syzbot


possible deadlock in find_and_lock_process_key

Status: closed as dup on 2023/11/27 22:16
Subsystems: fscrypt
[Documentation on labels]
Reported-by: syzbot+9d04b061c581795e18ce@syzkaller.appspotmail.com
First crash: 325d, last: 221d
Duplicate of
Title Repro Cause bisect Fix bisect Count Last Reported
possible deadlock in start_this_handle (4) fscrypt ext4 101 108d 592d
Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [fscrypt?] possible deadlock in find_and_lock_process_key 1 (2) 2023/11/27 22:16

Sample crash report:
fscrypt: key with description 'fscrypt:85baa174f0cb1142' has invalid payload
fscrypt: key with description 'fscrypt:85baa174f0cb1142' has invalid payload
======================================================
WARNING: possible circular locking dependency detected
6.8.0-rc7-syzkaller-00017-g29cd507cbec2 #0 Not tainted
------------------------------------------------------
syz-executor.2/4088 is trying to acquire lock:
ffff888029660cd8 (&type->lock_class#3){++++}-{3:3}, at: find_and_lock_process_key+0x97/0x390 fs/crypto/keysetup_v1.c:112

but task is already holding lock:
ffff888024484950 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0x10dd/0x15e0 fs/jbd2/transaction.c:463

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #2 (jbd2_handle){++++}-{0:0}:
       start_this_handle+0x1103/0x15e0 fs/jbd2/transaction.c:463
       jbd2__journal_start+0x395/0x850 fs/jbd2/transaction.c:520
       __ext4_journal_start_sb+0x347/0x5e0 fs/ext4/ext4_jbd2.c:112
       __ext4_journal_start fs/ext4/ext4_jbd2.h:326 [inline]
       ext4_dirty_inode+0xa1/0x130 fs/ext4/inode.c:5939
       __mark_inode_dirty+0x1e0/0xd60 fs/fs-writeback.c:2452
       mark_inode_dirty_sync include/linux/fs.h:2387 [inline]
       iput.part.0+0x5b/0x7b0 fs/inode.c:1762
       iput+0x5c/0x80 fs/inode.c:1755
       dentry_unlink_inode+0x295/0x440 fs/dcache.c:400
       __dentry_kill+0x1d0/0x600 fs/dcache.c:603
       shrink_kill fs/dcache.c:1048 [inline]
       shrink_dentry_list+0x140/0x5d0 fs/dcache.c:1075
       prune_dcache_sb+0xeb/0x150 fs/dcache.c:1156
       super_cache_scan+0x32a/0x550 fs/super.c:221
       do_shrink_slab+0x426/0x1120 mm/shrinker.c:435
       shrink_slab+0x18a/0x1310 mm/shrinker.c:662
       shrink_one+0x493/0x7b0 mm/vmscan.c:4767
       shrink_many mm/vmscan.c:4828 [inline]
       lru_gen_shrink_node mm/vmscan.c:4929 [inline]
       shrink_node+0x214d/0x3750 mm/vmscan.c:5888
       kswapd_shrink_node mm/vmscan.c:6693 [inline]
       balance_pgdat+0x9d2/0x1a90 mm/vmscan.c:6883
       kswapd+0x5be/0xc00 mm/vmscan.c:7143
       kthread+0x2c6/0x3b0 kernel/kthread.c:388
       ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
       ret_from_fork_asm+0x1b/0x30 arch/x86/entry/entry_64.S:243

