syzbot

======================================================
WARNING: possible circular locking dependency detected
6.13.0-rc6-syzkaller-00059-g643e2e259c2b #0 Not tainted
------------------------------------------------------
syz.3.1340/10019 is trying to acquire lock:
ffff888026148fa0 (&q->sysfs_lock){+.+.}-{4:4}, at: blk_mq_elv_switch_none block/blk-mq.c:4932 [inline]
ffff888026148fa0 (&q->sysfs_lock){+.+.}-{4:4}, at: __blk_mq_update_nr_hw_queues+0x446/0x14e0 block/blk-mq.c:5010

but task is already holding lock:
ffff888026148a70 (&q->q_usage_counter(io)#52){++++}-{0:0}, at: blk_mq_freeze_queue block/blk-mq.c:213 [inline]
ffff888026148a70 (&q->q_usage_counter(io)#52){++++}-{0:0}, at: __blk_mq_update_nr_hw_queues+0x1fc/0x14e0 block/blk-mq.c:5003

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #4 (&q->q_usage_counter(io)#52){++++}-{0:0}:
       bio_queue_enter block/blk.h:75 [inline]
       blk_mq_submit_bio+0x1fb6/0x24c0 block/blk-mq.c:3090
       __submit_bio+0x384/0x540 block/blk-core.c:629
       __submit_bio_noacct_mq block/blk-core.c:710 [inline]
       submit_bio_noacct_nocheck+0x698/0xd70 block/blk-core.c:739
       submit_bio_noacct+0x93a/0x1e20 block/blk-core.c:868
       mpage_bio_submit_read fs/mpage.c:75 [inline]
       mpage_readahead+0x41d/0x590 fs/mpage.c:377
       read_pages+0x1a8/0xdc0 mm/readahead.c:160
       page_cache_ra_unbounded+0x3dc/0x750 mm/readahead.c:295
       do_page_cache_ra mm/readahead.c:325 [inline]
       force_page_cache_ra+0x24b/0x340 mm/readahead.c:354
       page_cache_sync_ra+0x110/0x9c0 mm/readahead.c:566
       page_cache_sync_readahead include/linux/pagemap.h:1397 [inline]
       filemap_get_pages+0xd7b/0x1be0 mm/filemap.c:2537
       filemap_read+0x3ca/0xd70 mm/filemap.c:2637
       blkdev_read_iter+0x187/0x480 block/fops.c:770
       new_sync_read fs/read_write.c:484 [inline]
       vfs_read+0x87f/0xbe0 fs/read_write.c:565
       ksys_read+0x12b/0x250 fs/read_write.c:708
       do_syscall_x64 arch/x86/entry/common.c:52 [inline]
       do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #3 (mapping.invalidate_lock#2){++++}-{4:4}:
       down_read+0x9a/0x330 kernel/locking/rwsem.c:1524
       filemap_invalidate_lock_shared include/linux/fs.h:873 [inline]
       filemap_fault+0x2e0/0x2820 mm/filemap.c:3323
       __do_fault+0x10a/0x490 mm/memory.c:4907
       do_cow_fault mm/memory.c:5352 [inline]
       do_fault mm/memory.c:5458 [inline]
       do_pte_missing+0x99f/0x3e00 mm/memory.c:3979
       handle_pte_fault mm/memory.c:5801 [inline]
       __handle_mm_fault+0x103c/0x2a40 mm/memory.c:5944
       handle_mm_fault+0x3fa/0xaa0 mm/memory.c:6112
       faultin_page mm/gup.c:1196 [inline]
       __get_user_pages+0x8d9/0x3b50 mm/gup.c:1494
       __get_user_pages_locked mm/gup.c:1760 [inline]
       faultin_page_range+0x24a/0x980 mm/gup.c:1984
       madvise_populate mm/madvise.c:951 [inline]
       do_madvise+0x504/0x770 mm/madvise.c:1681
       __do_sys_madvise mm/madvise.c:1700 [inline]
       __se_sys_madvise mm/madvise.c:1698 [inline]
       __x64_sys_madvise+0xa9/0x110 mm/madvise.c:1698
       do_syscall_x64 arch/x86/entry/common.c:52 [inline]
       do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #2 (&mm->mmap_lock){++++}-{4:4}:
       __might_fault mm/memory.c:6751 [inline]
       __might_fault+0x11b/0x190 mm/memory.c:6744
       _inline_copy_from_user include/linux/uaccess.h:162 [inline]
       _copy_from_user+0x29/0xd0 lib/usercopy.c:18
       copy_from_user include/linux/uaccess.h:212 [inline]
       __blk_trace_setup+0xa8/0x180 kernel/trace/blktrace.c:626
       blk_trace_setup+0x47/0x70 kernel/trace/blktrace.c:648
       sg_ioctl_common drivers/scsi/sg.c:1114 [inline]
       sg_ioctl+0x65e/0x2750 drivers/scsi/sg.c:1156
       vfs_ioctl fs/ioctl.c:51 [inline]
       __do_sys_ioctl fs/ioctl.c:906 [inline]
       __se_sys_ioctl fs/ioctl.c:892 [inline]
       __x64_sys_ioctl+0x190/0x200 fs/ioctl.c:892
       do_syscall_x64 arch/x86/entry/common.c:52 [inline]
       do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #1 (&q->debugfs_mutex){+.+.}-{4:4}:
       __mutex_lock_common kernel/locking/mutex.c:585 [inline]
       __mutex_lock+0x19b/0xa60 kernel/locking/mutex.c:735
       blk_register_queue+0x13c/0x4f0 block/blk-sysfs.c:774
       add_disk_fwnode+0x785/0x1300 block/genhd.c:493
       add_disk include/linux/blkdev.h:753 [inline]
       brd_alloc.isra.0+0x5a2/0x840 drivers/block/brd.c:401
       brd_init+0x12b/0x1d0 drivers/block/brd.c:481
       do_one_initcall+0x128/0x700 init/main.c:1266
       do_initcall_level init/main.c:1328 [inline]
       do_initcalls init/main.c:1344 [inline]
       do_basic_setup init/main.c:1363 [inline]
       kernel_init_freeable+0x5c7/0x900 init/main.c:1577
       kernel_init+0x1c/0x2b0 init/main.c:1466
       ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

