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KCSAN: data-race in __d_lookup_rcu / shrink_dentry_list (3)

Status: auto-obsoleted due to no activity on 2023/11/01 01:55
Subsystems: fs
[Documentation on labels]
Reported-by: syzbot+5ba3af2320dde0017662@syzkaller.appspotmail.com
First crash: 456d, last: 456d
Similar bugs (2)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in __d_lookup_rcu / shrink_dentry_list fs 1 1050d 1050d 0/28 auto-closed as invalid on 2022/03/17 17:06
upstream KCSAN: data-race in __d_lookup_rcu / shrink_dentry_list (2) fs 1 603d 603d 0/28 auto-obsoleted due to no activity on 2023/06/07 20:30

Sample crash report:
==================================================================
BUG: KCSAN: data-race in __d_lookup_rcu / shrink_dentry_list

read-write to 0xffff88813c30c9c0 of 4 bytes by task 26853 on cpu 1:
 d_shrink_del fs/dcache.c:448 [inline]
 shrink_dentry_list+0x1c7/0x380 fs/dcache.c:1188
 shrink_dcache_sb+0x165/0x290 fs/dcache.c:1321
 reconfigure_super+0x3ef/0x580 fs/super.c:1118
 do_remount fs/namespace.c:2882 [inline]
 path_mount+0x969/0xb30 fs/namespace.c:3654
 do_mount fs/namespace.c:3675 [inline]
 __do_sys_mount fs/namespace.c:3884 [inline]
 __se_sys_mount+0x27f/0x2d0 fs/namespace.c:3861
 __x64_sys_mount+0x67/0x80 fs/namespace.c:3861
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

read to 0xffff88813c30c9c0 of 4 bytes by task 3107 on cpu 0:
 __d_lookup_rcu+0x42/0x290 fs/dcache.c:2360
 lookup_fast+0x8e/0x290 fs/namei.c:1628
 walk_component+0x3f/0x230 fs/namei.c:1997
 lookup_last fs/namei.c:2458 [inline]
 path_lookupat+0x10a/0x2a0 fs/namei.c:2482
 filename_lookup+0x126/0x300 fs/namei.c:2511
 vfs_statx+0xa2/0x430 fs/stat.c:240
 vfs_fstatat+0xcd/0x100 fs/stat.c:295
 __do_sys_newfstatat fs/stat.c:459 [inline]
 __se_sys_newfstatat+0x58/0x260 fs/stat.c:453
 __x64_sys_newfstatat+0x55/0x60 fs/stat.c:453
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

value changed: 0x00280400 -> 0x00200000

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 3107 Comm: syz-executor.3 Tainted: G        W          6.6.0-rc3-syzkaller-00025-g50768a425b46 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/06/2023
==================================================================

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2023/09/27 01:54 upstream 50768a425b46 0b6a67ac .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __d_lookup_rcu / shrink_dentry_list
* Struck through repros no longer work on HEAD.