syzbot


possible deadlock in ext4_ind_migrate

Status: upstream: reported on 2024/02/22 14:12
Reported-by: syzbot+fd478d786efc5e8813e9@syzkaller.appspotmail.com
First crash: 74d, last: 74d
Similar bugs (1)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream possible deadlock in ext4_ind_migrate ext4 1 509d 505d 0/26 auto-obsoleted due to no activity on 2023/04/13 14:51

Sample crash report:
======================================================
WARNING: possible circular locking dependency detected
5.15.148-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor.0/4013 is trying to acquire lock:
ffff0000d48b6bd8 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: ext4_ind_migrate+0x170/0x58c fs/ext4/migrate.c:625

but task is already holding lock:
ffff00012198abd0 (&sb->s_type->i_mutex_key#9){++++}-{3:3}, at: inode_lock include/linux/fs.h:787 [inline]
ffff00012198abd0 (&sb->s_type->i_mutex_key#9){++++}-{3:3}, at: vfs_fileattr_set+0x110/0xad4 fs/ioctl.c:685

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #2 (&sb->s_type->i_mutex_key#9){++++}-{3:3}:
       down_read+0xc0/0x398 kernel/locking/rwsem.c:1488
       inode_lock_shared include/linux/fs.h:797 [inline]
       ext4_bmap+0x58/0x36c fs/ext4/inode.c:3152
       bmap+0xa8/0xe8 fs/inode.c:1756
       jbd2_journal_bmap fs/jbd2/journal.c:980 [inline]
       __jbd2_journal_erase fs/jbd2/journal.c:1790 [inline]
       jbd2_journal_flush+0x63c/0xaa0 fs/jbd2/journal.c:2496
       ext4_ioctl_checkpoint fs/ext4/ioctl.c:849 [inline]
       __ext4_ioctl fs/ext4/ioctl.c:1267 [inline]
       ext4_ioctl+0x3454/0x61bc fs/ext4/ioctl.c:1276
       vfs_ioctl fs/ioctl.c:51 [inline]
       __do_sys_ioctl fs/ioctl.c:874 [inline]
       __se_sys_ioctl fs/ioctl.c:860 [inline]
       __arm64_sys_ioctl+0x14c/0x1c8 fs/ioctl.c:860
       __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
       invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52
       el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
       do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181
       el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:608
       el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:626
       el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584

-> #1 (&journal->j_checkpoint_mutex){+.+.}-{3:3}:
       __mutex_lock_common+0x194/0x2154 kernel/locking/mutex.c:596
       mutex_lock_io_nested+0xcc/0x12c kernel/locking/mutex.c:777
       __jbd2_log_wait_for_space+0x1a4/0x5cc fs/jbd2/checkpoint.c:71
       add_transaction_credits+0x814/0xb90 fs/jbd2/transaction.c:299
       start_this_handle+0x578/0x12a4 fs/jbd2/transaction.c:423
       jbd2__journal_start+0x29c/0x7b4 fs/jbd2/transaction.c:521
       __ext4_journal_start_sb+0x358/0x70c fs/ext4/ext4_jbd2.c:105
       __ext4_journal_start fs/ext4/ext4_jbd2.h:326 [inline]
       ext4_ind_migrate+0x1d0/0x58c fs/ext4/migrate.c:627
       ext4_ioctl_setflags fs/ext4/ioctl.c:457 [inline]
       ext4_fileattr_set+0xbe0/0x12d0 fs/ext4/ioctl.c:765
       vfs_fileattr_set+0x70c/0xad4 fs/ioctl.c:700
       do_vfs_ioctl+0x1634/0x2a38
       __do_sys_ioctl fs/ioctl.c:872 [inline]
       __se_sys_ioctl fs/ioctl.c:860 [inline]
       __arm64_sys_ioctl+0xe4/0x1c8 fs/ioctl.c:860
       __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
       invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52
       el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
       do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181
       el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:608
       el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:626
       el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584

