syzbot


KCSAN: data-race in __dput_to_list / lookup_fast

Status: auto-closed as invalid on 2022/01/18 12:06
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 347d, last: 347d

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

write to 0xffff8881058500c0 of 4 bytes by task 3523 on cpu 1:
 d_shrink_add fs/dcache.c:431 [inline]
 __dput_to_list+0x209/0x250 fs/dcache.c:903
 shrink_dentry_list+0x15d/0x300 fs/dcache.c:1175
 shrink_dcache_sb+0x188/0x2d0 fs/dcache.c:1296
 reconfigure_super+0x146/0x540 fs/super.c:891
 do_remount fs/namespace.c:2650 [inline]
 path_mount+0x13f9/0x1c40 fs/namespace.c:3310
 do_mount fs/namespace.c:3331 [inline]
 __do_sys_mount fs/namespace.c:3539 [inline]
 __se_sys_mount+0x24b/0x2f0 fs/namespace.c:3516
 __x64_sys_mount+0x63/0x70 fs/namespace.c:3516
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff8881058500c0 of 4 bytes by task 1439 on cpu 0:
 d_revalidate fs/namei.c:853 [inline]
 lookup_fast+0x172/0x360 fs/namei.c:1606
 walk_component+0x6d/0x360 fs/namei.c:1966
 link_path_walk+0x56b/0x930
 path_lookupat+0x8b/0x3d0 fs/namei.c:2448
 filename_lookup+0x130/0x310 fs/namei.c:2478
 user_path_at_empty+0x3e/0x110 fs/namei.c:2801
 user_path_at include/linux/namei.h:57 [inline]
 vfs_statx+0xa9/0x2a0 fs/stat.c:221
 vfs_fstatat fs/stat.c:243 [inline]
 __do_sys_newfstatat fs/stat.c:412 [inline]
 __se_sys_newfstatat+0x63/0x260 fs/stat.c:406
 __x64_sys_newfstatat+0x51/0x60 fs/stat.c:406
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x00200000 -> 0x00280400

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 1439 Comm: udevd Not tainted 5.16.0-rc5-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================

Crashes (1):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci2-upstream-kcsan-gce 2021/12/14 11:57 upstream 5472f14a3742 d018dd31 .config log report info KCSAN: data-race in __dput_to_list / lookup_fast
* Struck through repros no longer work on HEAD.