====================================================== WARNING: possible circular locking dependency detected 5.14.0-rc1-syzkaller #0 Not tainted ------------------------------------------------------ syz-executor.0/9995 is trying to acquire lock: ffffffff8c7d6b20 (fs_reclaim){+.+.}-{0:0}, at: __fs_reclaim_acquire+0x0/0x30 mm/page_alloc.c:4210 but task is already holding lock: ffff8880b9d4d0c8 (lock#2){-.-.}-{2:2}, at: local_lock_acquire+0x7/0x130 include/linux/local_lock_internal.h:41 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (lock#2){-.-.}-{2:2}: lock_acquire+0x182/0x4a0 kernel/locking/lockdep.c:5625 local_lock_acquire+0x23/0x130 include/linux/local_lock_internal.h:42 free_unref_page+0x242/0x550 mm/page_alloc.c:3427 mm_free_pgd kernel/fork.c:636 [inline] __mmdrop+0xae/0x3f0 kernel/fork.c:687 mmdrop include/linux/sched/mm.h:49 [inline] finish_task_switch+0x221/0x630 kernel/sched/core.c:4582 context_switch kernel/sched/core.c:4686 [inline] __schedule+0xc0f/0x11f0 kernel/sched/core.c:5940 preempt_schedule_notrace+0x12c/0x170 kernel/sched/core.c:6179 preempt_schedule_notrace_thunk+0x16/0x18 arch/x86/entry/thunk_64.S:36 rcu_read_unlock_sched_notrace include/linux/rcupdate.h:809 [inline] trace_lock_acquire+0xb4/0x190 include/trace/events/lock.h:13 lock_acquire+0xa4/0x4a0 kernel/locking/lockdep.c:5596 fs_reclaim_acquire+0x79/0xf0 mm/page_alloc.c:4569 might_alloc include/linux/sched/mm.h:198 [inline] slab_pre_alloc_hook mm/slab.h:485 [inline] slab_alloc_node mm/slub.c:2902 [inline] slab_alloc mm/slub.c:2989 [inline] kmem_cache_alloc+0x3a/0x340 mm/slub.c:2994 kmem_cache_zalloc include/linux/slab.h:711 [inline] attach_epitem fs/eventpoll.c:1414 [inline] ep_insert fs/eventpoll.c:1468 [inline] do_epoll_ctl+0x1392/0x2f70 fs/eventpoll.c:2133 __do_sys_epoll_ctl fs/eventpoll.c:2184 [inline] __se_sys_epoll_ctl fs/eventpoll.c:2175 [inline] __x64_sys_epoll_ctl+0x14e/0x190 fs/eventpoll.c:2175 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae -> #0 (fs_reclaim){+.+.}-{0:0}: check_prev_add kernel/locking/lockdep.c:3051 [inline] check_prevs_add+0x4f9/0x5b30 kernel/locking/lockdep.c:3174 validate_chain kernel/locking/lockdep.c:3789 [inline] __lock_acquire+0x4476/0x6100 kernel/locking/lockdep.c:5015 lock_acquire+0x182/0x4a0 kernel/locking/lockdep.c:5625 __fs_reclaim_acquire+0x20/0x30 mm/page_alloc.c:4552 fs_reclaim_acquire+0x59/0xf0 mm/page_alloc.c:4566 prepare_alloc_pages+0x151/0x5a0 mm/page_alloc.c:5164 __alloc_pages+0x14d/0x5f0 mm/page_alloc.c:5363 stack_depot_save+0x361/0x490 lib/stackdepot.c:303 save_stack+0xf9/0x1f0 mm/page_owner.c:120 __set_page_owner+0x42/0x2f0 mm/page_owner.c:181 prep_new_page mm/page_alloc.c:2433 [inline] __alloc_pages_bulk+0x9f2/0x1090 mm/page_alloc.c:5301 alloc_pages_bulk_array_node include/linux/gfp.h:557 [inline] vm_area_alloc_pages mm/vmalloc.c:2793 [inline] __vmalloc_area_node mm/vmalloc.c:2863 [inline] __vmalloc_node_range+0x3ad/0x7f0 mm/vmalloc.c:2966 __vmalloc_node mm/vmalloc.c:3015 [inline] vzalloc+0x75/0x80 mm/vmalloc.c:3085 allocate_partitions block/partitions/core.c:106 [inline] check_partition block/partitions/core.c:128 [inline] blk_add_partitions block/partitions/core.c:611 [inline] bdev_disk_changed+0x4d9/0x1690 block/partitions/core.c:697 loop_reread_partitions drivers/block/loop.c:652 [inline] loop_set_status+0x6b1/0x8e0 drivers/block/loop.c:1510 lo_ioctl+0xca2/0x23b0 drivers/block/loop.c:1620 blkdev_ioctl+0x332/0x690 block/ioctl.c:585 block_ioctl+0xae/0xf0 fs/block_dev.c:1602 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:1069 [inline] __se_sys_ioctl+0xfb/0x170 fs/ioctl.c:1055 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(lock#2); lock(fs_reclaim); lock(lock#2); lock(fs_reclaim); *** DEADLOCK *** 2 locks held by syz-executor.0/9995: #0: ffff88801e3d8518 (&disk->open_mutex){+.+.}-{3:3}, at: loop_reread_partitions drivers/block/loop.c:651 [inline] #0: ffff88801e3d8518 (&disk->open_mutex){+.+.}-{3:3}, at: loop_set_status+0x698/0x8e0 drivers/block/loop.c:1510 #1: ffff8880b9d4d0c8 (lock#2){-.-.}-{2:2}, at: local_lock_acquire+0x7/0x130 include/linux/local_lock_internal.h:41 stack backtrace: CPU: 1 PID: 9995 Comm: syz-executor.0 Not tainted 5.14.0-rc1-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x1ae/0x29f lib/dump_stack.c:105 print_circular_bug+0xb17/0xdc0 kernel/locking/lockdep.c:2009 check_noncircular+0x2cc/0x390 kernel/locking/lockdep.c:2131 check_prev_add kernel/locking/lockdep.c:3051 [inline] check_prevs_add+0x4f9/0x5b30 kernel/locking/lockdep.c:3174 validate_chain kernel/locking/lockdep.c:3789 [inline] __lock_acquire+0x4476/0x6100 kernel/locking/lockdep.c:5015 lock_acquire+0x182/0x4a0 kernel/locking/lockdep.c:5625 __fs_reclaim_acquire+0x20/0x30 mm/page_alloc.c:4552 fs_reclaim_acquire+0x59/0xf0 mm/page_alloc.c:4566 prepare_alloc_pages+0x151/0x5a0 mm/page_alloc.c:5164 __alloc_pages+0x14d/0x5f0 mm/page_alloc.c:5363 stack_depot_save+0x361/0x490 lib/stackdepot.c:303 save_stack+0xf9/0x1f0 mm/page_owner.c:120 __set_page_owner+0x42/0x2f0 mm/page_owner.c:181 prep_new_page mm/page_alloc.c:2433 [inline] __alloc_pages_bulk+0x9f2/0x1090 mm/page_alloc.c:5301 alloc_pages_bulk_array_node include/linux/gfp.h:557 [inline] vm_area_alloc_pages mm/vmalloc.c:2793 [inline] __vmalloc_area_node mm/vmalloc.c:2863 [inline] __vmalloc_node_range+0x3ad/0x7f0 mm/vmalloc.c:2966 __vmalloc_node mm/vmalloc.c:3015 [inline] vzalloc+0x75/0x80 mm/vmalloc.c:3085 allocate_partitions block/partitions/core.c:106 [inline] check_partition block/partitions/core.c:128 [inline] blk_add_partitions block/partitions/core.c:611 [inline] bdev_disk_changed+0x4d9/0x1690 block/partitions/core.c:697 loop_reread_partitions drivers/block/loop.c:652 [inline] loop_set_status+0x6b1/0x8e0 drivers/block/loop.c:1510 lo_ioctl+0xca2/0x23b0 drivers/block/loop.c:1620 blkdev_ioctl+0x332/0x690 block/ioctl.c:585 block_ioctl+0xae/0xf0 fs/block_dev.c:1602 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:1069 [inline] __se_sys_ioctl+0xfb/0x170 fs/ioctl.c:1055 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x466397 Code: 3c 1c 48 f7 d8 49 39 c4 72 b8 e8 a4 48 02 00 85 c0 78 bd 48 83 c4 08 4c 89 e0 5b 41 5c c3 0f 1f 44 00 00 b8 10 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f4896a8def8 EFLAGS: 00000202 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f4896a8df40 RCX: 0000000000466397 RDX: 00007f4896a8e050 RSI: 0000000000004c04 