linux-stable.git/kernel/events, branch v5.4.277

perf/core: Fix reentry problem in perf_output_read_group()

2024-04-13T10:51:30+00:00

commit 6b959ba22d34ca793ffdb15b5715457c78e38b1a upstream.

perf_output_read_group may respond to IPI request of other cores and invoke
__perf_install_in_context function. As a result, hwc configuration is modified.
causing inconsistency and unexpected consequences.

Interrupts are not disabled when perf_output_read_group reads PMU counter.
In this case, IPI request may be received from other cores.
As a result, PMU configuration is modified and an error occurs when
reading PMU counter:

		     CPU0                                         CPU1
						      __se_sys_perf_event_open
							perf_install_in_context
  perf_output_read_group                                  smp_call_function_single
    for_each_sibling_event(sub, leader) {                   generic_exec_single
      if ((sub != event) &&                                   remote_function
	  (sub->state == PERF_EVENT_STATE_ACTIVE))                    |
     <----RAISE IPI-----+
  __perf_install_in_context
    ctx_resched
      event_sched_out
	armpmu_del
	  ...
	  hwc->idx = -1; // event->hwc.idx is set to -1
  ...
  
	      sub->pmu->read(sub);
		armpmu_read
		  armv8pmu_read_counter
		    armv8pmu_read_hw_counter
		      int idx = event->hw.idx; // idx = -1
		      u64 val = armv8pmu_read_evcntr(idx);
			u32 counter = ARMV8_IDX_TO_COUNTER(idx); // invalid counter = 30
			read_pmevcntrn(counter) // undefined instruction

Signed-off-by: Yang Jihong 
Signed-off-by: Peter Zijlstra (Intel) 
Link: https://lkml.kernel.org/r/20220902082918.179248-1-yangjihong1@huawei.com
Signed-off-by: Thadeu Lima de Souza Cascardo 
Signed-off-by: Greg Kroah-Hartman

perf: Fix the nr_addr_filters fix

2024-02-23T07:25:03+00:00

[ Upstream commit 388a1fb7da6aaa1970c7e2a7d7fcd983a87a8484 ]

Thomas reported that commit 652ffc2104ec ("perf/core: Fix narrow
startup race when creating the perf nr_addr_filters sysfs file") made
the entire attribute group vanish, instead of only the nr_addr_filters
attribute.

Additionally a stray return.

Insufficient coffee was involved with both writing and merging the
patch.

Fixes: 652ffc2104ec ("perf/core: Fix narrow startup race when creating the perf nr_addr_filters sysfs file")
Reported-by: Thomas Richter 
Signed-off-by: Peter Zijlstra (Intel) 
Tested-by: Thomas Richter 
Link: https://lkml.kernel.org/r/20231122100756.GP8262@noisy.programming.kicks-ass.net
Signed-off-by: Sasha Levin

perf/core: Fix narrow startup race when creating the perf nr_addr_filters sysfs file

2024-02-23T07:24:54+00:00

[ Upstream commit 652ffc2104ec1f69dd4a46313888c33527145ccf ]

Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Peter Zijlstra (Intel) 
Link: https://lkml.kernel.org/r/2023061204-decal-flyable-6090@gregkh
Signed-off-by: Sasha Levin

perf: Fix perf_event_validate_size() lockdep splat

2023-12-20T14:41:23+00:00

commit 7e2c1e4b34f07d9aa8937fab88359d4a0fce468e upstream.

When lockdep is enabled, the for_each_sibling_event(sibling, event)
macro checks that event->ctx->mutex is held. When creating a new group
leader event, we call perf_event_validate_size() on a partially
initialized event where event->ctx is NULL, and so when
for_each_sibling_event() attempts to check event->ctx->mutex, we get a
splat, as reported by Lucas De Marchi:

  WARNING: CPU: 8 PID: 1471 at kernel/events/core.c:1950 __do_sys_perf_event_open+0xf37/0x1080

This only happens for a new event which is its own group_leader, and in
this case there cannot be any sibling events. Thus it's safe to skip the
check for siblings, which avoids having to make invasive and ugly
changes to for_each_sibling_event().

Avoid the splat by bailing out early when the new event is its own
group_leader.

Fixes: 382c27f4ed28f803 ("perf: Fix perf_event_validate_size()")
Closes: https://lore.kernel.org/lkml/20231214000620.3081018-1-lucas.demarchi@intel.com/
Closes: https://lore.kernel.org/lkml/ZXpm6gQ%2Fd59jGsuW@xpf.sh.intel.com/
Reported-by: Lucas De Marchi 
Reported-by: Pengfei Xu 
Signed-off-by: Mark Rutland 
Signed-off-by: Peter Zijlstra (Intel) 
Link: https://lkml.kernel.org/r/20231215112450.3972309-1-mark.rutland@arm.com
Signed-off-by: Greg Kroah-Hartman

perf: Fix perf_event_validate_size()

2023-12-13T17:18:15+00:00

[ Upstream commit 382c27f4ed28f803b1f1473ac2d8db0afc795a1b ]

Budimir noted that perf_event_validate_size() only checks the size of
the newly added event, even though the sizes of all existing events
can also change due to not all events having the same read_format.

When we attach the new event, perf_group_attach(), we do re-compute
the size for all events.

