syzbot


possible deadlock in ext4_evict_inode (3)

Status: upstream: reported on 2024/04/03 10:45
Reported-by: syzbot+7e989d2df8b9013c1d98@syzkaller.appspotmail.com
First crash: 73d, last: 73d
Similar bugs (7)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream possible deadlock in ext4_evict_inode (2) ext4 18 457d 633d 0/27 auto-obsoleted due to no activity on 2023/07/14 13:24
linux-5.15 possible deadlock in ext4_evict_inode (2) 2 95d 100d 0/3 upstream: reported on 2024/03/07 16:36
upstream possible deadlock in ext4_evict_inode (3) ext4 4 11d 120d 0/27 upstream: reported on 2024/02/15 21:18
upstream possible deadlock in ext4_evict_inode ext4 syz error error 38 2070d 2109d 15/27 fixed on 2020/05/22 17:31
linux-6.1 possible deadlock in ext4_evict_inode 2 340d 449d 0/3 auto-obsoleted due to no activity on 2023/10/19 10:40
linux-6.1 possible deadlock in ext4_evict_inode (2) 1 192d 192d 0/3 auto-obsoleted due to no activity on 2024/03/15 02:58
linux-5.15 possible deadlock in ext4_evict_inode 2 441d 445d 0/3 auto-obsoleted due to no activity on 2023/07/30 00:10

Sample crash report:
======================================================
WARNING: possible circular locking dependency detected
6.1.83-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor.3/7470 is trying to acquire lock:
ffff0000fa036650 (sb_internal){.+.+}-{0:0}, at: __sb_start_write include/linux/fs.h:1891 [inline]
ffff0000fa036650 (sb_internal){.+.+}-{0:0}, at: sb_start_intwrite include/linux/fs.h:2013 [inline]
ffff0000fa036650 (sb_internal){.+.+}-{0:0}, at: ext4_evict_inode+0x408/0x12cc fs/ext4/inode.c:240

but task is already holding lock:
ffff0000db50cb98 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: ext4_ext_migrate+0x234/0xee4 fs/ext4/migrate.c:437

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #3 (&sbi->s_writepages_rwsem){++++}-{0:0}:
       percpu_down_read+0x78/0x304 include/linux/percpu-rwsem.h:51
       ext4_writepages+0x18c/0x32b4 fs/ext4/inode.c:2703
       do_writepages+0x2e8/0x56c mm/page-writeback.c:2469
       filemap_fdatawrite_wbc+0x124/0x174 mm/filemap.c:388
       __filemap_fdatawrite_range mm/filemap.c:421 [inline]
       filemap_write_and_wait_range+0x17c/0x268 mm/filemap.c:674
       __iomap_dio_rw+0x864/0x1b34 fs/iomap/direct-io.c:573
       iomap_dio_rw+0x5c/0xa8 fs/iomap/direct-io.c:690
       ext4_dio_read_iter fs/ext4/file.c:94 [inline]
       ext4_file_read_iter+0x3a0/0x4d4 fs/ext4/file.c:145
       lo_rw_aio+0x91c/0xc84
       loop_handle_cmd drivers/block/loop.c:1909 [inline]
       loop_process_work+0x68c/0x24a4 drivers/block/loop.c:1944
       loop_workfn+0x54/0x68 drivers/block/loop.c:1968
       process_one_work+0x7ac/0x1404 kernel/workqueue.c:2292
       worker_thread+0x8e4/0xfec kernel/workqueue.c:2439
       kthread+0x250/0x2d8 kernel/kthread.c:376
       ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:864

