syzbot


possible deadlock in ext4_map_blocks (2)

Status: closed as dup on 2024/12/12 23:41
Subsystems: ext4
[Documentation on labels]
Reported-by: syzbot+c39928fd177c28b5fa1f@syzkaller.appspotmail.com
First crash: 177d, last: 128d
Duplicate of
Title Repro Cause bisect Fix bisect Count Last Reported
possible deadlock in xfs_vn_update_time block 1 167d 163d
Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [ext4?] possible deadlock in ext4_map_blocks (2) 1 (2) 2024/12/12 23:41
Similar bugs (4)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-6.1 possible deadlock in ext4_map_blocks origin:lts-only C inconclusive 379 2h59m 809d 0/3 upstream: reported C repro on 2023/03/08 04:51
linux-4.19 possible deadlock in ext4_map_blocks ext4 11 818d 955d 0/1 upstream: reported on 2022/10/12 20:37
upstream possible deadlock in ext4_map_blocks ext4 480 742d 964d 0/28 auto-obsoleted due to no activity on 2023/08/11 20:48
linux-5.15 possible deadlock in ext4_map_blocks origin:lts-only C done 496 13h58m 806d 0/3 upstream: reported C repro on 2023/03/11 16:28

Sample crash report:
======================================================
WARNING: possible circular locking dependency detected
6.13.0-rc7-syzkaller-00102-gce69b4019001 #0 Not tainted
------------------------------------------------------
syz.0.1551/13345 is trying to acquire lock:
ffff888064bf0288 (&ei->i_data_sem){++++}-{4:4}, at: ext4_map_blocks+0x3be/0x1990 fs/ext4/inode.c:665

but task is already holding lock:
ffff888064bf00c8 (&ei->xattr_sem){++++}-{4:4}, at: ext4_write_lock_xattr fs/ext4/xattr.h:154 [inline]
ffff888064bf00c8 (&ei->xattr_sem){++++}-{4:4}, at: ext4_convert_inline_data+0x3ba/0x620 fs/ext4/inline.c:2059

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #7 (&ei->xattr_sem){++++}-{4:4}:
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849
       down_write+0x99/0x220 kernel/locking/rwsem.c:1577
       ext4_write_lock_xattr fs/ext4/xattr.h:154 [inline]
       ext4_inline_data_truncate+0x1d5/0xcf0 fs/ext4/inline.c:1936
       ext4_truncate+0x3ca/0x11c0 fs/ext4/inode.c:4173
       ext4_setattr+0x113a/0x1da0 fs/ext4/inode.c:5541
       notify_change+0xbcc/0xe90 fs/attr.c:552
       do_truncate+0x220/0x310 fs/open.c:65
       handle_truncate fs/namei.c:3449 [inline]
       do_open fs/namei.c:3832 [inline]
       path_openat+0x2e1e/0x3590 fs/namei.c:3987
       do_filp_open+0x27f/0x4e0 fs/namei.c:4014
       do_sys_openat2+0x13e/0x1d0 fs/open.c:1402
       do_sys_open fs/open.c:1417 [inline]
       __do_sys_creat fs/open.c:1495 [inline]
       __se_sys_creat fs/open.c:1489 [inline]
       __x64_sys_creat+0x123/0x170 fs/open.c:1489
       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

-> #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:3222 [inline]
       filemap_fault+0x818/0x1490 mm/filemap.c:3321
       __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:3236 [inline]
       process_scheduled_works+0xa68/0x1840 kernel/workqueue.c:3317
       worker_thread+0x870/0xd30 kernel/workqueue.c:3398
       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:1225 [inline]
       scsi_execute_cmd+0x16c/0x10e0 drivers/scsi/scsi_lib.c:307
       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:3236 [inline]
       process_scheduled_works+0xa68/0x1840 kernel/workqueue.c:3317
       worker_thread+0x870/0xd30 kernel/workqueue.c:3398
       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)#23){++++}-{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_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_remove_blocks fs/ext4/extents.c:2547 [inline]
       ext4_ext_rm_leaf fs/ext4/extents.c:2712 [inline]
       ext4_ext_remove_space+0x240f/0x4e00 fs/ext4/extents.c:2961
       ext4_ext_truncate+0x159/0x2b0 fs/ext4/extents.c:4466
       ext4_truncate+0xa1b/0x11c0 fs/ext4/inode.c:4217
       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:3511
       do_mount fs/namespace.c:3851 [inline]
       __do_sys_mount fs/namespace.c:4061 [inline]
       __se_sys_mount+0x2d6/0x3c0 fs/namespace.c:4038
       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_read+0xb1/0xa40 kernel/locking/rwsem.c:1524
       ext4_map_blocks+0x3be/0x1990 fs/ext4/inode.c:665
       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

other info that might help us debug this:

