syzbot


possible deadlock in fscrypt_initialize

Status: upstream: reported on 2022/04/21 01:05
Reported-by: syzbot+1a748d0007eeac3ab079@syzkaller.appspotmail.com
First crash: 169d, last: 9d08h
duplicates (1):
Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
possible deadlock in evict (2) 22 9h44m 165d 0/24 closed as dup on 2022/04/21 19:37

Sample crash report:
======================================================
WARNING: possible circular locking dependency detected
6.0.0-rc3-syzkaller-00215-g0b3acd1cc022 #0 Not tainted
------------------------------------------------------
syz-executor.1/3708 is trying to acquire lock:
ffffffff8c141968 (fscrypt_init_mutex){+.+.}-{3:3}, at: fscrypt_initialize+0x3c/0xa0 fs/crypto/crypto.c:324

but task is already holding lock:
ffff888044666990 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0xfb4/0x14a0 fs/jbd2/transaction.c:461

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #2 (jbd2_handle){++++}-{0:0}:
       start_this_handle+0xfe7/0x14a0 fs/jbd2/transaction.c:463
       jbd2__journal_start+0x38c/0x910 fs/jbd2/transaction.c:520
       __ext4_journal_start_sb+0x3a3/0x490 fs/ext4/ext4_jbd2.c:105
       __ext4_journal_start fs/ext4/ext4_jbd2.h:326 [inline]
       ext4_dirty_inode+0x9d/0x110 fs/ext4/inode.c:5963
       __mark_inode_dirty+0x48b/0x1040 fs/fs-writeback.c:2381
       mark_inode_dirty_sync include/linux/fs.h:2467 [inline]
       iput.part.0+0x57/0x810 fs/inode.c:1771
       iput+0x58/0x70 fs/inode.c:1764
       dentry_unlink_inode+0x2b1/0x460 fs/dcache.c:401
       __dentry_kill+0x3c0/0x640 fs/dcache.c:607
       shrink_dentry_list+0x23c/0x800 fs/dcache.c:1201
       prune_dcache_sb+0xe7/0x140 fs/dcache.c:1282
       super_cache_scan+0x336/0x590 fs/super.c:104
       do_shrink_slab+0x428/0xbd0 mm/vmscan.c:831
       shrink_slab+0x17c/0x6f0 mm/vmscan.c:991
       shrink_node_memcgs mm/vmscan.c:3182 [inline]
       shrink_node+0x8c9/0x1e80 mm/vmscan.c:3304
       kswapd_shrink_node mm/vmscan.c:4086 [inline]
       balance_pgdat+0x8ef/0x1580 mm/vmscan.c:4277
       kswapd+0x79b/0xf80 mm/vmscan.c:4537
       kthread+0x2e4/0x3a0 kernel/kthread.c:376
       ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306

-> #1 (fs_reclaim){+.+.}-{0:0}:
       __fs_reclaim_acquire mm/page_alloc.c:4674 [inline]
       fs_reclaim_acquire+0x115/0x160 mm/page_alloc.c:4688
       might_alloc include/linux/sched/mm.h:271 [inline]
       slab_pre_alloc_hook mm/slab.h:700 [inline]
       slab_alloc_node mm/slab.c:3194 [inline]
       kmem_cache_alloc_node_trace+0x47/0x570 mm/slab.c:3601
       kmalloc_node include/linux/slab.h:618 [inline]
       kzalloc_node include/linux/slab.h:744 [inline]
       mempool_create_node mm/mempool.c:266 [inline]
       mempool_create+0x4e/0xc0 mm/mempool.c:255
       mempool_create_page_pool include/linux/mempool.h:107 [inline]
       fscrypt_initialize+0x86/0xa0 fs/crypto/crypto.c:330
       fscrypt_setup_encryption_info+0xef/0xe90 fs/crypto/keysetup.c:538
       fscrypt_get_encryption_info+0x34a/0x3f0 fs/crypto/keysetup.c:647
       fscrypt_setup_filename+0x238/0xec0 fs/crypto/fname.c:458
       __fscrypt_prepare_lookup+0x28/0xf0 fs/crypto/hooks.c:102
       fscrypt_prepare_lookup include/linux/fscrypt.h:952 [inline]
       ext4_fname_prepare_lookup+0x1ba/0x200 fs/ext4/crypto.c:46
       ext4_lookup_entry fs/ext4/namei.c:1740 [inline]
       ext4_lookup fs/ext4/namei.c:1815 [inline]
       ext4_lookup+0x12d/0x700 fs/ext4/namei.c:1806
       __lookup_slow+0x24c/0x460 fs/namei.c:1685
       lookup_slow fs/namei.c:1702 [inline]
       walk_component+0x33f/0x5a0 fs/namei.c:1993
       lookup_last fs/namei.c:2450 [inline]
       path_lookupat+0x1ba/0x840 fs/namei.c:2474
       filename_lookup+0x1ce/0x590 fs/namei.c:2503
       user_path_at_empty+0x42/0x60 fs/namei.c:2876
       user_path_at include/linux/namei.h:57 [inline]
       __do_sys_fspick fs/fsopen.c:181 [inline]
       __se_sys_fspick fs/fsopen.c:158 [inline]
       __x64_sys_fspick+0x180/0x380 fs/fsopen.c:158
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x63/0xcd