-> #0 (&q->sysfs_lock){+.+.}-{4:4}:
       check_prev_add kernel/locking/lockdep.c:3161 [inline]
       check_prevs_add kernel/locking/lockdep.c:3280 [inline]
       validate_chain kernel/locking/lockdep.c:3904 [inline]
       __lock_acquire+0x249e/0x3c40 kernel/locking/lockdep.c:5226
       lock_acquire.part.0+0x11b/0x380 kernel/locking/lockdep.c:5849
       __mutex_lock_common kernel/locking/mutex.c:585 [inline]
       __mutex_lock+0x19b/0xa60 kernel/locking/mutex.c:735
       blk_mq_elv_switch_none block/blk-mq.c:4932 [inline]
       __blk_mq_update_nr_hw_queues+0x446/0x14e0 block/blk-mq.c:5010
       blk_mq_update_nr_hw_queues+0x2a/0x40 block/blk-mq.c:5070
       nbd_start_device+0x15b/0xd70 drivers/block/nbd.c:1413
       nbd_start_device_ioctl drivers/block/nbd.c:1464 [inline]
       __nbd_ioctl drivers/block/nbd.c:1539 [inline]
       nbd_ioctl+0x21a/0xfd0 drivers/block/nbd.c:1579
       blkdev_ioctl+0x276/0x6d0 block/ioctl.c:693
       vfs_ioctl fs/ioctl.c:51 [inline]
       __do_sys_ioctl fs/ioctl.c:906 [inline]
       __se_sys_ioctl fs/ioctl.c:892 [inline]
       __x64_sys_ioctl+0x190/0x200 fs/ioctl.c:892
       do_syscall_x64 arch/x86/entry/common.c:52 [inline]
       do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

other info that might help us debug this:

