possible deadlock in ext4_setattr (3)

Status: auto-obsoleted due to no activity on 2025/04/10 15:09
Subsystems: ext4
[Documentation on labels]
Reported-by: syzbot+5854ffe0f8a3c5de4d2d@syzkaller.appspotmail.com
First crash: 593d, last: 571d
▶ ▼ Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [ext4?] possible deadlock in ext4_setattr (3) 0 (1) 2024/12/13 23:14
▶ ▼ Similar bugs (3)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-5.15 possible deadlock in ext4_setattr 4 6 1221d 1226d 0/3 auto-obsoleted due to no activity on 2023/07/21 04:14
upstream possible deadlock in ext4_setattr ext4 4 C done 7 1169d 1288d 22/29 fixed on 2023/07/01 16:05
upstream possible deadlock in ext4_setattr (2) ext4 4 2 767d 780d 0/29 auto-obsoleted due to no activity on 2024/09/26 14:43

Sample crash report:
======================================================
WARNING: possible circular locking dependency detected
6.13.0-rc5-syzkaller-00004-gccb98ccef0e5 #0 Not tainted
------------------------------------------------------
syz.0.3471/23943 is trying to acquire lock:
ffff8880781947e0 (&ei->i_data_sem/2){++++}-{4:4}, at: ext4_setattr+0x16e1/0x1da0 fs/ext4/inode.c:5504

but task is already holding lock:
ffff888078194af0 (mapping.invalidate_lock){++++}-{4:4}, at: filemap_invalidate_lock include/linux/fs.h:863 [inline]
ffff888078194af0 (mapping.invalidate_lock){++++}-{4:4}, at: ext4_setattr+0xf94/0x1da0 fs/ext4/inode.c:5452

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #7 (mapping.invalidate_lock){++++}-{4:4}:
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849
       down_read+0xb1/0xa40 kernel/locking/rwsem.c:1524
       filemap_invalidate_lock_shared include/linux/fs.h:873 [inline]
       page_cache_ra_unbounded+0x142/0x720 mm/readahead.c:226
       do_async_mmap_readahead mm/filemap.c:3231 [inline]
       filemap_fault+0x818/0x1490 mm/filemap.c:3330
       __do_fault+0x137/0x390 mm/memory.c:4907
       do_read_fault mm/memory.c:5322 [inline]
       do_fault mm/memory.c:5456 [inline]
       do_pte_missing mm/memory.c:3979 [inline]
       handle_pte_fault+0x39eb/0x5ed0 mm/memory.c:5801
       __handle_mm_fault mm/memory.c:5944 [inline]
       handle_mm_fault+0x1106/0x1bb0 mm/memory.c:6112
       faultin_page mm/gup.c:1196 [inline]
       __get_user_pages+0x1c82/0x49e0 mm/gup.c:1494
       __get_user_pages_locked mm/gup.c:1760 [inline]
       get_dump_page+0x155/0x2f0 mm/gup.c:2278
       dump_user_range+0x14d/0x970 fs/coredump.c:943
       elf_core_dump+0x3e9f/0x4790 fs/binfmt_elf.c:2129
       do_coredump+0x229d/0x3100 fs/coredump.c:758
       get_signal+0x140b/0x1750 kernel/signal.c:3002
       arch_do_signal_or_restart+0x96/0x860 arch/x86/kernel/signal.c:337
       exit_to_user_mode_loop kernel/entry/common.c:111 [inline]
       exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline]
       irqentry_exit_to_user_mode+0x7e/0x250 kernel/entry/common.c:231
       exc_page_fault+0x590/0x8b0 arch/x86/mm/fault.c:1542
       asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623

