linux.git/kernel/events, branch v6.1.1

Merge tag 'perf_urgent_for_v6.1_rc8' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2022-12-04T20:36:23+00:00

Pull perf fix from Borislav Petkov:

 - Fix a use-after-free case where the perf pending task callback would
   see an already freed event

* tag 'perf_urgent_for_v6.1_rc8' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf: Fix perf_pending_task() UaF

Merge tag 'net-6.1-rc8-2' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net

2022-11-29T17:52:10+00:00

Pull networking fixes from Jakub Kicinski:
 "Including fixes from bpf, can and wifi.

  Current release - new code bugs:

   - eth: mlx5e:
      - use kvfree() in mlx5e_accel_fs_tcp_create()
      - MACsec, fix RX data path 16 RX security channel limit
      - MACsec, fix memory leak when MACsec device is deleted
      - MACsec, fix update Rx secure channel active field
      - MACsec, fix add Rx security association (SA) rule memory leak

  Previous releases - regressions:

   - wifi: cfg80211: don't allow multi-BSSID in S1G

   - stmmac: set MAC's flow control register to reflect current settings

   - eth: mlx5:
      - E-switch, fix duplicate lag creation
      - fix use-after-free when reverting termination table

  Previous releases - always broken:

   - ipv4: fix route deletion when nexthop info is not specified

   - bpf: fix a local storage BPF map bug where the value's spin lock
     field can get initialized incorrectly

   - tipc: re-fetch skb cb after tipc_msg_validate

   - wifi: wilc1000: fix Information Element parsing

   - packet: do not set TP_STATUS_CSUM_VALID on CHECKSUM_COMPLETE

   - sctp: fix memory leak in sctp_stream_outq_migrate()

   - can: can327: fix potential skb leak when netdev is down

   - can: add number of missing netdev freeing on error paths

   - aquantia: do not purge addresses when setting the number of rings

   - wwan: iosm:
      - fix incorrect skb length leading to truncated packet
      - fix crash in peek throughput test due to skb UAF"

* tag 'net-6.1-rc8-2' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (79 commits)
  net: ethernet: renesas: ravb: Fix promiscuous mode after system resumed
  MAINTAINERS: Update maintainer list for chelsio drivers
  ionic: update MAINTAINERS entry
  sctp: fix memory leak in sctp_stream_outq_migrate()
  packet: do not set TP_STATUS_CSUM_VALID on CHECKSUM_COMPLETE
  net/mlx5: Lag, Fix for loop when checking lag
  Revert "net/mlx5e: MACsec, remove replay window size limitation in offload path"
  net: marvell: prestera: Fix a NULL vs IS_ERR() check in some functions
  net: tun: Fix use-after-free in tun_detach()
  net: mdiobus: fix unbalanced node reference count
  net: hsr: Fix potential use-after-free
  tipc: re-fetch skb cb after tipc_msg_validate
  mptcp: fix sleep in atomic at close time
  mptcp: don't orphan ssk in mptcp_close()
  dsa: lan9303: Correct stat name
  ipv4: Fix route deletion when nexthop info is not specified
  net: wwan: iosm: fix incorrect skb length
  net: wwan: iosm: fix crash in peek throughput test
  net: wwan: iosm: fix dma_alloc_coherent incompatible pointer type
  net: wwan: iosm: fix kernel test robot reported error
  ...

perf: Fix perf_pending_task() UaF

2022-11-29T16:42:49+00:00

Per syzbot it is possible for perf_pending_task() to run after the
event is free()'d. There are two related but distinct cases:

 - the task_work was already queued before destroying the event;
 - destroying the event itself queues the task_work.

The first cannot be solved using task_work_cancel() since
perf_release() itself might be called from a task_work (____fput),
which means the current->task_works list is already empty and
task_work_cancel() won't be able to find the perf_pending_task()
entry.

The simplest alternative is extending the perf_event lifetime to cover
the task_work.

The second is just silly, queueing a task_work while you know the
event is going away makes no sense and is easily avoided by
re-arranging how the event is marked STATE_DEAD and ensuring it goes
through STATE_OFF on the way down.

Reported-by: syzbot+9228d6098455bb209ec8@syzkaller.appspotmail.com
Signed-off-by: Peter Zijlstra (Intel) 
Tested-by: Marco Elver

perf: Consider OS filter fail

2022-11-24T09:12:23+00:00

Some PMUs (notably the traditional hardware kind) have boundary issues
with the OS filter. Specifically, it is possible for
perf_event_attr::exclude_kernel=1 events to trigger in-kernel due to
SKID or errata.

This can upset the sigtrap logic some and trigger the WARN.

However, if this invalid sample is the first we must not loose the
SIGTRAP, OTOH if it is the second, it must not override the
pending_addr with a (possibly) invalid one.

