syzbot

 sign-in | mailing list | source | docs
🐞 Open [969] ≡ Subsystems 🐞 Fixed [4558] 🐞 Invalid [10510] 📈 Kernel Health 📈 Bug Lifetimes 📈 Fuzzing 📈 Crashes 💬 Send us feedback

possible deadlock in delete_one_xattr (2)

Status: upstream: reported C repro on 2023/03/02 10:40
Labels: reiserfs (incorrect?)
Reported-by: syzbot+7a278bf8bfa794494110@syzkaller.appspotmail.com
First crash: 96d, last: 4d00h

Cause bisection: failed (error log, bisect log)
▶ ▼ Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [reiserfs?] possible deadlock in delete_one_xattr (2) 0 (2) 2023/05/08 16:48
▶ ▼ Similar bugs (3)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-4.19 possible deadlock in delete_one_xattr reiserfs 2 113d 174d 0/1 upstream: reported on 2022/12/10 02:38
upstream possible deadlock in delete_one_xattr reiserfs C error 4 114d 114d 0/24 closed as invalid on 2023/02/08 16:28
linux-4.14 possible deadlock in delete_one_xattr reiserfs 1 113d 113d 0/1 upstream: reported on 2023/02/08 17:45

Sample crash report:
overlayfs: upper fs needs to support d_type.
overlayfs: upper fs does not support tmpfile.
overlayfs: upper fs does not support RENAME_WHITEOUT.
======================================================
WARNING: possible circular locking dependency detected
6.4.0-rc1-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor174/4998 is trying to acquire lock:
ffff888073d4aaa0 (&type->i_mutex_dir_key#6/2){+.+.}-{3:3}, at: inode_lock_nested include/linux/fs.h:810 [inline]
ffff888073d4aaa0 (&type->i_mutex_dir_key#6/2){+.+.}-{3:3}, at: xattr_rmdir fs/reiserfs/xattr.c:107 [inline]
ffff888073d4aaa0 (&type->i_mutex_dir_key#6/2){+.+.}-{3:3}, at: delete_one_xattr+0x141/0x2d0 fs/reiserfs/xattr.c:339

but task is already holding lock:
ffff888073d496c0 (&type->i_mutex_dir_key#6/3){+.+.}-{3:3}, at: inode_lock_nested include/linux/fs.h:810 [inline]
ffff888073d496c0 (&type->i_mutex_dir_key#6/3){+.+.}-{3:3}, at: reiserfs_for_each_xattr+0x6fd/0x9a0 fs/reiserfs/xattr.c:310

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #2 (&type->i_mutex_dir_key#6/3){+.+.}-{3:3}:
       down_write_nested+0x96/0x200 kernel/locking/rwsem.c:1689
       inode_lock_nested include/linux/fs.h:810 [inline]
       open_xa_root fs/reiserfs/xattr.c:128 [inline]
       open_xa_dir+0x127/0x840 fs/reiserfs/xattr.c:153
       xattr_lookup+0x21/0x3d0 fs/reiserfs/xattr.c:396
       reiserfs_xattr_set_handle+0xfb/0xb00 fs/reiserfs/xattr.c:534
       reiserfs_xattr_set+0x454/0x5b0 fs/reiserfs/xattr.c:634
       trusted_set+0xa7/0xd0 fs/reiserfs/xattr_trusted.c:31
       __vfs_setxattr+0x173/0x1e0 fs/xattr.c:201
       __vfs_setxattr_noperm+0x129/0x5f0 fs/xattr.c:235
       __vfs_setxattr_locked+0x1d3/0x260 fs/xattr.c:296
       vfs_setxattr+0x143/0x340 fs/xattr.c:322
       ovl_do_setxattr fs/overlayfs/overlayfs.h:255 [inline]
       ovl_setxattr fs/overlayfs/overlayfs.h:267 [inline]
       ovl_make_workdir fs/overlayfs/super.c:1332 [inline]
       ovl_get_workdir fs/overlayfs/super.c:1436 [inline]
       ovl_fill_super+0x2276/0x7270 fs/overlayfs/super.c:1992
       mount_nodev+0x64/0x120 fs/super.c:1426
       legacy_get_tree+0x109/0x220 fs/fs_context.c:610
       vfs_get_tree+0x8d/0x350 fs/super.c:1510
       do_new_mount fs/namespace.c:3039 [inline]
       path_mount+0x134b/0x1e40 fs/namespace.c:3369
       do_mount fs/namespace.c:3382 [inline]
       __do_sys_mount fs/namespace.c:3591 [inline]
       __se_sys_mount fs/namespace.c:3568 [inline]
       __x64_sys_mount+0x283/0x300 fs/namespace.c:3568
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x63/0xcd