Fixes: a723968c0ed3 ("perf: Fix u16 overflows")
Reported-by: Budimir Markovic 
Signed-off-by: Peter Zijlstra (Intel) 
Signed-off-by: Sasha Levin

perf/core: Add a new read format to get a number of lost samples

2023-12-13T17:18:15+00:00

[ Upstream commit 119a784c81270eb88e573174ed2209225d646656 ]

Sometimes we want to know an accurate number of samples even if it's
lost.  Currenlty PERF_RECORD_LOST is generated for a ring-buffer which
might be shared with other events.  So it's hard to know per-event
lost count.

Add event->lost_samples field and PERF_FORMAT_LOST to retrieve it from
userspace.

Original-patch-by: Jiri Olsa 
Signed-off-by: Namhyung Kim 
Signed-off-by: Peter Zijlstra (Intel) 
Link: https://lkml.kernel.org/r/20220616180623.1358843-1-namhyung@kernel.org
Stable-dep-of: 382c27f4ed28 ("perf: Fix perf_event_validate_size()")
Signed-off-by: Sasha Levin

perf/core: Bail out early if the request AUX area is out of bound

2023-11-28T16:50:13+00:00

[ Upstream commit 54aee5f15b83437f23b2b2469bcf21bdd9823916 ]

When perf-record with a large AUX area, e.g 4GB, it fails with:

    #perf record -C 0 -m ,4G -e arm_spe_0// -- sleep 1
    failed to mmap with 12 (Cannot allocate memory)

and it reveals a WARNING with __alloc_pages():

	------------[ cut here ]------------
	WARNING: CPU: 44 PID: 17573 at mm/page_alloc.c:5568 __alloc_pages+0x1ec/0x248
	Call trace:
	 __alloc_pages+0x1ec/0x248
	 __kmalloc_large_node+0xc0/0x1f8
	 __kmalloc_node+0x134/0x1e8
	 rb_alloc_aux+0xe0/0x298
	 perf_mmap+0x440/0x660
	 mmap_region+0x308/0x8a8
	 do_mmap+0x3c0/0x528
	 vm_mmap_pgoff+0xf4/0x1b8
	 ksys_mmap_pgoff+0x18c/0x218
	 __arm64_sys_mmap+0x38/0x58
	 invoke_syscall+0x50/0x128
	 el0_svc_common.constprop.0+0x58/0x188
	 do_el0_svc+0x34/0x50
	 el0_svc+0x34/0x108
	 el0t_64_sync_handler+0xb8/0xc0
	 el0t_64_sync+0x1a4/0x1a8

'rb->aux_pages' allocated by kcalloc() is a pointer array which is used to
maintains AUX trace pages. The allocated page for this array is physically
contiguous (and virtually contiguous) with an order of 0..MAX_ORDER. If the
size of pointer array crosses the limitation set by MAX_ORDER, it reveals a
WARNING.

So bail out early with -ENOMEM if the request AUX area is out of bound,
e.g.:

    #perf record -C 0 -m ,4G -e arm_spe_0// -- sleep 1
    failed to mmap with 12 (Cannot allocate memory)

Signed-off-by: Shuai Xue 
Signed-off-by: Peter Zijlstra (Intel) 
Signed-off-by: Ingo Molnar 
Signed-off-by: Sasha Levin

perf/core: Fix potential NULL deref

2023-11-08T10:23:37+00:00

commit a71ef31485bb51b846e8db8b3a35e432cc15afb5 upstream.

Smatch is awesome.

Fixes: 32671e3799ca ("perf: Disallow mis-matched inherited group reads")
Reported-by: Dan Carpenter 
Signed-off-by: Peter Zijlstra (Intel) 
Signed-off-by: Ingo Molnar 
Signed-off-by: Greg Kroah-Hartman

perf: Disallow mis-matched inherited group reads

2023-10-25T09:53:24+00:00

commit 32671e3799ca2e4590773fd0e63aaa4229e50c06 upstream.

Because group consistency is non-atomic between parent (filedesc) and children
(inherited) events, it is possible for PERF_FORMAT_GROUP read() to try and sum
non-matching counter groups -- with non-sensical results.

Add group_generation to distinguish the case where a parent group removes and
adds an event and thus has the same number, but a different configuration of
events as inherited groups.

This became a problem when commit fa8c269353d5 ("perf/core: Invert
perf_read_group() loops") flipped the order of child_list and sibling_list.
Previously it would iterate the group (sibling_list) first, and for each
sibling traverse the child_list. In this order, only the group composition of
the parent is relevant. By flipping the order the group composition of the
child (inherited) events becomes an issue and the mis-match in group
composition becomes evident.

That said; even prior to this commit, while reading of a group that is not
equally inherited was not broken, it still made no sense.

(Ab)use ECHILD as error return to indicate issues with child process group
composition.

Fixes: fa8c269353d5 ("perf/core: Invert perf_read_group() loops")
Reported-by: Budimir Markovic 
Signed-off-by: Peter Zijlstra (Intel) 
Link: https://lkml.kernel.org/r/20231018115654.GK33217@noisy.programming.kicks-ass.net
Signed-off-by: Greg Kroah-Hartman

perf: Fix function pointer case

2023-08-11T09:53:54+00:00

commit 1af6239d1d3e61d33fd2f0ba53d3d1a67cc50574 upstream.

With the advent of CFI it is no longer acceptible to cast function
pointers.

The robot complains thusly:

  kernel-events-core.c:warning:cast-from-int-(-)(struct-perf_cpu_pmu_context-)-to-remote_function_f-(aka-int-(-)(void-)-)-converts-to-incompatible-function-type

Reported-by: kernel test robot 
Signed-off-by: Peter Zijlstra (Intel) 
Signed-off-by: Cixi Geng 
Signed-off-by: Greg Kroah-Hartman