linux-stable.git/kernel/events, branch v4.4.166 Linux kernel stable tree bpf: generally move prog destruction to RCU deferral 2018-11-10T15:41:37+00:00 Daniel Borkmann daniel@iogearbox.net 2016-06-30T15:24:43+00:00 e25dc63aa366fd0f61d1d9ba67b66f5d75fc4372 [ Upstream commit 1aacde3d22c42281236155c1ef6d7a5aa32a826b ] Jann Horn reported following analysis that could potentially result in a very hard to trigger (if not impossible) UAF race, to quote his event timeline: - Set up a process with threads T1, T2 and T3 - Let T1 set up a socket filter F1 that invokes another filter F2 through a BPF map [tail call] - Let T1 trigger the socket filter via a unix domain socket write, don't wait for completion - Let T2 call PERF_EVENT_IOC_SET_BPF with F2, don't wait for completion - Now T2 should be behind bpf_prog_get(), but before bpf_prog_put() - Let T3 close the file descriptor for F2, dropping the reference count of F2 to 2 - At this point, T1 should have looked up F2 from the map, but not finished executing it - Let T3 remove F2 from the BPF map, dropping the reference count of F2 to 1 - Now T2 should call bpf_prog_put() (wrong BPF program type), dropping the reference count of F2 to 0 and scheduling bpf_prog_free_deferred() via schedule_work() - At this point, the BPF program could be freed - BPF execution is still running in a freed BPF program While at PERF_EVENT_IOC_SET_BPF time it's only guaranteed that the perf event fd we're doing the syscall on doesn't disappear from underneath us for whole syscall time, it may not be the case for the bpf fd used as an argument only after we did the put. It needs to be a valid fd pointing to a BPF program at the time of the call to make the bpf_prog_get() and while T2 gets preempted, F2 must have dropped reference to 1 on the other CPU. The fput() from the close() in T3 should also add additionally delay to the reference drop via exit_task_work() when bpf_prog_release() gets called as well as scheduling bpf_prog_free_deferred(). That said, it makes nevertheless sense to move the BPF prog destruction generally after RCU grace period to guarantee that such scenario above, but also others as recently fixed in ceb56070359b ("bpf, perf: delay release of BPF prog after grace period") with regards to tail calls won't happen. Integrating bpf_prog_free_deferred() directly into the RCU callback is not allowed since the invocation might happen from either softirq or process context, so we're not permitted to block. Reviewing all bpf_prog_put() invocations from eBPF side (note, cBPF -> eBPF progs don't use this for their destruction) with call_rcu() look good to me. Since we don't know whether at the time of attaching the program, we're already part of a tail call map, we need to use RCU variant. However, due to this, there won't be severely more stress on the RCU callback queue: situations with above bpf_prog_get() and bpf_prog_put() combo in practice normally won't lead to releases, but even if they would, enough effort/ cycles have to be put into loading a BPF program into the kernel already. Reported-by: Jann Horn <jannh@google.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 1aacde3d22c42281236155c1ef6d7a5aa32a826b ]

Jann Horn reported following analysis that could potentially result
in a very hard to trigger (if not impossible) UAF race, to quote his
event timeline:

 - Set up a process with threads T1, T2 and T3
 - Let T1 set up a socket filter F1 that invokes another filter F2
   through a BPF map [tail call]
 - Let T1 trigger the socket filter via a unix domain socket write,
   don't wait for completion
 - Let T2 call PERF_EVENT_IOC_SET_BPF with F2, don't wait for completion
 - Now T2 should be behind bpf_prog_get(), but before bpf_prog_put()
 - Let T3 close the file descriptor for F2, dropping the reference
   count of F2 to 2
 - At this point, T1 should have looked up F2 from the map, but not
   finished executing it
 - Let T3 remove F2 from the BPF map, dropping the reference count of
   F2 to 1
 - Now T2 should call bpf_prog_put() (wrong BPF program type), dropping
   the reference count of F2 to 0 and scheduling bpf_prog_free_deferred()
   via schedule_work()
 - At this point, the BPF program could be freed
 - BPF execution is still running in a freed BPF program

While at PERF_EVENT_IOC_SET_BPF time it's only guaranteed that the perf
event fd we're doing the syscall on doesn't disappear from underneath us
for whole syscall time, it may not be the case for the bpf fd used as
an argument only after we did the put. It needs to be a valid fd pointing
to a BPF program at the time of the call to make the bpf_prog_get() and
while T2 gets preempted, F2 must have dropped reference to 1 on the other
CPU. The fput() from the close() in T3 should also add additionally delay
to the reference drop via exit_task_work() when bpf_prog_release() gets
called as well as scheduling bpf_prog_free_deferred().