RDI: 0000000000000007 RBP: 00000000004bfcb9 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 00007f4896a8e050 R13: 00007ffe8be5ffff R14: 00007f4896a8e300 R15: 0000000000022000 BUG: sleeping function called from invalid context at mm/page_alloc.c:5167 in_atomic(): 0, irqs_disabled(): 1, non_block: 0, pid: 9995, name: syz-executor.0 INFO: lockdep is turned off. irq event stamp: 3252 hardirqs last enabled at (3251): [] __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:160 [inline] hardirqs last enabled at (3251): [] _raw_spin_unlock_irqrestore+0x8b/0x120 kernel/locking/spinlock.c:191 hardirqs last disabled at (3252): [] __alloc_pages_bulk+0x801/0x1090 mm/page_alloc.c:5279 softirqs last enabled at (2998): [] invoke_softirq kernel/softirq.c:432 [inline] softirqs last enabled at (2998): [] __irq_exit_rcu+0x21b/0x260 kernel/softirq.c:636 softirqs last disabled at (2983): [] invoke_softirq kernel/softirq.c:432 [inline] softirqs last disabled at (2983): [] __irq_exit_rcu+0x21b/0x260 kernel/softirq.c:636 CPU: 1 PID: 9995 Comm: syz-executor.0 Not tainted 5.14.0-rc1-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x1ae/0x29f lib/dump_stack.c:105 ___might_sleep+0x4e5/0x6b0 kernel/sched/core.c:9154 prepare_alloc_pages+0x1c0/0x5a0 mm/page_alloc.c:5167 __alloc_pages+0x14d/0x5f0 mm/page_alloc.c:5363 stack_depot_save+0x361/0x490 lib/stackdepot.c:303 save_stack+0xf9/0x1f0 mm/page_owner.c:120 __set_page_owner+0x42/0x2f0 mm/page_owner.c:181 prep_new_page mm/page_alloc.c:2433 [inline] __alloc_pages_bulk+0x9f2/0x1090 mm/page_alloc.c:5301 alloc_pages_bulk_array_node include/linux/gfp.h:557 [inline] vm_area_alloc_pages mm/vmalloc.c:2793 [inline] __vmalloc_area_node mm/vmalloc.c:2863 [inline] __vmalloc_node_range+0x3ad/0x7f0 mm/vmalloc.c:2966 __vmalloc_node mm/vmalloc.c:3015 [inline] vzalloc+0x75/0x80 mm/vmalloc.c:3085 allocate_partitions block/partitions/core.c:106 [inline] check_partition block/partitions/core.c:128 [inline] blk_add_partitions block/partitions/core.c:611 [inline] bdev_disk_changed+0x4d9/0x1690 block/partitions/core.c:697 loop_reread_partitions drivers/block/loop.c:652 [inline] loop_set_status+0x6b1/0x8e0 drivers/block/loop.c:1510 lo_ioctl+0xca2/0x23b0 drivers/block/loop.c:1620 blkdev_ioctl+0x332/0x690 block/ioctl.c:585 block_ioctl+0xae/0xf0 fs/block_dev.c:1602 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:1069 [inline] __se_sys_ioctl+0xfb/0x170 fs/ioctl.c:1055 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x466397 Code: 3c 1c 48 f7 d8 49 39 c4 72 b8 e8 a4 48 02 00 85 c0 78 bd 48 83 c4 08 4c 89 e0 5b 41 5c c3 0f 1f 44 00 00 b8 10 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f4896a8def8 EFLAGS: 00000202 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f4896a8df40 RCX: 0000000000466397 RDX: 00007f4896a8e050 RSI: 0000000000004c04 RDI: 0000000000000007 RBP: 00000000004bfcb9 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 00007f4896a8e050 R13: 00007ffe8be5ffff R14: 00007f4896a8e300 R15: 0000000000022000 Dev loop0: unable to read RDB block 1 loop0: unable to read partition table loop0: partition table beyond EOD, truncated loop_reread_partitions: partition scan of loop0 () failed (rc=-5)