====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ syz.4.6504/29632 is trying to acquire lock: ffffffff8e883760 (fs_reclaim){+.+.}-{0:0}, at: might_alloc include/linux/sched/mm.h:317 [inline] ffffffff8e883760 (fs_reclaim){+.+.}-{0:0}, at: prepare_alloc_pages+0x152/0x650 mm/page_alloc.c:5018 but task is already holding lock: ffff888076e3c8a8 (mapping.invalidate_lock#2){++++}-{4:4}, at: filemap_invalidate_lock_shared include/linux/fs.h:1093 [inline] ffff888076e3c8a8 (mapping.invalidate_lock#2){++++}-{4:4}, at: filemap_fault+0x97c/0x1320 mm/filemap.c:3561 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #9 (mapping.invalidate_lock#2){++++}-{4:4}: down_read+0x47/0x2e0 kernel/locking/rwsem.c:1537 filemap_invalidate_lock_shared include/linux/fs.h:1093 [inline] filemap_fault+0x5ff/0x1320 mm/filemap.c:3542 __do_fault+0x138/0x390 mm/memory.c:5364 do_shared_fault mm/memory.c:5863 [inline] do_fault mm/memory.c:5937 [inline] do_pte_missing+0x5c4/0x3490 mm/memory.c:4477 handle_pte_fault mm/memory.c:6317 [inline] __handle_mm_fault mm/memory.c:6455 [inline] handle_mm_fault+0x1bec/0x3310 mm/memory.c:6624 do_user_addr_fault+0xa73/0x1340 arch/x86/mm/fault.c:1334 handle_page_fault arch/x86/mm/fault.c:1474 [inline] exc_page_fault+0x6a/0xc0 arch/x86/mm/fault.c:1527 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618 -> #8 (vm_lock){++++}-{0:0}: __vma_start_exclude_readers+0x28a/0x940 mm/mmap_lock.c:125 __vma_start_write+0xdc/0x290 mm/mmap_lock.c:148 vma_start_write include/linux/mmap_lock.h:303 [inline] mprotect_fixup+0x5ee/0xa80 mm/mprotect.c:768 setup_arg_pages+0x565/0xac0 fs/exec.c:670 load_elf_binary+0xc5e/0x2980 fs/binfmt_elf.c:1029 search_binary_handler fs/exec.c:1664 [inline] exec_binprm fs/exec.c:1696 [inline] bprm_execve+0x93d/0x1460 fs/exec.c:1748 kernel_execve+0x844/0x930 fs/exec.c:1892 try_to_run_init_process+0x13/0x60 init/main.c:1510 kernel_init+0xad/0x1d0 init/main.c:1638 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 -> #7 (&mm->mmap_lock){++++}-{4:4}: __might_fault+0xcb/0x130 mm/memory.c:7230 _inline_copy_from_user include/linux/uaccess.h:169 [inline] _copy_from_user+0x28/0xb0 lib/usercopy.c:18 copy_from_user include/linux/uaccess.h:223 [inline] csum_and_copy_from_user include/net/checksum.h:31 [inline] copy_from_user_iter_csum net/core/skbuff.c:7423 [inline] iterate_ubuf include/linux/iov_iter.h:30 [inline] iterate_and_advance2 include/linux/iov_iter.h:302 [inline] csum_and_copy_from_iter_full+0x1e7/0x1f00 net/core/skbuff.c:7435 ip_generic_getfrag+0x149/0x2d0 net/ipv4/ip_output.c:942 __ip6_append_data+0x36be/0x3c50 net/ipv6/ip6_output.c:1704 ip6_append_data+0x10f/0x280 net/ipv6/ip6_output.c:1857 rawv6_sendmsg+0x12d3/0x18e0 net/ipv6/raw.c:912 sock_sendmsg_nosec net/socket.c:727 [inline] __sock_sendmsg net/socket.c:742 [inline] ____sys_sendmsg+0x80a/0x9f0 net/socket.c:2592 ___sys_sendmsg+0x2a5/0x360 net/socket.c:2646 __sys_sendmsg net/socket.c:2678 [inline] __do_sys_sendmsg net/socket.c:2683 [inline] __se_sys_sendmsg net/socket.c:2681 [inline] __x64_sys_sendmsg+0x1bd/0x2a0 net/socket.c:2681 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #6 (sk_lock-AF_INET6){+.