That said, it makes nevertheless sense to move the BPF prog destruction
generally after RCU grace period to guarantee that such scenario above,
but also others as recently fixed in ceb56070359b ("bpf, perf: delay release
of BPF prog after grace period") with regards to tail calls won't happen.
Integrating bpf_prog_free_deferred() directly into the RCU callback is
not allowed since the invocation might happen from either softirq or
process context, so we're not permitted to block. Reviewing all bpf_prog_put()
invocations from eBPF side (note, cBPF -> eBPF progs don't use this for
their destruction) with call_rcu() look good to me.

Since we don't know whether at the time of attaching the program, we're
already part of a tail call map, we need to use RCU variant. However, due
to this, there won't be severely more stress on the RCU callback queue:
situations with above bpf_prog_get() and bpf_prog_put() combo in practice
normally won't lead to releases, but even if they would, enough effort/
cycles have to be put into loading a BPF program into the kernel already.

Reported-by: Jann Horn <jannh@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
perf/core: Don't leak event in the syscall error path 2018-11-10T15:41:36+00:00 Alexander Shishkin alexander.shishkin@linux.intel.com 2016-03-21T08:02:42+00:00 5796c70e5b1d62016bdc3b678346ffbd433d030a [ Upstream commit 201c2f85bd0bc13b712d9c0b3d11251b182e06ae ] In the error path, event_file not being NULL is used to determine whether the event itself still needs to be free'd, so fix it up to avoid leaking. Reported-by: Leon Yu <chianglungyu@gmail.com> Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vince Weaver <vincent.weaver@maine.edu> Fixes: 130056275ade ("perf: Do not double free") Link: http://lkml.kernel.org/r/87twk06yxp.fsf@ashishki-desk.ger.corp.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 201c2f85bd0bc13b712d9c0b3d11251b182e06ae ]

In the error path, event_file not being NULL is used to determine
whether the event itself still needs to be free'd, so fix it up to
avoid leaking.

Reported-by: Leon Yu <chianglungyu@gmail.com>
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Fixes: 130056275ade ("perf: Do not double free")
Link: http://lkml.kernel.org/r/87twk06yxp.fsf@ashishki-desk.ger.corp.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
perf/ring_buffer: Prevent concurent ring buffer access 2018-11-10T15:41:34+00:00 Jiri Olsa jolsa@redhat.com 2018-09-23T16:13:43+00:00 4f0336a8a0084e3bbddf71af87869aa9c612669a [ Upstream commit cd6fb677ce7e460c25bdd66f689734102ec7d642 ] Some of the scheduling tracepoints allow the perf_tp_event code to write to ring buffer under different cpu than the code is running on. This results in corrupted ring buffer data demonstrated in following perf commands: # perf record -e 'sched:sched_switch,sched:sched_wakeup' perf bench sched messaging # Running 'sched/messaging' benchmark: # 20 sender and receiver processes per group # 10 groups == 400 processes run Total time: 0.383 [sec] [ perf record: Woken up 8 times to write data ] 0x42b890 [0]: failed to process type: -1765585640 [ perf record: Captured and wrote 4.825 MB perf.data (29669 samples) ] # perf report --stdio 0x42b890 [0]: failed to process type: -1765585640 The reason for the corruption are some of the scheduling tracepoints, that have __perf_task dfined and thus allow to store data to another cpu ring buffer: sched_waking sched_wakeup sched_wakeup_new sched_stat_wait sched_stat_sleep sched_stat_iowait sched_stat_blocked The perf_tp_event function first store samples for current cpu related events defined for tracepoint: hlist_for_each_entry_rcu(event, head, hlist_entry) perf_swevent_event(event, count, &data, regs); And then iterates events of the 'task' and store the sample for any task's event that passes tracepoint checks: ctx = rcu_dereference(task->perf_event_ctxp[perf_sw_context]); list_for_each_entry_rcu(event, &ctx->event_list, event_entry) { if (event->attr.type != PERF_TYPE_TRACEPOINT) continue; if (event->attr.config != entry->type) continue; perf_swevent_event(event, count, &data, regs); } Above code can race with same code running on another cpu, ending up with 2 cpus trying to store under the same ring buffer, which is specifically not allowed. This patch prevents the problem, by allowing only events with the same current cpu to receive the event. NOTE: this requires the use of (per-task-)per-cpu buffers for this feature to work; perf-record does this. Signed-off-by: Jiri Olsa <jolsa@kernel.org> [peterz: small edits to Changelog] Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Andrew Vagin <avagin@openvz.org> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vince Weaver <vincent.weaver@maine.edu> Fixes: e6dab5ffab59 ("perf/trace: Add ability to set a target task for events") Link: http://lkml.kernel.org/r/20180923161343.GB15054@krava Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit cd6fb677ce7e460c25bdd66f689734102ec7d642 ]

