RBP: 000000000000c228 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 ====================================================== WARNING: possible circular locking dependency detected 5.18.0-rc2-syzkaller-00122-gb9b4c79e5830 #0 Not tainted ------------------------------------------------------ syz-executor615/3597 is trying to acquire lock: ffff888015d220a8 ((&sq->pending_timer)){+.-.}-{0:0}, at: del_timer_sync+0x33/0x1b0 kernel/time/timer.c:1363 but task is already holding lock: ffffffff9070b710 (&blkcg->lock){....}-{2:2}, at: spin_lock include/linux/spinlock.h:349 [inline] ffffffff9070b710 (&blkcg->lock){....}-{2:2}, at: blkcg_deactivate_policy block/blk-cgroup.c:1441 [inline] ffffffff9070b710 (&blkcg->lock){....}-{2:2}, at: blkcg_deactivate_policy+0x1e7/0x4e0 block/blk-cgroup.c:1423 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (&blkcg->lock){....}-{2:2}: __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline] _raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:154 spin_lock include/linux/spinlock.h:349 [inline] blkg_create+0x47b/0x1030 block/blk-cgroup.c:301 blkcg_init_queue+0xfe/0x810 block/blk-cgroup.c:1206 __alloc_disk_node+0x260/0x610 block/genhd.c:1381 __blk_alloc_disk+0x35/0x70 block/genhd.c:1421 brd_alloc.part.0+0x27f/0x7a0 drivers/block/brd.c:391 brd_alloc drivers/block/brd.c:374 [inline] brd_init+0x1b8/0x24b drivers/block/brd.c:477 do_one_initcall+0x103/0x650 init/main.c:1298 do_initcall_level init/main.c:1371 [inline] do_initcalls init/main.c:1387 [inline] do_basic_setup init/main.c:1406 [inline] kernel_init_freeable+0x6b1/0x73a init/main.c:1613 kernel_init+0x1a/0x1d0 init/main.c:1502 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:298 -> #1 (&q->queue_lock){..-.}-{2:2}: __raw_spin_lock_irq include/linux/spinlock_api_smp.h:119 [inline] _raw_spin_lock_irq+0x32/0x50 kernel/locking/spinlock.c:170 spin_lock_irq include/linux/spinlock.h:374 [inline] throtl_pending_timer_fn+0xf7/0x1690 block/blk-throttle.c:1152 call_timer_fn+0x1a5/0x6b0 kernel/time/timer.c:1421 expire_timers kernel/time/timer.c:1466 [inline] __run_timers.part.0+0x67c/0xa30 kernel/time/timer.c:1734 __run_timers kernel/time/timer.c:1715 [inline] run_timer_softirq+0xb3/0x1d0 kernel/time/timer.c:1747 __do_softirq+0x29b/0x9c2 kernel/softirq.c:558 invoke_softirq kernel/softirq.c:432 [inline] __irq_exit_rcu+0x123/0x180 kernel/softirq.c:637 irq_exit_rcu+0x5/0x20 kernel/softirq.c:649 sysvec_apic_timer_interrupt+0x93/0xc0 arch/x86/kernel/apic/apic.c:1097 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:645 dump_stack_lvl+0x12c/0x134 lib/dump_stack.c:108 fail_dump lib/fault-inject.c:52 [inline] should_fail.cold+0x5/0xa lib/fault-inject.c:146 should_failslab+0x5/0x10 mm/slab_common.c:1304 slab_pre_alloc_hook mm/slab.h:724 [inline] slab_alloc_node mm/slub.c:3131 [inline] slab_alloc