Chain exists of:
  &q->sysfs_lock --> mapping.invalidate_lock#2 --> &q->q_usage_counter(io)#52

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&q->q_usage_counter(io)#52);
                               lock(mapping.invalidate_lock#2);
                               lock(&q->q_usage_counter(io)#52);
  lock(&q->sysfs_lock);

 *** DEADLOCK ***

4 locks held by syz.3.1340/10019:
 #0: ffff888142b40998 (&nbd->config_lock){+.+.}-{4:4}, at: nbd_ioctl+0x151/0xfd0 drivers/block/nbd.c:1572
 #1: ffff888142b408d8 (&set->tag_list_lock){+.+.}-{4:4}, at: blk_mq_update_nr_hw_queues+0x20/0x40 block/blk-mq.c:5069
 #2: ffff888026148a70 (&q->q_usage_counter(io)#52){++++}-{0:0}, at: blk_mq_freeze_queue block/blk-mq.c:213 [inline]
 #2: ffff888026148a70 (&q->q_usage_counter(io)#52){++++}-{0:0}, at: __blk_mq_update_nr_hw_queues+0x1fc/0x14e0 block/blk-mq.c:5003
 #3: ffff888026148aa8 (&q->q_usage_counter(queue)#36){+.+.}-{0:0}, at: blk_mq_freeze_queue block/blk-mq.c:213 [inline]
 #3: ffff888026148aa8 (&q->q_usage_counter(queue)#36){+.+.}-{0:0}, at: __blk_mq_update_nr_hw_queues+0x1fc/0x14e0 block/blk-mq.c:5003

stack backtrace:
CPU: 0 UID: 0 PID: 10019 Comm: syz.3.1340 Not tainted 6.13.0-rc6-syzkaller-00059-g643e2e259c2b #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+0x116/0x1f0 lib/dump_stack.c:120
 print_circular_bug+0x419/0x5d0 kernel/locking/lockdep.c:2074
 check_noncircular+0x31a/0x400 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 kernel/locking/lockdep.c:3904 [inline]
 __lock_acquire+0x249e/0x3c40 kernel/locking/lockdep.c:5226
 lock_acquire.part.0+0x11b/0x380 kernel/locking/lockdep.c:5849
 __mutex_lock_common kernel/locking/mutex.c:585 [inline]
 __mutex_lock+0x19b/0xa60 kernel/locking/mutex.c:735
 blk_mq_elv_switch_none block/blk-mq.c:4932 [inline]
 __blk_mq_update_nr_hw_queues+0x446/0x14e0 block/blk-mq.c:5010
 blk_mq_update_nr_hw_queues+0x2a/0x40 block/blk-mq.c:5070
 nbd_start_device+0x15b/0xd70 drivers/block/nbd.c:1413
 nbd_start_device_ioctl drivers/block/nbd.c:1464 [inline]
 __nbd_ioctl drivers/block/nbd.c:1539 [inline]
 nbd_ioctl+0x21a/0xfd0 drivers/block/nbd.c:1579
 blkdev_ioctl+0x276/0x6d0 block/ioctl.c:693
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:906 [inline]
 __se_sys_ioctl fs/ioctl.c:892 [inline]
 __x64_sys_ioctl+0x190/0x200 fs/ioctl.c:892
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f03f5585d29
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:00007f03f633e038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f03f5776080 RCX: 00007f03f5585d29
RDX: 0000000000000000 RSI: 000000000000ab03 RDI: 0000000000000005
RBP: 00007f03f5601b08 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000001 R14: 00007f03f5776080 R15: 00007ffed8ffc478
 </TASK>