-> #6 (&mm->mmap_lock){++++}-{4:4}:
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849
       __might_fault+0xc6/0x120 mm/memory.c:6751
       _inline_copy_from_user include/linux/uaccess.h:162 [inline]
       _copy_from_user+0x2a/0xc0 lib/usercopy.c:18
       copy_from_user include/linux/uaccess.h:212 [inline]
       __blk_trace_setup kernel/trace/blktrace.c:626 [inline]
       blk_trace_ioctl+0x1ad/0x9a0 kernel/trace/blktrace.c:740
       blkdev_ioctl+0x40c/0x6a0 block/ioctl.c:682
       vfs_ioctl fs/ioctl.c:51 [inline]
       __do_sys_ioctl fs/ioctl.c:906 [inline]
       __se_sys_ioctl+0xf7/0x170 fs/ioctl.c:892
       do_syscall_x64 arch/x86/entry/common.c:52 [inline]
       do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #5 (&q->debugfs_mutex){+.+.}-{4:4}:
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849
       __mutex_lock_common kernel/locking/mutex.c:585 [inline]
       __mutex_lock+0x1ac/0xee0 kernel/locking/mutex.c:735
       blk_mq_init_sched+0x3fa/0x830 block/blk-mq-sched.c:473
       elevator_init_mq+0x20e/0x320 block/elevator.c:610
       add_disk_fwnode+0x10d/0xf80 block/genhd.c:413
       sd_probe+0xba6/0x1100 drivers/scsi/sd.c:4024
       really_probe+0x2ba/0xad0 drivers/base/dd.c:658
       __driver_probe_device+0x1a2/0x390 drivers/base/dd.c:800
       driver_probe_device+0x50/0x430 drivers/base/dd.c:830
       __device_attach_driver+0x2d6/0x530 drivers/base/dd.c:958
       bus_for_each_drv+0x250/0x2e0 drivers/base/bus.c:459
       __device_attach_async_helper+0x22d/0x300 drivers/base/dd.c:987
       async_run_entry_fn+0xaa/0x420 kernel/async.c:129
       process_one_work kernel/workqueue.c:3229 [inline]
       process_scheduled_works+0xa68/0x1840 kernel/workqueue.c:3310
       worker_thread+0x870/0xd30 kernel/workqueue.c:3391
       kthread+0x2f2/0x390 kernel/kthread.c:389
       ret_from_fork+0x4d/0x80 arch/x86/kernel/process.c:147
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

-> #4 (&q->q_usage_counter(queue)#50){++++}-{0:0}:
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849
       blk_queue_enter+0xe1/0x600 block/blk-core.c:328
       blk_mq_alloc_request+0x4fa/0xaa0 block/blk-mq.c:652
       scsi_alloc_request drivers/scsi/scsi_lib.c:1222 [inline]
       scsi_execute_cmd+0x177/0x1090 drivers/scsi/scsi_lib.c:304
       read_capacity_16+0x2b4/0x1450 drivers/scsi/sd.c:2655
       sd_read_capacity drivers/scsi/sd.c:2824 [inline]
       sd_revalidate_disk+0x1013/0xbce0 drivers/scsi/sd.c:3734
       sd_probe+0x9fa/0x1100 drivers/scsi/sd.c:4010
       really_probe+0x2ba/0xad0 drivers/base/dd.c:658
       __driver_probe_device+0x1a2/0x390 drivers/base/dd.c:800
       driver_probe_device+0x50/0x430 drivers/base/dd.c:830
       __device_attach_driver+0x2d6/0x530 drivers/base/dd.c:958
       bus_for_each_drv+0x250/0x2e0 drivers/base/bus.c:459
       __device_attach_async_helper+0x22d/0x300 drivers/base/dd.c:987
       async_run_entry_fn+0xaa/0x420 kernel/async.c:129
       process_one_work kernel/workqueue.c:3229 [inline]
       process_scheduled_works+0xa68/0x1840 kernel/workqueue.c:3310
       worker_thread+0x870/0xd30 kernel/workqueue.c:3391
       kthread+0x2f2/0x390 kernel/kthread.c:389
       ret_from_fork+0x4d/0x80 arch/x86/kernel/process.c:147
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

