Messages in this thread | | | From | Kaia Yadira <> | Date | Tue, 11 Jan 2022 21:35:47 +0800 | Subject | KCSAN: data-race in tick_nohz_stop_tick / tick_nohz_stop_tick |
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Hello,
When using Syzkaller to fuzz the latest Linux kernel, the following crash was triggered.
HEAD commit: a7904a538933 Linux 5.16-rc6 git tree: upstream console output: KCSAN: data-race in tick_nohz_stop_tick / tick_nohz_stop_tick kernel config: https://paste.ubuntu.com/p/QB39MJKWKb/plain/ Syzlang reproducer: https://paste.ubuntu.com/p/Xtr5t49Jv6/plain/
If you fix this issue, please add the following tag to the commit:
Reported-by: Hypericum <hypericumperforatum4444@gmail.com>
I think there are two threads visit the variable tick_do_timer_cpu without locking.
reproducer log: https://paste.ubuntu.com/p/tXZnXYszKs/plain/ reproducer report: ================================================================== BUG: KCSAN: data-race in tick_nohz_stop_tick / tick_nohz_stop_tick
write to 0xffffffff85ebf1e0 of 4 bytes by task 0 on cpu 7: tick_nohz_stop_tick+0xa5/0x410 kernel/time/tick-sched.c:873 __tick_nohz_idle_stop_tick kernel/time/tick-sched.c:1062 [inline] tick_nohz_idle_stop_tick+0xde/0x1a0 kernel/time/tick-sched.c:1083 cpuidle_idle_call kernel/sched/idle.c:192 [inline] do_idle+0xe3/0x250 kernel/sched/idle.c:306 cpu_startup_entry+0x15/0x20 kernel/sched/idle.c:403 secondary_startup_64_no_verify+0xb1/0xbb
read to 0xffffffff85ebf1e0 of 4 bytes by task 0 on cpu 0: tick_nohz_stop_tick+0x7f/0x410 kernel/time/tick-sched.c:872 __tick_nohz_idle_stop_tick kernel/time/tick-sched.c:1062 [inline] tick_nohz_idle_stop_tick+0xde/0x1a0 kernel/time/tick-sched.c:1083 cpuidle_idle_call kernel/sched/idle.c:192 [inline] do_idle+0xe3/0x250 kernel/sched/idle.c:306 cpu_startup_entry+0x15/0x20 kernel/sched/idle.c:403 rest_init+0xed/0xf0 init/main.c:725 arch_call_rest_init+0xa/0xb start_kernel+0x5de/0x663 init/main.c:1135 secondary_startup_64_no_verify+0xb1/0xbb
value changed: 0x00000007 -> 0xffffffff
Reported by Kernel Concurrency Sanitizer on: CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.16.0-rc8+ #11 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1.1 04/01/2014 ==================================================================
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