syzbot


KCSAN: data-race in d_lru_add / step_into (5)

Status: moderation: reported on 2024/06/28 16:36
Subsystems: fs
[Documentation on labels]
Reported-by: syzbot+593f82c706a019d08270@syzkaller.appspotmail.com
First crash: 14d, last: 14d
Similar bugs (4)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in d_lru_add / step_into (3) fs 1 204d 204d 0/27 auto-obsoleted due to no activity on 2024/01/25 14:18
upstream KCSAN: data-race in d_lru_add / step_into (2) fs 1 255d 255d 0/27 auto-obsoleted due to no activity on 2023/12/05 18:48
upstream KCSAN: data-race in d_lru_add / step_into fs 2 668d 698d 0/27 auto-obsoleted due to no activity on 2022/10/18 18:24
upstream KCSAN: data-race in d_lru_add / step_into (4) fs 1 156d 156d 0/27 auto-obsoleted due to no activity on 2024/03/13 17:08

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

write to 0xffff88810781f0c0 of 4 bytes by task 12658 on cpu 1:
 d_lru_add+0x45/0xe0 fs/dcache.c:426
 retain_dentry fs/dcache.c:712 [inline]
 fast_dput+0x26b/0x2b0 fs/dcache.c:799
 dput+0x24/0xd0 fs/dcache.c:839
 done_path_create fs/namei.c:3950 [inline]
 do_mkdirat+0x139/0x2a0 fs/namei.c:4157
 __do_sys_mkdirat fs/namei.c:4169 [inline]
 __se_sys_mkdirat fs/namei.c:4167 [inline]
 __x64_sys_mkdirat+0x50/0x60 fs/namei.c:4167
 x64_sys_call+0x2ce5/0x2d70 arch/x86/include/generated/asm/syscalls_64.h:259
 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 0xffff88810781f0c0 of 4 bytes by task 12662 on cpu 0:
 __d_entry_type include/linux/dcache.h:397 [inline]
 d_is_symlink include/linux/dcache.h:427 [inline]
 step_into+0x12f/0x810 fs/namei.c:1847
 walk_component+0x169/0x230 fs/namei.c:2010
 lookup_last fs/namei.c:2469 [inline]
 path_lookupat+0x10a/0x2b0 fs/namei.c:2493
 filename_lookup+0x127/0x300 fs/namei.c:2522
 user_path_at_empty+0x42/0x120 fs/namei.c:2929
 user_path_at include/linux/namei.h:58 [inline]
 __do_sys_chdir fs/open.c:558 [inline]
 __se_sys_chdir+0x4f/0x150 fs/open.c:552
 __x64_sys_chdir+0x1f/0x30 fs/open.c:552
 x64_sys_call+0x2b05/0x2d70 arch/x86/include/generated/asm/syscalls_64.h:81
 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: 0x00200000 -> 0x00280040

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 12662 Comm: syz.2.2860 Not tainted 6.10.0-rc5-syzkaller-00200-g5bbd9b249880 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/07/2024
==================================================================

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/06/28 16:35 upstream 5bbd9b249880 757f06b1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in d_lru_add / step_into
* Struck through repros no longer work on HEAD.