Some of the scheduling tracepoints allow the perf_tp_event
code to write to ring buffer under different cpu than the
code is running on.

This results in corrupted ring buffer data demonstrated in
following perf commands:

  # perf record -e 'sched:sched_switch,sched:sched_wakeup' perf bench sched messaging
  # Running 'sched/messaging' benchmark:
  # 20 sender and receiver processes per group
  # 10 groups == 400 processes run

       Total time: 0.383 [sec]
  [ perf record: Woken up 8 times to write data ]
  0x42b890 [0]: failed to process type: -1765585640
  [ perf record: Captured and wrote 4.825 MB perf.data (29669 samples) ]

  # perf report --stdio
  0x42b890 [0]: failed to process type: -1765585640

The reason for the corruption are some of the scheduling tracepoints,
that have __perf_task dfined and thus allow to store data to another
cpu ring buffer:

  sched_waking
  sched_wakeup
  sched_wakeup_new
  sched_stat_wait
  sched_stat_sleep
  sched_stat_iowait
  sched_stat_blocked

The perf_tp_event function first store samples for current cpu
related events defined for tracepoint:

    hlist_for_each_entry_rcu(event, head, hlist_entry)
      perf_swevent_event(event, count, &data, regs);

And then iterates events of the 'task' and store the sample
for any task's event that passes tracepoint checks:

  ctx = rcu_dereference(task->perf_event_ctxp[perf_sw_context]);

  list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
    if (event->attr.type != PERF_TYPE_TRACEPOINT)
      continue;
    if (event->attr.config != entry->type)
      continue;

    perf_swevent_event(event, count, &data, regs);
  }

Above code can race with same code running on another cpu,
ending up with 2 cpus trying to store under the same ring
buffer, which is specifically not allowed.

This patch prevents the problem, by allowing only events with the same
current cpu to receive the event.

NOTE: this requires the use of (per-task-)per-cpu buffers for this
feature to work; perf-record does this.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
[peterz: small edits to Changelog]
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andrew Vagin <avagin@openvz.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Fixes: e6dab5ffab59 ("perf/trace: Add ability to set a target task for events")
Link: http://lkml.kernel.org/r/20180923161343.GB15054@krava
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
perf/core: Fix perf_output_read_group() 2018-05-30T05:49:12+00:00 Peter Zijlstra peterz@infradead.org 2018-03-09T11:52:04+00:00 9a1dcfb8ff30b3afe121d11606ed332cd1536c16 [ Upstream commit 9e5b127d6f33468143d90c8a45ca12410e4c3fa7 ] Mark reported his arm64 perf fuzzer runs sometimes splat like: armv8pmu_read_counter+0x1e8/0x2d8 armpmu_event_update+0x8c/0x188 armpmu_read+0xc/0x18 perf_output_read+0x550/0x11e8 perf_event_read_event+0x1d0/0x248 perf_event_exit_task+0x468/0xbb8 do_exit+0x690/0x1310 do_group_exit+0xd0/0x2b0 get_signal+0x2e8/0x17a8 do_signal+0x144/0x4f8 do_notify_resume+0x148/0x1e8 work_pending+0x8/0x14 which asserts that we only call pmu::read() on ACTIVE events. The above callchain does: perf_event_exit_task() perf_event_exit_task_context() task_ctx_sched_out() // INACTIVE perf_event_exit_event() perf_event_set_state(EXIT) // EXIT sync_child_event() perf_event_read_event() perf_output_read() perf_output_read_group() leader->pmu->read() Which results in doing a pmu::read() on an !ACTIVE event. I _think_ this is 'new' since we added attr.inherit_stat, which added the perf_event_read_event() to the exit path, without that perf_event_read_output() would only trigger from samples and for @event to trigger a sample, it's leader _must_ be ACTIVE too. Still, adding this check makes it consistent with the @sub case for the siblings. Reported-and-Tested-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Stephane Eranian <eranian@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vince Weaver <vincent.weaver@maine.edu> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Sasha Levin <alexander.levin@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
[ Upstream commit 9e5b127d6f33468143d90c8a45ca12410e4c3fa7 ]

