======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Tainted: G L
------------------------------------------------------
syz.5.14358/11733 is trying to acquire lock:
ffffffff8ea85640 (fs_reclaim){+.+.}-{0:0}, at: might_alloc include/linux/sched/mm.h:317 [inline]
ffffffff8ea85640 (fs_reclaim){+.+.}-{0:0}, at: prepare_alloc_pages+0x152/0x650 mm/page_alloc.c:4990
but task is already holding lock:
ffff8880372b7178 (&mm->mmap_lock){++++}-{4:4}, at: mmap_read_lock_killable include/linux/mmap_lock.h:601 [inline]
ffff8880372b7178 (&mm->mmap_lock){++++}-{4:4}, at: dump_user_range+0x1c5/0x12c0 fs/coredump.c:1360
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #7 (&mm->mmap_lock){++++}-{4:4}:
__might_fault+0xcb/0x130 mm/memory.c:7340
_copy_from_iter+0x100/0x1670 lib/iov_iter.c:271
copy_from_iter include/linux/uio.h:228 [inline]
copy_from_iter_full include/linux/uio.h:245 [inline]
skb_do_copy_data_nocache include/net/sock.h:2303 [inline]
skb_copy_to_page_nocache include/net/sock.h:2329 [inline]
tcp_sendmsg_locked+0x2121/0x5360 net/ipv4/tcp.c:1311
tcp_sendmsg+0x2f/0x50 net/ipv4/tcp.c:1452
sock_sendmsg_nosec net/socket.c:787 [inline]
__sock_sendmsg net/socket.c:802 [inline]
sock_write_iter+0x406/0x4f0 net/socket.c:1254
new_sync_write fs/read_write.c:595 [inline]
vfs_write+0x61d/0xb90 fs/read_write.c:688
ksys_write+0x150/0x270 fs/read_write.c:740
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #6 (sk_lock-AF_INET){+.+.}-{0:0}:
lock_sock_nested+0x41/0x100 net/core/sock.c:3787
lock_sock include/net/sock.h:1713 [inline]
inet_shutdown+0x6a/0x390 net/ipv4/af_inet.c:915
nbd_mark_nsock_dead+0x2e9/0x560 drivers/block/nbd.c:318
recv_work+0x1c2e/0x1d40 drivers/block/nbd.c:1021
process_one_work kernel/workqueue.c:3314 [inline]
process_scheduled_works+0xb5d/0x1860 kernel/workqueue.c:3397
worker_thread+0xa53/0xfc0 kernel/workqueue.c:3478
kthread+0x389/0x470 kernel/kthread.c:436
ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
-> #5 (&nsock->tx_lock){+.+.}-{4:4}:
__mutex_lock_common kernel/locking/mutex.c:646 [inline]
__mutex_lock+0x1a3/0x1550 kernel/locking/mutex.c:820
nbd_handle_cmd drivers/block/nbd.c:1143 [inline]
nbd_queue_rq+0x37b/0x1100 drivers/block/nbd.c:1207
blk_mq_dispatch_rq_list+0xa70/0x1910 block/blk-mq.c:2148
__blk_mq_do_dispatch_sched block/blk-mq-sched.c:168 [inline]
blk_mq_do_dispatch_sched block/blk-mq-sched.c:182 [inline]
__blk_mq_sched_dispatch_requests+0xdcc/0x1600 block/blk-mq-sched.c:307
blk_mq_sched_dispatch_requests+0xd7/0x190 block/blk-mq-sched.c:329
blk_mq_run_hw_queue+0x348/0x4f0 block/blk-mq.c:2386
blk_mq_dispatch_list+0xd16/0xe10 include/linux/spinlock.h:-1
blk_mq_flush_plug_list+0x48d/0x570 block/blk-mq.c:2997
__blk_flush_plug+0x3ed/0x4d0 block/blk-core.c:1230
blk_finish_plug block/blk-core.c:1257 [inline]
__submit_bio+0x28d/0x580 block/blk-core.c:649
__submit_bio_noacct_mq block/blk-core.c:722 [inline]
submit_bio_noacct_nocheck+0x2f4/0xa40 block/blk-core.c:753