-> #0 (fscrypt_init_mutex){+.+.}-{3:3}:
       check_prev_add kernel/locking/lockdep.c:3095 [inline]
       check_prevs_add kernel/locking/lockdep.c:3214 [inline]
       validate_chain kernel/locking/lockdep.c:3829 [inline]
       __lock_acquire+0x2a43/0x56d0 kernel/locking/lockdep.c:5053
       lock_acquire kernel/locking/lockdep.c:5666 [inline]
       lock_acquire+0x1ab/0x570 kernel/locking/lockdep.c:5631
       __mutex_lock_common kernel/locking/mutex.c:603 [inline]
       __mutex_lock+0x12f/0x1350 kernel/locking/mutex.c:747
       fscrypt_initialize+0x3c/0xa0 fs/crypto/crypto.c:324
       fscrypt_setup_encryption_info+0xef/0xe90 fs/crypto/keysetup.c:538
       fscrypt_get_encryption_info+0x34a/0x3f0 fs/crypto/keysetup.c:647
       fscrypt_setup_filename+0x238/0xec0 fs/crypto/fname.c:458
       ext4_fname_setup_filename+0x88/0x110 fs/ext4/crypto.c:28
       ext4_find_entry fs/ext4/namei.c:1720 [inline]
       __ext4_unlink+0xa6/0x9d0 fs/ext4/namei.c:3202
       ext4_unlink+0x5b0/0x9d0 fs/ext4/namei.c:3278
       vfs_unlink+0x351/0x920 fs/namei.c:4229
       do_unlinkat+0x3cc/0x650 fs/namei.c:4297
       __do_sys_unlink fs/namei.c:4345 [inline]
       __se_sys_unlink fs/namei.c:4343 [inline]
       __x64_sys_unlink+0xc6/0x110 fs/namei.c:4343
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x63/0xcd

other info that might help us debug this:

Chain exists of:
  fscrypt_init_mutex --> fs_reclaim --> jbd2_handle

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(jbd2_handle);
                               lock(fs_reclaim);
                               lock(jbd2_handle);
  lock(fscrypt_init_mutex);

 *** DEADLOCK ***

4 locks held by syz-executor.1/3708:
 #0: ffff888044722460 (sb_writers#5){.+.+}-{0:0}, at: do_unlinkat+0x17f/0x650 fs/namei.c:4276
 #1: ffff888028af6800 (&type->i_mutex_dir_key#3/1){+.+.}-{3:3}, at: inode_lock_nested include/linux/fs.h:791 [inline]
 #1: ffff888028af6800 (&type->i_mutex_dir_key#3/1){+.+.}-{3:3}, at: do_unlinkat+0x26c/0x650 fs/namei.c:4280
 #2: ffff888028bea840 (&sb->s_type->i_mutex_key#7){++++}-{3:3}, at: inode_lock include/linux/fs.h:756 [inline]
 #2: ffff888028bea840 (&sb->s_type->i_mutex_key#7){++++}-{3:3}, at: vfs_unlink+0xd5/0x920 fs/namei.c:4218
 #3: ffff888044666990 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0xfb4/0x14a0 fs/jbd2/transaction.c:461

