syzbot


KCSAN: data-race in __dentry_kill / __dentry_kill (4)

Status: moderation: reported on 2024/10/21 06:27
Subsystems: fs
[Documentation on labels]
Reported-by: syzbot+d2d8117208036e13d980@syzkaller.appspotmail.com
First crash: 1d14h, last: 1d14h
Similar bugs (3)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in __dentry_kill / __dentry_kill (2) fs 1 131d 131d 0/28 auto-obsoleted due to no activity on 2024/07/18 14:41
upstream KCSAN: data-race in __dentry_kill / __dentry_kill (3) fs 1 72d 72d 0/28 auto-obsoleted due to no activity on 2024/09/15 09:01
upstream KCSAN: data-race in __dentry_kill / __dentry_kill fs 1 195d 195d 0/28 auto-obsoleted due to no activity on 2024/05/15 11:32

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

write to 0xffff888106d89f00 of 4 bytes by task 3271 on cpu 1:
 d_lru_del fs/dcache.c:449 [inline]
 __dentry_kill+0xa3/0x4c0 fs/dcache.c:610
 dput+0x5c/0xd0 fs/dcache.c:857
 proc_invalidate_siblings_dcache+0x1e3/0x2b0 fs/proc/inode.c:143
 proc_flush_pid+0x1d/0x30 fs/proc/base.c:3477
 release_task+0xad9/0xc20 kernel/exit.c:280
 wait_task_zombie kernel/exit.c:1250 [inline]
 wait_consider_task+0x116e/0x1680 kernel/exit.c:1477
 do_wait_thread kernel/exit.c:1540 [inline]
 __do_wait+0x100/0x500 kernel/exit.c:1658
 do_wait+0xaf/0x270 kernel/exit.c:1692
 kernel_wait4+0x164/0x1d0 kernel/exit.c:1851
 __do_sys_wait4 kernel/exit.c:1879 [inline]
 __se_sys_wait4 kernel/exit.c:1875 [inline]
 __x64_sys_wait4+0x94/0x120 kernel/exit.c:1875
 x64_sys_call+0x2529/0x2d60 arch/x86/include/generated/asm/syscalls_64.h:62
 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

read to 0xffff888106d89f00 of 4 bytes by task 10148 on cpu 0:
 dentry_unlist fs/dcache.c:585 [inline]
 __dentry_kill+0x2af/0x4c0 fs/dcache.c:629
 dput+0x5c/0xd0 fs/dcache.c:857
 proc_invalidate_siblings_dcache+0x1e3/0x2b0 fs/proc/inode.c:143
 proc_flush_pid+0x1d/0x30 fs/proc/base.c:3477
 release_task+0xb7f/0xc20 kernel/exit.c:280
 exit_notify kernel/exit.c:776 [inline]
 do_exit+0xf62/0x17f0 kernel/exit.c:959
 do_group_exit+0x102/0x150 kernel/exit.c:1088
 get_signal+0xf2a/0x1070 kernel/signal.c:2917
 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

value changed: 0x0028000c -> 0x0000000c

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 10148 Comm: syz.2.2110 Not tainted 6.12.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
==================================================================

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/10/21 06:26 upstream 42f7652d3eb5 cd6fc0a3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __dentry_kill / __dentry_kill
* Struck through repros no longer work on HEAD.