submit_bh fs/buffer.c:2742 [inline]
block_read_full_folio+0x599/0x830 fs/buffer.c:2344
filemap_read_folio+0x137/0x3b0 mm/filemap.c:2502
do_read_cache_folio+0x358/0x590 mm/filemap.c:4107
read_mapping_folio include/linux/pagemap.h:1017 [inline]
read_part_sector+0xb6/0x2b0 block/partitions/core.c:724
adfspart_check_ICS+0xb1/0x960 block/partitions/acorn.c:356
check_partition block/partitions/core.c:143 [inline]
blk_add_partitions block/partitions/core.c:591 [inline]
bdev_disk_changed+0x817/0x1770 block/partitions/core.c:695
blkdev_get_whole+0x380/0x510 block/bdev.c:756
bdev_open+0x31e/0xd30 block/bdev.c:965
blkdev_open+0x470/0x610 block/fops.c:697
do_dentry_open+0x822/0x13a0 fs/open.c:947
vfs_open+0x3b/0x340 fs/open.c:1079
do_open fs/namei.c:4699 [inline]
path_openat+0x2e08/0x3860 fs/namei.c:4858
do_file_open+0x23e/0x4a0 fs/namei.c:4887
do_sys_openat2+0x113/0x200 fs/open.c:1364
do_sys_open fs/open.c:1370 [inline]
__do_sys_openat fs/open.c:1386 [inline]
__se_sys_openat fs/open.c:1381 [inline]
__x64_sys_openat+0x138/0x170 fs/open.c:1381
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #4 (&cmd->lock){+.+.}-{4:4}:
__mutex_lock_common kernel/locking/mutex.c:646 [inline]
__mutex_lock+0x1a3/0x1550 kernel/locking/mutex.c:820
nbd_queue_rq+0xc6/0x1100 drivers/block/nbd.c:1199
blk_mq_dispatch_rq_list+0xa70/0x1910 block/blk-mq.c:2148
__blk_mq_do_dispatch_sched block/blk-mq-sched.c:168 [inline]
blk_mq_do_dispatch_sched block/blk-mq-sched.c:182 [inline]
__blk_mq_sched_dispatch_requests+0xdcc/0x1600 block/blk-mq-sched.c:307
blk_mq_sched_dispatch_requests+0xd7/0x190 block/blk-mq-sched.c:329
blk_mq_run_hw_queue+0x348/0x4f0 block/blk-mq.c:2386
blk_mq_dispatch_list+0xd16/0xe10 include/linux/spinlock.h:-1
blk_mq_flush_plug_list+0x48d/0x570 block/blk-mq.c:2997
__blk_flush_plug+0x3ed/0x4d0 block/blk-core.c:1230
blk_finish_plug block/blk-core.c:1257 [inline]
__submit_bio+0x28d/0x580 block/blk-core.c:649
__submit_bio_noacct_mq block/blk-core.c:722 [inline]
submit_bio_noacct_nocheck+0x2f4/0xa40 block/blk-core.c:753
submit_bh fs/buffer.c:2742 [inline]
block_read_full_folio+0x599/0x830 fs/buffer.c:2344
filemap_read_folio+0x137/0x3b0 mm/filemap.c:2502
do_read_cache_folio+0x358/0x590 mm/filemap.c:4107
read_mapping_folio include/linux/pagemap.h:1017 [inline]
read_part_sector+0xb6/0x2b0 block/partitions/core.c:724
adfspart_check_ICS+0xb1/0x960 block/partitions/acorn.c:356
check_partition block/partitions/core.c:143 [inline]
blk_add_partitions block/partitions/core.c:591 [inline]
bdev_disk_changed+0x817/0x1770 block/partitions/core.c:695
blkdev_get_whole+0x380/0x510 block/bdev.c:756
bdev_open+0x31e/0xd30 block/bdev.c:965
blkdev_open+0x470/0x610 block/fops.c:697
do_dentry_open+0x822/0x13a0 fs/open.c:947
vfs_open+0x3b/0x340 fs/open.c:1079
do_open fs/namei.c:4699 [inline]
path_openat+0x2e08/0x3860 fs/namei.c:4858
do_file_open+0x23e/0x4a0 fs/namei.c:4887
do_sys_openat2+0x113/0x200 fs/open.c:1364