-> #2 (&sb->s_type->i_mutex_key#9){++++}-{3:3}:
       down_read+0x64/0x308 kernel/locking/rwsem.c:1520
       inode_lock_shared include/linux/fs.h:768 [inline]
       ext4_bmap+0x58/0x35c fs/ext4/inode.c:3176
       bmap+0xa8/0xe8 fs/inode.c:1842
       jbd2_journal_bmap fs/jbd2/journal.c:977 [inline]
       __jbd2_journal_erase fs/jbd2/journal.c:1794 [inline]
       jbd2_journal_flush+0x4bc/0xa5c fs/jbd2/journal.c:2496
       ext4_ioctl_checkpoint fs/ext4/ioctl.c:1086 [inline]
       __ext4_ioctl fs/ext4/ioctl.c:1594 [inline]
       ext4_ioctl+0x3834/0x6afc fs/ext4/ioctl.c:1614
       vfs_ioctl fs/ioctl.c:51 [inline]
       __do_sys_ioctl fs/ioctl.c:870 [inline]
       __se_sys_ioctl fs/ioctl.c:856 [inline]
       __arm64_sys_ioctl+0x14c/0x1c8 fs/ioctl.c:856
       __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
       invoke_syscall+0x98/0x2c0 arch/arm64/kernel/syscall.c:52
       el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
       do_el0_svc+0x64/0x218 arch/arm64/kernel/syscall.c:206
       el0_svc+0x58/0x168 arch/arm64/kernel/entry-common.c:637
       el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
       el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585

-> #1 (&journal->j_checkpoint_mutex){+.+.}-{3:3}:
       __mutex_lock_common+0x190/0x21a0 kernel/locking/mutex.c:603
       mutex_lock_io_nested+0x6c/0x88 kernel/locking/mutex.c:833
       __jbd2_log_wait_for_space+0x1a4/0x5cc fs/jbd2/checkpoint.c:71
       add_transaction_credits+0x7dc/0xafc fs/jbd2/transaction.c:298
       start_this_handle+0x5c4/0x13ac fs/jbd2/transaction.c:422
       jbd2__journal_start+0x298/0x544 fs/jbd2/transaction.c:520
       __ext4_journal_start_sb+0x304/0x6f4 fs/ext4/ext4_jbd2.c:105
       __ext4_journal_start fs/ext4/ext4_jbd2.h:326 [inline]
       ext4_evict_inode+0x7cc/0x12cc fs/ext4/inode.c:251
       evict+0x260/0x68c fs/inode.c:666
       iput_final fs/inode.c:1791 [inline]
       iput+0x7c0/0x8a4 fs/inode.c:1817
       do_unlinkat+0x530/0x70c fs/namei.c:4399
       __do_sys_unlinkat fs/namei.c:4435 [inline]
       __se_sys_unlinkat fs/namei.c:4428 [inline]
       __arm64_sys_unlinkat+0xcc/0xfc fs/namei.c:4428
       __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
       invoke_syscall+0x98/0x2c0 arch/arm64/kernel/syscall.c:52
       el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
       do_el0_svc+0x64/0x218 arch/arm64/kernel/syscall.c:206
       el0_svc+0x58/0x168 arch/arm64/kernel/entry-common.c:637
       el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
       el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585

-> #0 (sb_internal){.+.+}-{0:0}:
       check_prev_add kernel/locking/lockdep.c:3090 [inline]
       check_prevs_add kernel/locking/lockdep.c:3209 [inline]
       validate_chain kernel/locking/lockdep.c:3825 [inline]
       __lock_acquire+0x3338/0x7680 kernel/locking/lockdep.c:5049
       lock_acquire+0x26c/0x7cc kernel/locking/lockdep.c:5662
       percpu_down_read+0x78/0x304 include/linux/percpu-rwsem.h:51
       __sb_start_write include/linux/fs.h:1891 [inline]
       sb_start_intwrite include/linux/fs.h:2013 [inline]
       ext4_evict_inode+0x408/0x12cc fs/ext4/inode.c:240
       evict+0x260/0x68c fs/inode.c:666
       iput_final fs/inode.c:1791 [inline]
       iput+0x7c0/0x8a4 fs/inode.c:1817
       ext4_ext_migrate+0xc3c/0xee4 fs/ext4/migrate.c:587
       ext4_ioctl_setflags fs/ext4/ioctl.c:695 [inline]
       ext4_fileattr_set+0xc1c/0x12c8 fs/ext4/ioctl.c:1008
       vfs_fileattr_set+0x70c/0xad4 fs/ioctl.c:696
       do_vfs_ioctl+0x14cc/0x26f8
       __do_sys_ioctl fs/ioctl.c:868 [inline]
       __se_sys_ioctl fs/ioctl.c:856 [inline]
       __arm64_sys_ioctl+0xe4/0x1c8 fs/ioctl.c:856
       __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
       invoke_syscall+0x98/0x2c0 arch/arm64/kernel/syscall.c:52
       el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
       do_el0_svc+0x64/0x218 arch/arm64/kernel/syscall.c:206
       el0_svc+0x58/0x168 arch/arm64/kernel/entry-common.c:637
       el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
       el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585

other info that might help us debug this:

