syzbot


KCSAN: data-race in __d_drop / dput (2)

Status: auto-closed as invalid on 2022/03/19 02:06
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 297d, last: 297d
similar bugs (3):
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in __d_drop / dput 1 333d 333d 0/24 auto-closed as invalid on 2022/02/10 17:36
upstream KCSAN: data-race in __d_drop / dput (3) 2 213d 222d 0/24 auto-closed as invalid on 2022/06/11 11:25
upstream KCSAN: data-race in __d_drop / dput (4) 1 107d 107d 0/24 auto-closed as invalid on 2022/09/25 01:35

Sample crash report:
loop4: detected capacity change from 0 to 262160
==================================================================
BUG: KCSAN: data-race in __d_drop / dput

write to 0xffff888135e97550 of 8 bytes by task 15888 on cpu 0:
 __d_drop+0x16a/0x250 fs/dcache.c:508
 d_invalidate+0x4a/0x1a0 fs/dcache.c:1730
 lookup_dcache fs/namei.c:1575 [inline]
 __lookup_hash+0x16c/0x180 fs/namei.c:1593
 do_unlinkat+0x169/0x540 fs/namei.c:4202
 __do_sys_unlink fs/namei.c:4266 [inline]
 __se_sys_unlink fs/namei.c:4264 [inline]
 __x64_sys_unlink+0x2c/0x30 fs/namei.c:4264
 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 0xffff888135e97550 of 8 bytes by task 15885 on cpu 1:
 hlist_bl_unhashed include/linux/list_bl.h:54 [inline]
 d_unhashed include/linux/dcache.h:332 [inline]
 fast_dput fs/dcache.c:837 [inline]
 dput+0xae/0x430 fs/dcache.c:900
 handle_mounts fs/namei.c:1552 [inline]
 step_into+0x468/0xf70 fs/namei.c:1850
 walk_component+0x1a1/0x360 fs/namei.c:2026
 lookup_last fs/namei.c:2475 [inline]
 path_lookupat+0x12d/0x3d0 fs/namei.c:2499
 filename_lookup+0x130/0x310 fs/namei.c:2528
 user_path_at_empty+0x3e/0x110 fs/namei.c:2851
 user_path_at include/linux/namei.h:57 [inline]
 __do_sys_chdir fs/open.c:490 [inline]
 __se_sys_chdir+0x51/0x170 fs/open.c:484
 __x64_sys_chdir+0x1b/0x20 fs/open.c:484
 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: 0xffff8882378800d8 -> 0x0000000000000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 15885 Comm: syz-executor.4 Not tainted 5.17.0-rc3-syzkaller-00188-g1d41d2e82623-dirty #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 2022/02/12 02:02 upstream 1d41d2e82623 8b9ca619 .config log report info KCSAN: data-race in __d_drop / dput
* Struck through repros no longer work on HEAD.