft.net>
On tilepro without CONFIG_PCI, we can't provide inlines of these
functions, as we don't have readl/writel.
In addition, fix memset_io() signature to take a volatile void *.
Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
This was shown up by running with "allmodconfig". I used
EXPORT_SYMBOL() to match existing conventions in files that
were already exporting symbols, or that were exported that way
by other architectures, and otherwise EXPORT_SYMBOL_GPL().
Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
uprobe_perf_open/close call the costly uprobe_apply() every time,
we can avoid it if:
- "nr_systemwide != 0" is not changed.
- There is another process/thread with the same ->mm.
- copy_proccess() does inherit_event(). dup_mmap() preserves the
inserted breakpoints.
- event->attr.enable_on_exec == T, we can rely on uprobe_mmap()
called by exec/mmap paths.
- tp_target is exiting. Only _close() checks PF_EXITING, I don't
think TRACE_REG_PERF_OPEN can hit the dying task too often.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Change uprobe_trace_func() and uprobe_perf_func() to return "int". Change
uprobe_dispatcher() to return "trace_ret | perf_ret" although this is not
needed, currently TP_FLAG_TRACE/TP_FLAG_PROFILE are mutually exclusive.
The only functional change is that uprobe_perf_func() checks the filtering
too and returns UPROBE_HANDLER_REMOVE if nobody wants to trace current.
Testing:
# perf probe -x /lib/libc.so.6 syscall
# perf record -e probe_libc:syscall -i perl -e 'fork; syscall -1 for 1..10; wait'
# perf report --show-total-period
100.00% 10 perl libc-2.8.so [.] syscall
Before this patch:
# cat /sys/kernel/debug/tracing/uprobe_profile
/lib/libc.so.6 syscall 20
A child process doesn't have a counter, but still it hits this breakoint
"copied" by dup_mmap().
After the patch:
# cat /sys/kernel/debug/tracing/uprobe_profile
/lib/libc.so.6 syscall 11
The child process hits this int3 only once and does unapply_uprobe().
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Finally implement uprobe_perf_filter() which checks ->nr_systemwide or
->perf_events to figure out whether we need to insert the breakpoint.
uprobe_perf_open/close are changed to do uprobe_apply(true/false) when
the new perf event comes or goes away.
Note that currently this is very suboptimal:
- uprobe_register() called by TRACE_REG_PERF_REGISTER becomes a
heavy nop, consumer->filter() always returns F at this stage.
As it was already discussed we need uprobe_register_only() to
avoid the costly register_for_each_vma() when possible.
- uprobe_apply() is oftenly overkill. Unless "nr_systemwide != 0"
changes we need uprobe_apply_mm(), unapply_uprobe() is almost
what we need.
- uprobe_apply() can be simply avoided sometimes, see the next
changes.
Testing:
# perf probe -x /lib/libc.so.6 syscall
# perl -e 'syscall -1 while 1' &
[1] 530
# perf record -e probe_libc:syscall perl -e 'syscall -1 for 1..10; sleep 1'
# perf report --show-total-period
100.00% 10 perl libc-2.8.so [.] syscall
Before this patch:
# cat /sys/kernel/debug/tracing/uprobe_profile
/lib/libc.so.6 syscall 79291
A huge ->nrhit == 79291 reflects the fact that the background process
530 constantly hits this breakpoint too, even if doesn't contribute to
the output.
After the patch:
# cat /sys/kernel/debug/tracing/uprobe_profile
/lib/libc.so.6 syscall 10
This shows that only the target process was punished by int3.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Introduce "struct trace_uprobe_filter" which records the "active"
perf_event's attached to ftrace_event_call. For the start we simply
use list_head, we can optimize this later if needed. For example, we
do not really need to record an event with ->parent != NULL, we can
rely on parent->child_list. And we can certainly do some optimizations
for the case when 2 events have the same ->tp_target or tp_target->mm.
Change trace_uprobe_register() to process TRACE_REG_PERF_OPEN/CLOSE
and add/del this perf_event to the list.
We can probably avoid any locking, but lets start with the "obvioulsy
correct" trace_uprobe_filter->rwlock which protects everything.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Currently it is not possible to change the filtering constraints after
uprobe_register(), so a consumer can not, say, start to trace a task/mm
which was previously filtered out, or remove the no longer needed bp's.
