syzbot


KCSAN: data-race in dentry_lru_isolate / dput

Status: auto-closed as invalid on 2020/06/18 13:23
Subsystems: fs
[Documentation on labels]
First crash: 1434d, last: 1434d

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

write to 0xffff8880afd15600 of 4 bytes by task 1787 on cpu 0:
 d_lru_isolate fs/dcache.c:442 [inline]
 dentry_lru_isolate+0x122/0x190 fs/dcache.c:1147
 __list_lru_walk_one+0x10b/0x390 mm/list_lru.c:222
 list_lru_walk_one+0x78/0xa0 mm/list_lru.c:266
 list_lru_shrink_walk include/linux/list_lru.h:195 [inline]
 prune_dcache_sb+0x7e/0xb0 fs/dcache.c:1201
 super_cache_scan+0x1cb/0x2c0 fs/super.c:105
 do_shrink_slab+0x2a9/0x5b0 mm/vmscan.c:512
 shrink_slab mm/vmscan.c:673 [inline]
 shrink_slab+0x153/0x540 mm/vmscan.c:646
 shrink_node_memcgs mm/vmscan.c:2673 [inline]
 shrink_node+0x357/0x1000 mm/vmscan.c:2777
 kswapd_shrink_node mm/vmscan.c:3523 [inline]
 balance_pgdat+0x64c/0xd10 mm/vmscan.c:3681
 kswapd+0x3f3/0x8c0 mm/vmscan.c:3935
 kthread+0x203/0x230 kernel/kthread.c:268
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:352

read to 0xffff8880afd15600 of 4 bytes by task 3952 on cpu 1:
 fast_dput fs/dcache.c:727 [inline]
 dput+0x4b/0x700 fs/dcache.c:846
 step_into+0x1b5/0x1090 fs/namei.c:1685
 walk_component+0xde/0x390 fs/namei.c:1852
 lookup_last fs/namei.c:2295 [inline]
 path_lookupat.isra.0+0x119/0x350 fs/namei.c:2319
 filename_lookup+0x145/0x2c0 fs/namei.c:2352
 user_path_at_empty+0x47/0x60 fs/namei.c:2632
 user_path_at include/linux/namei.h:59 [inline]
 vfs_statx+0xdb/0x190 fs/stat.c:197
 vfs_lstat include/linux/fs.h:3284 [inline]
 __do_sys_newlstat+0x50/0xb0 fs/stat.c:364
 __se_sys_newlstat fs/stat.c:358 [inline]
 __x64_sys_newlstat+0x37/0x50 fs/stat.c:358
 do_syscall_64+0xc7/0x3b0 arch/x86/entry/common.c:295
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 3952 Comm: systemd-udevd Not tainted 5.7.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2020/04/24 16:00 https://github.com/google/ktsan.git kcsan 7c3cd68e5d38 03d97a1b .config console log report ci2-upstream-kcsan-gce
* Struck through repros no longer work on HEAD.