Fixes: ca6c21327c6a ("perf: Fix missing SIGTRAPs")
Reported-by: Pengfei Xu 
Signed-off-by: Peter Zijlstra (Intel) 
Reviewed-by: Marco Elver 
Tested-by: Pengfei Xu 
Link: https://lkml.kernel.org/r/Y3hDYiXwRnJr8RYG@xpf.sh.intel.com

perf: Fixup SIGTRAP and sample_flags interaction

2022-11-24T09:12:23+00:00

The perf_event_attr::sigtrap functionality relies on data->addr being
set. However commit 7b0846301531 ("perf: Use sample_flags for addr")
changed this to only initialize data->addr when not 0.

Fixes: 7b0846301531 ("perf: Use sample_flags for addr")
Signed-off-by: Peter Zijlstra (Intel) 
Link: https://lkml.kernel.org/r/Y3426b4OimE%2FI5po%40hirez.programming.kicks-ass.net

bpf, perf: Use subprog name when reporting subprog ksymbol

2022-11-15T14:36:57+00:00

Since commit bfea9a8574f3 ("bpf: Add name to struct bpf_ksym"), when
reporting subprog ksymbol to perf, prog name instead of subprog name is
used. The backtrace of bpf program with subprogs will be incorrect as
shown below:

  ffffffffc02deace bpf_prog_e44a3057dcb151f8_overwrite+0x66
  ffffffffc02de9f7 bpf_prog_e44a3057dcb151f8_overwrite+0x9f
  ffffffffa71d8d4e trace_call_bpf+0xce
  ffffffffa71c2938 perf_call_bpf_enter.isra.0+0x48

overwrite is the entry program and it invokes the overwrite_htab subprog
through bpf_loop, but in above backtrace, overwrite program just jumps
inside itself.

Fixing it by using subprog name when reporting subprog ksymbol. After
the fix, the output of perf script will be correct as shown below:

  ffffffffc031aad2 bpf_prog_37c0bec7d7c764a4_overwrite_htab+0x66
  ffffffffc031a9e7 bpf_prog_c7eb827ef4f23e71_overwrite+0x9f
  ffffffffa3dd8d4e trace_call_bpf+0xce
  ffffffffa3dc2938 perf_call_bpf_enter.isra.0+0x48

Fixes: bfea9a8574f3 ("bpf: Add name to struct bpf_ksym")
Signed-off-by: Hou Tao 
Signed-off-by: Daniel Borkmann 
Acked-by: Jiri Olsa 
Link: https://lore.kernel.org/bpf/20221114095733.158588-1-houtao@huaweicloud.com

perf: Improve missing SIGTRAP checking

2022-11-08T09:39:27+00:00

To catch missing SIGTRAP we employ a WARN in __perf_event_overflow(),
which fires if pending_sigtrap was already set: returning to user space
without consuming pending_sigtrap, and then having the event fire again
would re-enter the kernel and trigger the WARN.

This, however, seemed to miss the case where some events not associated
with progress in the user space task can fire and the interrupt handler
runs before the IRQ work meant to consume pending_sigtrap (and generate
the SIGTRAP).

syzbot gifted us this stack trace:

 | WARNING: CPU: 0 PID: 3607 at kernel/events/core.c:9313 __perf_event_overflow
 | Modules linked in:
 | CPU: 0 PID: 3607 Comm: syz-executor100 Not tainted 6.1.0-rc2-syzkaller-00073-g88619e77b33d #0
 | Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/11/2022
 | RIP: 0010:__perf_event_overflow+0x498/0x540 kernel/events/core.c:9313
 | <...>
 | Call Trace:
 |  
 |  perf_swevent_hrtimer+0x34f/0x3c0 kernel/events/core.c:10729
 |  __run_hrtimer kernel/time/hrtimer.c:1685 [inline]
 |  __hrtimer_run_queues+0x1c6/0xfb0 kernel/time/hrtimer.c:1749
 |  hrtimer_interrupt+0x31c/0x790 kernel/time/hrtimer.c:1811
 |  local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1096 [inline]
 |  __sysvec_apic_timer_interrupt+0x17c/0x640 arch/x86/kernel/apic/apic.c:1113
 |  sysvec_apic_timer_interrupt+0x40/0xc0 arch/x86/kernel/apic/apic.c:1107
 |  asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:649
 | <...>
 |  

In this case, syzbot produced a program with event type
PERF_TYPE_SOFTWARE and config PERF_COUNT_SW_CPU_CLOCK. The hrtimer
manages to fire again before the IRQ work got a chance to run, all while
never having returned to user space.

Improve the WARN to check for real progress in user space: approximate
this by storing a 32-bit hash of the current IP into pending_sigtrap,
and if an event fires while pending_sigtrap still matches the previous
IP, we assume no progress (false negatives are possible given we could
return to user space and trigger again on the same IP).

