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KCSAN: data-race in __dentry_kill / step_into (9)

Status: moderation: reported on 2025/05/03 22:30
Subsystems: fs
[Documentation on labels]
Reported-by: syzbot+03eeb7a335f7bec13d0c@syzkaller.appspotmail.com
First crash: 109d, last: 4d07h
▶ ▼ Similar bugs (8)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in __dentry_kill / step_into (6) fs 6 1 491d 491d 0/29 auto-obsoleted due to no activity on 2024/05/21 11:40
upstream KCSAN: data-race in __dentry_kill / step_into (8) fs 6 23 182d 415d 0/29 auto-obsoleted due to no activity on 2025/04/17 06:32
upstream KCSAN: data-race in __dentry_kill / step_into fs 6 1 1776d 1776d 0/29 auto-closed as invalid on 2020/11/14 02:21
upstream KCSAN: data-race in __dentry_kill / step_into (5) fs 6 106 537d 622d 0/29 auto-obsoleted due to no activity on 2024/04/05 18:21
upstream KCSAN: data-race in __dentry_kill / step_into (4) fs 6 1 1271d 1271d 0/29 auto-closed as invalid on 2022/04/03 02:19
upstream KCSAN: data-race in __dentry_kill / step_into (7) fs 6 2 452d 456d 0/29 auto-obsoleted due to no activity on 2024/06/29 19:22
upstream KCSAN: data-race in __dentry_kill / step_into (2) fs 6 3 1531d 1569d 0/29 auto-closed as invalid on 2021/07/16 10:59
upstream KCSAN: data-race in __dentry_kill / step_into (3) fs 6 5 1334d 1391d 0/29 auto-closed as invalid on 2022/01/30 10:25

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

read-write to 0xffff888119cdfcc0 of 4 bytes by task 3302 on cpu 0:
 dentry_unlist fs/dcache.c:614 [inline]
 __dentry_kill+0x230/0x4b0 fs/dcache.c:683
 dput+0x5e/0xd0 fs/dcache.c:911
 __fput+0x444/0x650 fs/file_table.c:476
 fput_close_sync+0x6e/0x120 fs/file_table.c:573
 __do_sys_close fs/open.c:1587 [inline]
 __se_sys_close fs/open.c:1572 [inline]
 __x64_sys_close+0x56/0xf0 fs/open.c:1572
 x64_sys_call+0x2738/0x2ff0 arch/x86/include/generated/asm/syscalls_64.h:4
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd2/0x200 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff888119cdfcc0 of 4 bytes by task 3311 on cpu 1:
 __d_entry_type include/linux/dcache.h:411 [inline]
 d_is_symlink include/linux/dcache.h:441 [inline]
 step_into+0x12f/0x820 fs/namei.c:1972
 open_last_lookups fs/namei.c:3834 [inline]
 path_openat+0x13e8/0x2170 fs/namei.c:4043
 do_filp_open+0x109/0x230 fs/namei.c:4073
 do_sys_openat2+0xa6/0x110 fs/open.c:1435
 do_sys_open fs/open.c:1450 [inline]
 __do_sys_openat fs/open.c:1466 [inline]
 __se_sys_openat fs/open.c:1461 [inline]
 __x64_sys_openat+0xf2/0x120 fs/open.c:1461
 x64_sys_call+0x2e9c/0x2ff0 arch/x86/include/generated/asm/syscalls_64.h:258
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd2/0x200 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x00200080 -> 0x00004080

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 3311 Comm: syz-executor Not tainted 6.17.0-rc1-syzkaller-00211-g90d970cade8e #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
==================================================================
==================================================================
BUG: KCSAN: data-race in __dentry_kill / lookup_fast

read-write to 0xffff888119de1480 of 4 bytes by task 3302 on cpu 0:
 dentry_unlist fs/dcache.c:614 [inline]
 __dentry_kill+0x230/0x4b0 fs/dcache.c:683
 dput+0x5e/0xd0 fs/dcache.c:911
 do_unlinkat+0x259/0x480 fs/namei.c:4653
 __do_sys_unlink fs/namei.c:4696 [inline]
 __se_sys_unlink fs/namei.c:4694 [inline]
 __x64_sys_unlink+0x2e/0x40 fs/namei.c:4694
 x64_sys_call+0x2dc0/0x2ff0 arch/x86/include/generated/asm/syscalls_64.h:88
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd2/0x200 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff888119de1480 of 4 bytes by task 3311 on cpu 1:
 d_revalidate fs/namei.c:928 [inline]
 lookup_fast+0xf0/0x320 fs/namei.c:1756
 lookup_fast_for_open fs/namei.c:3745 [inline]
 open_last_lookups fs/namei.c:3778 [inline]
 path_openat+0x43c/0x2170 fs/namei.c:4043
 do_filp_open+0x109/0x230 fs/namei.c:4073
 do_sys_openat2+0xa6/0x110 fs/open.c:1435
 do_sys_open fs/open.c:1450 [inline]
 __do_sys_openat fs/open.c:1466 [inline]
 __se_sys_openat fs/open.c:1461 [inline]
 __x64_sys_openat+0xf2/0x120 fs/open.c:1461
 x64_sys_call+0x2e9c/0x2ff0 arch/x86/include/generated/asm/syscalls_64.h:258
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd2/0x200 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x00200080 -> 0x00004080