-> #1 (fs_reclaim){+.+.}-{0:0}:
       __fs_reclaim_acquire mm/page_alloc.c:3692 [inline]
       fs_reclaim_acquire+0x104/0x150 mm/page_alloc.c:3706
       might_alloc include/linux/sched/mm.h:303 [inline]
       slab_pre_alloc_hook mm/slub.c:3761 [inline]
       slab_alloc_node mm/slub.c:3842 [inline]
       __do_kmalloc_node mm/slub.c:3980 [inline]
       __kmalloc+0xb5/0x440 mm/slub.c:3994
       kmalloc include/linux/slab.h:594 [inline]
       setup_v1_file_key_derived fs/crypto/keysetup_v1.c:278 [inline]
       fscrypt_setup_v1_file_key+0x167/0x550 fs/crypto/keysetup_v1.c:299
       fscrypt_setup_v1_file_key_via_subscribed_keyrings+0x159/0x2e0 fs/crypto/keysetup_v1.c:321
       setup_file_encryption_key fs/crypto/keysetup.c:485 [inline]
       fscrypt_setup_encryption_info+0xb6d/0x1080 fs/crypto/keysetup.c:590
       fscrypt_get_encryption_info+0x3d7/0x4b0 fs/crypto/keysetup.c:675
       fscrypt_setup_filename+0x238/0xd80 fs/crypto/fname.c:458
       __fscrypt_prepare_lookup+0x2c/0xf0 fs/crypto/hooks.c:100
       fscrypt_prepare_lookup include/linux/fscrypt.h:979 [inline]
       ext4_fname_prepare_lookup+0x1e0/0x350 fs/ext4/crypto.c:48
       ext4_lookup_entry fs/ext4/namei.c:1764 [inline]
       ext4_lookup+0x14b/0x740 fs/ext4/namei.c:1839
       lookup_one_qstr_excl+0x11d/0x190 fs/namei.c:1608
       filename_create+0x1ed/0x530 fs/namei.c:3896
       do_symlinkat+0xbf/0x310 fs/namei.c:4503
       __do_sys_symlinkat fs/namei.c:4526 [inline]
       __se_sys_symlinkat fs/namei.c:4523 [inline]
       __x64_sys_symlinkat+0x97/0xc0 fs/namei.c:4523
       do_syscall_x64 arch/x86/entry/common.c:52 [inline]
       do_syscall_64+0xd5/0x270 arch/x86/entry/common.c:83
       entry_SYSCALL_64_after_hwframe+0x6f/0x77

-> #0 (&type->lock_class#3){++++}-{3:3}:
       check_prev_add kernel/locking/lockdep.c:3134 [inline]
       check_prevs_add kernel/locking/lockdep.c:3253 [inline]
       validate_chain kernel/locking/lockdep.c:3869 [inline]
       __lock_acquire+0x244f/0x3b40 kernel/locking/lockdep.c:5137
       lock_acquire kernel/locking/lockdep.c:5754 [inline]
       lock_acquire+0x1ae/0x520 kernel/locking/lockdep.c:5719
       down_read+0x9a/0x330 kernel/locking/rwsem.c:1526
       find_and_lock_process_key+0x97/0x390 fs/crypto/keysetup_v1.c:112
       fscrypt_setup_v1_file_key_via_subscribed_keyrings+0x115/0x2e0 fs/crypto/keysetup_v1.c:310
       setup_file_encryption_key fs/crypto/keysetup.c:485 [inline]
       fscrypt_setup_encryption_info+0xb6d/0x1080 fs/crypto/keysetup.c:590
       fscrypt_get_encryption_info+0x3d7/0x4b0 fs/crypto/keysetup.c:675
       fscrypt_setup_filename+0x238/0xd80 fs/crypto/fname.c:458
       ext4_fname_setup_filename+0xa3/0x260 fs/ext4/crypto.c:28
       ext4_add_entry+0x2e3/0xdf0 fs/ext4/namei.c:2401
       ext4_rename+0x16a9/0x28a0 fs/ext4/namei.c:3937
       ext4_rename2+0x1bc/0x270 fs/ext4/namei.c:4215
       vfs_rename+0xf87/0x20b0 fs/namei.c:4883
       do_renameat2+0xc54/0xdc0 fs/namei.c:5040
       __do_sys_renameat fs/namei.c:5081 [inline]
       __se_sys_renameat fs/namei.c:5078 [inline]
       __x64_sys_renameat+0xc6/0x100 fs/namei.c:5078
       do_syscall_x64 arch/x86/entry/common.c:52 [inline]
       do_syscall_64+0xd5/0x270 arch/x86/entry/common.c:83
       entry_SYSCALL_64_after_hwframe+0x6f/0x77

other info that might help us debug this:

Chain exists of:
  &type->lock_class#3 --> fs_reclaim --> jbd2_handle

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  rlock(jbd2_handle);
                               lock(fs_reclaim);
                               lock(jbd2_handle);
  rlock(&type->lock_class#3);

