syzbot


possible deadlock in ext4_truncate

Status: closed as dup on 2024/12/12 23:40
Subsystems: ext4
[Documentation on labels]
Reported-by: syzbot+449c80b8f4946f26184b@syzkaller.appspotmail.com
First crash: 18d, last: 7d16h
Duplicate of
Title Repro Cause bisect Fix bisect Count Last Reported
possible deadlock in xfs_vn_update_time block 1 13d 9d02h
Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [ext4?] possible deadlock in ext4_truncate 1 (2) 2024/12/12 23:40

Sample crash report:
EXT4-fs (loop1): mounted filesystem 00000000-0000-0000-0000-000000000000 r/w without journal. Quota mode: none.
======================================================
WARNING: possible circular locking dependency detected
6.13.0-rc2-syzkaller-00292-ga446e965a188 #0 Not tainted
------------------------------------------------------
syz.1.7403/26160 is trying to acquire lock:
ffff888023666f80
 (&ei->i_data_sem){++++}-{4:4}, at: ext4_truncate+0x994/0x11c0 fs/ext4/inode.c:4212

but task is already holding lock:
ffff888023667290 (mapping.invalidate_lock){++++}-{4:4}, at: filemap_invalidate_lock include/linux/fs.h:863 [inline]
ffff888023667290 (mapping.invalidate_lock){++++}-{4:4}, at: ext4_truncate_failed_write fs/ext4/truncate.h:20 [inline]
ffff888023667290 (mapping.invalidate_lock){++++}-{4:4}, at: ext4_inode_extension_cleanup+0xac/0x2f0 fs/ext4/file.c:341

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #6 (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

-> #5 (&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

-> #4 (&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

-> #3 (&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

-> #2 (&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

-> #1 (&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_commit_super+0x2e0/0x450 fs/ext4/super.c:6236
       ext4_handle_error+0x71a/0x8e0 fs/ext4/super.c:727
       __ext4_error+0x277/0x3b0 fs/ext4/super.c:837
       ext4_validate_block_bitmap+0xe78/0x1200 fs/ext4/balloc.c:440
       ext4_read_block_bitmap_nowait+0x61f/0xa80 fs/ext4/balloc.c:557
       ext4_mb_init_cache+0x413/0x13f0 fs/ext4/mballoc.c:1337
       ext4_mb_init_group+0x329/0x600 fs/ext4/mballoc.c:1543
       ext4_mb_load_buddy_gfp+0xc49/0xe60 fs/ext4/mballoc.c:1613
       ext4_mb_clear_bb fs/ext4/mballoc.c:6451 [inline]
       ext4_free_blocks+0xc9c/0x2240 fs/ext4/mballoc.c:6652
       ext4_free_branches+0x4cc/0x6e0 fs/ext4/indirect.c:1083
       ext4_ind_truncate+0x7c7/0xd60 fs/ext4/indirect.c:1164
       ext4_truncate+0x9f0/0x11c0 fs/ext4/inode.c:4219
       ext4_process_orphan+0x1aa/0x2d0 fs/ext4/orphan.c:339
       ext4_orphan_cleanup+0xb77/0x13d0 fs/ext4/orphan.c:474
       __ext4_fill_super fs/ext4/super.c:5610 [inline]
       ext4_fill_super+0x64dc/0x6e60 fs/ext4/super.c:5733
       get_tree_bdev_flags+0x48e/0x5c0 fs/super.c:1636
       vfs_get_tree+0x92/0x2b0 fs/super.c:1814
       do_new_mount+0x2be/0xb40 fs/namespace.c:3507
       do_mount fs/namespace.c:3847 [inline]
       __do_sys_mount fs/namespace.c:4057 [inline]
       __se_sys_mount+0x2d6/0x3c0 fs/namespace.c:4034
       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){++++}-{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_truncate+0x994/0x11c0 fs/ext4/inode.c:4212
       ext4_truncate_failed_write fs/ext4/truncate.h:22 [inline]
       ext4_inode_extension_cleanup+0xd7/0x2f0 fs/ext4/file.c:341
       ext4_dio_write_iter fs/ext4/file.c:587 [inline]
       ext4_file_write_iter+0x1813/0x1c50 fs/ext4/file.c:715
       new_sync_write fs/read_write.c:586 [inline]
       vfs_write+0xaed/0xd30 fs/read_write.c:679
       ksys_write+0x18f/0x2b0 fs/read_write.c:731
       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 --> &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);

 *** DEADLOCK ***

4 locks held by syz.1.7403/26160:
 #0: ffff888031bff0b8 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x254/0x320 fs/file.c:1191
 #1: ffff888063286420 (sb_writers#4){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2964 [inline]
 #1: ffff888063286420 (sb_writers#4){.+.+}-{0:0}, at: vfs_write+0x225/0xd30 fs/read_write.c:675
 #2: ffff8880236670f0 (&sb->s_type->i_mutex_key#8){++++}-{4:4}, at: inode_lock include/linux/fs.h:818 [inline]
 #2: ffff8880236670f0 (&sb->s_type->i_mutex_key#8){++++}-{4:4}, at: ext4_dio_write_iter fs/ext4/file.c:531 [inline]
 #2: ffff8880236670f0 (&sb->s_type->i_mutex_key#8){++++}-{4:4}, at: ext4_file_write_iter+0x624/0x1c50 fs/ext4/file.c:715
 #3: ffff888023667290 (mapping.invalidate_lock){++++}-{4:4}, at: filemap_invalidate_lock include/linux/fs.h:863 [inline]
 #3: ffff888023667290 (mapping.invalidate_lock){++++}-{4:4}, at: ext4_truncate_failed_write fs/ext4/truncate.h:20 [inline]
 #3: ffff888023667290 (mapping.invalidate_lock){++++}-{4:4}, at: ext4_inode_extension_cleanup+0xac/0x2f0 fs/ext4/file.c:341

stack backtrace:
CPU: 1 UID: 0 PID: 26160 Comm: syz.1.7403 Not tainted 6.13.0-rc2-syzkaller-00292-ga446e965a188 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/25/2024
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_truncate+0x994/0x11c0 fs/ext4/inode.c:4212
 ext4_truncate_failed_write fs/ext4/truncate.h:22 [inline]
 ext4_inode_extension_cleanup+0xd7/0x2f0 fs/ext4/file.c:341
 ext4_dio_write_iter fs/ext4/file.c:587 [inline]
 ext4_file_write_iter+0x1813/0x1c50 fs/ext4/file.c:715
 new_sync_write fs/read_write.c:586 [inline]
 vfs_write+0xaed/0xd30 fs/read_write.c:679
 ksys_write+0x18f/0x2b0 fs/read_write.c:731
 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: 0033:0x7f857db85d19
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:00007f857b9f6038 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f857dd75fa0 RCX: 00007f857db85d19
RDX: 0000000000000002 RSI: 0000000020002580 RDI: 0000000000000004
RBP: 00007f857dc01a20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f857dd75fa0 R15: 00007ffc34290118
 </TASK>

Crashes (3):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/12/14 08:50 upstream a446e965a188 7cbfbb3a .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root possible deadlock in ext4_truncate
2024/12/03 07:15 upstream cdd30ebb1b9f 578925bc .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root possible deadlock in ext4_truncate
2024/12/03 05:37 linux-next f486c8aa16b8 578925bc .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root possible deadlock in ext4_truncate
* Struck through repros no longer work on HEAD.