syzbot


KCSAN: data-race in link_path_walk / shrink_dentry_list (7)

Status: auto-closed as invalid on 2022/09/03 00:29
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 131d, last: 131d
similar bugs (6):
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in link_path_walk / shrink_dentry_list (5) 1 269d 269d 0/24 auto-closed as invalid on 2022/04/17 20:20
upstream KCSAN: data-race in link_path_walk / shrink_dentry_list (6) 1 207d 207d 0/24 auto-closed as invalid on 2022/06/18 02:44
upstream KCSAN: data-race in link_path_walk / shrink_dentry_list (4) 10 305d 441d 0/24 auto-closed as invalid on 2022/03/12 22:14
upstream KCSAN: data-race in link_path_walk / shrink_dentry_list (2) 3 563d 597d 0/24 auto-closed as invalid on 2021/06/27 19:17
upstream KCSAN: data-race in link_path_walk / shrink_dentry_list (3) 2 476d 481d 0/24 auto-closed as invalid on 2021/09/22 09:34
upstream KCSAN: data-race in link_path_walk / shrink_dentry_list 1 871d 871d 0/24 auto-closed as invalid on 2020/08/23 06:27

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

read-write to 0xffff8881293969c0 of 4 bytes by task 5859 on cpu 0:
 d_shrink_del fs/dcache.c:448 [inline]
 shrink_dentry_list+0x1cf/0x380 fs/dcache.c:1188
 shrink_dcache_sb+0x16d/0x2b0 fs/dcache.c:1321
 reconfigure_super+0x146/0x540 fs/super.c:888
 do_remount fs/namespace.c:2702 [inline]
 path_mount+0x984/0xb60 fs/namespace.c:3362
 do_mount fs/namespace.c:3383 [inline]
 __do_sys_mount fs/namespace.c:3591 [inline]
 __se_sys_mount+0x281/0x2d0 fs/namespace.c:3568
 __x64_sys_mount+0x63/0x70 fs/namespace.c:3568
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

read to 0xffff8881293969c0 of 4 bytes by task 28142 on cpu 1:
 __d_entry_type include/linux/dcache.h:385 [inline]
 d_can_lookup include/linux/dcache.h:400 [inline]
 link_path_walk+0x476/0x7a0 fs/namei.c:2351
 path_lookupat+0x7b/0x2b0 fs/namei.c:2492
 filename_lookup+0x130/0x310 fs/namei.c:2522
 vfs_statx+0xa3/0x3d0 fs/stat.c:228
 vfs_fstatat fs/stat.c:255 [inline]
 vfs_lstat include/linux/fs.h:3144 [inline]
 __do_sys_newlstat fs/stat.c:411 [inline]
 __se_sys_newlstat+0x6a/0x270 fs/stat.c:405
 __x64_sys_newlstat+0x2d/0x40 fs/stat.c:405
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

value changed: 0x00280400 -> 0x00200000

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 28142 Comm: syz-executor.1 Tainted: G        W         5.19.0-rc8-syzkaller-00146-ge65c6a46df94-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/22/2022
==================================================================

Crashes (1):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci2-upstream-kcsan-gce 2022/07/30 00:20 upstream e65c6a46df94 fef302b1 .config log report info KCSAN: data-race in link_path_walk / shrink_dentry_list
* Struck through repros no longer work on HEAD.