Introduce uprobe_apply() which simply does register_for_each_vma() again
to consult uprobe_consumer->filter() and install/remove the breakpoints.
The only complication is that register_for_each_vma() can no longer
assume that uprobe->consumers should be consulter if is_register == T,
so we change it to accept "struct uprobe_consumer *new" instead.
Unlike uprobe_register(), uprobe_apply(true) doesn't do "unregister" if
register_for_each_vma() fails, it is up to caller to handle the error.
Note: we probably need to cleanup the current interface, it is strange
that uprobe_apply/unregister need inode/offset. We should either change
uprobe_register() to return "struct uprobe *", or add a private ->uprobe
member in uprobe_consumer. And in the long term uprobe_apply() should
take a single argument, uprobe or consumer, even "bool add" should go
away.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
sys_perf_event_open()->perf_init_event(event) is called before
find_get_context(event), this means that event->ctx == NULL when
class->reg(TRACE_REG_PERF_REGISTER/OPEN) is called and thus it
can't know if this event is per-task or system-wide.
This patch adds hw_perf_event->tp_target for PERF_TYPE_TRACEPOINT,
this is analogous to PERF_TYPE_BREAKPOINT/bp_target we already have.
The patch also moves ->bp_target up so that it can overlap with the
new member, this can help the compiler to generate the better code.
trace_uprobe_register() will use it for prefiltering to avoid the
unnecessary breakpoints in mm's we do not want to trace.
->tp_target doesn't have its own reference, but we can rely on the
fact that either sys_perf_event_open() holds a reference, or it is
equal to event->ctx->task. So this pointer is always valid until
free_event().
Also add the "struct list_head tp_list" into this union. It is not
strictly necessary, but it can simplify the next changes and we can
add it for free.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
OVMF (an implementation of UEFI based on TianoCore used in virtual
environments) now has the ability to boot Linux natively; this is used
for "qemu -kernel" and similar things in a UEFI environment.
Accordingly, assign it a bootloader ID.
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Move tu->nhit++ from uprobe_trace_func() to uprobe_dispatcher().
->nhit counts how many time we hit the breakpoint inserted by this
uprobe, we do not want to loose this info if uprobe was enabled by
sys_perf_event_open().
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
trace_uprobe->consumer and "struct uprobe_trace_consumer" add the
unnecessary indirection and complicate the code for no reason.
This patch simply embeds uprobe_consumer into "struct trace_uprobe",
all other changes only fix the compilation errors.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
probe_event_enable/disable() check tu->consumer != NULL to avoid the
wrong uprobe_register/unregister().
We are going to kill this pointer and "struct uprobe_trace_consumer",
so we add the new helper, is_trace_uprobe_enabled(), which can rely
on TP_FLAG_TRACE/TP_FLAG_PROFILE instead.
Note: the current logic doesn't look optimal, it is not clear why
TP_FLAG_TRACE/TP_FLAG_PROFILE are mutually exclusive, we will probably
change this later.
Also kill the unused TP_FLAG_UPROBE.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
probe_event_enable/disable() check tu->inode != NULL at the start.
This is ugly, if igrab() can fail create_trace_uprobe() should not
succeed and "postpone" the failure.
And S_ISREG(inode->i_mode) check added by d24d7dbf is not safe.
Note: alloc_uprobe() should probably check igrab() != NULL as well.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
probe_event_enable() does uprobe_register() and only after that sets
utc->tu and tu->consumer/flags. This can race with uprobe_dispatcher()
which can miss these assignments or see them out of order. Nothing
really bad can happen, but this doesn't look clean/safe.
And this does not allow to use uprobe_consumer->filter() we are going
to add, it is called by uprobe_register() and it needs utc->tu.
Change this code to initialize everything before uprobe_register(), and
reset tu->consumer/flags if it fails. We can't race with event_disable(),
the caller holds event_mutex, and if we could the code would be wrong
anyway.
In fact I think uprobe_trace_consumer should die, it buys nothing but
complicates the code. We can simply add uprobe_consumer into trace_uprobe.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
create_trace_uprobe() does kern_path() to find ->d_inode, but forgets
to do path_put(). We can do this right after igrab().