stack backtrace:
CPU: 1 PID: 3708 Comm: syz-executor.1 Not tainted 6.0.0-rc3-syzkaller-00215-g0b3acd1cc022 #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.14.0-2 04/01/2014
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
 check_noncircular+0x25f/0x2e0 kernel/locking/lockdep.c:2175
 check_prev_add kernel/locking/lockdep.c:3095 [inline]
 check_prevs_add kernel/locking/lockdep.c:3214 [inline]
 validate_chain kernel/locking/lockdep.c:3829 [inline]
 __lock_acquire+0x2a43/0x56d0 kernel/locking/lockdep.c:5053
 lock_acquire kernel/locking/lockdep.c:5666 [inline]
 lock_acquire+0x1ab/0x570 kernel/locking/lockdep.c:5631
 __mutex_lock_common kernel/locking/mutex.c:603 [inline]
 __mutex_lock+0x12f/0x1350 kernel/locking/mutex.c:747
 fscrypt_initialize+0x3c/0xa0 fs/crypto/crypto.c:324
 fscrypt_setup_encryption_info+0xef/0xe90 fs/crypto/keysetup.c:538
 fscrypt_get_encryption_info+0x34a/0x3f0 fs/crypto/keysetup.c:647
 fscrypt_setup_filename+0x238/0xec0 fs/crypto/fname.c:458
 ext4_fname_setup_filename+0x88/0x110 fs/ext4/crypto.c:28
 ext4_find_entry fs/ext4/namei.c:1720 [inline]
 __ext4_unlink+0xa6/0x9d0 fs/ext4/namei.c:3202
 ext4_unlink+0x5b0/0x9d0 fs/ext4/namei.c:3278
 vfs_unlink+0x351/0x920 fs/namei.c:4229
 do_unlinkat+0x3cc/0x650 fs/namei.c:4297
 __do_sys_unlink fs/namei.c:4345 [inline]
 __se_sys_unlink fs/namei.c:4343 [inline]
 __x64_sys_unlink+0xc6/0x110 fs/namei.c:4343
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f199f088bb7
Code: 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 b8 57 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fff999a9378 EFLAGS: 00000206 ORIG_RAX: 0000000000000057
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f199f088bb7
RDX: 00007fff999a93b0 RSI: 00007fff999a93b0 RDI: 00007fff999a9440
RBP: 00007fff999a9440 R08: 0000000000000001 R09: 00007fff999a9210
R10: 00005555571b0893 R11: 0000000000000206 R12: 00007f199f0e242e
R13: 00007fff999aa540 R14: 00005555571b0850 R15: 00007fff999ab640
 </TASK>

Crashes (9):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci-qemu-upstream 2022/09/03 04:05 upstream 0b3acd1cc022 49e94a20 .config log report info possible deadlock in fscrypt_initialize
ci-qemu-upstream 2022/08/10 11:19 upstream 200e340f2196 aaa9eaa0 .config log report info possible deadlock in fscrypt_initialize
ci-qemu-upstream 2022/07/30 05:26 upstream e65c6a46df94 fef302b1 .config log report info possible deadlock in fscrypt_initialize
ci-qemu-upstream 2022/07/27 23:44 upstream 4a57a8400075 fb95c74d .config log report info possible deadlock in fscrypt_initialize
ci-qemu-upstream 2022/06/29 12:18 upstream 941e3e791269 1434eec0 .config log report info possible deadlock in fscrypt_initialize
ci-qemu-upstream 2022/05/05 13:01 upstream a7391ad35724 b3f09415 .config log report info possible deadlock in fscrypt_initialize
ci-qemu-upstream 2022/04/17 01:01 upstream 90ea17a9e27b 8bcc32a6 .config log report info possible deadlock in fscrypt_initialize
ci-qemu-upstream-386 2022/09/24 12:39 upstream a63f2e7cb110 0042f2b4 .config log report info possible deadlock in fscrypt_initialize
ci-qemu-upstream-386 2022/09/03 17:09 upstream d895ec7938c4 28811d0a .config log report info possible deadlock in fscrypt_initialize
* Struck through repros no longer work on HEAD.