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KCSAN: data-race in do_epoll_wait / ep_poll_callback (11)

Status: moderation: reported on 2024/03/01 03:09
Subsystems: fs
[Documentation on labels]
Reported-by: syzbot+86b4d7adeeb367c1d6f7@syzkaller.appspotmail.com
First crash: 48d, last: 20d
Similar bugs (10)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in do_epoll_wait / ep_poll_callback (7) fs 1 803d 803d 0/26 auto-closed as invalid on 2022/03/12 11:24
upstream KCSAN: data-race in do_epoll_wait / ep_poll_callback (9) fs 9 418d 537d 0/26 auto-obsoleted due to no activity on 2023/04/08 19:56
upstream KCSAN: data-race in do_epoll_wait / ep_poll_callback (6) fs 1 845d 845d 0/26 auto-closed as invalid on 2022/01/29 14:05
upstream KCSAN: data-race in do_epoll_wait / ep_poll_callback (2) fs 2 1166d 1169d 0/26 auto-closed as invalid on 2021/03/14 02:07
upstream KCSAN: data-race in do_epoll_wait / ep_poll_callback (5) fs 2 950d 961d 0/26 auto-closed as invalid on 2021/10/15 22:14
upstream KCSAN: data-race in do_epoll_wait / ep_poll_callback (4) fs 1 1044d 1044d 0/26 auto-closed as invalid on 2021/07/14 13:56
upstream KCSAN: data-race in do_epoll_wait / ep_poll_callback (3) fs 1 1114d 1114d 0/26 auto-closed as invalid on 2021/05/17 11:16
upstream KCSAN: data-race in do_epoll_wait / ep_poll_callback (8) fs 1 753d 753d 0/26 auto-closed as invalid on 2022/05/01 05:30
upstream KCSAN: data-race in do_epoll_wait / ep_poll_callback fs 221 1354d 1390d 0/26 auto-closed as invalid on 2020/08/31 10:40
upstream KCSAN: data-race in do_epoll_wait / ep_poll_callback (10) fs 2 143d 129d 0/26 auto-obsoleted due to no activity on 2024/01/01 00:54

Sample crash report:
==================================================================
BUG: KCSAN: data-race in do_epoll_wait / ep_poll_callback

write to 0xffff88814594bee8 of 4 bytes by task 18495 on cpu 1:
 ep_send_events fs/eventpoll.c:1850 [inline]
 ep_poll fs/eventpoll.c:1969 [inline]
 do_epoll_wait+0x855/0xef0 fs/eventpoll.c:2428
 __do_sys_epoll_wait fs/eventpoll.c:2440 [inline]
 __se_sys_epoll_wait fs/eventpoll.c:2435 [inline]
 __x64_sys_epoll_wait+0x137/0x170 fs/eventpoll.c:2435
 do_syscall_64+0xd3/0x1d0
 entry_SYSCALL_64_after_hwframe+0x6d/0x75

read to 0xffff88814594bee8 of 4 bytes by task 18508 on cpu 0:
 ep_poll_callback+0x4a8/0x5b0 fs/eventpoll.c:1351
 __wake_up_common kernel/sched/wait.c:89 [inline]
 __wake_up_common_lock kernel/sched/wait.c:106 [inline]
 __wake_up_sync_key+0x51/0x80 kernel/sched/wait.c:173
 unix_write_space+0xcd/0x150 net/unix/af_unix.c:547
 sock_wfree+0x11e/0x330 net/core/sock.c:2482
 unix_destruct_scm+0x12e/0x160 net/unix/af_unix.c:1881
 skb_release_head_state+0xbb/0x1a0 net/core/skbuff.c:1188
 skb_release_all net/core/skbuff.c:1200 [inline]
 __kfree_skb+0x16/0x150 net/core/skbuff.c:1216
 kfree_skb_reason+0xb0/0x2b0 net/core/skbuff.c:1252
 kfree_skb include/linux/skbuff.h:1262 [inline]
 unix_release_sock+0x642/0x790 net/unix/af_unix.c:659
 unix_release+0x57/0x80 net/unix/af_unix.c:1049
 __sock_release net/socket.c:659 [inline]
 sock_close+0x68/0x150 net/socket.c:1421
 __fput+0x2c1/0x660 fs/file_table.c:422
 __fput_sync+0x44/0x60 fs/file_table.c:507
 __do_sys_close fs/open.c:1556 [inline]
 __se_sys_close+0x101/0x1b0 fs/open.c:1541
 __x64_sys_close+0x1f/0x30 fs/open.c:1541
 do_syscall_64+0xd3/0x1d0
 entry_SYSCALL_64_after_hwframe+0x6d/0x75

value changed: 0xe000101e -> 0xe0000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 18508 Comm: syz-executor.0 Tainted: G        W          6.9.0-rc1-syzkaller-00178-g317c7bc0ef03 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
==================================================================

Crashes (3):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/03/29 13:40 upstream 317c7bc0ef03 c52bcb23 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in do_epoll_wait / ep_poll_callback
2024/03/08 06:09 upstream 3aaa8ce7a335 cf82cde1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in do_epoll_wait / ep_poll_callback
2024/03/01 03:08 upstream 87adedeba51a 352ab904 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in do_epoll_wait / ep_poll_callback
* Struck through repros no longer work on HEAD.