======================================================
WARNING: possible circular locking dependency detected
6.13.0-rc5-syzkaller-00006-g56e6a3499e14 #0 Not tainted
------------------------------------------------------
syz.9.3502/20118 is trying to acquire lock:
ffff88805716cde0 (&mm->mmap_lock){++++}-{4:4}, at: mmap_read_lock_killable+0x1d/0x70 include/linux/mmap_lock.h:153
but task is already holding lock:
ffff888148c00148 (&sb->s_type->i_mutex_key#3){++++}-{4:4}, at: iterate_dir+0x20c/0x800 fs/readdir.c:101
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #6 (&sb->s_type->i_mutex_key#3){++++}-{4:4}:
lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849
down_write+0x99/0x220 kernel/locking/rwsem.c:1577
inode_lock include/linux/fs.h:818 [inline]
start_creating+0x130/0x310 fs/debugfs/inode.c:374
debugfs_create_dir+0x25/0x430 fs/debugfs/inode.c:582
blk_register_queue+0x194/0x400 block/blk-sysfs.c:775
add_disk_fwnode+0x648/0xf80 block/genhd.c:493
add_disk include/linux/blkdev.h:753 [inline]
brd_alloc+0x547/0x790 drivers/block/brd.c:401
brd_init+0x126/0x1b0 drivers/block/brd.c:481
do_one_initcall+0x248/0x870 init/main.c:1266
do_initcall_level+0x157/0x210 init/main.c:1328
do_initcalls+0x3f/0x80 init/main.c:1344
kernel_init_freeable+0x435/0x5d0 init/main.c:1577
kernel_init+0x1d/0x2b0 init/main.c:1466
ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
-> #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+0x2b8/0xad0 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+0x24e/0x2e0 drivers/base/bus.c:459
__device_attach_async_helper+0x22d/0x300 drivers/base/dd.c:987
async_run_entry_fn+0xa8/0x420 kernel/async.c:129
process_one_work kernel/workqueue.c:3229 [inline]
process_scheduled_works+0xa66/0x1840 kernel/workqueue.c:3310
worker_thread+0x870/0xd30 kernel/workqueue.c:3391
kthread+0x2f0/0x390 kernel/kthread.c:389
ret_from_fork+0x4b/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+0x2b8/0xad0 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+0x24e/0x2e0 drivers/base/bus.c:459
__device_attach_async_helper+0x22d/0x300 drivers/base/dd.c:987
async_run_entry_fn+0xa8/0x420 kernel/async.c:129
process_one_work kernel/workqueue.c:3229 [inline]
process_scheduled_works+0xa66/0x1840 kernel/workqueue.c:3310
worker_thread+0x870/0xd30 kernel/workqueue.c:3391
kthread+0x2f0/0x390 kernel/kthread.c:389
ret_from_fork+0x4b/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]
__nbd_set_size drivers/block/nbd.c:351 [inline]
nbd_set_size+0x2e0/0x8f0 drivers/block/nbd.c:388
nbd_start_device_ioctl drivers/block/nbd.c:1464 [inline]
__nbd_ioctl drivers/block/nbd.c:1539 [inline]
nbd_ioctl+0x5dc/0xf40 drivers/block/nbd.c:1579
blkdev_ioctl+0x57d/0x6a0 block/ioctl.c:693
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:906 [inline]
__se_sys_ioctl+0xf5/0x170 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)#50){++++}-{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]
block_read_full_folio+0x9b3/0xae0 fs/buffer.c:2446
filemap_read_folio+0x148/0x3b0 mm/filemap.c:2366
filemap_update_page mm/filemap.c:2450 [inline]
filemap_get_pages+0x18ca/0x2080 mm/filemap.c:2571
filemap_read+0x452/0xf50 mm/filemap.c:2646
blkdev_read_iter+0x2d8/0x430 block/fops.c:770
new_sync_read fs/read_write.c:484 [inline]
vfs_read+0x991/0xb70 fs/read_write.c:565
ksys_read+0x18f/0x2b0 fs/read_write.c:708
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 (mapping.invalidate_lock#2){++++}-{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+0x135/0x390 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+0x1053/0x1ad0 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+0x229b/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
-> #0 (&mm->mmap_lock){++++}-{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_killable+0xca/0xd30 kernel/locking/rwsem.c:1547