-> #1 (&type->i_mutex_dir_key#6){++++}-{3:3}:
       down_write+0x92/0x200 kernel/locking/rwsem.c:1573
       inode_lock include/linux/fs.h:775 [inline]
       vfs_rename+0x4f9/0x17a0 fs/namei.c:4821
       do_renameat2+0xc04/0xd40 fs/namei.c:5002
       __do_sys_rename fs/namei.c:5048 [inline]
       __se_sys_rename fs/namei.c:5046 [inline]
       __x64_sys_rename+0x81/0xa0 fs/namei.c:5046
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x63/0xcd

-> #0 (&type->i_mutex_dir_key#6/2){+.+.}-{3:3}:
       check_prev_add kernel/locking/lockdep.c:3108 [inline]
       check_prevs_add kernel/locking/lockdep.c:3227 [inline]
       validate_chain kernel/locking/lockdep.c:3842 [inline]
       __lock_acquire+0x2f21/0x5df0 kernel/locking/lockdep.c:5074
       lock_acquire kernel/locking/lockdep.c:5691 [inline]
       lock_acquire+0x1b1/0x520 kernel/locking/lockdep.c:5656
       down_write_nested+0x96/0x200 kernel/locking/rwsem.c:1689
       inode_lock_nested include/linux/fs.h:810 [inline]
       xattr_rmdir fs/reiserfs/xattr.c:107 [inline]
       delete_one_xattr+0x141/0x2d0 fs/reiserfs/xattr.c:339
       reiserfs_for_each_xattr+0x70e/0x9a0 fs/reiserfs/xattr.c:312
       reiserfs_delete_xattrs+0x20/0xa0 fs/reiserfs/xattr.c:365
       reiserfs_evict_inode+0x2e7/0x540 fs/reiserfs/inode.c:53
       evict+0x2ed/0x6b0 fs/inode.c:665
       iput_final fs/inode.c:1747 [inline]
       iput.part.0+0x50a/0x740 fs/inode.c:1773
       iput+0x5c/0x80 fs/inode.c:1763
       dentry_unlink_inode+0x2b1/0x460 fs/dcache.c:401
       __dentry_kill+0x3c0/0x640 fs/dcache.c:607
       dentry_kill fs/dcache.c:745 [inline]
       dput+0x6ac/0xe10 fs/dcache.c:913
       cleanup_mnt+0x286/0x3d0 fs/namespace.c:1176
       task_work_run+0x16f/0x270 kernel/task_work.c:179
       exit_task_work include/linux/task_work.h:38 [inline]
       do_exit+0xad3/0x2960 kernel/exit.c:871
       do_group_exit+0xd4/0x2a0 kernel/exit.c:1021
       __do_sys_exit_group kernel/exit.c:1032 [inline]
       __se_sys_exit_group kernel/exit.c:1030 [inline]
       __x64_sys_exit_group+0x3e/0x50 kernel/exit.c:1030
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x63/0xcd

other info that might help us debug this:

Chain exists of:
  &type->i_mutex_dir_key#6/2 --> &type->i_mutex_dir_key#6 --> &type->i_mutex_dir_key#6/3

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&type->i_mutex_dir_key#6/3);
                               lock(&type->i_mutex_dir_key#6);
                               lock(&type->i_mutex_dir_key#6/3);
  lock(&type->i_mutex_dir_key#6/2);

