possible deadlock in exfat_get_block (2)

Status: auto-obsoleted due to no activity on 2025/04/20 11:08
Subsystems: exfat
[Documentation on labels]
Reported-by: syzbot+32b7df93cfaf0062bf37@syzkaller.appspotmail.com
First crash: 590d, last: 585d
▶ ▼ Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [exfat?] possible deadlock in exfat_get_block (2) 0 (1) 2025/01/10 06:23
▶ ▼ Similar bugs (3)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-5.15 possible deadlock in exfat_get_block origin:upstream 4 syz, C error 111 1104d 1258d 0/3 auto-obsoleted due to no activity on 2023/10/19 14:45
upstream possible deadlock in exfat_get_block exfat 4 syz, C error done 317 1104d 1407d 0/29 auto-obsoleted due to no activity on 2023/10/21 18:47
linux-6.1 possible deadlock in exfat_get_block origin:lts-only 4 syz unreliable 225 1106d 1239d 0/3 upstream: reported syz repro on 2023/03/29 01:00

Sample crash report:
======================================================
WARNING: possible circular locking dependency detected
6.13.0-rc6-syzkaller-00130-g2144da25584e #0 Not tainted
------------------------------------------------------
syz.7.3019/19290 is trying to acquire lock:
ffff88802887c0e8 (&sbi->s_lock#3){+.+.}-{4:4}, at: exfat_get_block+0x1c3/0x2180 fs/exfat/inode.c:278

but task is already holding lock:
ffff8880564d5e60 (mapping.invalidate_lock#6){.+.+}-{4:4}, at: filemap_invalidate_lock_shared include/linux/fs.h:873 [inline]
ffff8880564d5e60 (mapping.invalidate_lock#6){.+.+}-{4:4}, at: page_cache_ra_unbounded+0x142/0x720 mm/readahead.c:226

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #7 (mapping.invalidate_lock#6){.+.+}-{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]
       filemap_fault+0x615/0x1490 mm/filemap.c:3323
       __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
       do_user_addr_fault arch/x86/mm/fault.c:1338 [inline]
       handle_page_fault arch/x86/mm/fault.c:1481 [inline]
       exc_page_fault+0x459/0x8b0 arch/x86/mm/fault.c:1539
       asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623

-> #6 (&vma->vm_lock->lock){++++}-{4:4}:
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849
       down_write+0x99/0x220 kernel/locking/rwsem.c:1577
       vma_start_write include/linux/mm.h:770 [inline]
       vma_link+0x28c/0x500 mm/vma.c:1691
       insert_vm_struct+0x2f7/0x410 mm/mmap.c:1744
       __bprm_mm_init fs/exec.c:289 [inline]
       bprm_mm_init fs/exec.c:393 [inline]
       alloc_bprm+0x5a6/0xa30 fs/exec.c:1544
       kernel_execve+0x99/0xa50 fs/exec.c:1974
       try_to_run_init_process init/main.c:1394 [inline]
       kernel_init+0xed/0x2b0 init/main.c:1522
       ret_from_fork+0x4d/0x80 arch/x86/kernel/process.c:147
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

-> #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)#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
       submit_bh fs/buffer.c:2819 [inline]
       __sync_dirty_buffer+0x23d/0x390 fs/buffer.c:2857
       exfat_set_volume_dirty+0x5d/0x80 fs/exfat/super.c:124
       exfat_rmdir+0x3cc/0x830 fs/exfat/namei.c:973
       vfs_rmdir+0x3a5/0x510 fs/namei.c:4394
       do_rmdir+0x3b5/0x580 fs/namei.c:4453
       __do_sys_rmdir fs/namei.c:4472 [inline]
       __se_sys_rmdir fs/namei.c:4470 [inline]
       __x64_sys_rmdir+0x47/0x50 fs/namei.c:4470
       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 (&sbi->s_lock#3){+.+.}-{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
       __mutex_lock_common kernel/locking/mutex.c:585 [inline]
       __mutex_lock+0x1ac/0xee0 kernel/locking/mutex.c:735
       exfat_get_block+0x1c3/0x2180 fs/exfat/inode.c:278
       do_mpage_readpage+0x7ba/0x1720 fs/mpage.c:225
       mpage_readahead+0x456/0x780 fs/mpage.c:374
       read_pages+0x178/0x750 mm/readahead.c:160
       page_cache_ra_unbounded+0x606/0x720 mm/readahead.c:295
       do_sync_mmap_readahead+0x499/0x970
       filemap_fault+0x8a9/0x1490 mm/filemap.c:3335
       __do_fault+0x137/0x390 mm/memory.c:4907
       do_shared_fault mm/memory.c:5386 [inline]
       do_fault mm/memory.c:5460 [inline]
       do_pte_missing mm/memory.c:3979 [inline]
       handle_pte_fault+0xfcf/0x5ed0 mm/memory.c:5801
       __handle_mm_fault mm/memory.c:5944 [inline]
       handle_mm_fault+0x1106/0x1bb0 mm/memory.c:6112
       do_user_addr_fault arch/x86/mm/fault.c:1338 [inline]
       handle_page_fault arch/x86/mm/fault.c:1481 [inline]
       exc_page_fault+0x459/0x8b0 arch/x86/mm/fault.c:1539
       asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623