do_sys_open fs/open.c:1370 [inline]
__do_sys_openat fs/open.c:1386 [inline]
__se_sys_openat fs/open.c:1381 [inline]
__x64_sys_openat+0x138/0x170 fs/open.c:1381
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #3 (set->srcu){.+.+}-{0:0}:
srcu_lock_sync include/linux/srcu.h:199 [inline]
__synchronize_srcu+0xca/0x300 kernel/rcu/srcutree.c:1481
elevator_switch+0x1e8/0x7a0 block/elevator.c:576
elevator_change+0x2cc/0x450 block/elevator.c:681
elevator_set_default+0x36c/0x430 block/elevator.c:754
blk_register_queue+0x3e9/0x4e0 block/blk-sysfs.c:987
__add_disk+0x677/0xd50 block/genhd.c:528
add_disk_fwnode+0xfb/0x480 block/genhd.c:597
add_disk include/linux/blkdev.h:794 [inline]
nbd_dev_add+0x72c/0xb50 drivers/block/nbd.c:1984
nbd_init+0x168/0x1f0 drivers/block/nbd.c:2692
do_one_initcall+0x250/0x870 init/main.c:1392
do_initcall_level+0x104/0x190 init/main.c:1454
do_initcalls+0x59/0xa0 init/main.c:1470
kernel_init_freeable+0x2a6/0x3e0 init/main.c:1703
kernel_init+0x1d/0x1d0 init/main.c:1593
ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
-> #2 (&q->elevator_lock){+.+.}-{4:4}:
__mutex_lock_common kernel/locking/mutex.c:646 [inline]
__mutex_lock+0x1a3/0x1550 kernel/locking/mutex.c:820
elevator_change+0x1b3/0x450 block/elevator.c:679
elevator_set_none+0xb5/0x140 block/elevator.c:769
blk_mq_elv_switch_none block/blk-mq.c:5134 [inline]
__blk_mq_update_nr_hw_queues block/blk-mq.c:5179 [inline]
blk_mq_update_nr_hw_queues+0x5e7/0x1a60 block/blk-mq.c:5244
nbd_start_device+0x17f/0xb10 drivers/block/nbd.c:1489
nbd_genl_connect+0x165b/0x1cf0 drivers/block/nbd.c:2239
genl_family_rcv_msg_doit+0x22a/0x330 net/netlink/genetlink.c:1114
genl_family_rcv_msg net/netlink/genetlink.c:1194 [inline]
genl_rcv_msg+0x61c/0x7a0 net/netlink/genetlink.c:1209
netlink_rcv_skb+0x232/0x4b0 net/netlink/af_netlink.c:2555
genl_rcv+0x28/0x40 net/netlink/genetlink.c:1218
netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline]
netlink_unicast+0x75c/0x8e0 net/netlink/af_netlink.c:1344
netlink_sendmsg+0x813/0xb40 net/netlink/af_netlink.c:1899
sock_sendmsg_nosec net/socket.c:787 [inline]
__sock_sendmsg net/socket.c:802 [inline]
____sys_sendmsg+0x972/0x9f0 net/socket.c:2698
___sys_sendmsg+0x2a5/0x360 net/socket.c:2752
__sys_sendmsg net/socket.c:2784 [inline]
__do_sys_sendmsg net/socket.c:2789 [inline]
__se_sys_sendmsg net/socket.c:2787 [inline]
__x64_sys_sendmsg+0x1bd/0x2a0 net/socket.c:2787
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #1 (&q->q_usage_counter(io)#50){++++}-{0:0}:
blk_alloc_queue+0x546/0x680 block/blk-core.c:461
blk_mq_alloc_queue block/blk-mq.c:4453 [inline]
__blk_mq_alloc_disk+0x197/0x390 block/blk-mq.c:4500
nbd_dev_add+0x499/0xb50 drivers/block/nbd.c:1954
nbd_init+0x168/0x1f0 drivers/block/nbd.c:2692
do_one_initcall+0x250/0x870 init/main.c:1392
do_initcall_level+0x104/0x190 init/main.c:1454
do_initcalls+0x59/0xa0 init/main.c:1470
kernel_init_freeable+0x2a6/0x3e0 init/main.c:1703
