KCSAN: data-race in __se_sys_perf_event_open / find_get

KCSAN: data-race in __se_sys_perf_event_open / find_get_context
Status: moderation: reported on 2021/05/27 11:10
Reported-by: syzbot+c611b5beb8dec04ff9b2@syzkaller.appspotmail.com
Fix commit: 6c605f837115 perf: Fix data race between pin_count increment/decrement
Patched on: [ci-qemu-upstream ci-qemu-upstream-386 ci-qemu2-arm64 ci-qemu2-arm64-compat ci-qemu2-arm64-mte ci-qemu2-riscv64 ci-upstream-bpf-kasan-gce ci-upstream-bpf-next-kasan-gce ci-upstream-gce-leak ci-upstream-kasan-gce ci-upstream-kasan-gce-386 ci-upstream-kasan-gce-root ci-upstream-kasan-gce-selinux-root ci-upstream-kasan-gce-smack-root ci-upstream-kmsan-gce ci-upstream-kmsan-gce-386 ci-upstream-linux-next-kasan-gce-root ci-upstream-net-kasan-gce ci-upstream-net-this-kasan-gce ci2-upstream-kcsan-gce ci2-upstream-usb], missing on: [ci-qemu2-arm32]
First crash: 85d, last: 45d

Sample crash report:

==================================================================
BUG: KCSAN: data-race in __se_sys_perf_event_open / find_get_context

write to 0xffff888237c2d520 of 4 bytes by task 4144 on cpu 0:
 find_get_context+0x310/0x5c0 kernel/events/core.c:4612
 __do_sys_perf_event_open kernel/events/core.c:12085 [inline]
 __se_sys_perf_event_open+0x85e/0x2740 kernel/events/core.c:11921
 __x64_sys_perf_event_open+0x63/0x70 kernel/events/core.c:11921
 do_syscall_64+0x4a/0x90 arch/x86/entry/common.c:47
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff888237c2d520 of 4 bytes by task 4145 on cpu 1:
 perf_unpin_context kernel/events/core.c:1520 [inline]
 __do_sys_perf_event_open kernel/events/core.c:12316 [inline]
 __se_sys_perf_event_open+0x1be2/0x2740 kernel/events/core.c:11921
 __x64_sys_perf_event_open+0x63/0x70 kernel/events/core.c:11921
 do_syscall_64+0x4a/0x90 arch/x86/entry/common.c:47
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x00000001 -> 0x00000002

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 4145 Comm: syz-executor.4 Not tainted 5.13.0-rc5-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================

Crashes (7):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report	VM info	Title
ci2-upstream-kcsan-gce	2021/06/07 23:07	upstream	614124bea77e	b718257f	.config	log	report	info	KCSAN: data-race in __se_sys_perf_event_open / find_get_context
ci2-upstream-kcsan-gce	2021/05/24 18:58	upstream	c4681547bcce	3c7fef33	.config	log	report	info	KCSAN: data-race in __se_sys_perf_event_open / find_get_context
ci2-upstream-kcsan-gce	2021/05/22 11:41	upstream	45af60e7ced0	3c7fef33	.config	log	report	info	KCSAN: data-race in __se_sys_perf_event_open / find_get_context
ci2-upstream-kcsan-gce	2021/05/20 03:55	upstream	c3d0e3fd41b7	a343ba6b	.config	log	report	info	KCSAN: data-race in __se_sys_perf_event_open / find_get_context
ci2-upstream-kcsan-gce	2021/05/15 01:33	upstream	bd3c9cdb21a2	8bdd5343	.config	log	report	info	KCSAN: data-race in __se_sys_perf_event_open / find_get_context
ci2-upstream-kcsan-gce	2021/05/08 16:28	upstream	dd860052c99b	bc5434be	.config	log	report	info	KCSAN: data-race in __se_sys_perf_event_open / find_get_context
ci2-upstream-kcsan-gce	2021/04/29 15:42	upstream	d72cd4ad4174	77e2b668	.config	log	report	info	KCSAN: data-race in __se_sys_perf_event_open / find_get_context