============================================ WARNING: possible recursive locking detected syzkaller #0 Not tainted -------------------------------------------- udevd/5385 is trying to acquire lock: ffff888072f8ca18 (&qs->lock){-.-.}-{2:2}, at: queue_stack_map_push_elem+0x16c/0x5e0 kernel/bpf/queue_stack_maps.c:214 but task is already holding lock: ffff888072f8d218 (&qs->lock){-.-.}-{2:2}, at: queue_stack_map_push_elem+0x16c/0x5e0 kernel/bpf/queue_stack_maps.c:214 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(&qs->lock); lock(&qs->lock); *** DEADLOCK *** May be due to missing lock nesting notation 4 locks held by udevd/5385: #0: ffff8881427864c8 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_get_by_dev+0x13d/0xa60 block/bdev.c:832 #1: ffffffff8c92b120 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline] #1: ffffffff8c92b120 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline] #1: ffffffff8c92b120 (rcu_read_lock){....}-{1:2}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2284 [inline] #1: ffffffff8c92b120 (rcu_read_lock){....}-{1:2}, at: bpf_trace_run2+0xda/0x3b0 kernel/trace/bpf_trace.c:2324 #2: ffff888072f8d218 (&qs->lock){-.-.}-{2:2}, at: queue_stack_map_push_elem+0x16c/0x5e0 kernel/bpf/queue_stack_maps.c:214 #3: ffffffff8c92b120 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline] #3: ffffffff8c92b120 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline] #3: ffffffff8c92b120 (rcu_read_lock){....}-{1:2}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2284 [inline] #3: ffffffff8c92b120 (rcu_read_lock){....}-{1:2}, at: bpf_trace_run2+0xda/0x3b0 kernel/trace/bpf_trace.c:2324 stack backtrace: CPU: 1 PID: 5385 Comm: udevd Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 Call Trace: dump_stack_lvl+0x168/0x22e lib/dump_stack.c:106 __lock_acquire+0x122f/0x7c50 kernel/locking/lockdep.c:-1 lock_acquire+0x1b4/0x490 kernel/locking/lockdep.c:5662 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xa4/0xf0 kernel/locking/spinlock.c:162 queue_stack_map_push_elem+0x16c/0x5e0 kernel/bpf/queue_stack_maps.c:214 bpf_prog_80daba7f9ca62790+0x3a/0x3e bpf_dispatcher_nop_func include/linux/bpf.h:1012 [inline] __bpf_prog_run include/linux/filter.h:603 [inline] bpf_prog_run include/linux/filter.h:610 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:2285 [inline] bpf_trace_run2+0x1cd/0x3b0 kernel/trace/bpf_trace.c:2324 __traceiter_contention_end+0x74/0xa0 include/trace/events/lock.h:122 trace_contention_end+0x13f/0x190 include/trace/events/lock.h:122 __pv_queued_spin_lock_slowpath+0x7e8/0x9c0 kernel/locking/qspinlock.c:560 pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:591 [inline] queued_spin_lock_slowpath+0x43/0x50 arch/x86/include/asm/qspinlock.h:51 queued_spin_lock include/asm-generic/qspinlock.h:114 [inline] do_raw_spin_lock+0x217/0x280 kernel/locking/spinlock_debug.c:115 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:111 [inline] _raw_spin_lock_irqsave+0xb0/0xf0 kernel/locking/spinlock.c:162 queue_stack_map_push_elem+0x16c/0x5e0 kernel/bpf/queue_stack_maps.c:214 bpf_prog_80daba7f9ca62790+0x3a/0x3e bpf_dispatcher_nop_func include/linux/bpf.h:1012 [inline] __bpf_prog_run include/linux/filter.h:603 [inline] bpf_prog_run include/linux/filter.h:610 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:2285 [inline] bpf_trace_run2+0x1cd/0x3b0 kernel/trace/bpf_trace.c:2324 __traceiter_contention_end+0x74/0xa0 include/trace/events/lock.h:122 trace_contention_end+0x123/0x170 include/trace/events/lock.h:122 __mutex_lock_common kernel/locking/mutex.c:612 [inline] __mutex_lock+0x194/0xaf0 kernel/locking/mutex.c:747 blkdev_get_by_dev+0x13d/0xa60 block/bdev.c:832 blkdev_open+0x11e/0x2e0 block/fops.c:500 do_dentry_open+0x7e9/0x10d0 fs/open.c:882 do_open fs/namei.c:3634 [inline] path_openat+0x25c6/0x2e70 fs/namei.c:3791 do_filp_open+0x1c1/0x3c0 fs/namei.c:3818 do_sys_openat2+0x142/0x490 fs/open.c:1320 do_sys_open fs/open.c:1336 [inline] __do_sys_openat fs/open.c:1352 [inline] __se_sys_openat fs/open.c:1347 [inline] __x64_sys_openat+0x135/0x160 fs/open.c:1347 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7fd0306a7407 Code: 48 89 fa 4c 89 df e8 38 aa 00 00 8b 93 08 03 00 00 59 5e 48 83 f8 fc 74 1a 5b c3 0f 1f 84 00 00 00 00 00 48 8b 44 24 10 0f 05 <5b> c3 0f 1f 80 00 00 00 00 83 e2 39 83 fa 08 75 de e8 23 ff ff ff RSP: 002b:00007ffe0b5c5c40 EFLAGS: 00000202 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007fd030ea7880 RCX: 00007fd0306a7407 RDX: 00000000000a0800 RSI: 00005632a8a5d1d0 RDI: ffffffffffffff9c RBP: 00005632a8a42910 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 00005632a8c03110 R13: 00005632a8a5a410 R14: 0000000000000000 R15: 00005632a8c03110