syzbot


KCSAN: data-race in __ep_remove / __fput (3)

Status: auto-obsoleted due to no activity on 2024/03/14 21:07
Subsystems: fs
[Documentation on labels]
Reported-by: syzbot+2409b92bfc0d90a0f081@syzkaller.appspotmail.com
First crash: 66d, last: 66d
Similar bugs (2)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in __ep_remove / __fput fs 1 294d 294d 0/26 auto-obsoleted due to no activity on 2023/07/30 19:06
upstream KCSAN: data-race in __ep_remove / __fput (2) fs 1 253d 253d 0/26 auto-obsoleted due to no activity on 2023/09/09 12:48

Sample crash report:
==================================================================
BUG: KCSAN: data-race in __ep_remove / __fput

write to 0xffff8881042fd4d0 of 8 bytes by task 21157 on cpu 1:
 __ep_remove+0x3b8/0x440 fs/eventpoll.c:743
 ep_remove_safe fs/eventpoll.c:781 [inline]
 ep_clear_and_put+0x158/0x260 fs/eventpoll.c:817
 ep_eventpoll_release+0x32/0x40 fs/eventpoll.c:833
 __fput+0x299/0x630 fs/file_table.c:376
 ____fput+0x15/0x20 fs/file_table.c:404
 task_work_run+0x135/0x1a0 kernel/task_work.c:180
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:108 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:201 [inline]
 syscall_exit_to_user_mode+0xbd/0x130 kernel/entry/common.c:212
 do_syscall_64+0xda/0x1d0 arch/x86/entry/common.c:89
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

read to 0xffff8881042fd4d0 of 8 bytes by task 21156 on cpu 0:
 eventpoll_release include/linux/eventpoll.h:45 [inline]
 __fput+0x217/0x630 fs/file_table.c:367
 __fput_sync+0x44/0x50 fs/file_table.c:461
 __do_sys_close fs/open.c:1554 [inline]
 __se_sys_close+0xfa/0x1a0 fs/open.c:1539
 __x64_sys_close+0x1f/0x30 fs/open.c:1539
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x1d0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

value changed: 0xffff8881037e36b0 -> 0x0000000000000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 21156 Comm: syz-executor.1 Not tainted 6.8.0-rc3-syzkaller-00047-g047371968ffc #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024
==================================================================

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/02/08 21:06 upstream 047371968ffc 7f07e9b0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __ep_remove / __fput
* Struck through repros no longer work on HEAD.