+.}-{0:0}: lock_sock_nested+0x48/0x100 net/core/sock.c:3780 lock_sock include/net/sock.h:1709 [inline] inet_shutdown+0x6a/0x390 net/ipv4/af_inet.c:919 nbd_mark_nsock_dead+0x2e9/0x560 drivers/block/nbd.c:318 recv_work+0x1c7f/0x1d90 drivers/block/nbd.c:1021 process_one_work kernel/workqueue.c:3276 [inline] process_scheduled_works+0xb6e/0x18c0 kernel/workqueue.c:3359 worker_thread+0xa53/0xfc0 kernel/workqueue.c:3440 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x51e/0xb90 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:614 [inline] __mutex_lock+0x19f/0x1300 kernel/locking/mutex.c:776 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+0x2f4/0xa70 block/blk-core.c:753 submit_bh fs/buffer.c:2826 [inline] block_read_full_folio+0x599/0x830 fs/buffer.c:2444 filemap_read_folio+0x137/0x3b0 mm/filemap.c:2501 do_read_cache_folio+0x358/0x590 mm/filemap.c:4106 read_mapping_folio include/linux/pagemap.h:1017 [inline] read_part_sector+0xb6/0x2b0 block/partitions/core.c:723 adfspart_check_ICS+0xa5/0xa40 block/partitions/acorn.c:360 check_partition block/partitions/core.c:142 [inline] blk_add_partitions block/partitions/core.c:590 [inline] bdev_disk_changed+0x7ba/0x1550 block/partitions/core.c:694 blkdev_get_whole+0x380/0x510 block/bdev.c:764 bdev_open+0x31e/0xd30 block/bdev.c:973 blkdev_open+0x470/0x610 block/fops.c:697 do_dentry_open+0x785/0x14e0 fs/open.c:949 vfs_open+0x3b/0x340 fs/open.c:1081 do_open fs/namei.c:4677 [inline] path_openat+0x2e08/0x3860 fs/namei.c:4836 do_file_open+0x23e/0x4a0 fs/namei.c:4865 do_sys_openat2+0x113/0x200 fs/open.c:1366 do_sys_open fs/open.c:1372 [inline] __do_sys_openat fs/open.c:1388 [inline] __se_sys_openat fs/open.c:1383 [inline] __x64_sys_openat+0x138/0x170 fs/open.c:1383 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 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:614 [inline] __mutex_lock+0x19f/0x1300 kernel/locking/mutex.c:776 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+0x2f4/0xa70 block/blk-core.c:753 submit_bh fs/buffer.c:2826 [inline] block_read_full_folio+0x599/0x830 fs/buffer.c:2444 filemap_read_folio+0x137/0x3b0 mm/filemap.c:2501 do_read_cache_folio+0x358/0x590 mm/filemap.c:4106 read_mapping_folio include/linux/pagemap.h:1017 [inline] read_part_sector+0xb6/0x2b0 block/partitions/core.c:723 adfspart_check_ICS+0xa5/0xa40 block/partitions/acorn.c:360 check_partition block/partitions/core.c:142 [inline] blk_add_partitions block/partitions/core.c:590 [inline] bdev_disk_changed+0x7ba/0x1550 block/partitions/core.c:694 blkdev_get_whole+0x380/0x510 block/bdev.c:764 bdev_open+0x31e/0xd30 block/bdev.c:973 blkdev_open+0x470/0x610 block/fops.c:697 do_dentry_open+0x785/0x14e0 fs/open.c:949 vfs_open+0x3b/0x340 fs/open.c:1081 do_open fs/namei.c:4677 [inline] path_openat+0x2e08/0x3860 fs/namei.c:4836 do_file_open+0x23e/0x4a0 fs/namei.c:4865 do_sys_openat2+0x113/0x200 fs/open.c:1366 do_sys_open fs/open.c:1372 [inline] __do_sys_openat