Fixes: ca6c21327c6a ("perf: Fix missing SIGTRAPs")
Reported-by: syzbot+b8ded3e2e2c6adde4990@syzkaller.appspotmail.com
Signed-off-by: Marco Elver 
Signed-off-by: Peter Zijlstra (Intel) 
Link: https://lkml.kernel.org/r/20221031093513.3032814-1-elver@google.com

perf/hw_breakpoint: test: Skip the test if dependencies unmet

2022-11-02T11:22:05+00:00

Running the test currently fails on non-SMP systems, despite being
enabled by default. This means that running the test with:

 ./tools/testing/kunit/kunit.py run --arch x86_64 hw_breakpoint

results in every hw_breakpoint test failing with:

 # test_one_cpu: failed to initialize: -22
 not ok 1 - test_one_cpu

Instead, use kunit_skip(), which will mark the test as skipped, and give
a more comprehensible message:

 ok 1 - test_one_cpu # SKIP not enough cpus

This makes it more obvious that the test is not suited to the test
environment, and so wasn't run, rather than having run and failed.

Signed-off-by: David Gow 
Signed-off-by: Peter Zijlstra (Intel) 
Reviewed-by: Daniel Latypov 
Acked-by: Marco Elver 
Link: https://lore.kernel.org/r/20221026141040.1609203-1-davidgow@google.com

perf: Fix missing raw data on tracepoint events

2022-10-27T08:27:30+00:00

Since commit 838d9bb62d13 ("perf: Use sample_flags for raw_data")
raw data is not being output on tracepoints due to the PERF_SAMPLE_RAW
field not being set. Fix this by setting it for tracepoint events.

This fixes the following test failure:

  perf test "sched_switch" -vvv

   35: Track with sched_switch
  --- start ---
  test child forked, pid 1828
  ...
  Using CPUID 0x00000000410fd400
  sched_switch: cpu: 2 prev_tid -14687 next_tid 0
  sched_switch: cpu: 2 prev_tid -14687 next_tid 0
  Missing sched_switch events
  4613 events recorded
  test child finished with -1
  ---- end ----
  Track with sched_switch: FAILED!

Fixes: 838d9bb62d13 ("perf: Use sample_flags for raw_data")
Signed-off-by: James Clark 
Signed-off-by: Peter Zijlstra (Intel) 
Acked-by: Namhyung Kim 
Tested-by: SeongJae Park 
Tested-by: Athira Rajeev 
Link: https://lore.kernel.org/r/20221012143857.48198-1-james.clark@arm.com

perf: Fix missing SIGTRAPs

2022-10-17T14:32:05+00:00

Marco reported:

Due to the implementation of how SIGTRAP are delivered if
perf_event_attr::sigtrap is set, we've noticed 3 issues:

  1. Missing SIGTRAP due to a race with event_sched_out() (more
     details below).

  2. Hardware PMU events being disabled due to returning 1 from
     perf_event_overflow(). The only way to re-enable the event is
     for user space to first "properly" disable the event and then
     re-enable it.

  3. The inability to automatically disable an event after a
     specified number of overflows via PERF_EVENT_IOC_REFRESH.

The worst of the 3 issues is problem (1), which occurs when a
pending_disable is "consumed" by a racing event_sched_out(), observed
as follows:

		CPU0			|	CPU1
	--------------------------------+---------------------------
	__perf_event_overflow()		|
	 perf_event_disable_inatomic()	|
	  pending_disable = CPU0	| ...
					| _perf_event_enable()
					|  event_function_call()
					|   task_function_call()
					|    /* sends IPI to CPU0 */
					| ...
	 __perf_event_enable()		+---------------------------
	  ctx_resched()
	   task_ctx_sched_out()
	    ctx_sched_out()
	     group_sched_out()
	      event_sched_out()
	       pending_disable = -1
	
	
	 perf_pending_event()
	  perf_pending_event_disable()
	   /* Fails to send SIGTRAP because no pending_disable! */
	

In the above case, not only is that particular SIGTRAP missed, but also
all future SIGTRAPs because 'event_limit' is not reset back to 1.

To fix, rework pending delivery of SIGTRAP via IRQ-work by introduction
of a separate 'pending_sigtrap', no longer using 'event_limit' and
'pending_disable' for its delivery.

Additionally; and different to Marco's proposed patch:

 - recognise that pending_disable effectively duplicates oncpu for
   the case where it is set. As such, change the irq_work handler to
   use ->oncpu to target the event and use pending_* as boolean toggles.

 - observe that SIGTRAP targets the ctx->task, so the context switch
   optimization that carries contexts between tasks is invalid. If
   the irq_work were delayed enough to hit after a context switch the
   SIGTRAP would be delivered to the wrong task.

 - observe that if the event gets scheduled out
   (rotation/migration/context-switch/...) the irq-work would be
   insufficient to deliver the SIGTRAP when the event gets scheduled
   back in (the irq-work might still be pending on the old CPU).

   Therefore have event_sched_out() convert the pending sigtrap into a
   task_work which will deliver the signal at return_to_user.

Fixes: 97ba62b27867 ("perf: Add support for SIGTRAP on perf events")
Reported-by: Dmitry Vyukov 
Debugged-by: Dmitry Vyukov 
Reported-by: Marco Elver 
Debugged-by: Marco Elver 
Signed-off-by: Peter Zijlstra (Intel) 
Reviewed-by: Marco Elver 
Tested-by: Marco Elver