Mark reported his arm64 perf fuzzer runs sometimes splat like:

  armv8pmu_read_counter+0x1e8/0x2d8
  armpmu_event_update+0x8c/0x188
  armpmu_read+0xc/0x18
  perf_output_read+0x550/0x11e8
  perf_event_read_event+0x1d0/0x248
  perf_event_exit_task+0x468/0xbb8
  do_exit+0x690/0x1310
  do_group_exit+0xd0/0x2b0
  get_signal+0x2e8/0x17a8
  do_signal+0x144/0x4f8
  do_notify_resume+0x148/0x1e8
  work_pending+0x8/0x14

which asserts that we only call pmu::read() on ACTIVE events.

The above callchain does:

  perf_event_exit_task()
    perf_event_exit_task_context()
      task_ctx_sched_out() // INACTIVE
      perf_event_exit_event()
        perf_event_set_state(EXIT) // EXIT
        sync_child_event()
          perf_event_read_event()
            perf_output_read()
              perf_output_read_group()
                leader->pmu->read()

Which results in doing a pmu::read() on an !ACTIVE event.

I _think_ this is 'new' since we added attr.inherit_stat, which added
the perf_event_read_event() to the exit path, without that
perf_event_read_output() would only trigger from samples and for
@event to trigger a sample, it's leader _must_ be ACTIVE too.

Still, adding this check makes it consistent with the @sub case for
the siblings.

Reported-and-Tested-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
perf/cgroup: Fix child event counting bug 2018-05-30T05:49:05+00:00 Song Liu songliubraving@fb.com 2018-03-12T16:59:43+00:00 14fd6ba8248b82c4bf3efa960bbf15a85b09cce0 [ Upstream commit c917e0f259908e75bd2a65877e25f9d90c22c848 ] When a perf_event is attached to parent cgroup, it should count events for all children cgroups: parent_group <---- perf_event \ - child_group <---- process(es) However, in our tests, we found this perf_event cannot report reliable results. Here is an example case: # create cgroups mkdir -p /sys/fs/cgroup/p/c # start perf for parent group perf stat -e instructions -G "p" # on another console, run test process in child cgroup: stressapptest -s 2 -M 1000 & echo $! > /sys/fs/cgroup/p/c/cgroup.procs # after the test process is done, stop perf in the first console shows <not counted> instructions p The instruction should not be "not counted" as the process runs in the child cgroup. We found this is because perf_event->cgrp and cpuctx->cgrp are not identical, thus perf_event->cgrp are not updated properly. This patch fixes this by updating perf_cgroup properly for ancestor cgroup(s). Reported-by: Ephraim Park <ephiepark@fb.com> Signed-off-by: Song Liu <songliubraving@fb.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: <jolsa@redhat.com> Cc: <kernel-team@fb.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vince Weaver <vincent.weaver@maine.edu> Link: http://lkml.kernel.org/r/20180312165943.1057894-1-songliubraving@fb.com Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Sasha Levin <alexander.levin@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
[ Upstream commit c917e0f259908e75bd2a65877e25f9d90c22c848 ]

When a perf_event is attached to parent cgroup, it should count events
for all children cgroups:

   parent_group   <---- perf_event
     \
      - child_group  <---- process(es)

However, in our tests, we found this perf_event cannot report reliable
results. Here is an example case:

  # create cgroups
  mkdir -p /sys/fs/cgroup/p/c
  # start perf for parent group
  perf stat -e instructions -G "p"

  # on another console, run test process in child cgroup:
  stressapptest -s 2 -M 1000 & echo $! > /sys/fs/cgroup/p/c/cgroup.procs

  # after the test process is done, stop perf in the first console shows

       <not counted>      instructions              p

The instruction should not be "not counted" as the process runs in the
child cgroup.

