kernfs: can not remove 'nr_tags', no directory WARNING: CPU: 0 PID: 4769 at fs/kernfs/dir.c:1557 kernfs_remove_by_name_ns+0xcc/0x158 fs/kernfs/dir.c:1556 Modules linked in: CPU: 0 PID: 4769 Comm: syz-executor.1 Not tainted 5.15.181-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/19/2025 pstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : kernfs_remove_by_name_ns+0xcc/0x158 fs/kernfs/dir.c:1556 lr : kernfs_remove_by_name_ns+0xcc/0x158 fs/kernfs/dir.c:1556 sp : ffff800020107790 x29: ffff800020107790 x28: ffff0000cc831000 x27: 0000000000000000 x26: 0000000000000002 x25: ffff8000148eaba8 x24: 1ffff000022f275c x23: dfff800000000000 x22: ffff8000148eabe0 x21: 0000000000000000 x20: 0000000000000000 x19: ffff800011793b40 x18: 0000000000000002 x17: 0000000040000000 x16: ffff8000111a3970 x15: 0000000000000002 x14: 0000000000ff0100 x13: 1ffff0000282a06b x12: 0000000000ff0100 x11: 0000000000000000 x10: 0000000000000000 x9 : c415659d3bfebc00 x8 : c415659d3bfebc00 x7 : 0000000000000000 x6 : 0000000000000000 x5 : 0000000000000080 x4 : 0000000000000000 x3 : ffff800008503848 x2 : 0000000000000001 x1 : 0000000100000000 x0 : 000000000000002e Call trace: kernfs_remove_by_name_ns+0xcc/0x158 fs/kernfs/dir.c:1556 kernfs_remove_by_name include/linux/kernfs.h:598 [inline] remove_files fs/sysfs/group.c:28 [inline] sysfs_remove_group+0xf8/0x288 fs/sysfs/group.c:289 sysfs_remove_groups+0x5c/0xb4 fs/sysfs/group.c:313 __kobject_del+0x90/0x2d4 lib/kobject.c:619 kobject_del+0x48/0x68 lib/kobject.c:651 blk_mq_unregister_hctx block/blk-mq-sysfs.c:183 [inline] blk_mq_sysfs_unregister+0x198/0x268 block/blk-mq-sysfs.c:309 __blk_mq_update_nr_hw_queues block/blk-mq.c:3786 [inline] blk_mq_update_nr_hw_queues+0x4d0/0xbfc block/blk-mq.c:3826 nbd_start_device+0x14c/0xb40 drivers/block/nbd.c:1301 nbd_start_device_ioctl drivers/block/nbd.c:1351 [inline] __nbd_ioctl drivers/block/nbd.c:1427 [inline] nbd_ioctl+0x514/0xc50 drivers/block/nbd.c:1467 blkdev_ioctl+0x5f8/0xbb8 block/ioctl.c:604 block_ioctl+0xa4/0x118 block/fops.c:493 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:874 [inline] __se_sys_ioctl fs/ioctl.c:860 [inline] __arm64_sys_ioctl+0x14c/0x1c8 fs/ioctl.c:860 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142 do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181 el0_svc+0x78/0x1e0 arch/arm64/kernel/entry-common.c:608 el0t_64_sync_handler+0xcc/0xe4 arch/arm64/kernel/entry-common.c:626 el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584 irq event stamp: 2108 hardirqs last enabled at (2107): [] raw_spin_rq_unlock_irq kernel/sched/sched.h:1338 [inline] hardirqs last enabled at (2107): [] finish_lock_switch+0xb0/0x1c4 kernel/sched/core.c:4784 hardirqs last disabled at (2108): [] el1_dbg+0x24/0x80 arch/arm64/kernel/entry-common.c:396 softirqs last enabled at (442): [] local_bh_enable+0x10/0x34 include/linux/bottom_half.h:31 softirqs last disabled at (440): [] local_bh_disable+0x10/0x34 include/linux/bottom_half.h:18 ---[ end trace 7c5743ebc6d8c251 ]--- ------------[ cut here ]------------ kernfs: can not remove 'nr_reserved_tags', no directory WARNING: CPU: 0 PID: 4769 at fs/kernfs/dir.c:1557 kernfs_remove_by_name_ns+0xcc/0x158 fs/kernfs/dir.c:1556 Modules linked in: CPU: 0 PID: 4769 Comm: syz-executor.1 Tainted: G W 5.15.181-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/19/2025 pstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : kernfs_remove_by_name_ns+0xcc/0x158 fs/kernfs/dir.c:1556 lr : kernfs_remove_by_name_ns+0xcc/0x158 fs/kernfs/dir.c:1556 sp : ffff800020107790 x29: ffff800020107790 x28: ffff0000cc831000 x27: 0000000000000000 x26: 0000000000000002 x25: ffff8000148eabb0 x24: 1ffff000022f275c x23: dfff800000000000 x22: ffff8000148eac40 x21: 0000000000000000 x20: 0000000000000000 x19: ffff800011793b80 x18: 0000000000000002 x17: 0000000040000000 x16: ffff8000111a3970 x15: 0000000000000002 