other info that might help us debug this:

Chain exists of:
  &sbi->s_lock#3 --> &vma->vm_lock->lock --> mapping.invalidate_lock#6

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  rlock(mapping.invalidate_lock#6);
                               lock(&vma->vm_lock->lock);
                               lock(mapping.invalidate_lock#6);
  lock(&sbi->s_lock#3);

 *** DEADLOCK ***

1 lock held by syz.7.3019/19290:
 #0: ffff8880564d5e60 (mapping.invalidate_lock#6){.+.+}-{4:4}, at: filemap_invalidate_lock_shared include/linux/fs.h:873 [inline]
 #0: ffff8880564d5e60 (mapping.invalidate_lock#6){.+.+}-{4:4}, at: page_cache_ra_unbounded+0x142/0x720 mm/readahead.c:226

stack backtrace:
CPU: 1 UID: 0 PID: 19290 Comm: syz.7.3019 Not tainted 6.13.0-rc6-syzkaller-00130-g2144da25584e #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
 __mutex_lock_common kernel/locking/mutex.c:585 [inline]
 __mutex_lock+0x1ac/0xee0 kernel/locking/mutex.c:735
 exfat_get_block+0x1c3/0x2180 fs/exfat/inode.c:278
 do_mpage_readpage+0x7ba/0x1720 fs/mpage.c:225
 mpage_readahead+0x456/0x780 fs/mpage.c:374
 read_pages+0x178/0x750 mm/readahead.c:160
 page_cache_ra_unbounded+0x606/0x720 mm/readahead.c:295
 do_sync_mmap_readahead+0x499/0x970
 filemap_fault+0x8a9/0x1490 mm/filemap.c:3335
 __do_fault+0x137/0x390 mm/memory.c:4907
 do_shared_fault mm/memory.c:5386 [inline]
 do_fault mm/memory.c:5460 [inline]
 do_pte_missing mm/memory.c:3979 [inline]
 handle_pte_fault+0xfcf/0x5ed0 mm/memory.c:5801
 __handle_mm_fault mm/memory.c:5944 [inline]
 handle_mm_fault+0x1106/0x1bb0 mm/memory.c:6112
 do_user_addr_fault arch/x86/mm/fault.c:1338 [inline]
 handle_page_fault arch/x86/mm/fault.c:1481 [inline]
 exc_page_fault+0x459/0x8b0 arch/x86/mm/fault.c:1539
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623
RIP: 0033:0x7f1ff394d308
Code: fc 89 37 c3 c5 fa 6f 06 c5 fa 6f 4c 16 f0 c5 fa 7f 07 c5 fa 7f 4c 17 f0 c3 66 0f 1f 84 00 00 00 00 00 48 8b 4c 16 f8 48 8b 36 <48> 89 37 48 89 4c 17 f8 c3 c5 fe 6f 54 16 e0 c5 fe 6f 5c 16 c0 c5
RSP: 002b:00007ffc9485b718 EFLAGS: 00010246
RAX: 0000000020000100 RBX: 0000000000000004 RCX: 0031656c69662f2e
RDX: 0000000000000008 RSI: 0031656c69662f2e RDI: 0000000020000100
RBP: 00007f1ff3b77ba0 R08: 00007f1ff3600000 R09: 0000000000000001
R10: 0000000000000001 R11: 0000000000000009 R12: 00000000000fea43
R13: 00007f1ff3b75fa0 R14: 0000000000000032 R15: fffffffffffffffe
 </TASK>

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/01/10 11:07 upstream 2144da25584e 67d7ec0a .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root possible deadlock in exfat_get_block
2025/01/06 06:10 upstream ab75170520d4 f3558dbf .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root possible deadlock in exfat_get_block
* Struck through repros no longer work on HEAD.