kernel_init+0x1d/0x1d0 init/main.c:1593
ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
-> #0 (fs_reclaim){+.+.}-{0:0}:
check_prev_add kernel/locking/lockdep.c:3165 [inline]
check_prevs_add kernel/locking/lockdep.c:3284 [inline]
validate_chain kernel/locking/lockdep.c:3908 [inline]
__lock_acquire+0x15a5/0x2cf0 kernel/locking/lockdep.c:5237
lock_acquire+0x106/0x350 kernel/locking/lockdep.c:5868
__fs_reclaim_acquire mm/page_alloc.c:4320 [inline]
fs_reclaim_acquire+0x71/0x100 mm/page_alloc.c:4334
might_alloc include/linux/sched/mm.h:317 [inline]
prepare_alloc_pages+0x152/0x650 mm/page_alloc.c:4990
__alloc_frozen_pages_noprof+0x12f/0x380 mm/page_alloc.c:5210
alloc_pages_mpol+0x235/0x490 mm/mempolicy.c:2490
alloc_frozen_pages_noprof mm/mempolicy.c:2561 [inline]
alloc_pages_noprof+0xac/0x2a0 mm/mempolicy.c:2581
pagetable_alloc_noprof include/linux/mm.h:3651 [inline]
__pud_alloc_one_noprof include/asm-generic/pgalloc.h:181 [inline]
pud_alloc_one_noprof include/asm-generic/pgalloc.h:206 [inline]
__pud_alloc+0x3a/0x460 mm/memory.c:6796
pud_alloc include/linux/mm.h:3561 [inline]
__handle_mm_fault mm/memory.c:6487 [inline]
handle_mm_fault+0x2b2c/0x3170 mm/memory.c:6734
faultin_page mm/gup.c:1126 [inline]
__get_user_pages+0x167f/0x2730 mm/gup.c:1428
__get_user_pages_locked mm/gup.c:1692 [inline]
get_dump_page+0x1b5/0x410 mm/gup.c:2192
dump_user_range+0x20a/0x12c0 fs/coredump.c:1372
elf_core_dump+0x34c2/0x3ad0 fs/binfmt_elf.c:2109
coredump_write+0x12b0/0x19d0 fs/coredump.c:1053
do_coredump fs/coredump.c:1132 [inline]
vfs_coredump+0x3807/0x4530 fs/coredump.c:1206
get_signal+0x1107/0x1330 kernel/signal.c:3023
arch_do_signal_or_restart+0xbc/0x840 arch/x86/kernel/signal.c:337
__exit_to_user_mode_loop kernel/entry/common.c:64 [inline]
exit_to_user_mode_loop kernel/entry/common.c:98 [inline]
__exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
irqentry_exit_to_user_mode_prepare include/linux/irq-entry-common.h:244 [inline]
irqentry_exit_to_user_mode include/linux/irq-entry-common.h:315 [inline]
irqentry_exit+0x2aa/0x8b0 kernel/entry/common.c:162
asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618
other info that might help us debug this:
Chain exists of:
fs_reclaim --> sk_lock-AF_INET --> &mm->mmap_lock
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
rlock(&mm->mmap_lock);
lock(sk_lock-AF_INET);
lock(&mm->mmap_lock);
lock(fs_reclaim);
*** DEADLOCK ***
2 locks held by syz.5.14358/11733:
#0: ffff88806b3f8410 (sb_writers#13){.+.+}-{0:0}, at: do_coredump fs/coredump.c:1132 [inline]
#0: ffff88806b3f8410 (sb_writers#13){.+.+}-{0:0}, at: vfs_coredump+0x3807/0x4530 fs/coredump.c:1206
#1: ffff8880372b7178 (&mm->mmap_lock){++++}-{4:4}, at: mmap_read_lock_killable include/linux/mmap_lock.h:601 [inline]
#1: ffff8880372b7178 (&mm->mmap_lock){++++}-{4:4}, at: dump_user_range+0x1c5/0x12c0 fs/coredump.c:1360
stack backtrace:
