syzbot


possible deadlock in ext4_inline_data_truncate

Status: upstream: reported on 2025/06/26 19:05
Reported-by: syzbot+b40a9744c4f223588fff@syzkaller.appspotmail.com
First crash: 4d08h, last: 4d08h
Similar bugs (3)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream possible deadlock in ext4_inline_data_truncate (3) ext4 3 168d 194d 0/29 auto-obsoleted due to no activity on 2025/04/23 23:26
upstream possible deadlock in ext4_inline_data_truncate (2) ext4 3 369d 393d 0/29 auto-obsoleted due to no activity on 2024/10/04 10:20
upstream possible deadlock in ext4_inline_data_truncate ext4 1 835d 831d 0/29 auto-obsoleted due to no activity on 2023/07/17 03:13

Sample crash report:
EXT4-fs (loop2): mounted filesystem without journal. Opts: min_batch_time=0x000000000000000d,mb_optimize_scan=0x0000000000000001,noblock_validity,,errors=continue. Quota mode: none.
======================================================
WARNING: possible circular locking dependency detected
5.15.185-syzkaller #0 Not tainted
------------------------------------------------------
syz.2.359/5369 is trying to acquire lock:
ffff0000e9509eb0 (&ei->xattr_sem){++++}-{3:3}, at: ext4_write_lock_xattr fs/ext4/xattr.h:155 [inline]
ffff0000e9509eb0 (&ei->xattr_sem){++++}-{3:3}, at: ext4_inline_data_truncate+0x158/0xa24 fs/ext4/inline.c:1941

but task is already holding lock:
ffff0000e950a378 (mapping.invalidate_lock){++++}-{3:3}, at: filemap_invalidate_lock include/linux/fs.h:832 [inline]
ffff0000e950a378 (mapping.invalidate_lock){++++}-{3:3}, at: ext4_setattr+0xa34/0x142c fs/ext4/inode.c:5505

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #6 (mapping.invalidate_lock){++++}-{3:3}:
       down_read+0xc0/0x390 kernel/locking/rwsem.c:1498
       filemap_invalidate_lock_shared include/linux/fs.h:842 [inline]
       filemap_fault+0x4b0/0xeac mm/filemap.c:3081
       __do_fault+0x120/0x5d0 mm/memory.c:3928
       do_read_fault mm/memory.c:4264 [inline]
       do_fault mm/memory.c:4392 [inline]
       handle_pte_fault mm/memory.c:4650 [inline]
       __handle_mm_fault mm/memory.c:4785 [inline]
       handle_mm_fault+0x1b4c/0x2950 mm/memory.c:4883
       __do_page_fault arch/arm64/mm/fault.c:505 [inline]
       do_page_fault+0x694/0xad4 arch/arm64/mm/fault.c:605
       do_translation_fault+0xe0/0x130 arch/arm64/mm/fault.c:686
       do_mem_abort+0x6c/0x1ac arch/arm64/mm/fault.c:819
       el0_da+0x90/0x1fc arch/arm64/kernel/entry-common.c:494
       el0t_64_sync_handler+0xd8/0xe4 arch/arm64/kernel/entry-common.c:629
       el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584

-> #5 (&mm->mmap_lock){++++}-{3:3}:
       __might_fault+0xc8/0x128 mm/memory.c:5357
       _copy_to_user include/linux/uaccess.h:174 [inline]
       copy_to_user include/linux/uaccess.h:200 [inline]
       fiemap_fill_next_extent+0x15c/0x3e0 fs/ioctl.c:144
       ocfs2_fiemap_inline fs/ocfs2/extent_map.c:725 [inline]
       ocfs2_fiemap+0x73c/0x98c fs/ocfs2/extent_map.c:762
       ioctl_fiemap fs/ioctl.c:219 [inline]
       do_vfs_ioctl+0x18d8/0x2370 fs/ioctl.c:814
       __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+0x78/0x1e0 arch/arm64/kernel/entry-common.c:608
       el0t_64_sync_handler+0xcc/0xe4 arch/arm64/kernel/entry-common.c:626
       el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584