mmap_read_lock_killable+0x1d/0x70 include/linux/mmap_lock.h:153
get_mmap_lock_carefully mm/memory.c:6158 [inline]
lock_mm_and_find_vma+0x29c/0x2f0 mm/memory.c:6209
do_user_addr_fault arch/x86/mm/fault.c:1361 [inline]
handle_page_fault arch/x86/mm/fault.c:1481 [inline]
exc_page_fault+0x1bf/0x8b0 arch/x86/mm/fault.c:1539
asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623
filldir64+0x2b1/0x690 fs/readdir.c:371
dir_emit include/linux/fs.h:3745 [inline]
dcache_readdir+0x3a5/0x650 fs/libfs.c:209
iterate_dir+0x571/0x800 fs/readdir.c:108
__do_sys_getdents64 fs/readdir.c:403 [inline]
__se_sys_getdents64+0x1e2/0x4b0 fs/readdir.c:389
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:
&mm->mmap_lock --> &q->debugfs_mutex --> &sb->s_type->i_mutex_key#3
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
rlock(&sb->s_type->i_mutex_key#3);
lock(&q->debugfs_mutex);
lock(&sb->s_type->i_mutex_key#3);
rlock(&mm->mmap_lock);
*** DEADLOCK ***
2 locks held by syz.9.3502/20118:
#0: ffff888031ce1978 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x254/0x320 fs/file.c:1191
#1: ffff888148c00148 (&sb->s_type->i_mutex_key#3){++++}-{4:4}, at: iterate_dir+0x20c/0x800 fs/readdir.c:101
stack backtrace:
CPU: 1 UID: 0 PID: 20118 Comm: syz.9.3502 Not tainted 6.13.0-rc5-syzkaller-00006-g56e6a3499e14 #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_read_killable+0xca/0xd30 kernel/locking/rwsem.c:1547
mmap_read_lock_killable+0x1d/0x70 include/linux/mmap_lock.h:153
get_mmap_lock_carefully mm/memory.c:6158 [inline]
lock_mm_and_find_vma+0x29c/0x2f0 mm/memory.c:6209
do_user_addr_fault arch/x86/mm/fault.c:1361 [inline]
handle_page_fault arch/x86/mm/fault.c:1481 [inline]
exc_page_fault+0x1bf/0x8b0 arch/x86/mm/fault.c:1539
asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623
RIP: 0010:filldir64+0x2b1/0x690 fs/readdir.c:372
Code: 87 56 02 00 00 0f 01 cb 0f ae e8 48 8b 44 24 58 49 89 46 08 48 8b 4c 24 18 48 8b 44 24 50 48 89 01 48 8b 44 24 20 8b 54 24 34 <66> 89 41 10 88 51 12 4d 63 f7 42 c6 44 31 13 00 48 8d 69 13 bf 07
RSP: 0018:ffffc900043a7c58 EFLAGS: 00050283
RAX: 0000000000000018 RBX: 0000000020001008 RCX: 0000000020000ff0
RDX: 0000000000000004 RSI: 0000000020000fc8 RDI: 0000000020001008
RBP: 00007ffffffff000 R08: ffffffff821a39fa R09: 1ffff1100549cb40
R10: dffffc0000000000 R11: ffffed100549cb41 R12: ffff888148fdd500
R13: ffffc900043a7e50 R14: 0000000020000fc8 R15: 0000000000000003
dir_emit include/linux/fs.h:3745 [inline]
dcache_readdir+0x3a5/0x650 fs/libfs.c:209
iterate_dir+0x571/0x800 fs/readdir.c:108
__do_sys_getdents64 fs/readdir.c:403 [inline]
__se_sys_getdents64+0x1e2/0x4b0 fs/readdir.c:389
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: 0033:0x7f6a8d785d29
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:00007f6a8e580038 EFLAGS: 00000246 ORIG_RAX: 00000000000000d9
RAX: ffffffffffffffda RBX: 00007f6a8d976160 RCX: 00007f6a8d785d29
RDX: 0000000000001000 RSI: 0000000020000f80 RDI: 0000000000000007
RBP: 00007f6a8d801b08 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f6a8d976160 R15: 00007ffdc8c39ca8
</TASK>
----------------
Code disassembly (best guess):
0: 87 56 02 xchg %edx,0x2(%rsi)
3: 00 00 add %al,(%rax)
5: 0f 01 cb stac
8: 0f ae e8 lfence
b: 48 8b 44 24 58 mov 0x58(%rsp),%rax
10: 49 89 46 08 mov %rax,0x8(%r14)
14: 48 8b 4c 24 18 mov 0x18(%rsp),%rcx
19: 48 8b 44 24 50 mov 0x50(%rsp),%rax
1e: 48 89 01 mov %rax,(%rcx)
21: 48 8b 44 24 20 mov 0x20(%rsp),%rax
26: 8b 54 24 34 mov 0x34(%rsp),%edx
* 2a: 66 89 41 10 mov %ax,0x10(%rcx) <-- trapping instruction
2e: 88 51 12 mov %dl,0x12(%rcx)
31: 4d 63 f7 movslq %r15d,%r14
34: 42 c6 44 31 13 00 movb $0x0,0x13(%rcx,%r14,1)
3a: 48 8d 69 13 lea 0x13(%rcx),%rbp
3e: bf .byte 0xbf
3f: 07 (bad)