-> #0
 (
&sbi->s_writepages_rwsem
){++++}-{0:0}
:
       check_prev_add kernel/locking/lockdep.c:3053 [inline]
       check_prevs_add kernel/locking/lockdep.c:3172 [inline]
       validate_chain kernel/locking/lockdep.c:3788 [inline]
       __lock_acquire+0x32d4/0x7638 kernel/locking/lockdep.c:5012
       lock_acquire+0x240/0x77c kernel/locking/lockdep.c:5623
       percpu_down_write+0xd8/0x3b0 kernel/locking/percpu-rwsem.c:217
       ext4_ind_migrate+0x170/0x58c fs/ext4/migrate.c:625
       ext4_ioctl_setflags fs/ext4/ioctl.c:457 [inline]
       ext4_fileattr_set+0xbe0/0x12d0 fs/ext4/ioctl.c:765
       vfs_fileattr_set+0x70c/0xad4 fs/ioctl.c:700
       do_vfs_ioctl+0x1634/0x2a38
       __do_sys_ioctl fs/ioctl.c:872 [inline]
       __se_sys_ioctl fs/ioctl.c:860 [inline]
       __arm64_sys_ioctl+0xe4/0x1c8 fs/ioctl.c:860
       __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
       invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52
       el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
       do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181
       el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:608
       el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:626
       el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584

other info that might help us debug this:

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


 Possible unsafe locking scenario:

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

 *** DEADLOCK ***

2 locks held by syz-executor.0/4013:
 #0: ffff0000d48b4460 (sb_writers#3){.+.+}-{0:0}, at: mnt_want_write_file+0x64/0x1e8 fs/namespace.c:421
 #1: ffff00012198abd0 (&sb->s_type->i_mutex_key#9){++++}-{3:3}, at: inode_lock include/linux/fs.h:787 [inline]
 #1: ffff00012198abd0 (&sb->s_type->i_mutex_key#9){++++}-{3:3}, at: vfs_fileattr_set+0x110/0xad4 fs/ioctl.c:685

stack backtrace:
CPU: 0 PID: 4013 Comm: syz-executor.0 Not tainted 5.15.148-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024
Call trace:
 dump_backtrace+0x0/0x530 arch/arm64/kernel/stacktrace.c:152
 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:216
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x108/0x170 lib/dump_stack.c:106
 dump_stack+0x1c/0x58 lib/dump_stack.c:113
 print_circular_bug+0x150/0x1b8 kernel/locking/lockdep.c:2011
 check_noncircular+0x2cc/0x378 kernel/locking/lockdep.c:2133
 check_prev_add kernel/locking/lockdep.c:3053 [inline]
 check_prevs_add kernel/locking/lockdep.c:3172 [inline]
 validate_chain kernel/locking/lockdep.c:3788 [inline]
 __lock_acquire+0x32d4/0x7638 kernel/locking/lockdep.c:5012
 lock_acquire+0x240/0x77c kernel/locking/lockdep.c:5623
 percpu_down_write+0xd8/0x3b0 kernel/locking/percpu-rwsem.c:217
 ext4_ind_migrate+0x170/0x58c fs/ext4/migrate.c:625
 ext4_ioctl_setflags fs/ext4/ioctl.c:457 [inline]
 ext4_fileattr_set+0xbe0/0x12d0 fs/ext4/ioctl.c:765
 vfs_fileattr_set+0x70c/0xad4 fs/ioctl.c:700
 do_vfs_ioctl+0x1634/0x2a38
 __do_sys_ioctl fs/ioctl.c:872 [inline]
 __se_sys_ioctl fs/ioctl.c:860 [inline]
 __arm64_sys_ioctl+0xe4/0x1c8 fs/ioctl.c:860
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
 do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181
 el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:608
 el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:626
 el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/02/22 14:12 linux-5.15.y 6139f2a02fe0 345111b5 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 possible deadlock in ext4_ind_migrate
* Struck through repros no longer work on HEAD.