syzbot


KCSAN: data-race in hrtimer_reprogram / print_cpu (12)

Status: moderation: reported on 2024/11/04 15:45
Subsystems: kernel
[Documentation on labels]
Reported-by: syzbot+47ebcf8d96df0c45cad5@syzkaller.appspotmail.com
First crash: 2d09h, last: 2d09h
Similar bugs (11)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in hrtimer_reprogram / print_cpu (11) kernel 6 129d 148d 0/28 auto-obsoleted due to no activity on 2024/08/04 04:55
upstream KCSAN: data-race in hrtimer_reprogram / print_cpu (9) kernel 7 241d 296d 0/28 auto-obsoleted due to no activity on 2024/04/14 23:48
upstream KCSAN: data-race in hrtimer_reprogram / print_cpu (6) kernel 19 473d 658d 0/28 auto-obsoleted due to no activity on 2023/08/26 13:01
upstream KCSAN: data-race in hrtimer_reprogram / print_cpu kernel 1 1692d 1692d 0/28 auto-closed as invalid on 2020/05/29 16:43
upstream KCSAN: data-race in hrtimer_reprogram / print_cpu (2) kernel 1 1525d 1525d 0/28 auto-closed as invalid on 2020/10/08 05:09
upstream KCSAN: data-race in hrtimer_reprogram / print_cpu (5) kernel 11 752d 835d 0/28 auto-obsoleted due to no activity on 2022/11/20 13:25
upstream KCSAN: data-race in hrtimer_reprogram / print_cpu (3) kernel 1 1095d 1095d 0/28 auto-closed as invalid on 2021/12/12 15:07
upstream KCSAN: data-race in hrtimer_reprogram / print_cpu (10) kernel 2 193d 194d 0/28 auto-obsoleted due to no activity on 2024/06/01 18:17
upstream KCSAN: data-race in hrtimer_reprogram / print_cpu (7) kernel 3 427d 437d 0/28 auto-obsoleted due to no activity on 2023/10/11 12:54
upstream KCSAN: data-race in hrtimer_reprogram / print_cpu (4) kernel 1 1059d 1059d 0/28 auto-closed as invalid on 2022/01/17 18:45
upstream KCSAN: data-race in hrtimer_reprogram / print_cpu (8) kernel 1 351d 331d 0/28 auto-obsoleted due to no activity on 2023/12/26 20:48

Sample crash report:
==================================================================
BUG: KCSAN: data-race in hrtimer_reprogram / print_cpu

write to 0xffff888237d1ffa0 of 8 bytes by task 27269 on cpu 1:
 __hrtimer_reprogram kernel/time/hrtimer.c:657 [inline]
 hrtimer_reprogram+0x1a2/0x220 kernel/time/hrtimer.c:864
 hrtimer_start_range_ns+0x512/0x580 kernel/time/hrtimer.c:1303
 hrtimer_start_expires include/linux/hrtimer.h:289 [inline]
 hrtimer_restart include/linux/hrtimer.h:297 [inline]
 common_hrtimer_rearm+0xa6/0xc0 kernel/time/posix-timers.c:249
 posixtimer_rearm+0xc7/0x1a0 kernel/time/posix-timers.c:267
 dequeue_signal+0x273/0x420 kernel/signal.c:694
 get_signal+0x376/0x1070 kernel/signal.c:2797
 arch_do_signal_or_restart+0x95/0x4b0 arch/x86/kernel/signal.c:337
 exit_to_user_mode_loop kernel/entry/common.c:111 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0x59/0x130 kernel/entry/common.c:218
 do_syscall_64+0xd6/0x1c0 arch/x86/entry/common.c:89
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff888237d1ffa0 of 8 bytes by task 27279 on cpu 0:
 print_cpu+0x2fb/0x670 kernel/time/timer_list.c:133
 timer_list_show+0x115/0x180 kernel/time/timer_list.c:295
 seq_read_iter+0x2d1/0x930 fs/seq_file.c:230
 proc_reg_read_iter+0x118/0x190 fs/proc/inode.c:299
 copy_splice_read+0x3a0/0x5d0 fs/splice.c:365
 do_splice_read fs/splice.c:985 [inline]
 splice_direct_to_actor+0x269/0x670 fs/splice.c:1089
 do_splice_direct_actor fs/splice.c:1207 [inline]
 do_splice_direct+0xd7/0x150 fs/splice.c:1233
 do_sendfile+0x39b/0x970 fs/read_write.c:1388
 __do_sys_sendfile64 fs/read_write.c:1455 [inline]
 __se_sys_sendfile64 fs/read_write.c:1441 [inline]
 __x64_sys_sendfile64+0x110/0x150 fs/read_write.c:1441
 x64_sys_call+0xed5/0x2d60 arch/x86/include/generated/asm/syscalls_64.h:41
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xc9/0x1c0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x000000569a149a4d -> 0x000000569a0e2b82

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 27279 Comm: syz.5.6581 Tainted: G        W          6.12.0-rc6-syzkaller #0
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
==================================================================
loop5: detected capacity change from 0 to 1024
EXT4-fs: quotafile must be on filesystem root

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/11/04 15:44 upstream 59b723cd2adb f00eed24 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in hrtimer_reprogram / print_cpu
* Struck through repros no longer work on HEAD.