loop3: unable to read partition table loop_reread_partitions: partition scan of loop3 (Cj̽?}6 q-) failed (rc=-5) ====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Tainted: G W ------------------------------------------------------ syz.5.4054/16706 is trying to acquire lock: ffff00000e668210 (&root->kernfs_iattr_rwsem){++++}-{4:4}, at: kernfs_iop_getattr+0x88/0xfc fs/kernfs/inode.c:192 but task is already holding lock: ffff000014a0b810 (&q->q_usage_counter(io)#20){++++}-{0:0}, at: blk_mq_freeze_queue_nomemsave+0x18/0x30 block/blk-mq.c:206 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (&q->q_usage_counter(io)#20){++++}-{0:0}: lock_acquire kernel/locking/lockdep.c:5886 [inline] lock_acquire+0x3d0/0x44c kernel/locking/lockdep.c:5843 blk_alloc_queue+0x4e0/0x640 block/blk-core.c:504 blk_mq_alloc_queue+0x148/0x224 block/blk-mq.c:4420 __blk_mq_alloc_disk+0x20/0x120 block/blk-mq.c:4467 loop_add+0x3ac/0x96c drivers/block/loop.c:2071 loop_init+0x108/0x12c drivers/block/loop.c:2310 do_one_initcall+0x134/0xb20 init/main.c:1357 do_initcall_level init/main.c:1419 [inline] do_initcalls init/main.c:1435 [inline] do_basic_setup init/main.c:1455 [inline] kernel_init_freeable+0x5ec/0x670 init/main.c:1670 kernel_init+0x2c/0x14c init/main.c:1560 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:854 -> #1 (fs_reclaim){+.+.}-{0:0}: lock_acquire kernel/locking/lockdep.c:5886 [inline] lock_acquire+0x3d0/0x44c kernel/locking/lockdep.c:5843 __fs_reclaim_acquire mm/page_alloc.c:4375 [inline] fs_reclaim_acquire+0x130/0x158 mm/page_alloc.c:4389 might_alloc include/linux/sched/mm.h:316 [inline] slab_pre_alloc_hook mm/slub.c:4636 [inline] slab_alloc_node mm/slub.c:4974 [inline] kmem_cache_alloc_noprof+0x64/0x610 mm/slub.c:5010 __kernfs_iattrs+0x114/0x380 fs/kernfs/inode.c:36 kernfs_iattrs fs/kernfs/inode.c:60 [inline] __kernfs_setattr+0x4c/0x2a0 fs/kernfs/inode.c:73 kernfs_iop_setattr+0xc0/0xfc fs/kernfs/inode.c:127 notify_change+0x6e8/0xbe8 fs/attr.c:556 do_truncate+0x188/0x1d0 fs/open.c:68 handle_truncate fs/namei.c:4300 [inline] do_open fs/namei.c:4841 [inline] path_openat+0x13e8/0x1e40 fs/namei.c:5000 do_file_open+0x18c/0x380 fs/namei.c:5029 do_sys_openat2+0xdc/0x180 fs/open.c:1417 do_sys_open fs/open.c:1423 [inline] __do_sys_openat fs/open.c:1439 [inline] __se_sys_openat fs/open.c:1434 [inline] __arm64_sys_openat+0x134/0x1e0 fs/open.c:1434 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x74/0x240 arch/arm64/kernel/syscall.c:49 el0_svc_common.constprop.0+0xac/0x230 arch/arm64/kernel/syscall.c:121 do_el0_svc+0x40/0x58 arch/arm64/kernel/syscall.c:140 el0_svc+0x58/0x2a4 arch/arm64/kernel/entry-common.c:758 el0t_64_sync_handler+0xa0/0xe4 arch/arm64/kernel/entry-common.c:777 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:590 -> #0 (&root->kernfs_iattr_rwsem){++++}-{4:4}: check_prev_add+0x114/0xca0 kernel/locking/lockdep.c:3181 check_prevs_add kernel/locking/lockdep.c:3300 [inline] validate_chain kernel/locking/lockdep.c:3924 [inline] __lock_acquire+0x13f4/0x1a5c kernel/locking/lockdep.c:5253 lock_acquire kernel/locking/lockdep.c:5886 [inline] lock_acquire+0x3d0/0x44c kernel/locking/lockdep.c:5843 down_read+0xb8/0x31c kernel/locking/rwsem.c:1574 kernfs_iop_getattr+0x88/0xfc fs/kernfs/inode.c:192 vfs_getattr_nosec+0x220/0x380 fs/stat.c:213 vfs_getattr+0x40/0x60 fs/stat.c:262 loop_update_dio_alignment+0x11c/0x340 drivers/block/loop.c:463 loop_assign_backing_file drivers/block/loop.c:524 [inline] loop_change_fd drivers/block/loop.c:604 [inline] lo_ioctl+0xf0c/0x1760 drivers/block/loop.c:1567 lo_compat_ioctl+0xc8/0x1a0 drivers/block/loop.c:1727 compat_blkdev_ioctl+0x5f4/0x850 block/ioctl.c:854 __do_compat_sys_ioctl fs/ioctl.c:695 [inline] __se_compat_sys_ioctl fs/ioctl.c:638 [inline] __arm64_compat_sys_ioctl+0x1a8/0x218 fs/ioctl.c:638 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x74/0x240 arch/arm64/kernel/syscall.c:49 el0_svc_common.constprop.0+0xac/0x230 arch/arm64/kernel/syscall.c:121 do_el0_svc_compat+0x40/0x58 arch/arm64/kernel/syscall.c:146 el0_svc_compat+0x54/0x264 arch/arm64/kernel/entry-common.c:909 el0t_32_sync_handler+0x88/0xac arch/arm64/kernel/entry-common.c:927 el0t_32_sync+0x19c/0x1a0 arch/arm64/kernel/entry.S:595 other info that might help us debug this: Chain exists of: &root->kernfs_iattr_rwsem --> fs_reclaim --> &q->q_usage_counter(io)#20 Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&q->q_usage_counter(io)#20); lock(fs_reclaim); lock(&q->q_usage_counter(io)#20); rlock(&root->kernfs_iattr_rwsem); *** DEADLOCK *** locks held by syz.5.4054/16706: 3, last CPU#0: #0: ffff000014a32430 (&lo->lo_mutex){+.+.}-{4:4}, at: loop_global_lock_killable+0x28/0xb8 drivers/block/loop.c:119 #1: ffff000014a0b810 (&q->q_usage_counter(io)#20){++++}-{0:0}, at: blk_mq_freeze_queue_nomemsave+0x18/0x30 block/blk-mq.c:206 #2: ffff000014a0b848 (&q->q_usage_counter(queue)#4){+.+.}-{0:0}, at: blk_mq_freeze_queue_nomemsave+0x18/0x30 block/blk-mq.c:206 stack backtrace: CPU: 0 UID: 0 PID: 16706 Comm: syz.5.4054 Tainted: G W syzkaller #0 PREEMPT Tainted: [W]=WARN Hardware name: linux,dummy-virt (DT) Call trace: show_stack+0x18/0x24 arch/arm64/kernel/stacktrace.c:499 (C) __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x7c/0xb0 lib/dump_stack.c:120 dump_stack+0x1c/0x28 lib/dump_stack.c:129 print_circular_bug+0x23c/0x284 kernel/locking/lockdep.c:2059 check_noncircular+0x174/0x194 kernel/locking/lockdep.c:2191 check_prev_add+0x114/0xca0 kernel/locking/lockdep.c:3181 check_prevs_add kernel/locking/lockdep.c:3300 [inline] validate_chain kernel/locking/lockdep.c:3924 [inline] __lock_acquire+0x13f4/0x1a5c kernel/locking/lockdep.c:5253 lock_acquire kernel/locking/lockdep.c:5886 [inline] lock_acquire+0x3d0/0x44c kernel/locking/lockdep.c:5843 down_read+0xb8/0x31c kernel/locking/rwsem.c:1574 kernfs_iop_getattr+0x88/0xfc fs/kernfs/inode.c:192 vfs_getattr_nosec+0x220/0x380 fs/stat.c:213 vfs_getattr+0x40/0x60 fs/stat.c:262 loop_update_dio_alignment+0x11c/0x340 drivers/block/loop.c:463 loop_assign_backing_file drivers/block/loop.c:524 [inline] loop_change_fd drivers/block/loop.c:604 [inline] lo_ioctl+0xf0c/0x1760 drivers/block/loop.c:1567 lo_compat_ioctl+0xc8/0x1a0 drivers/block/loop.c:1727 compat_blkdev_ioctl+0x5f4/0x850 block/ioctl.c:854 __do_compat_sys_ioctl fs/ioctl.c:695 [inline] __se_compat_sys_ioctl fs/ioctl.c:638 [inline] __arm64_compat_sys_ioctl+0x1a8/0x218 fs/ioctl.c:638 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x74/0x240 arch/arm64/kernel/syscall.c:49 el0_svc_common.constprop.0+0xac/0x230 arch/arm64/kernel/syscall.c:121 do_el0_svc_compat+0x40/0x58 arch/arm64/kernel/syscall.c:146 el0_svc_compat+0x54/0x264 arch/arm64/kernel/entry-common.c:909 el0t_32_sync_handler+0x88/0xac arch/arm64/kernel/entry-common.c:927 el0t_32_sync+0x19c/0x1a0 arch/arm64/kernel/entry.S:595 loop3: unable to read partition table loop_reread_partitions: partition scan of loop3 (Cj̽?}6 q-) failed (rc=-5)