 *** DEADLOCK ***

6 locks held by syz-executor.2/4088:
 #0: ffff888024480420 (sb_writers#5){.+.+}-{0:0}, at: do_renameat2+0x3d6/0xdc0 fs/namei.c:4970
 #1: ffff888024480708 (&type->s_vfs_rename_key#2){+.+.}-{3:3}, at: lock_rename fs/namei.c:3073 [inline]
 #1: ffff888024480708 (&type->s_vfs_rename_key#2){+.+.}-{3:3}, at: do_renameat2+0x4ef/0xdc0 fs/namei.c:4975
 #2: ffff88802e932c00 (&type->i_mutex_dir_key#3/1){+.+.}-{3:3}, at: inode_lock_nested include/linux/fs.h:839 [inline]
 #2: ffff88802e932c00 (&type->i_mutex_dir_key#3/1){+.+.}-{3:3}, at: lock_two_directories+0x92/0x2d0 fs/namei.c:3039
 #3: ffff888060038400 (&type->i_mutex_dir_key#3/5){+.+.}-{3:3}, at: inode_lock_nested include/linux/fs.h:839 [inline]
 #3: ffff888060038400 (&type->i_mutex_dir_key#3/5){+.+.}-{3:3}, at: lock_two_directories+0xc6/0x2d0 fs/namei.c:3040
 #4: ffff88801933f200 (&type->i_mutex_dir_key#3/2){+.+.}-{3:3}, at: inode_lock_nested include/linux/fs.h:839 [inline]
 #4: ffff88801933f200 (&type->i_mutex_dir_key#3/2){+.+.}-{3:3}, at: vfs_rename+0x117e/0x20b0 fs/namei.c:4846
 #5: ffff888024484950 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0x10dd/0x15e0 fs/jbd2/transaction.c:463

stack backtrace:
CPU: 2 PID: 4088 Comm: syz-executor.2 Not tainted 6.8.0-rc7-syzkaller-00017-g29cd507cbec2 #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xd9/0x1b0 lib/dump_stack.c:106
 check_noncircular+0x31b/0x400 kernel/locking/lockdep.c:2187
 check_prev_add kernel/locking/lockdep.c:3134 [inline]
 check_prevs_add kernel/locking/lockdep.c:3253 [inline]
 validate_chain kernel/locking/lockdep.c:3869 [inline]
 __lock_acquire+0x244f/0x3b40 kernel/locking/lockdep.c:5137
 lock_acquire kernel/locking/lockdep.c:5754 [inline]
 lock_acquire+0x1ae/0x520 kernel/locking/lockdep.c:5719
 down_read+0x9a/0x330 kernel/locking/rwsem.c:1526
 find_and_lock_process_key+0x97/0x390 fs/crypto/keysetup_v1.c:112
 fscrypt_setup_v1_file_key_via_subscribed_keyrings+0x115/0x2e0 fs/crypto/keysetup_v1.c:310
 setup_file_encryption_key fs/crypto/keysetup.c:485 [inline]
 fscrypt_setup_encryption_info+0xb6d/0x1080 fs/crypto/keysetup.c:590
 fscrypt_get_encryption_info+0x3d7/0x4b0 fs/crypto/keysetup.c:675
 fscrypt_setup_filename+0x238/0xd80 fs/crypto/fname.c:458
 ext4_fname_setup_filename+0xa3/0x260 fs/ext4/crypto.c:28
 ext4_add_entry+0x2e3/0xdf0 fs/ext4/namei.c:2401
 ext4_rename+0x16a9/0x28a0 fs/ext4/namei.c:3937
 ext4_rename2+0x1bc/0x270 fs/ext4/namei.c:4215
 vfs_rename+0xf87/0x20b0 fs/namei.c:4883
 do_renameat2+0xc54/0xdc0 fs/namei.c:5040
 __do_sys_renameat fs/namei.c:5081 [inline]
 __se_sys_renameat fs/namei.c:5078 [inline]
 __x64_sys_renameat+0xc6/0x100 fs/namei.c:5078
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xd5/0x270 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x6f/0x77
RIP: 0033:0x7fb76cc7dda9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fb76d9fc0c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000108
RAX: ffffffffffffffda RBX: 00007fb76cdabf80 RCX: 00007fb76cc7dda9
RDX: 0000000000000004 RSI: 0000000020000100 RDI: ffffffffffffff9c
RBP: 00007fb76ccca47a R08: 0000000000000000 R09: 0000000000000000
R10: 0000000020000140 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000000b R14: 00007fb76cdabf80 R15: 00007ffc80b01f98
 </TASK>
fscrypt: key with description 'fscrypt:85baa174f0cb1142' has invalid payload

Crashes (6):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/03/05 23:44 upstream 29cd507cbec2 f39a7eed .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream possible deadlock in find_and_lock_process_key
2024/02/29 00:27 upstream e326df53af00 352ab904 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream possible deadlock in find_and_lock_process_key
2024/02/26 12:33 upstream d206a76d7d27 23536c23 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream possible deadlock in find_and_lock_process_key
2023/12/13 10:00 upstream 88035e5694a8 ebcad15c .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream possible deadlock in find_and_lock_process_key
2023/12/08 12:09 upstream 5e3f5b81de80 28b24332 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream possible deadlock in find_and_lock_process_key
2023/11/22 20:51 upstream 9b6de136b5f0 03e12510 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream possible deadlock in find_and_lock_process_key
* Struck through repros no longer work on HEAD.