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
The original pull message for uprobes (commit 654443e2) noted:
This tree includes uprobes support in 'perf probe' - but SystemTap
(and other tools) can take advantage of user probe points as well.
In order to actually be usable in module-based tools like SystemTap, the
interface needs to be exported. This patch first adds the obvious
exports for uprobe_register and uprobe_unregister. Then it also adds
one for task_user_regset_view, which is necessary to get the correct
state of userspace registers.
Signed-off-by: Josh Stone <jistone@redhat.com>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
utask->xol_vaddr is either zero or valid, remove the bogus
IS_ERR_VALUE() check in xol_free_insn_slot().
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Anton Arapov <anton@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
handle_swbp() does get_utask() before can_skip_sstep() for no reason,
we do not need ->utask if can_skip_sstep() succeeds.
Move get_utask() to pre_ssout() who actually starts to use it. Move
the initialization of utask->active_uprobe/state as well. This way
the whole initialization is consolidated in pre_ssout().
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Anton Arapov <anton@redhat.com>
pre_ssout() should do xol_free_insn_slot() if arch_uprobe_pre_xol()
fails, otherwise nobody will free the allocated slot.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Anton Arapov <anton@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
pre_ssout()->xol_get_insn_slot() path is confusing and buggy. This patch
cleanups the code, the next one fixes the bug.
Change xol_get_insn_slot() to only allocate the slot and do nothing more,
move the initialization of utask->xol_vaddr/vaddr into pre_ssout().
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Anton Arapov <anton@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Rename add_utask() into get_utask() and change it to allocate on
demand to simplify the caller. Like get_xol_area() it will have
more users.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Anton Arapov <anton@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Currently only xol_get_insn_slot() does get_xol_area() + xol_alloc_area(),
but this will have more users and we do not want to copy-and-paste this
code. This patch simply moves xol_alloc_area() into get_xol_area() to
simplify the current and future code.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Anton Arapov <anton@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Move alloc_page() from xol_add_vma() to xol_alloc_area() to cleanup
the code. This separates the memory allocations and consolidates the
-EALREADY cleanups and the error handling.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Anton Arapov <anton@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Change handle_swbp() to set regs->ip = bp_vaddr in advance, this is
what consumer->handler() needs but uprobe_get_swbp_addr() is not
exported.
This also simplifies the code and makes it more consistent across
the supported architectures. handle_swbp() becomes the only caller
of uprobe_get_swbp_addr().
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
__skip_sstep() doesn't update regs->ip. Currently this is correct
but only "by accident" and it doesn't skip the whole insn. Change
it to advance ->ip by the length of the detected 0x66*0x90 sequence.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Currrently the are 2 problems with pre-filtering:
1. It is not possible to add/remove a task (mm) after uprobe_register()
2. A forked child inherits all breakpoints and uprobe_consumer can not
control this.
This patch does the first step to improve the filtering. handler_chain()
removes the breakpoints installed by this uprobe from current->mm if all
handlers return UPROBE_HANDLER_REMOVE.
Note that handler_chain() relies on ->register_rwsem to avoid the race
with uprobe_register/unregister which can add/del a consumer, or even
remove and then insert the new uprobe at the same address.
Perhaps we will add uprobe_apply_mm(uprobe, mm, is_register) and teach
copy_mm() to do filter(UPROBE_FILTER_FORK), but I think this change makes
sense anyway.
Note: instead of checking the retcode from uc->handler, we could add
uc->filter(UPROBE_FILTER_BPHIT). But I think this is not optimal to
call 2 hooks in a row. This buys nothing, and if handler/filter do
something nontrivial they will probably do the same work twice.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Finally add uprobe_consumer->filter() and change consumer_filter()
to actually call this method.
Note that ->filter() accepts mm_struct, not task_struct. Because:
1. We do not have for_each_mm_user(mm, task).
2. Even if we implement for_each_mm_user(), ->filter() can
use it itself.
3. It is not clear who will actually need this interface to
do the "nontrivial" filtering.