 *** DEADLOCK ***

1 lock held by syz-executor174/4998:
 #0: ffff888073d496c0 (&type->i_mutex_dir_key#6/3){+.+.}-{3:3}, at: inode_lock_nested include/linux/fs.h:810 [inline]
 #0: ffff888073d496c0 (&type->i_mutex_dir_key#6/3){+.+.}-{3:3}, at: reiserfs_for_each_xattr+0x6fd/0x9a0 fs/reiserfs/xattr.c:310

stack backtrace:
CPU: 0 PID: 4998 Comm: syz-executor174 Not tainted 6.4.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/14/2023
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xd9/0x150 lib/dump_stack.c:106
 check_noncircular+0x25f/0x2e0 kernel/locking/lockdep.c:2188
 check_prev_add kernel/locking/lockdep.c:3108 [inline]
 check_prevs_add kernel/locking/lockdep.c:3227 [inline]
 validate_chain kernel/locking/lockdep.c:3842 [inline]
 __lock_acquire+0x2f21/0x5df0 kernel/locking/lockdep.c:5074
 lock_acquire kernel/locking/lockdep.c:5691 [inline]
 lock_acquire+0x1b1/0x520 kernel/locking/lockdep.c:5656
 down_write_nested+0x96/0x200 kernel/locking/rwsem.c:1689
 inode_lock_nested include/linux/fs.h:810 [inline]
 xattr_rmdir fs/reiserfs/xattr.c:107 [inline]
 delete_one_xattr+0x141/0x2d0 fs/reiserfs/xattr.c:339
 reiserfs_for_each_xattr+0x70e/0x9a0 fs/reiserfs/xattr.c:312
 reiserfs_delete_xattrs+0x20/0xa0 fs/reiserfs/xattr.c:365
 reiserfs_evict_inode+0x2e7/0x540 fs/reiserfs/inode.c:53
 evict+0x2ed/0x6b0 fs/inode.c:665
 iput_final fs/inode.c:1747 [inline]
 iput.part.0+0x50a/0x740 fs/inode.c:1773
 iput+0x5c/0x80 fs/inode.c:1763
 dentry_unlink_inode+0x2b1/0x460 fs/dcache.c:401
 __dentry_kill+0x3c0/0x640 fs/dcache.c:607
 dentry_kill fs/dcache.c:745 [inline]
 dput+0x6ac/0xe10 fs/dcache.c:913
 cleanup_mnt+0x286/0x3d0 fs/namespace.c:1176
 task_work_run+0x16f/0x270 kernel/task_work.c:179
 exit_task_work include/linux/task_work.h:38 [inline]
 do_exit+0xad3/0x2960 kernel/exit.c:871
 do_group_exit+0xd4/0x2a0 kernel/exit.c:1021
 __do_sys_exit_group kernel/exit.c:1032 [inline]
 __se_sys_exit_group kernel/exit.c:1030 [inline]
 __x64_sys_exit_group+0x3e/0x50 kernel/exit.c:1030
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f73aae31bb9
Code: Unable to access opcode bytes at 0x7f73aae31b8f.
RSP: 002b:00007fff0a6df368 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 00007f73aaea8330 RCX: 00007f73aae31bb9
RDX: 000000000000003c RSI: 00000000000000e7 RDI: 0000000000000001
RBP: 0000000000000001 R08: ffffffffffffffc0 R09: 00007f73aaea2e40
R10: 00007f73aaea2

Crashes (3):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets Manager Title
2023/05/08 16:47 upstream ac9a78681b92 90c93c40 .config strace log report syz C [disk image] [vmlinux] [kernel image] [mounted in repro] ci-upstream-kasan-gce-root possible deadlock in delete_one_xattr
2023/05/29 15:53 linux-next 715abedee4cd cf184559 .config strace log report syz C [disk image] [vmlinux] [kernel image] [mounted in repro] ci-upstream-linux-next-kasan-gce-root possible deadlock in delete_one_xattr
2023/02/26 10:33 upstream 2fcd07b7ccd5 ee50e71c .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root possible deadlock in delete_one_xattr
* Struck through repros no longer work on HEAD.