syzbot


KCSAN: data-race in dentry_lru_isolate / lookup_fast

Status: auto-closed as invalid on 2022/03/16 21:21
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 289d, last: 289d
similar bugs (2):
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in dentry_lru_isolate / lookup_fast (2) 1 156d 156d 0/24 auto-closed as invalid on 2022/07/28 09:19
upstream KCSAN: data-race in dentry_lru_isolate / lookup_fast (3) 1 66d 66d 0/24 auto-obsoleted due to no activity on 2022/10/26 06:37

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

write to 0xffff88813397ac00 of 4 bytes by task 1828 on cpu 0:
 d_lru_shrink_move fs/dcache.c:480 [inline]
 dentry_lru_isolate+0x134/0x200 fs/dcache.c:1257
 __list_lru_walk_one+0xfb/0x320 mm/list_lru.c:231
 list_lru_walk_one+0x75/0x90 mm/list_lru.c:275
 list_lru_shrink_walk include/linux/list_lru.h:195 [inline]
 prune_dcache_sb+0x67/0xa0 fs/dcache.c:1280
 super_cache_scan+0x23e/0x2e0 fs/super.c:104
 do_shrink_slab+0x2ae/0x600 mm/vmscan.c:773
 shrink_slab_memcg+0x1c2/0x440 mm/vmscan.c:842
 shrink_slab+0x5c/0x1c0 mm/vmscan.c:921
 shrink_node_memcgs+0x27a/0x410 mm/vmscan.c:3172
 shrink_node+0x8f6/0x1190 mm/vmscan.c:3293
 shrink_zones+0x2d1/0x5e0 mm/vmscan.c:3530
 do_try_to_free_pages+0x181/0x720 mm/vmscan.c:3588
 try_to_free_mem_cgroup_pages+0x1cb/0x420 mm/vmscan.c:3902
 reclaim_high mm/memcontrol.c:2300 [inline]
 mem_cgroup_handle_over_high+0x15b/0x480 mm/memcontrol.c:2484
 tracehook_notify_resume include/linux/tracehook.h:197 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:175 [inline]
 exit_to_user_mode_prepare+0x139/0x190 kernel/entry/common.c:207
 __syscall_exit_to_user_mode_work kernel/entry/common.c:289 [inline]
 syscall_exit_to_user_mode+0x20/0x40 kernel/entry/common.c:300
 do_syscall_64+0x50/0xd0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff88813397ac00 of 4 bytes by task 12890 on cpu 1:
 d_revalidate fs/namei.c:853 [inline]
 lookup_fast+0x172/0x360 fs/namei.c:1656
 walk_component+0x6d/0x360 fs/namei.c:2016
 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: 0x00280000 -> 0x00008000

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 12890 Comm: syz-executor.1 Not tainted 5.17.0-rc3-syzkaller-00043-gf4bc5bbb5fef-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 2022/02/09 21:18 upstream f4bc5bbb5fef 0b33604d .config log report info KCSAN: data-race in dentry_lru_isolate / lookup_fast
* Struck through repros no longer work on HEAD.