Another argument is "enum uprobe_filter_ctx", consumer->filter() can
use it to figure out why/where it was called. For example, perhaps
we can add UPROBE_FILTER_PRE_REGISTER used by build_map_info() to
quickly "nack" the unwanted mm's. In this case consumer should know
that it is called under ->i_mmap_mutex.
See the previous discussion at http://marc.info/?t=135214229700002
Perhaps we should pass more arguments, vma/vaddr?
Note: this patch obviously can't help to filter out the child created
by fork(), this will be addressed later.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
filter_chain() was added into install_breakpoint/remove_breakpoint to
simplify the initial changes but this is sub-optimal.
This patch shifts the callsite to the callers, register_for_each_vma()
and uprobe_mmap(). This way:
- It will be easier to add the new arguments. This is the main reason,
we can do more optimizations later.
- register_for_each_vma(is_register => true) can be optimized, we only
need to consult the new consumer. The previous consumers were already
asked when they called uprobe_register().
This patch also moves the MMF_HAS_UPROBES check from remove_breakpoint(),
this allows to avoid the potentionally costly filter_chain(). Note that
register_for_each_vma(is_register => false) doesn't really need to take
->consumer_rwsem, but I don't think it makes sense to optimize this and
introduce filter_chain_lockless().
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
uprobe_register() and uprobe_unregister() are the only users of
mutex_lock(uprobes_hash(inode)), and the only reason why we can't
simply remove it is that we need to ensure that delete_uprobe() is
not possible after alloc_uprobe() and before consumer_add().
IOW, we need to ensure that when we take uprobe->register_rwsem
this uprobe is still valid and we didn't race with _unregister()
which called delete_uprobe() in between.
With this patch uprobe_register() simply checks uprobe_is_active()
and retries if it hits this very unlikely race. uprobes_mutex[] is
no longer needed and can be removed.
There is another reason for this change, prepare_uprobe() should be
folded into alloc_uprobe() and we do not want to hold the extra locks
around read_mapping_page/etc.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Anton Arapov <anton@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
The lifetime of uprobe->rb_node and uprobe->inode is not refcounted,
delete_uprobe() is called when we detect that uprobe has no consumers,
and it would be deadly wrong to do this twice.
Change delete_uprobe() to WARN() if it was already called. We use
RB_CLEAR_NODE() to mark uprobe "inactive", then RB_EMPTY_NODE() can
be used to detect this case.
RB_EMPTY_NODE() is not used directly, we add the trivial helper for
the next change.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Anton Arapov <anton@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
uprobe_events counts the number of uprobes in uprobes_tree but
it is used as a boolean. We can use RB_EMPTY_ROOT() instead.
Probably no_uprobe_events() added by this patch can have more
callers, say, mmf_recalc_uprobes().
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Anton Arapov <anton@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Now that ->register_rwsem is safe under ->mmap_sem we can kill
->copy_mutex and abuse down_write(&uprobe->consumer_rwsem).
This makes prepare_uprobe() even more ugly, but we should kill
it anyway.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Simply remove UPROBE_RUN_HANDLER and the corresponding code.
It can only help if uprobe has a single consumer, and in fact
it is no longer needed after handler_chain() was changed to use
->register_rwsem, we simply can not race with uprobe_register().
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Now that it safe to use ->consumer_rwsem under ->mmap_sem we can
almost finish the implementation of filter_chain(). It still lacks
the actual uc->filter(...) call but othewrwise it is ready, just
it pretends that ->filter() always returns true.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Introduce uprobe->register_rwsem. It is taken for writing around
__uprobe_register/unregister.
Change handler_chain() to use this sem rather than consumer_rwsem.
The main reason for this change is that we have the nasty problem
with mmap_sem/consumer_rwsem dependency. filter_chain() needs to
protect uprobe->consumers like handler_chain(), but they can not
use the same lock. filter_chain() can be called under ->mmap_sem
(currently this is always true), but we want to allow ->handler()
to play with the probed task's memory, and this needs ->mmap_sem.
Alternatively we could use srcu, but synchronize_srcu() is very
slow and ->register_rwsem allows us to do more. In particular, we
can teach handler_chain() to do remove_breakpoint() if this bp is
"nacked" by all consumers, we know that we can't race with the
new consumer which does uprobe_register().
See also the next patches. uprobes_mutex[] is almost ready to die.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
