================================================================== BUG: KCSAN: data-race in perf_event_update_userpage / perf_event_update_userpage read to 0xffff888123c34008 of 4 bytes by task 24106 on cpu 1: perf_event_update_userpage+0xa4/0x340 kernel/events/core.c:5403 cpu_clock_event_add+0x3d/0x60 kernel/events/core.c:9674 event_sched_in.isra.0.part.0+0x1d5/0x560 kernel/events/core.c:2367 event_sched_in kernel/events/core.c:2339 [inline] group_sched_in+0xd1/0x2c0 kernel/events/core.c:2403 flexible_sched_in kernel/events/core.c:3418 [inline] flexible_sched_in+0x399/0x540 kernel/events/core.c:3407 visit_groups_merge+0x1d9/0x320 kernel/events/core.c:3366 ctx_flexible_sched_in kernel/events/core.c:3455 [inline] ctx_sched_in+0x1b4/0x360 kernel/events/core.c:3500 perf_event_sched_in+0x77/0xb0 kernel/events/core.c:2512 perf_event_context_sched_in kernel/events/core.c:3540 [inline] __perf_event_task_sched_in+0x354/0x390 kernel/events/core.c:3579 perf_event_task_sched_in include/linux/perf_event.h:1150 [inline] finish_task_switch+0x108/0x260 kernel/sched/core.c:3221 context_switch kernel/sched/core.c:3387 [inline] __schedule+0x319/0x640 kernel/sched/core.c:4069 schedule+0x47/0xd0 kernel/sched/core.c:4136 freezable_schedule include/linux/freezer.h:172 [inline] futex_wait_queue_me+0x18d/0x290 kernel/futex.c:2627 futex_wait+0x19b/0x3f0 kernel/futex.c:2733 do_futex+0xe9/0x18d0 kernel/futex.c:3644 __do_sys_futex kernel/futex.c:3705 [inline] __se_sys_futex kernel/futex.c:3673 [inline] __x64_sys_futex+0x2cd/0x3f0 kernel/futex.c:3673 do_syscall_64+0xcc/0x370 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x44/0xa9 write to 0xffff888123c34008 of 4 bytes by task 24102 on cpu 0: perf_event_update_userpage+0x28a/0x340 kernel/events/core.c:5419 perf_mmap+0xe00/0xeb0 kernel/events/core.c:5877 call_mmap include/linux/fs.h:1900 [inline] mmap_region+0x83c/0xd50 mm/mmap.c:1806 do_mmap+0x6d4/0xba0 mm/mmap.c:1577 do_mmap_pgoff include/linux/mm.h:2353 [inline] vm_mmap_pgoff+0x12d/0x190 mm/util.c:496 ksys_mmap_pgoff+0x2d8/0x420 mm/mmap.c:1629 __do_sys_mmap arch/x86/kernel/sys_x86_64.c:100 [inline] __se_sys_mmap arch/x86/kernel/sys_x86_64.c:91 [inline] __x64_sys_mmap+0x91/0xc0 arch/x86/kernel/sys_x86_64.c:91 do_syscall_64+0xcc/0x370 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Reported by Kernel Concurrency Sanitizer on: CPU: 0 PID: 24102 Comm: syz-executor.3 Not tainted 5.4.0-rc6+ #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 ==================================================================