We found this is because perf_event->cgrp and cpuctx->cgrp are not
identical, thus perf_event->cgrp are not updated properly.

This patch fixes this by updating perf_cgroup properly for ancestor
cgroup(s).

Reported-by: Ephraim Park <ephiepark@fb.com>
Signed-off-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: <jolsa@redhat.com>
Cc: <kernel-team@fb.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Link: http://lkml.kernel.org/r/20180312165943.1057894-1-songliubraving@fb.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
perf/core: Fix possible Spectre-v1 indexing for ->aux_pages[] 2018-05-16T08:06:52+00:00 Peter Zijlstra peterz@infradead.org 2018-04-20T12:03:18+00:00 f21e5918a98369190d4e167b011a5e9a62e9f2ad commit 4411ec1d1993e8dbff2898390e3fed280d88e446 upstream. > kernel/events/ring_buffer.c:871 perf_mmap_to_page() warn: potential spectre issue 'rb->aux_pages' Userspace controls @pgoff through the fault address. Sanitize the array index before doing the array dereference. Reported-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: <stable@kernel.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vince Weaver <vincent.weaver@maine.edu> Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 4411ec1d1993e8dbff2898390e3fed280d88e446 upstream.

> kernel/events/ring_buffer.c:871 perf_mmap_to_page() warn: potential spectre issue 'rb->aux_pages'

Userspace controls @pgoff through the fault address. Sanitize the
array index before doing the array dereference.

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: <stable@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
perf: Remove superfluous allocation error check 2018-05-16T08:06:50+00:00 Jiri Olsa jolsa@kernel.org 2018-04-15T09:23:52+00:00 f17aafae9e4ba6df607f895bb09ae08ba3270fb1 commit bfb3d7b8b906b66551424d7636182126e1d134c8 upstream. If the get_callchain_buffers fails to allocate the buffer it will decrease the nr_callchain_events right away. There's no point of checking the allocation error for nr_callchain_events > 1. Removing that check. Signed-off-by: Jiri Olsa <jolsa@kernel.org> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: syzkaller-bugs@googlegroups.com Cc: x86@kernel.org Link: http://lkml.kernel.org/r/20180415092352.12403-3-jolsa@kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit bfb3d7b8b906b66551424d7636182126e1d134c8 upstream.

If the get_callchain_buffers fails to allocate the buffer it will
decrease the nr_callchain_events right away.

There's no point of checking the allocation error for
nr_callchain_events > 1. Removing that check.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: syzkaller-bugs@googlegroups.com
Cc: x86@kernel.org
Link: http://lkml.kernel.org/r/20180415092352.12403-3-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
perf/core: Fix the perf_cpu_time_max_percent check 2018-05-16T08:06:45+00:00 Tan Xiaojun tanxiaojun@huawei.com 2017-02-23T06:04:39+00:00 609124d60341bf8870318c201cec50548824f2e2 commit 1572e45a924f254d9570093abde46430c3172e3d upstream. Use "proc_dointvec_minmax" instead of "proc_dointvec" to check the input value from user-space. If not, we can set a big value and some vars will overflow like "sysctl_perf_event_sample_rate" which will cause a lot of unexpected problems. Signed-off-by: Tan Xiaojun <tanxiaojun@huawei.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: <acme@kernel.org> Cc: <alexander.shishkin@linux.intel.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vince Weaver <vincent.weaver@maine.edu> Link: http://lkml.kernel.org/r/1487829879-56237-1-git-send-email-tanxiaojun@huawei.com Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 1572e45a924f254d9570093abde46430c3172e3d upstream.