-> #4 (&ocfs2_file_ip_alloc_sem_key){++++}-{3:3}:
       down_read+0xc0/0x390 kernel/locking/rwsem.c:1498
       ocfs2_read_virt_blocks+0x228/0x858 fs/ocfs2/extent_map.c:976
       ocfs2_read_dir_block fs/ocfs2/dir.c:508 [inline]
       ocfs2_find_entry_el fs/ocfs2/dir.c:715 [inline]
       ocfs2_find_entry+0x314/0x1b84 fs/ocfs2/dir.c:1091
       ocfs2_find_files_on_disk+0x10c/0x388 fs/ocfs2/dir.c:1995
       ocfs2_lookup_ino_from_name+0x60/0x114 fs/ocfs2/dir.c:2017
       _ocfs2_get_system_file_inode fs/ocfs2/sysfile.c:136 [inline]
       ocfs2_get_system_file_inode+0x288/0x5ec fs/ocfs2/sysfile.c:112
       ocfs2_init_global_system_inodes+0x2a8/0x594 fs/ocfs2/super.c:458
       ocfs2_initialize_super fs/ocfs2/super.c:2279 [inline]
       ocfs2_fill_super+0x3128/0x4074 fs/ocfs2/super.c:995
       mount_bdev+0x264/0x358 fs/super.c:1400
       ocfs2_mount+0x44/0x58 fs/ocfs2/super.c:1187
       legacy_get_tree+0xd4/0x16c fs/fs_context.c:611
       vfs_get_tree+0x90/0x274 fs/super.c:1530
       do_new_mount+0x228/0x810 fs/namespace.c:3010
       path_mount+0x5b4/0x1000 fs/namespace.c:3340
       do_mount fs/namespace.c:3353 [inline]
       __do_sys_mount fs/namespace.c:3561 [inline]
       __se_sys_mount fs/namespace.c:3538 [inline]
       __arm64_sys_mount+0x514/0x5e4 fs/namespace.c:3538
       __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+0x78/0x1e0 arch/arm64/kernel/entry-common.c:608
       el0t_64_sync_handler+0xcc/0xe4 arch/arm64/kernel/entry-common.c:626
       el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584

-> #3 (&osb->system_file_mutex){+.+.}-{3:3}:
       __mutex_lock_common+0x194/0x1edc kernel/locking/mutex.c:596
       __mutex_lock kernel/locking/mutex.c:729 [inline]
       mutex_lock_nested+0xac/0x11c kernel/locking/mutex.c:743
       ocfs2_get_system_file_inode+0x15c/0x5ec fs/ocfs2/sysfile.c:101
       ocfs2_reserve_local_alloc_bits+0xe0/0x260c fs/ocfs2/localalloc.c:626
       ocfs2_reserve_clusters_with_limit+0x198/0x9e0 fs/ocfs2/suballoc.c:1162
       ocfs2_reserve_clusters fs/ocfs2/suballoc.c:1223 [inline]
       ocfs2_lock_allocators+0x27c/0x518 fs/ocfs2/suballoc.c:2669
       ocfs2_extend_allocation+0x328/0x1504 fs/ocfs2/file.c:588
       ocfs2_extend_no_holes+0x1a8/0x424 fs/ocfs2/file.c:1030
       ocfs2_acquire_dquot+0x530/0xa2c fs/ocfs2/quota_global.c:841
       dqget+0x658/0xcf4 fs/quota/dquot.c:988
       ocfs2_setattr+0xc08/0x16c4 fs/ocfs2/file.c:1246
       notify_change+0xa08/0xcd8 fs/attr.c:505
       chown_common+0x42c/0x5a0 fs/open.c:680
       vfs_fchown fs/open.c:748 [inline]
       ksys_fchown+0xe0/0x158 fs/open.c:759
       __do_sys_fchown fs/open.c:767 [inline]
       __se_sys_fchown fs/open.c:765 [inline]
       __arm64_sys_fchown+0x7c/0x94 fs/open.c:765
       __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+0x78/0x1e0 arch/arm64/kernel/entry-common.c:608
       el0t_64_sync_handler+0xcc/0xe4 arch/arm64/kernel/entry-common.c:626
       el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584