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 3311 Comm: syz-executor Not tainted 6.17.0-rc1-syzkaller-00211-g90d970cade8e #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
==================================================================
==================================================================
BUG: KCSAN: data-race in __dentry_kill / fast_dput

write to 0xffff888119f61310 of 8 bytes by task 3302 on cpu 0:
 __d_drop fs/dcache.c:575 [inline]
 __dentry_kill+0x142/0x4b0 fs/dcache.c:667
 dput+0x5e/0xd0 fs/dcache.c:911
 __fput+0x444/0x650 fs/file_table.c:476
 fput_close_sync+0x6e/0x120 fs/file_table.c:573
 __do_sys_close fs/open.c:1587 [inline]
 __se_sys_close fs/open.c:1572 [inline]
 __x64_sys_close+0x56/0xf0 fs/open.c:1572
 x64_sys_call+0x2738/0x2ff0 arch/x86/include/generated/asm/syscalls_64.h:4
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd2/0x200 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff888119f61310 of 8 bytes by task 3311 on cpu 1:
 hlist_bl_unhashed include/linux/list_bl.h:54 [inline]
 d_unhashed include/linux/dcache.h:361 [inline]
 retain_dentry fs/dcache.c:752 [inline]
 fast_dput+0x5f/0x2c0 fs/dcache.c:848
 dput+0x24/0xd0 fs/dcache.c:905
 __fput+0x444/0x650 fs/file_table.c:476
 fput_close_sync+0x6e/0x120 fs/file_table.c:573
 __do_sys_close fs/open.c:1587 [inline]
 __se_sys_close fs/open.c:1572 [inline]
 __x64_sys_close+0x56/0xf0 fs/open.c:1572
 x64_sys_call+0x2738/0x2ff0 arch/x86/include/generated/asm/syscalls_64.h:4
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd2/0x200 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0xffff888237676c68 -> 0x0000000000000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 3311 Comm: syz-executor Not tainted 6.17.0-rc1-syzkaller-00211-g90d970cade8e #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
==================================================================
==================================================================
BUG: KCSAN: data-race in __dentry_kill / step_into

read-write to 0xffff8881072d7240 of 4 bytes by task 3302 on cpu 0:
 dentry_unlist fs/dcache.c:614 [inline]
 __dentry_kill+0x230/0x4b0 fs/dcache.c:683
 dput+0x5e/0xd0 fs/dcache.c:911
 do_unlinkat+0x259/0x480 fs/namei.c:4653
 __do_sys_unlink fs/namei.c:4696 [inline]
 __se_sys_unlink fs/namei.c:4694 [inline]
 __x64_sys_unlink+0x2e/0x40 fs/namei.c:4694
 x64_sys_call+0x2dc0/0x2ff0 arch/x86/include/generated/asm/syscalls_64.h:88
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd2/0x200 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff8881072d7240 of 4 bytes by task 3311 on cpu 1:
 __d_entry_type include/linux/dcache.h:411 [inline]
 d_is_symlink include/linux/dcache.h:441 [inline]
 step_into+0x12f/0x820 fs/namei.c:1972
 open_last_lookups fs/namei.c:3834 [inline]
 path_openat+0x13e8/0x2170 fs/namei.c:4043
 do_filp_open+0x109/0x230 fs/namei.c:4073
 do_sys_openat2+0xa6/0x110 fs/open.c:1435
 do_sys_open fs/open.c:1450 [inline]
 __do_sys_openat fs/open.c:1466 [inline]
 __se_sys_openat fs/open.c:1461 [inline]
 __x64_sys_openat+0xf2/0x120 fs/open.c:1461
 x64_sys_call+0x2e9c/0x2ff0 arch/x86/include/generated/asm/syscalls_64.h:258
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd2/0x200 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x00200080 -> 0x00004080