-> #3 (&q->limits_lock){+.+.}-{4:4}:
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849
       __mutex_lock_common kernel/locking/mutex.c:585 [inline]
       __mutex_lock+0x1ac/0xee0 kernel/locking/mutex.c:735
       queue_limits_start_update include/linux/blkdev.h:947 [inline]
       loop_reconfigure_limits+0x43f/0x900 drivers/block/loop.c:998
       loop_set_block_size drivers/block/loop.c:1473 [inline]
       lo_simple_ioctl drivers/block/loop.c:1496 [inline]
       lo_ioctl+0x1351/0x1f50 drivers/block/loop.c:1559
       blkdev_ioctl+0x57f/0x6a0 block/ioctl.c:693
       vfs_ioctl fs/ioctl.c:51 [inline]
       __do_sys_ioctl fs/ioctl.c:906 [inline]
       __se_sys_ioctl+0xf7/0x170 fs/ioctl.c:892
       do_syscall_x64 arch/x86/entry/common.c:52 [inline]
       do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #2 (&q->q_usage_counter(io)#24){++++}-{0:0}:
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849
       bio_queue_enter block/blk.h:75 [inline]
       blk_mq_submit_bio+0x1536/0x2390 block/blk-mq.c:3090
       __submit_bio+0x2c6/0x560 block/blk-core.c:629
       __submit_bio_noacct_mq block/blk-core.c:710 [inline]
       submit_bio_noacct_nocheck+0x4d3/0xe30 block/blk-core.c:739
       ext4_read_block_bitmap_nowait+0x7c5/0xa80 fs/ext4/balloc.c:551
       ext4_mb_prefetch+0x240/0x380 fs/ext4/mballoc.c:2749
       ext4_mb_regular_allocator+0xb44/0x3bb0 fs/ext4/mballoc.c:2898
       ext4_mb_new_blocks+0x10a8/0x4e00 fs/ext4/mballoc.c:6217
       ext4_ext_map_blocks+0x1be0/0x7d30 fs/ext4/extents.c:4379
       ext4_map_create_blocks fs/ext4/inode.c:516 [inline]
       ext4_map_blocks+0x8bf/0x1990 fs/ext4/inode.c:702
       ext4_convert_inline_data_nolock+0x479/0xe00 fs/ext4/inline.c:1211
       ext4_convert_inline_data+0x4de/0x620 fs/ext4/inline.c:2061
       ext4_fallocate+0xec/0x1ea0 fs/ext4/extents.c:4766
       vfs_fallocate+0x56b/0x6e0 fs/open.c:327
       ksys_fallocate fs/open.c:351 [inline]
       __do_sys_fallocate fs/open.c:356 [inline]
       __se_sys_fallocate fs/open.c:354 [inline]
       __x64_sys_fallocate+0xbc/0x110 fs/open.c:354
       do_syscall_x64 arch/x86/entry/common.c:52 [inline]
       do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #1 (&lg->lg_mutex){+.+.}-{4:4}:
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849
       __mutex_lock_common kernel/locking/mutex.c:585 [inline]
       __mutex_lock+0x1ac/0xee0 kernel/locking/mutex.c:735
       ext4_mb_group_or_file fs/ext4/mballoc.c:5786 [inline]
       ext4_mb_initialize_context+0x8ac/0xce0 fs/ext4/mballoc.c:5830
       ext4_mb_new_blocks+0x681/0x4e00 fs/ext4/mballoc.c:6204
       ext4_ext_map_blocks+0x1be0/0x7d30 fs/ext4/extents.c:4379
       ext4_map_create_blocks fs/ext4/inode.c:516 [inline]
       ext4_map_blocks+0x8bf/0x1990 fs/ext4/inode.c:702
       ext4_getblk+0x1fa/0x880 fs/ext4/inode.c:849
       ext4_bread+0x2e/0x180 fs/ext4/inode.c:912
       ext4_quota_write+0x223/0x580 fs/ext4/super.c:7285
       write_blk fs/quota/quota_tree.c:70 [inline]
       get_free_dqblk+0x334/0x690 fs/quota/quota_tree.c:136
       do_insert_tree+0x2c5/0x1490 fs/quota/quota_tree.c:347
       do_insert_tree+0xbd6/0x1490 fs/quota/quota_tree.c:402
       dq_insert_tree fs/quota/quota_tree.c:432 [inline]
       qtree_write_dquot+0x496/0x5b0 fs/quota/quota_tree.c:451
       v2_write_dquot+0x17a/0x270 fs/quota/quota_v2.c:372
       dquot_acquire+0x351/0x680 fs/quota/dquot.c:470
       ext4_acquire_dquot+0x301/0x4c0 fs/ext4/super.c:6934
       dqget+0x772/0xeb0 fs/quota/dquot.c:977
       dquot_transfer+0x2c2/0x6d0 fs/quota/dquot.c:2140
       ext4_setattr+0xb49/0x1da0 fs/ext4/inode.c:5400
       notify_change+0xbcc/0xe90 fs/attr.c:552
       chown_common+0x501/0x850 fs/open.c:778
       do_fchownat+0x16a/0x240 fs/open.c:809
       __do_sys_lchown fs/open.c:834 [inline]
       __se_sys_lchown fs/open.c:832 [inline]
       __x64_sys_lchown+0x85/0xa0 fs/open.c:832
       do_syscall_x64 arch/x86/entry/common.c:52 [inline]
       do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #0 (&ei->i_data_sem/2){++++}-{4:4}:
       check_prev_add kernel/locking/lockdep.c:3161 [inline]
       check_prevs_add kernel/locking/lockdep.c:3280 [inline]
       validate_chain+0x18ef/0x5920 kernel/locking/lockdep.c:3904
       __lock_acquire+0x1397/0x2100 kernel/locking/lockdep.c:5226
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849
       down_write+0x99/0x220 kernel/locking/rwsem.c:1577
       ext4_setattr+0x16e1/0x1da0 fs/ext4/inode.c:5504
       notify_change+0xbcc/0xe90 fs/attr.c:552
       do_truncate+0x220/0x310 fs/open.c:65
       vfs_truncate+0x2e1/0x3b0 fs/open.c:111
       do_sys_truncate+0xdb/0x190 fs/open.c:134
       do_syscall_x64 arch/x86/entry/common.c:52 [inline]
       do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