-> #2 (&ocfs2_quota_ip_alloc_sem_key){++++}-{3:3}:
       down_write+0xbc/0x12c kernel/locking/rwsem.c:1551
       ocfs2_create_local_dquot+0x15c/0x1368 fs/ocfs2/quota_local.c:1224
       ocfs2_acquire_dquot+0x6b0/0xa2c fs/ocfs2/quota_global.c:871
       dqget+0x658/0xcf4 fs/quota/dquot.c:988
       __dquot_initialize+0x2d4/0xa80 fs/quota/dquot.c:1517
       dquot_initialize+0x24/0x34 fs/quota/dquot.c:1579
       ocfs2_get_init_inode+0x134/0x1a8 fs/ocfs2/namei.c:202
       ocfs2_mknod+0x758/0x1e88 fs/ocfs2/namei.c:310
       ocfs2_create+0x180/0x468 fs/ocfs2/namei.c:674
       lookup_open fs/namei.c:3462 [inline]
       open_last_lookups fs/namei.c:3532 [inline]
       path_openat+0x1144/0x26e4 fs/namei.c:3739
       do_filp_open+0x164/0x330 fs/namei.c:3769
       do_sys_openat2+0x128/0x3d8 fs/open.c:1253
       do_sys_open fs/open.c:1269 [inline]
       __do_sys_openat fs/open.c:1285 [inline]
       __se_sys_openat fs/open.c:1280 [inline]
       __arm64_sys_openat+0x120/0x154 fs/open.c:1280
       __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+0x78/0x1e0 arch/arm64/kernel/entry-common.c:608
       el0t_64_sync_handler+0xcc/0xe4 arch/arm64/kernel/entry-common.c:626
       el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584

-> #1 (&dquot->dq_lock){+.+.}-{3:3}:
       __mutex_lock_common+0x194/0x1edc kernel/locking/mutex.c:596
       __mutex_lock kernel/locking/mutex.c:729 [inline]
       mutex_lock_nested+0xac/0x11c kernel/locking/mutex.c:743
       wait_on_dquot fs/quota/dquot.c:356 [inline]
       dqget+0x5e8/0xcf4 fs/quota/dquot.c:983
       dquot_transfer+0x240/0x3cc fs/quota/dquot.c:2157
       ext4_setattr+0x588/0x142c fs/ext4/inode.c:5451
       notify_change+0xa08/0xcd8 fs/attr.c:505
       chown_common+0x42c/0x5a0 fs/open.c:680
       vfs_fchown fs/open.c:748 [inline]
       ksys_fchown+0xe0/0x158 fs/open.c:759
       __do_sys_fchown fs/open.c:767 [inline]
       __se_sys_fchown fs/open.c:765 [inline]
       __arm64_sys_fchown+0x7c/0x94 fs/open.c:765
       __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+0x78/0x1e0 arch/arm64/kernel/entry-common.c:608
       el0t_64_sync_handler+0xcc/0xe4 arch/arm64/kernel/entry-common.c:626
       el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584