x14: 0000000000ff0100 x13: 1ffff0000282a06b x12: 0000000000ff0100 x11: 0000000000000000 x10: 0000000000000000 x9 : c415659d3bfebc00 x8 : c415659d3bfebc00 x7 : 0000000000000000 x6 : 0000000000000000 x5 : 0000000000000080 x4 : 0000000000000000 x3 : ffff800008503848 x2 : 0000000000000001 x1 : 0000000100000000 x0 : 0000000000000037 Call trace: kernfs_remove_by_name_ns+0xcc/0x158 fs/kernfs/dir.c:1556 kernfs_remove_by_name include/linux/kernfs.h:598 [inline] remove_files fs/sysfs/group.c:28 [inline] sysfs_remove_group+0xf8/0x288 fs/sysfs/group.c:289 sysfs_remove_groups+0x5c/0xb4 fs/sysfs/group.c:313 __kobject_del+0x90/0x2d4 lib/kobject.c:619 kobject_del+0x48/0x68 lib/kobject.c:651 blk_mq_unregister_hctx block/blk-mq-sysfs.c:183 [inline] blk_mq_sysfs_unregister+0x198/0x268 block/blk-mq-sysfs.c:309 __blk_mq_update_nr_hw_queues block/blk-mq.c:3786 [inline] blk_mq_update_nr_hw_queues+0x4d0/0xbfc block/blk-mq.c:3826 nbd_start_device+0x14c/0xb40 drivers/block/nbd.c:1301 nbd_start_device_ioctl drivers/block/nbd.c:1351 [inline] __nbd_ioctl drivers/block/nbd.c:1427 [inline] nbd_ioctl+0x514/0xc50 drivers/block/nbd.c:1467 blkdev_ioctl+0x5f8/0xbb8 block/ioctl.c:604 block_ioctl+0xa4/0x118 block/fops.c:493 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:874 [inline] __se_sys_ioctl fs/ioctl.c:860 [inline] __arm64_sys_ioctl+0x14c/0x1c8 fs/ioctl.c:860 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142 do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181 el0_svc+0x78/0x1e0 arch/arm64/kernel/entry-common.c:608 el0t_64_sync_handler+0xcc/0xe4 arch/arm64/kernel/entry-common.c:626 el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584 irq event stamp: 2508 hardirqs last enabled at (2507): [] raw_spin_rq_unlock_irq kernel/sched/sched.h:1338 [inline] hardirqs last enabled at (2507): [] finish_lock_switch+0xb0/0x1c4 kernel/sched/core.c:4784 hardirqs last disabled at (2508): [] el1_dbg+0x24/0x80 arch/arm64/kernel/entry-common.c:396 softirqs last enabled at (2476): [] softirq_handle_end kernel/softirq.c:401 [inline] softirqs last enabled at (2476): [] handle_softirqs+0xa4c/0xbf0 kernel/softirq.c:586 softirqs last disabled at (2111): [] __do_softirq kernel/softirq.c:592 [inline] softirqs last disabled at (2111): [] do_softirq_own_stack include/asm-generic/softirq_stack.h:10 [inline] softirqs last disabled at (2111): [] invoke_softirq kernel/softirq.c:439 [inline] softirqs last disabled at (2111): [] __irq_exit_rcu+0x240/0x440 kernel/softirq.c:641 ---[ end trace 7c5743ebc6d8c252 ]--- ------------[ cut here ]------------ kernfs: can not remove 'cpu_list', no directory WARNING: CPU: 0 PID: 4769 at fs/kernfs/dir.c:1557 kernfs_remove_by_name_ns+0xcc/0x158 fs/kernfs/dir.c:1556 Modules linked in: CPU: 0 PID: 4769 Comm: syz-executor.1 Tainted: G W 5.15.181-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/19/2025 pstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : kernfs_remove_by_name_ns+0xcc/0x158 fs/kernfs/dir.c:1556 lr : kernfs_remove_by_name_ns+0xcc/0x158 fs/kernfs/dir.c:1556 sp : ffff800020107790 x29: ffff800020107790 x28: ffff0000cc831000 x27: 0000000000000000 x26: 0000000000000002 x25: ffff8000148eabb8 x24: 1ffff000022f275c x23: dfff800000000000 x22: ffff8000148eaca0 x21: 0000000000000000 x20: 0000000000000000 x19: ffff800011793bc0 x18: 0000000000000002 x17: 0000000040000000 x16: ffff8000111a3970 x15: 0000000000000002 x14: 0000000000ff0100 x13: 1ffff0000282a06b x12: 0000000000ff0100 x11: 0000000000000000 x10: 0000000000000000 x9 : c415659d3bfebc00 x8 : c415659d3bfebc00 x7 : 0000000000000000 x6 : 0000000000000000 x5 : 0000000000000080 x4 : 0000000000000000 x3 : ffff800008503848 x2 : 0000000000000001 x1 : 0000000100000000 x0 : 000000000000002f Call trace: kernfs_remove_by_name_ns+0xcc/0x158 fs/kernfs/dir.c:1556 kernfs_remove_by_name include/linux/kernfs.h:598 [inline] remove_files fs/sysfs/group.c:28 [inline] sysfs_remove_group+0xf8/0x288 fs/sysfs/group.c:289 sysfs_remove_groups+0x5c/0xb4 fs/sysfs/group.c:313 __kobject_del+0x90/0x2d4 lib/kobject.c:619 kobject_del+0x48/0x68 lib/kobject.c:651 blk_mq_unregister_hctx block/blk-mq-sysfs.c:183 [inline] blk_mq_sysfs_unregister+0x198/0x268 block/blk-mq-sysfs.c:309 __blk_mq_update_nr_hw_queues block/blk-mq.c:3786 [inline] blk_mq_update_nr_hw_queues+0x4d0/0xbfc block/blk-mq.c:3826 nbd_start_device+0x14c/0xb40 drivers/block/nbd.c:1301 nbd_start_device_ioctl drivers/block/nbd.c:1351 [inline] __nbd_ioctl drivers/block/nbd.c:1427 [inline] nbd_ioctl+0x514/0xc50 drivers/block/nbd.c:1467 blkdev_ioctl+0x5f8/0xbb8 block/ioctl.c:604 block_ioctl+0xa4/0x118 block/fops.c:493 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:874 [inline] __se_sys_ioctl fs/ioctl.c:860 [inline] __arm64_sys_ioctl+0x14c/0x1c8 fs/ioctl.c:860 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142 do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181 el0_svc+0x78/0x1e0 arch/arm64/kernel/entry-common.c:608 el0t_64_sync_handler+0xcc/0xe4 arch/arm64/kernel/entry-common.c:626 el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584 irq event stamp: 3060 hardirqs last enabled at (3059): [] raw_spin_rq_unlock_irq kernel/sched/sched.h:1338 [inline] hardirqs last enabled at (3059): [] finish_lock_switch+0xb0/0x1c4 kernel/sched/core.c:4784 hardirqs last disabled at (3060): [] el1_dbg+0x24/0x80 arch/arm64/kernel/entry-common.c:396 softirqs last enabled at (3030): [] softirq_handle_end kernel/softirq.c:401 [inline] softirqs last enabled at (3030): [] handle_softirqs+0xa4c/0xbf0 kernel/softirq.c:586 softirqs last disabled at (2513): [] __do_softirq kernel/softirq.c:592 [inline] softirqs last disabled at (2513): [] do_softirq_own_stack include/asm-generic/softirq_stack.h:10 [inline] softirqs last disabled at (2513): [] invoke_softirq kernel/softirq.c:439 [inline] softirqs last disabled at (2513): [] __irq_exit_rcu+0x240/0x440 kernel/softirq.c:641 ---[ end trace 7c5743ebc6d8c253 ]--- FAULT_INJECTION: forcing a failure. name failslab, interval 1, probability 0, space 0, times 0 CPU: 0 PID: 4769 Comm: syz-executor.1 Tainted: G W 5.15.181-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/19/2025 Call trace: dump_backtrace+0x0/0x43c arch/arm64/kernel/stacktrace.c:152 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:216 __dump_stack+0x30/0x40 lib/dump_stack.c:88 dump_stack_lvl+0xf8/0x160 lib/dump_stack.c:106 dump_stack+0x1c/0x5c lib/dump_stack.c:113 fail_dump lib/fault-inject.c:52 [inline] should_fail+0x3c0/0x51c lib/fault-inject.c:146 __should_failslab+0xbc/0x10c mm/failslab.c:33 should_failslab+0x10/0x28 mm/slab_common.c:1350 slab_pre_alloc_hook+0x64/0xec mm/slab.h:494 slab_alloc_node mm/slub.c:3134 [inline] __kmalloc_node+0xb8/0x520 mm/slub.c:4451 kmalloc_array_node include/linux/slab.h:697 [inline] kcalloc_node include/linux/slab.h:702 [inline] blk_mq_realloc_hw_ctxs+0xb8/0x133c block/blk-mq.c:3230 __blk_mq_update_nr_hw_queues block/blk-mq.c:3798 [inline] blk_mq_update_nr_hw_queues+0x62c/0xbfc block/blk-mq.c:3826 nbd_start_device+0x14c/0xb40 drivers/block/nbd.c:1301 nbd_start_device_ioctl drivers/block/nbd.c:1351 [inline] __nbd_ioctl drivers/block/nbd.c:1427 [inline] nbd_ioctl+0x514/0xc50 drivers/block/nbd.c:1467 blkdev_ioctl+0x5f8/0xbb8 block/ioctl.c:604 block_ioctl+0xa4/0x118 block/fops.c:493 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:874 [inline] __se_sys_ioctl fs/ioctl.c:860 [inline] __arm64_sys_ioctl+0x14c/0x1c8 fs/ioctl.c:860 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142 do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181 el0_svc+0x78/0x1e0 arch/arm64/kernel/entry-common.c:608 el0t_64_sync_handler+0xcc/0xe4 arch/arm64/kernel/entry-common.c:626 el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584 Increasing nr_hw_queues to 2 fails, fallback to 1