CPU: 0 UID: 0 PID: 11733 Comm: syz.5.14358 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
Call Trace:
<TASK>
dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
print_circular_bug+0x2e1/0x300 kernel/locking/lockdep.c:2043
check_noncircular+0x12e/0x150 kernel/locking/lockdep.c:2175
check_prev_add kernel/locking/lockdep.c:3165 [inline]
check_prevs_add kernel/locking/lockdep.c:3284 [inline]
validate_chain kernel/locking/lockdep.c:3908 [inline]
__lock_acquire+0x15a5/0x2cf0 kernel/locking/lockdep.c:5237
lock_acquire+0x106/0x350 kernel/locking/lockdep.c:5868
__fs_reclaim_acquire mm/page_alloc.c:4320 [inline]
fs_reclaim_acquire+0x71/0x100 mm/page_alloc.c:4334
might_alloc include/linux/sched/mm.h:317 [inline]
prepare_alloc_pages+0x152/0x650 mm/page_alloc.c:4990
__alloc_frozen_pages_noprof+0x12f/0x380 mm/page_alloc.c:5210
alloc_pages_mpol+0x235/0x490 mm/mempolicy.c:2490
alloc_frozen_pages_noprof mm/mempolicy.c:2561 [inline]
alloc_pages_noprof+0xac/0x2a0 mm/mempolicy.c:2581
pagetable_alloc_noprof include/linux/mm.h:3651 [inline]
__pud_alloc_one_noprof include/asm-generic/pgalloc.h:181 [inline]
pud_alloc_one_noprof include/asm-generic/pgalloc.h:206 [inline]
__pud_alloc+0x3a/0x460 mm/memory.c:6796
pud_alloc include/linux/mm.h:3561 [inline]
__handle_mm_fault mm/memory.c:6487 [inline]
handle_mm_fault+0x2b2c/0x3170 mm/memory.c:6734
faultin_page mm/gup.c:1126 [inline]
__get_user_pages+0x167f/0x2730 mm/gup.c:1428
__get_user_pages_locked mm/gup.c:1692 [inline]
get_dump_page+0x1b5/0x410 mm/gup.c:2192
dump_user_range+0x20a/0x12c0 fs/coredump.c:1372
elf_core_dump+0x34c2/0x3ad0 fs/binfmt_elf.c:2109
coredump_write+0x12b0/0x19d0 fs/coredump.c:1053
do_coredump fs/coredump.c:1132 [inline]
vfs_coredump+0x3807/0x4530 fs/coredump.c:1206
get_signal+0x1107/0x1330 kernel/signal.c:3023
arch_do_signal_or_restart+0xbc/0x840 arch/x86/kernel/signal.c:337
__exit_to_user_mode_loop kernel/entry/common.c:64 [inline]
exit_to_user_mode_loop kernel/entry/common.c:98 [inline]
__exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
irqentry_exit_to_user_mode_prepare include/linux/irq-entry-common.h:244 [inline]
irqentry_exit_to_user_mode include/linux/irq-entry-common.h:315 [inline]
irqentry_exit+0x2aa/0x8b0 kernel/entry/common.c:162
asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618
RIP: 0033:0x7f83d1052b27
Code: e8 8e fa ff ff 89 f2 48 8d 3d c5 3e 1b 00 48 8d 35 be f8 1d 00 31 c0 e8 e7 f8 ff ff 0f 1f 80 00 00 00 00 53 89 fb 48 83 ec 10 <64> 8b 04 25 a4 ff ff ff 85 c0 74 2a 89 fe 31 c0 bf 3c 00 00 00 e8
RSP: 002b:00007f83d2084120 EFLAGS: 00010202
RAX: 0000000000000000 RBX: 000000000000000b RCX: 00007f83d119ce59
RDX: 00007f83d2084140 RSI: 00007f83d2084270 RDI: 000000000000000b
RBP: 00007f83d1232d6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000
R13: 00007f83d1416038 R14: 00007f83d1415fa0 R15: 00007ffe4e9c6b68
</TASK>
syz.5.14358: attempt to access beyond end of device
loop5: rw=2049, sector=1256, nr_sectors = 12 limit=256