-> #0 (&ei->xattr_sem){++++}-{3:3}:
       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+0x2928/0x651c kernel/locking/lockdep.c:5012
       lock_acquire+0x1f4/0x620 kernel/locking/lockdep.c:5623
       down_write+0xbc/0x12c kernel/locking/rwsem.c:1551
       ext4_write_lock_xattr fs/ext4/xattr.h:155 [inline]
       ext4_inline_data_truncate+0x158/0xa24 fs/ext4/inline.c:1941
       ext4_truncate+0x38c/0xf94 fs/ext4/inode.c:4206
       ext4_setattr+0xc20/0x142c fs/ext4/inode.c:5582
       notify_change+0xa08/0xcd8 fs/attr.c:505
       do_truncate+0x178/0x1f0 fs/open.c:65
       vfs_truncate+0x23c/0x2b0 fs/open.c:111
       do_sys_truncate+0xe8/0x1b0 fs/open.c:134
       __do_sys_truncate fs/open.c:146 [inline]
       __se_sys_truncate fs/open.c:144 [inline]
       __arm64_sys_truncate+0x5c/0x70 fs/open.c:144
       __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+0x78/0x1e0 arch/arm64/kernel/entry-common.c:608
       el0t_64_sync_handler+0xcc/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:
  &ei->xattr_sem --> &mm->mmap_lock --> mapping.invalidate_lock

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(mapping.invalidate_lock);
                               lock(&mm->mmap_lock);
                               lock(mapping.invalidate_lock);
  lock(&ei->xattr_sem);

 *** DEADLOCK ***

3 locks held by syz.2.359/5369:
 #0: ffff0000e6d76460 (sb_writers#3){.+.+}-{0:0}, at: mnt_want_write+0x44/0x9c fs/namespace.c:377
 #1: ffff0000e950a1d8 (&sb->s_type->i_mutex_key#9){++++}-{3:3}, at: inode_lock include/linux/fs.h:787 [inline]
 #1: ffff0000e950a1d8 (&sb->s_type->i_mutex_key#9){++++}-{3:3}, at: do_truncate+0x164/0x1f0 fs/open.c:63
 #2: ffff0000e950a378 (mapping.invalidate_lock){++++}-{3:3}, at: filemap_invalidate_lock include/linux/fs.h:832 [inline]
 #2: ffff0000e950a378 (mapping.invalidate_lock){++++}-{3:3}, at: ext4_setattr+0xa34/0x142c fs/ext4/inode.c:5505

stack backtrace:
CPU: 1 PID: 5369 Comm: syz.2.359 Not tainted 5.15.185-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Call trace:
 dump_backtrace+0x0/0x43c arch/arm64/kernel/stacktrace.c:152
 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:216
 __dump_stack+0x30/0x40 lib/dump_stack.c:88
 dump_stack_lvl+0xf8/0x160 lib/dump_stack.c:106
 dump_stack+0x1c/0x5c lib/dump_stack.c:113
 print_circular_bug+0x148/0x1b0 kernel/locking/lockdep.c:2011
 check_noncircular+0x240/0x2d4 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+0x2928/0x651c kernel/locking/lockdep.c:5012
 lock_acquire+0x1f4/0x620 kernel/locking/lockdep.c:5623
 down_write+0xbc/0x12c kernel/locking/rwsem.c:1551
 ext4_write_lock_xattr fs/ext4/xattr.h:155 [inline]
 ext4_inline_data_truncate+0x158/0xa24 fs/ext4/inline.c:1941
 ext4_truncate+0x38c/0xf94 fs/ext4/inode.c:4206
 ext4_setattr+0xc20/0x142c fs/ext4/inode.c:5582
 notify_change+0xa08/0xcd8 fs/attr.c:505
 do_truncate+0x178/0x1f0 fs/open.c:65
 vfs_truncate+0x23c/0x2b0 fs/open.c:111
 do_sys_truncate+0xe8/0x1b0 fs/open.c:134
 __do_sys_truncate fs/open.c:146 [inline]
 __se_sys_truncate fs/open.c:144 [inline]
 __arm64_sys_truncate+0x5c/0x70 fs/open.c:144
 __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+0x78/0x1e0 arch/arm64/kernel/entry-common.c:608
 el0t_64_sync_handler+0xcc/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
2025/06/26 19:04 linux-5.15.y 1c700860e8bc 803ce19b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 possible deadlock in ext4_inline_data_truncate
* Struck through repros no longer work on HEAD.