Chain exists of:
  &ei->i_data_sem --> mapping.invalidate_lock --> &ei->xattr_sem

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&ei->xattr_sem);
                               lock(mapping.invalidate_lock);
                               lock(&ei->xattr_sem);
  rlock(&ei->i_data_sem);

 *** DEADLOCK ***

3 locks held by syz.0.1551/13345:
 #0: ffff88805b746420 (sb_writers#4){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2964 [inline]
 #0: ffff88805b746420 (sb_writers#4){.+.+}-{0:0}, at: vfs_fallocate+0x4fe/0x6e0 fs/open.c:326
 #1: ffff888064bf03f8 (&sb->s_type->i_mutex_key#8){++++}-{4:4}, at: inode_lock include/linux/fs.h:818 [inline]
 #1: ffff888064bf03f8 (&sb->s_type->i_mutex_key#8){++++}-{4:4}, at: ext4_fallocate+0xe4/0x1ea0 fs/ext4/extents.c:4765
 #2: ffff888064bf00c8 (&ei->xattr_sem){++++}-{4:4}, at: ext4_write_lock_xattr fs/ext4/xattr.h:154 [inline]
 #2: ffff888064bf00c8 (&ei->xattr_sem){++++}-{4:4}, at: ext4_convert_inline_data+0x3ba/0x620 fs/ext4/inline.c:2059

stack backtrace:
CPU: 0 UID: 0 PID: 13345 Comm: syz.0.1551 Not tainted 6.13.0-rc7-syzkaller-00102-gce69b4019001 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024
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_read+0xb1/0xa40 kernel/locking/rwsem.c:1524
 ext4_map_blocks+0x3be/0x1990 fs/ext4/inode.c:665
 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
RIP: 0033:0x7f7f07185d29
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:00007f7f07fd3038 EFLAGS: 00000246 ORIG_RAX: 000000000000011d
RAX: ffffffffffffffda RBX: 00007f7f07376080 RCX: 00007f7f07185d29
RDX: 000000000007fffe RSI: 0000000000000011 RDI: 000000000000000a
RBP: 00007f7f07201b08 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000007000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f7f07376080 R15: 00007ffdd7ed03d8
 </TASK>

Crashes (14):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/01/17 06:28 upstream ce69b4019001 f9e07a6e .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root possible deadlock in ext4_map_blocks
2025/01/09 16:57 upstream eea6e4b4dfb8 40f46913 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root possible deadlock in ext4_map_blocks
2025/01/09 16:01 upstream eea6e4b4dfb8 40f46913 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root possible deadlock in ext4_map_blocks
2025/01/09 09:11 upstream eea6e4b4dfb8 f3558dbf .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root possible deadlock in ext4_map_blocks
2025/01/05 12:29 upstream ab75170520d4 f3558dbf .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root possible deadlock in ext4_map_blocks
2025/01/01 22:10 upstream 56e6a3499e14 d3ccff63 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root possible deadlock in ext4_map_blocks
2024/12/26 13:25 upstream 9b2ffa6148b1 d3ccff63 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root possible deadlock in ext4_map_blocks
2024/12/25 14:10 upstream 9b2ffa6148b1 444551c4 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root possible deadlock in ext4_map_blocks
2024/12/22 20:30 upstream bcde95ce32b6 b4fbdbd4 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root possible deadlock in ext4_map_blocks
2024/12/17 20:10 upstream 59dbb9d81adf c8c15bb2 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root possible deadlock in ext4_map_blocks
2024/12/07 21:08 upstream 7503345ac5f5 9ac0fdc6 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root possible deadlock in ext4_map_blocks
2024/12/01 04:19 upstream 0e287d31b62b 68914665 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root possible deadlock in ext4_map_blocks
2024/11/30 23:43 upstream 0e287d31b62b 68914665 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root possible deadlock in ext4_map_blocks
2024/11/29 16:21 linux-next f486c8aa16b8 68914665 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root possible deadlock in ext4_map_blocks
* Struck through repros no longer work on HEAD.