fs/open.c:1388 [inline] __se_sys_openat fs/open.c:1383 [inline] __x64_sys_openat+0x138/0x170 fs/open.c:1383 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 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+0x366/0x430 block/blk-sysfs.c:946 __add_disk+0x677/0xd50 block/genhd.c:528 add_disk_fwnode+0xfb/0x480 block/genhd.c:597 add_disk include/linux/blkdev.h:785 [inline] nbd_dev_add+0x72c/0xb50 drivers/block/nbd.c:1984 nbd_init+0x168/0x1f0 drivers/block/nbd.c:2692 do_one_initcall+0x250/0x8d0 init/main.c:1382 do_initcall_level+0x104/0x190 init/main.c:1444 do_initcalls+0x59/0xa0 init/main.c:1460 kernel_init_freeable+0x2a6/0x3e0 init/main.c:1692 kernel_init+0x1d/0x1d0 init/main.c:1582 ret_from_fork+0x51e/0xb90 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:614 [inline] __mutex_lock+0x19f/0x1300 kernel/locking/mutex.c:776 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:5110 [inline] __blk_mq_update_nr_hw_queues block/blk-mq.c:5155 [inline] blk_mq_update_nr_hw_queues+0x5e7/0x1a60 block/blk-mq.c:5220 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:2550 genl_rcv+0x28/0x40 net/netlink/genetlink.c:1218 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline] netlink_unicast+0x80f/0x9b0 net/netlink/af_netlink.c:1344 netlink_sendmsg+0x813/0xb40 net/netlink/af_netlink.c:1894 sock_sendmsg_nosec net/socket.c:727 [inline] __sock_sendmsg net/socket.c:742 [inline] ____sys_sendmsg+0x972/0x9f0 net/socket.c:2592 ___sys_sendmsg+0x2a5/0x360 net/socket.c:2646 __sys_sendmsg net/socket.c:2678 [inline] __do_sys_sendmsg net/socket.c:2683 [inline] __se_sys_sendmsg net/socket.c:2681 [inline] __x64_sys_sendmsg+0x1bd/0x2a0 net/socket.c:2681 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #1 (&q->q_usage_counter(io)#49){++++}-{0:0}: blk_alloc_queue+0x546/0x680 block/blk-core.c:461 blk_mq_alloc_queue block/blk-mq.c:4429 [inline] __blk_mq_alloc_disk+0x197/0x390 block/blk-mq.c:4476 nbd_dev_add+0x499/0xb50 drivers/block/nbd.c:1954 nbd_init+0x168/0x1f0 drivers/block/nbd.c:2692 do_one_initcall+0x250/0x8d0 init/main.c:1382 do_initcall_level+0x104/0x190 init/main.c:1444 do_initcalls+0x59/0xa0 init/main.c:1460 kernel_init_freeable+0x2a6/0x3e0 init/main.c:1692 kernel_init+0x1d/0x1d0 init/main.c:1582 ret_from_fork+0x51e/0xb90 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+0xf0/0x2e0 kernel/locking/lockdep.c:5868 __fs_reclaim_acquire mm/page_alloc.c:4348 [inline] fs_reclaim_acquire+0x71/0x100 mm/page_alloc.c:4362 might_alloc include/linux/sched/mm.h:317 [inline] prepare_alloc_pages+0x152/0x650 mm/page_alloc.c:5018 __alloc_frozen_pages_noprof+0x12f/0x380 mm/page_alloc.c:5239 alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2490 alloc_frozen_pages_noprof mm/mempolicy.c:2561 [inline] alloc_pages_noprof+0xa8/0x1a0 mm/mempolicy.c:2581 folio_alloc_noprof+0x1e/0x30 mm/mempolicy.c:2591 filemap_alloc_folio_noprof+0x111/0x470 mm/filemap.c:1013 __filemap_get_folio_mpol+0x3fc/0xb00 mm/filemap.c:2011 __filemap_get_folio include/linux/pagemap.h:763 [inline] filemap_fault+0x9ac/0x1320 