Use "proc_dointvec_minmax" instead of "proc_dointvec" to check the input
value from user-space.

If not, we can set a big value and some vars will overflow like
"sysctl_perf_event_sample_rate" which will cause a lot of unexpected
problems.

Signed-off-by: Tan Xiaojun <tanxiaojun@huawei.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: <acme@kernel.org>
Cc: <alexander.shishkin@linux.intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Link: http://lkml.kernel.org/r/1487829879-56237-1-git-send-email-tanxiaojun@huawei.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
perf: Return proper values for user stack errors 2018-04-29T05:50:01+00:00 Jiri Olsa jolsa@kernel.org 2018-04-15T09:23:50+00:00 585af47e21ba3c2ac1f7a20fff17744b51af884f commit 78b562fbfa2cf0a9fcb23c3154756b690f4905c1 upstream. Return immediately when we find issue in the user stack checks. The error value could get overwritten by following check for PERF_SAMPLE_REGS_INTR. Signed-off-by: Jiri Olsa <jolsa@kernel.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: syzkaller-bugs@googlegroups.com Cc: x86@kernel.org Fixes: 60e2364e60e8 ("perf: Add ability to sample machine state on interrupt") Link: http://lkml.kernel.org/r/20180415092352.12403-1-jolsa@kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 78b562fbfa2cf0a9fcb23c3154756b690f4905c1 upstream.

Return immediately when we find issue in the user stack checks. The
error value could get overwritten by following check for
PERF_SAMPLE_REGS_INTR.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: syzkaller-bugs@googlegroups.com
Cc: x86@kernel.org
Fixes: 60e2364e60e8 ("perf: Add ability to sample machine state on interrupt")
Link: http://lkml.kernel.org/r/20180415092352.12403-1-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
perf/core: Correct event creation with PERF_FORMAT_GROUP 2018-04-13T17:50:19+00:00 Peter Zijlstra peterz@infradead.org 2017-05-30T09:45:12+00:00 a8dd3dfefcf5d0213e28e22ce7863d0dc17f2eb9 [ Upstream commit ba5213ae6b88fb170c4771fef6553f759c7d8cdd ] Andi was asking about PERF_FORMAT_GROUP vs inherited events, which led to the discovery of a bug from commit: 3dab77fb1bf8 ("perf: Rework/fix the whole read vs group stuff") - PERF_SAMPLE_GROUP = 1U << 4, + PERF_SAMPLE_READ = 1U << 4, - if (attr->inherit && (attr->sample_type & PERF_SAMPLE_GROUP)) + if (attr->inherit && (attr->read_format & PERF_FORMAT_GROUP)) is a clear fail :/ While this changes user visible behaviour; it was previously possible to create an inherited event with PERF_SAMPLE_READ; this is deemed acceptible because its results were always incorrect. Reported-by: Andi Kleen <ak@linux.intel.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vince Weaver <vince@deater.net> Fixes: 3dab77fb1bf8 ("perf: Rework/fix the whole read vs group stuff") Link: http://lkml.kernel.org/r/20170530094512.dy2nljns2uq7qa3j@hirez.programming.kicks-ass.net Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Sasha Levin <alexander.levin@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
[ Upstream commit ba5213ae6b88fb170c4771fef6553f759c7d8cdd ]

Andi was asking about PERF_FORMAT_GROUP vs inherited events, which led
to the discovery of a bug from commit:

  3dab77fb1bf8 ("perf: Rework/fix the whole read vs group stuff")

 -       PERF_SAMPLE_GROUP                       = 1U << 4,
 +       PERF_SAMPLE_READ                        = 1U << 4,

 -       if (attr->inherit && (attr->sample_type & PERF_SAMPLE_GROUP))
 +       if (attr->inherit && (attr->read_format & PERF_FORMAT_GROUP))

is a clear fail :/

While this changes user visible behaviour; it was previously possible
to create an inherited event with PERF_SAMPLE_READ; this is deemed
acceptible because its results were always incorrect.

Reported-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vince@deater.net>
Fixes:  3dab77fb1bf8 ("perf: Rework/fix the whole read vs group stuff")
Link: http://lkml.kernel.org/r/20170530094512.dy2nljns2uq7qa3j@hirez.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>