mm/slub.c:3225 [inline] __kmem_cache_alloc_lru mm/slub.c:3232 [inline] kmem_cache_alloc+0x5e/0x3b0 mm/slub.c:3242 kmem_cache_zalloc include/linux/slab.h:704 [inline] lsm_inode_alloc security/security.c:593 [inline] security_inode_alloc+0x34/0x160 security/security.c:1023 inode_init_always+0x5d8/0xd70 fs/inode.c:195 alloc_inode+0x82/0x230 fs/inode.c:267 new_inode_pseudo fs/inode.c:1018 [inline] new_inode+0x27/0x2f0 fs/inode.c:1047 bdev_alloc+0x21/0x2e0 block/bdev.c:479 __alloc_disk_node+0xfe/0x610 block/genhd.c:1371 __blk_mq_alloc_disk+0x133/0x1c0 block/blk-mq.c:3930 loop_add+0x33d/0x910 drivers/block/loop.c:2012 loop_control_ioctl+0x130/0x4d0 drivers/block/loop.c:2186 __do_compat_sys_ioctl+0x1c7/0x290 fs/ioctl.c:968 do_syscall_32_irqs_on arch/x86/entry/common.c:112 [inline] __do_fast_syscall_32+0x65/0xf0 arch/x86/entry/common.c:178 do_fast_syscall_32+0x2f/0x70 arch/x86/entry/common.c:203 entry_SYSENTER_compat_after_hwframe+0x4d/0x5c -> #0 ((&sq->pending_timer)){+.-.}-{0:0}: check_prev_add kernel/locking/lockdep.c:3065 [inline] check_prevs_add kernel/locking/lockdep.c:3188 [inline] validate_chain kernel/locking/lockdep.c:3803 [inline] __lock_acquire+0x2ac6/0x56c0 kernel/locking/lockdep.c:5029 lock_acquire kernel/locking/lockdep.c:5641 [inline] lock_acquire+0x1ab/0x510 kernel/locking/lockdep.c:5606 del_timer_sync+0x5b/0x1b0 kernel/time/timer.c:1364 throtl_pd_free+0x15/0x40 block/blk-throttle.c:500 blkcg_deactivate_policy block/blk-cgroup.c:1445 [inline] blkcg_deactivate_policy+0x2d2/0x4e0 block/blk-cgroup.c:1423 blk_throtl_exit+0x8a/0x1a0 block/blk-throttle.c:2335 blkcg_init_queue+0x225/0x810 block/blk-cgroup.c:1226 __alloc_disk_node+0x260/0x610 block/genhd.c:1381 __blk_mq_alloc_disk+0x133/0x1c0 block/blk-mq.c:3930 loop_add+0x33d/0x910 drivers/block/loop.c:2012 loop_control_ioctl+0x130/0x4d0 drivers/block/loop.c:2186 __do_compat_sys_ioctl+0x1c7/0x290 fs/ioctl.c:968 do_syscall_32_irqs_on arch/x86/entry/common.c:112 [inline] __do_fast_syscall_32+0x65/0xf0 arch/x86/entry/common.c:178 do_fast_syscall_32+0x2f/0x70 arch/x86/entry/common.c:203 entry_SYSENTER_compat_after_hwframe+0x4d/0x5c other info that might help us debug this: Chain exists of: (&sq->pending_timer) --> &q->queue_lock --> &blkcg->lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&blkcg->lock); lock(&q->queue_lock); lock(&blkcg->lock); lock((&sq->pending_timer)); *** DEADLOCK *** 2 locks held by syz-executor615/3597: #0: ffff88801e5daf10 (&q->queue_lock){..-.}-{2:2}, at: spin_lock_irq include/linux/spinlock.h:374 [inline] #0: ffff88801e5daf10 (&q->queue_lock){..-.}-{2:2}, at: blkcg_deactivate_policy block/blk-cgroup.c:1434 [inline] #0: ffff88801e5daf10 (&q->queue_lock){..-.}-{2:2}, at: blkcg_deactivate_policy+0xfe/0x4e0 block/blk-cgroup.c:1423 #1: ffffffff9070b710 (&blkcg->lock){....