mm/filemap.c:3564 __do_fault+0x138/0x390 mm/memory.c:5364 do_shared_fault mm/memory.c:5863 [inline] do_fault mm/memory.c:5937 [inline] do_pte_missing+0x5c4/0x3490 mm/memory.c:4477 handle_pte_fault mm/memory.c:6317 [inline] __handle_mm_fault mm/memory.c:6455 [inline] handle_mm_fault+0x1bec/0x3310 mm/memory.c:6624 do_user_addr_fault+0xa73/0x1340 arch/x86/mm/fault.c:1334 handle_page_fault arch/x86/mm/fault.c:1474 [inline] exc_page_fault+0x6a/0xc0 arch/x86/mm/fault.c:1527 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 --> vm_lock --> mapping.invalidate_lock#2 Possible unsafe locking scenario: CPU0 CPU1 ---- ---- rlock(mapping.invalidate_lock#2); lock(vm_lock); lock(mapping.invalidate_lock#2); lock(fs_reclaim); *** DEADLOCK *** 1 lock held by syz.4.6504/29632: #0: ffff888076e3c8a8 (mapping.invalidate_lock#2){++++}-{4:4}, at: filemap_invalidate_lock_shared include/linux/fs.h:1093 [inline] #0: ffff888076e3c8a8 (mapping.invalidate_lock#2){++++}-{4:4}, at: filemap_fault+0x97c/0x1320 mm/filemap.c:3561 stack backtrace: CPU: 0 UID: 0 PID: 29632 Comm: syz.4.6504 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026 Call Trace: 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+0xf0/0x2e0 kernel/locking/lockdep.c:5868 __fs_reclaim_acquire mm/page_alloc.c:4348 [inline] fs_reclaim_acquire+0x71/0x100 mm/page_alloc.c:4362 might_alloc include/linux/sched/mm.h:317 [inline] prepare_alloc_pages+0x152/0x650 mm/page_alloc.c:5018 __alloc_frozen_pages_noprof+0x12f/0x380 mm/page_alloc.c:5239 alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2490 alloc_frozen_pages_noprof mm/mempolicy.c:2561 [inline] alloc_pages_noprof+0xa8/0x1a0 mm/mempolicy.c:2581 folio_alloc_noprof+0x1e/0x30 mm/mempolicy.c:2591 filemap_alloc_folio_noprof+0x111/0x470 mm/filemap.c:1013 __filemap_get_folio_mpol+0x3fc/0xb00 mm/filemap.c:2011 __filemap_get_folio include/linux/pagemap.h:763 [inline] filemap_fault+0x9ac/0x1320 mm/filemap.c:3564 __do_fault+0x138/0x390 mm/memory.c:5364 do_shared_fault mm/memory.c:5863 [inline] do_fault mm/memory.c:5937 [inline] do_pte_missing+0x5c4/0x3490 mm/memory.c:4477 handle_pte_fault mm/memory.c:6317 [inline] __handle_mm_fault mm/memory.c:6455 [inline] handle_mm_fault+0x1bec/0x3310 mm/memory.c:6624 do_user_addr_fault+0xa73/0x1340 arch/x86/mm/fault.c:1334 handle_page_fault arch/x86/mm/fault.c:1474 [inline] exc_page_fault+0x6a/0xc0 arch/x86/mm/fault.c:1527 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618 RIP: 0033:0x7f552b870fa0 Code: 89 dc 41 83 e4 03 0f 85 ca 01 00 00 4c 89 ff be 04 00 00 00 e8 81 93 fe ff 49 8b 47 40 41 83 47 30 04 48 8d 50 fc 49 89 57 40 <89> 68 fc 41 8b 47 30 48 83 c4 28 5b 5d 41 5c 41 5d 41 5e 41 5f c3 RSP: 002b:00007ffda90df700 EFLAGS: 00010216 RAX: 0000001b2e523f74 RBX: ffffffffffffff74 RCX: ffffffff823c49ce RDX: 0000001b2e523f70 RSI: 0000000000000004 RDI: 00007f552c745720 RBP: 0000000000000000 R08: 00007f552bc00000 R09: 00007f552bc02000 R10: 00000000823c49d2 R11: 0000000000000000 R12: 0000000000000000 R13: 000000000007ffff R14: ffffffff823c49ce R15: 00007f552c745720