syzbot

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BUG: KCSAN: data-race in event_sched_out / perf_mmap

read to 0xffff8881524194c8 of 8 bytes by task 28507 on cpu 0:
 __perf_update_times kernel/events/core.c:632 [inline]
 perf_event_update_time kernel/events/core.c:647 [inline]
 perf_event_set_state kernel/events/core.c:666 [inline]
 event_sched_out+0x2be/0x830 kernel/events/core.c:2364
 group_sched_out+0xf0/0x1f0 kernel/events/core.c:2390
 ctx_sched_out+0x3ab/0x470 kernel/events/core.c:3332
 task_ctx_sched_out kernel/events/core.c:2725 [inline]
 perf_event_context_sched_out kernel/events/core.c:3537 [inline]
 __perf_event_task_sched_out+0x679/0xf10 kernel/events/core.c:3640
 perf_event_task_sched_out include/linux/perf_event.h:1236 [inline]
 prepare_task_switch+0x13b/0x140 kernel/sched/core.c:4796
 context_switch kernel/sched/core.c:4938 [inline]
 __schedule+0x387/0x690 kernel/sched/core.c:6295
 schedule+0x81/0xb0 kernel/sched/core.c:6368
 rwsem_down_read_slowpath kernel/locking/rwsem.c:1032 [inline]
 __down_read_common+0x2f5/0x4b0 kernel/locking/rwsem.c:1214
 __down_read kernel/locking/rwsem.c:1223 [inline]
 down_read+0x16/0x20 kernel/locking/rwsem.c:1463
 mmap_read_lock include/linux/mmap_lock.h:117 [inline]
 __mm_populate+0xff/0x370 mm/gup.c:1586
 mm_populate include/linux/mm.h:2695 [inline]
 vm_mmap_pgoff+0x160/0x1f0 mm/util.c:524
 ksys_mmap_pgoff+0x265/0x320 mm/mmap.c:1630
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

write to 0xffff8881524194c8 of 8 bytes by task 28518 on cpu 1:
 perf_event_update_time kernel/events/core.c:649 [inline]
 perf_mmap+0xbfa/0xe50 kernel/events/core.c:6402
 call_mmap include/linux/fs.h:2079 [inline]
 mmap_region+0xb04/0x10b0 mm/mmap.c:1793
 do_mmap+0x781/0xc20 mm/mmap.c:1582
 vm_mmap_pgoff+0x117/0x1f0 mm/util.c:519
 ksys_mmap_pgoff+0x265/0x320 mm/mmap.c:1630
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x0000000002265c29 -> 0x00000000022972b9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 28518 Comm: syz-executor.5 Not tainted 5.17.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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