}-{2:2}, at: spin_lock include/linux/spinlock.h:349 [inline] #1: ffffffff9070b710 (&blkcg->lock){....}-{2:2}, at: blkcg_deactivate_policy block/blk-cgroup.c:1441 [inline] #1: ffffffff9070b710 (&blkcg->lock){....}-{2:2}, at: blkcg_deactivate_policy+0x1e7/0x4e0 block/blk-cgroup.c:1423 stack backtrace: CPU: 1 PID: 3597 Comm: syz-executor615 Not tainted 5.18.0-rc2-syzkaller-00122-gb9b4c79e5830 #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+0xcd/0x134 lib/dump_stack.c:106 check_noncircular+0x25f/0x2e0 kernel/locking/lockdep.c:2145 check_prev_add kernel/locking/lockdep.c:3065 [inline] check_prevs_add kernel/locking/lockdep.c:3188 [inline] validate_chain kernel/locking/lockdep.c:3803 [inline] __lock_acquire+0x2ac6/0x56c0 kernel/locking/lockdep.c:5029 lock_acquire kernel/locking/lockdep.c:5641 [inline] lock_acquire+0x1ab/0x510 kernel/locking/lockdep.c:5606 del_timer_sync+0x5b/0x1b0 kernel/time/timer.c:1364 throtl_pd_free+0x15/0x40 block/blk-throttle.c:500 blkcg_deactivate_policy block/blk-cgroup.c:1445 [inline] blkcg_deactivate_policy+0x2d2/0x4e0 block/blk-cgroup.c:1423 blk_throtl_exit+0x8a/0x1a0 block/blk-throttle.c:2335 blkcg_init_queue+0x225/0x810 block/blk-cgroup.c:1226 __alloc_disk_node+0x260/0x610 block/genhd.c:1381 __blk_mq_alloc_disk+0x133/0x1c0 block/blk-mq.c:3930 loop_add+0x33d/0x910 drivers/block/loop.c:2012 loop_control_ioctl+0x130/0x4d0 drivers/block/loop.c:2186 __do_compat_sys_ioctl+0x1c7/0x290 fs/ioctl.c:968 do_syscall_32_irqs_on arch/x86/entry/common.c:112 [inline] __do_fast_syscall_32+0x65/0xf0 arch/x86/entry/common.c:178 do_fast_syscall_32+0x2f/0x70 arch/x86/entry/common.c:203 entry_SYSENTER_compat_after_hwframe+0x4d/0x5c RIP: 0023:0xf7ef7549 Code: 03 74 c0 01 10 05 03 74 b8 01 10 06 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 8d b4 26 00 00 00 00 8d b4 26 00 00 00 00 RSP: 002b:00000000ff8dd73c EFLAGS: 00000246 ORIG_RAX: 0000000000000036 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000004c80 RDX: 0000000000000000 RSI: 0000000000000002 RDI: 0000000000040000 RBP: 000000000000c228 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 ---------------- Code disassembly (best guess): 0: 03 74 c0 01 add 0x1(%rax,%rax,8),%esi 4: 10 05 03 74 b8 01 adc %al,0x1b87403(%rip) # 0x1b8740d a: 10 06 adc %al,(%rsi) c: 03 74 b4 01 add 0x1(%rsp,%rsi,4),%esi 10: 10 07 adc %al,(%rdi) 12: 03 74 b0 01 add 0x1(%rax,%rsi,4),%esi 16: 10 08 adc %cl,(%rax) 18: 03 74 d8 01 add 0x1(%rax,%rbx,8),%esi 1c: 00 00 add %al,(%rax) 1e: 00 00 add %al,(%rax) 20: 00 51 52 add %dl,0x52(%rcx) 23: 55 push %rbp 24: 89 e5 mov %esp,%ebp 26: 0f 34 sysenter 28: cd 80 int $0x80 * 2a: 5d pop %rbp <-- trapping instruction 2b: 5a pop %rdx 2c: 59 pop %rcx 2d: c3 retq 2e: 90 nop 2f: 90 nop 30: 90 nop 31: 90 nop 32: 8d b4 26 00 00 00 00 lea 0x0(%rsi,%riz,1),%esi 39: 8d b4 26 00 00 00 00 lea 0x0(%rsi,%riz,1),%esi