Chain exists of:
  sb_internal --> &sb->s_type->i_mutex_key#9 --> &sbi->s_writepages_rwsem

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&sbi->s_writepages_rwsem);
                               lock(&sb->s_type->i_mutex_key#9);
                               lock(&sbi->s_writepages_rwsem);
  lock(sb_internal);

 *** DEADLOCK ***

3 locks held by syz-executor.3/7470:
 #0: ffff0000fa036460 (sb_writers#3){.+.+}-{0:0}, at: mnt_want_write_file+0x64/0x1e8 fs/namespace.c:437
 #1: ffff0000f1be2c20 (&sb->s_type->i_mutex_key#9){++++}-{3:3}, at: inode_lock include/linux/fs.h:758 [inline]
 #1: ffff0000f1be2c20 (&sb->s_type->i_mutex_key#9){++++}-{3:3}, at: vfs_fileattr_set+0x110/0xad4 fs/ioctl.c:681
 #2: ffff0000db50cb98 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: ext4_ext_migrate+0x234/0xee4 fs/ext4/migrate.c:437

stack backtrace:
CPU: 1 PID: 7470 Comm: syz-executor.3 Not tainted 6.1.83-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
Call trace:
 dump_backtrace+0x1c8/0x1f4 arch/arm64/kernel/stacktrace.c:158
 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:165
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x108/0x170 lib/dump_stack.c:106
 dump_stack+0x1c/0x5c lib/dump_stack.c:113
 print_circular_bug+0x150/0x1b8 kernel/locking/lockdep.c:2048
 check_noncircular+0x2cc/0x378 kernel/locking/lockdep.c:2170
 check_prev_add kernel/locking/lockdep.c:3090 [inline]
 check_prevs_add kernel/locking/lockdep.c:3209 [inline]
 validate_chain kernel/locking/lockdep.c:3825 [inline]
 __lock_acquire+0x3338/0x7680 kernel/locking/lockdep.c:5049
 lock_acquire+0x26c/0x7cc kernel/locking/lockdep.c:5662
 percpu_down_read+0x78/0x304 include/linux/percpu-rwsem.h:51
 __sb_start_write include/linux/fs.h:1891 [inline]
 sb_start_intwrite include/linux/fs.h:2013 [inline]
 ext4_evict_inode+0x408/0x12cc fs/ext4/inode.c:240
 evict+0x260/0x68c fs/inode.c:666
 iput_final fs/inode.c:1791 [inline]
 iput+0x7c0/0x8a4 fs/inode.c:1817
 ext4_ext_migrate+0xc3c/0xee4 fs/ext4/migrate.c:587
 ext4_ioctl_setflags fs/ext4/ioctl.c:695 [inline]
 ext4_fileattr_set+0xc1c/0x12c8 fs/ext4/ioctl.c:1008
 vfs_fileattr_set+0x70c/0xad4 fs/ioctl.c:696
 do_vfs_ioctl+0x14cc/0x26f8
 __do_sys_ioctl fs/ioctl.c:868 [inline]
 __se_sys_ioctl fs/ioctl.c:856 [inline]
 __arm64_sys_ioctl+0xe4/0x1c8 fs/ioctl.c:856
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x2c0 arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
 do_el0_svc+0x64/0x218 arch/arm64/kernel/syscall.c:206
 el0_svc+0x58/0x168 arch/arm64/kernel/entry-common.c:637
 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/04/03 10:44 linux-6.1.y e5cd595e23c1 7925100d .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 possible deadlock in ext4_evict_inode
* Struck through repros no longer work on HEAD.