Yang Jihong 1d1bfe30da perf/core: Fix perf_sample_data not properly initialized for different swevents in perf_tp_event() ... data->sample_flags may be modified in perf_prepare_sample(), in perf_tp_event(), different swevents use the same on-stack perf_sample_data, the previous swevent may change sample_flags in perf_prepare_sample(), as a result, some members of perf_sample_data are not correctly initialized when next swevent_event preparing sample (for example data->id, the value varies according to swevent). A simple scenario triggers this problem is as follows: # perf record -e sched:sched_switch --switch-output-event sched:sched_switch -a sleep 1 [ perf record: dump data: Woken up 0 times ] [ perf record: Dump perf.data.2023041209014396 ] [ perf record: dump data: Woken up 0 times ] [ perf record: Dump perf.data.2023041209014662 ] [ perf record: dump data: Woken up 0 times ] [ perf record: Dump perf.data.2023041209014910 ] [ perf record: Woken up 0 times to write data ] [ perf record: Dump perf.data.2023041209015164 ] [ perf record: Captured and wrote 0.069 MB perf.data.<timestamp> ] # ls -l total 860 -rw------- 1 root root 95694 Apr 12 09:01 perf.data.2023041209014396 -rw------- 1 root root 606430 Apr 12 09:01 perf.data.2023041209014662 -rw------- 1 root root 82246 Apr 12 09:01 perf.data.2023041209014910 -rw------- 1 root root 82342 Apr 12 09:01 perf.data.2023041209015164 # perf script -i perf.data.2023041209014396 0x11d58 [0x80]: failed to process type: 9 [Bad address] Solution: Re-initialize perf_sample_data after each event is processed. Note that data->raw->frag.data may be accessed in perf_tp_event_match(). Therefore, need to init sample_data and then go through swevent hlist to prevent reference of NULL pointer, reported by [1]. After fix: # perf record -e sched:sched_switch --switch-output-event sched:sched_switch -a sleep 1 [ perf record: dump data: Woken up 0 times ] [ perf record: Dump perf.data.2023041209442259 ] [ perf record: dump data: Woken up 0 times ] [ perf record: Dump perf.data.2023041209442514 ] [ perf record: dump data: Woken up 0 times ] [ perf record: Dump perf.data.2023041209442760 ] [ perf record: Woken up 0 times to write data ] [ perf record: Dump perf.data.2023041209443003 ] [ perf record: Captured and wrote 0.069 MB perf.data.<timestamp> ] # ls -l total 864 -rw------- 1 root root 100166 Apr 12 09:44 perf.data.2023041209442259 -rw------- 1 root root 606438 Apr 12 09:44 perf.data.2023041209442514 -rw------- 1 root root 82246 Apr 12 09:44 perf.data.2023041209442760 -rw------- 1 root root 82342 Apr 12 09:44 perf.data.2023041209443003 # perf script -i perf.data.2023041209442259 | head -n 5 perf 232 [000] 66.846217: sched:sched_switch: prev_comm=perf prev_pid=232 prev_prio=120 prev_state=D ==> next_comm=perf next_pid=234 next_prio=120 perf 234 [000] 66.846449: sched:sched_switch: prev_comm=perf prev_pid=234 prev_prio=120 prev_state=S ==> next_comm=perf next_pid=232 next_prio=120 perf 232 [000] 66.846546: sched:sched_switch: prev_comm=perf prev_pid=232 prev_prio=120 prev_state=R ==> next_comm=perf next_pid=234 next_prio=120 perf 234 [000] 66.846606: sched:sched_switch: prev_comm=perf prev_pid=234 prev_prio=120 prev_state=S ==> next_comm=perf next_pid=232 next_prio=120 perf 232 [000] 66.846646: sched:sched_switch: prev_comm=perf prev_pid=232 prev_prio=120 prev_state=R ==> next_comm=perf next_pid=234 next_prio=120 [1] Link: https://lore.kernel.org/oe-lkp/202304250929.efef2caa-yujie.liu@intel.com Fixes: bb447c27a4 ("perf/core: Set data->sample_flags in perf_prepare_sample()") Signed-off-by: Yang Jihong <yangjihong1@huawei.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20230425103217.130600-1-yangjihong1@huawei.com		2023-05-08 10:58:26 +02:00
..
callchain.c	uaccess: remove CONFIG_SET_FS	2022-02-25 09:36:06 +01:00
core.c	perf/core: Fix perf_sample_data not properly initialized for different swevents in perf_tp_event()	2023-05-08 10:58:26 +02:00
hw_breakpoint_test.c	perf/hw_breakpoint: remove MODULE_LICENSE in non-modules	2023-04-13 13:13:52 -07:00
hw_breakpoint.c	perf/hw_breakpoint: Annotate tsk->perf_event_mutex vs ctx->mutex	2022-10-04 13:32:09 +02:00
internal.h	perf/core: Fix perf_mmap fail when CONFIG_PERF_USE_VMALLOC enabled	2022-04-19 21:15:42 +02:00
Makefile	perf/hw_breakpoint: Add KUnit test for constraints accounting	2022-08-30 10:56:20 +02:00
ring_buffer.c	mm, treewide: redefine MAX_ORDER sanely	2023-04-05 19:42:46 -07:00
uprobes.c	mm/mmap: remove __vma_adjust()	2023-02-09 16:51:38 -08:00