other info that might help us debug this:

Chain exists of:
  &ei->i_data_sem/2 --> &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->i_data_sem/2);

 *** DEADLOCK ***

3 locks held by syz.0.3471/23943:
 #0: ffff888075850420 (sb_writers#4){.+.+}-{0:0}, at: mnt_want_write+0x3f/0x90 fs/namespace.c:515
 #1: ffff888078194950 (&sb->s_type->i_mutex_key#8){++++}-{4:4}, at: inode_lock include/linux/fs.h:818 [inline]
 #1: ffff888078194950 (&sb->s_type->i_mutex_key#8){++++}-{4:4}, at: do_truncate+0x20c/0x310 fs/open.c:63
 #2: ffff888078194af0 (mapping.invalidate_lock){++++}-{4:4}, at: filemap_invalidate_lock include/linux/fs.h:863 [inline]
 #2: ffff888078194af0 (mapping.invalidate_lock){++++}-{4:4}, at: ext4_setattr+0xf94/0x1da0 fs/ext4/inode.c:5452

stack backtrace:
CPU: 0 UID: 0 PID: 23943 Comm: syz.0.3471 Not tainted 6.13.0-rc5-syzkaller-00004-gccb98ccef0e5 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
 print_circular_bug+0x13a/0x1b0 kernel/locking/lockdep.c:2074
 check_noncircular+0x36a/0x4a0 kernel/locking/lockdep.c:2206
 check_prev_add kernel/locking/lockdep.c:3161 [inline]
 check_prevs_add kernel/locking/lockdep.c:3280 [inline]
 validate_chain+0x18ef/0x5920 kernel/locking/lockdep.c:3904
 __lock_acquire+0x1397/0x2100 kernel/locking/lockdep.c:5226
 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849
 down_write+0x99/0x220 kernel/locking/rwsem.c:1577
 ext4_setattr+0x16e1/0x1da0 fs/ext4/inode.c:5504
 notify_change+0xbcc/0xe90 fs/attr.c:552
 do_truncate+0x220/0x310 fs/open.c:65
 vfs_truncate+0x2e1/0x3b0 fs/open.c:111
 do_sys_truncate+0xdb/0x190 fs/open.c:134
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7ffb9db85d29
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffb9b9d5038 EFLAGS: 00000246 ORIG_RAX: 000000000000004c
RAX: ffffffffffffffda RBX: 00007ffb9dd76080 RCX: 00007ffb9db85d29
RDX: 0000000000000000 RSI: 000000000008fff5 RDI: 0000000020000180
RBP: 00007ffb9dc01b08 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000001 R14: 00007ffb9dd76080 R15: 00007ffc47775948
 </TASK>

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/12/31 15:08 upstream ccb98ccef0e5 d3ccff63 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root possible deadlock in ext4_setattr
2024/12/09 23:10 upstream 7cb1b4663150 9ac0fdc6 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root possible deadlock in ext4_setattr
* Struck through repros no longer work on HEAD.