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 3311 Comm: syz-executor Not tainted 6.17.0-rc1-syzkaller-00211-g90d970cade8e #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
==================================================================
==================================================================
BUG: KCSAN: data-race in __dentry_kill / step_into

read-write to 0xffff8881004b5cc0 of 4 bytes by task 3302 on cpu 0:
 dentry_unlist fs/dcache.c:614 [inline]
 __dentry_kill+0x230/0x4b0 fs/dcache.c:683
 dput+0x5e/0xd0 fs/dcache.c:911
 __fput+0x444/0x650 fs/file_table.c:476
 fput_close_sync+0x6e/0x120 fs/file_table.c:573
 __do_sys_close fs/open.c:1587 [inline]
 __se_sys_close fs/open.c:1572 [inline]
 __x64_sys_close+0x56/0xf0 fs/open.c:1572
 x64_sys_call+0x2738/0x2ff0 arch/x86/include/generated/asm/syscalls_64.h:4
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd2/0x200 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff8881004b5cc0 of 4 bytes by task 3311 on cpu 1:
 __follow_mount_rcu fs/namei.c:1572 [inline]
 handle_mounts fs/namei.c:1623 [inline]
 step_into+0xe3/0x820 fs/namei.c:1967
 open_last_lookups fs/namei.c:3834 [inline]
 path_openat+0x13e8/0x2170 fs/namei.c:4043
 do_filp_open+0x109/0x230 fs/namei.c:4073
 do_sys_openat2+0xa6/0x110 fs/open.c:1435
 do_sys_open fs/open.c:1450 [inline]
 __do_sys_openat fs/open.c:1466 [inline]
 __se_sys_openat fs/open.c:1461 [inline]
 __x64_sys_openat+0xf2/0x120 fs/open.c:1461
 x64_sys_call+0x2e9c/0x2ff0 arch/x86/include/generated/asm/syscalls_64.h:258
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd2/0x200 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x00200080 -> 0x00004080

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 3311 Comm: syz-executor Not tainted 6.17.0-rc1-syzkaller-00211-g90d970cade8e #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
==================================================================
==================================================================
BUG: KCSAN: data-race in __dentry_kill / lookup_fast

read-write to 0xffff888119cc8cc0 of 4 bytes by task 3302 on cpu 0:
 dentry_unlist fs/dcache.c:614 [inline]
 __dentry_kill+0x230/0x4b0 fs/dcache.c:683
 dput+0x5e/0xd0 fs/dcache.c:911
 __fput+0x444/0x650 fs/file_table.c:476
 fput_close_sync+0x6e/0x120 fs/file_table.c:573
 __do_sys_close fs/open.c:1587 [inline]
 __se_sys_close fs/open.c:1572 [inline]
 __x64_sys_close+0x56/0xf0 fs/open.c:1572
 x64_sys_call+0x2738/0x2ff0 arch/x86/include/generated/asm/syscalls_64.h:4
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd2/0x200 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff888119cc8cc0 of 4 bytes by task 3311 on cpu 1:
 d_revalidate fs/namei.c:928 [inline]
 lookup_fast+0xf0/0x320 fs/namei.c:1756
 lookup_fast_for_open fs/namei.c:3745 [inline]
 open_last_lookups fs/namei.c:3778 [inline]
 path_openat+0x43c/0x2170 fs/namei.c:4043
 do_filp_open+0x109/0x230 fs/namei.c:4073
 do_sys_openat2+0xa6/0x110 fs/open.c:1435
 do_sys_open fs/open.c:1450 [inline]
 __do_sys_openat fs/open.c:1466 [inline]
 __se_sys_openat fs/open.c:1461 [inline]
 __x64_sys_openat+0xf2/0x120 fs/open.c:1461
 x64_sys_call+0x2e9c/0x2ff0 arch/x86/include/generated/asm/syscalls_64.h:258
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd2/0x200 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x00200080 -> 0x00004080

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 3311 Comm: syz-executor Not tainted 6.17.0-rc1-syzkaller-00211-g90d970cade8e #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
==================================================================

Crashes (6):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/08/17 03:03 upstream 90d970cade8e 1804e95e .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __dentry_kill / step_into
2025/07/20 00:54 upstream bf61759db409 7117feec .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __dentry_kill / step_into
2025/07/04 17:06 upstream 4c06e63b9203 d869b261 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __dentry_kill / step_into
2025/05/28 15:03 upstream feacb1774bd5 874a1386 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __dentry_kill / step_into
2025/05/15 05:48 upstream c94d59a126cb d6b2ee52 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __dentry_kill / step_into
2025/05/03 22:29 upstream 2a239ffbebb5 b0714e37 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __dentry_kill / step_into
* Struck through repros no longer work on HEAD.