====================================================== WARNING: possible circular locking dependency detected 6.12.0-rc5-syzkaller-01053-gdbb9a7ef3478 #0 Not tainted ------------------------------------------------------ syz.4.2526/15232 is trying to acquire lock: ffff88801aca0018 (&pool->lock){-.-.}-{2:2}, at: try_to_grab_pending kernel/workqueue.c:2081 [inline] ffff88801aca0018 (&pool->lock){-.-.}-{2:2}, at: work_grab_pending+0x294/0xae0 kernel/workqueue.c:2157 but task is already holding lock: ffff8880b8729430 (krc.lock){..-.}-{2:2}, at: krc_this_cpu_lock kernel/rcu/tree.c:3312 [inline] ffff8880b8729430 (krc.lock){..-.}-{2:2}, at: add_ptr_to_bulk_krc_lock kernel/rcu/tree.c:3725 [inline] ffff8880b8729430 (krc.lock){..-.}-{2:2}, at: kvfree_call_rcu+0x18a/0x790 kernel/rcu/tree.c:3811 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #3 (krc.lock){..-.}-{2:2}: lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5825 __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline] _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154 krc_this_cpu_lock kernel/rcu/tree.c:3312 [inline] add_ptr_to_bulk_krc_lock kernel/rcu/tree.c:3725 [inline] kvfree_call_rcu+0x18a/0x790 kernel/rcu/tree.c:3811 trie_delete_elem+0x546/0x6a0 kernel/bpf/lpm_trie.c:540 0xffffffffa000206f bpf_dispatcher_nop_func include/linux/bpf.h:1265 [inline] __bpf_prog_run include/linux/filter.h:701 [inline] bpf_prog_run include/linux/filter.h:708 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:2316 [inline] bpf_trace_run4+0x334/0x590 kernel/trace/bpf_trace.c:2359 __traceiter_sched_switch+0x98/0xd0 include/trace/events/sched.h:222 trace_sched_switch include/trace/events/sched.h:222 [inline] __schedule+0x2340/0x4bd0 kernel/sched/core.c:6687 preempt_schedule_common+0x84/0xd0 kernel/sched/core.c:6869 preempt_schedule+0xe1/0xf0 kernel/sched/core.c:6893 preempt_schedule_thunk+0x1a/0x30 arch/x86/entry/thunk.S:12 class_preempt_destructor include/linux/preempt.h:480 [inline] try_to_wake_up+0x9f3/0x14b0 kernel/sched/core.c:4288 wake_up_process kernel/sched/core.c:4414 [inline] wake_up_q+0xc8/0x120 kernel/sched/core.c:1067 futex_wake+0x523/0x5c0 kernel/futex/waitwake.c:199 do_futex+0x392/0x560 kernel/futex/syscalls.c:107 __do_sys_futex kernel/futex/syscalls.c:179 [inline] __se_sys_futex+0x3f9/0x480 kernel/futex/syscalls.c:160 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #2 (&rq->__lock){-.-.}-{2:2}: lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5825 _raw_spin_lock_nested+0x31/0x40 kernel/locking/spinlock.c:378 raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:598 raw_spin_rq_lock kernel/sched/sched.h:1505 [inline] task_rq_lock+0xc6/0x360 kernel/sched/core.c:700 cgroup_move_task+0x9b/0x5a0 kernel/sched/psi.c:1161 css_set_move_task+0x72e/0x950 kernel/cgroup/cgroup.c:898 cgroup_post_fork+0x256/0x880 kernel/cgroup/cgroup.c:6692 copy_process+0x39e9/0x3d50 kernel/fork.c:2598 kernel_clone+0x226/0x8f0 kernel/fork.c:2784 user_mode_thread+0x132/0x1a0 kernel/fork.c:2862 rest_init+0x23/0x300 init/main.c:712 start_kernel+0x47f/0x500 init/main.c:1105 x86_64_start_reservations+0x2a/0x30 arch/x86/kernel/head64.c:507 x86_64_start_kernel+0x9f/0xa0 arch/x86/kernel/head64.c:488 common_startup_64+0x13e/0x147 -> #1 (&p->pi_lock){-.-.}-{2:2}: lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5825 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xd5/0x120 kernel/locking/spinlock.c:162 class_raw_spinlock_irqsave_constructor include/linux/spinlock.h:551 [inline] try_to_wake_up+0xbe/0x14b0 kernel/sched/core.c:4165 create_worker+0x507/0x720 kernel/workqueue.c:2825 workqueue_init+0x520/0x8a0 kernel/workqueue.c:7902 kernel_init_freeable+0x3fe/0x5d0 init/main.c:1564 kernel_init+0x1d/0x2b0 init/main.c:1469 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 -> #0 (&pool->lock){-.-.}-{2:2}: check_prev_add kernel/locking/lockdep.c:3161 [inline] check_prevs_add kernel/locking/lockdep.c:3280 [inline] validate_chain+0x18ef/0x5920 kernel/locking/lockdep.c:3904 __lock_acquire+0x1384/0x2050 kernel/locking/lockdep.c:5202 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5825 __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline] _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154 try_to_grab_pending kernel/workqueue.c:2081 [inline] work_grab_pending+0x294/0xae0 kernel/workqueue.c:2157 mod_delayed_work_on+0xd4/0x370 kernel/workqueue.c:2585 kvfree_call_rcu+0x47f/0x790 kernel/rcu/tree.c:3839 trie_update_elem+0x7e5/0xc00 kernel/bpf/lpm_trie.c:441 bpf_map_update_value+0x4d3/0x540 kernel/bpf/syscall.c:203 generic_map_update_batch+0x60d/0x900 kernel/bpf/syscall.c:1849 bpf_map_do_batch+0x39a/0x660 kernel/bpf/syscall.c:5162 __sys_bpf+0x377/0x810 __do_sys_bpf kernel/bpf/syscall.c:5760 [inline] __se_sys_bpf kernel/bpf/syscall.c:5758 [inline] __x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:5758 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f other info that might help us debug this: Chain exists of: &pool->lock --> &rq->__lock --> krc.lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(krc.lock); lock(&rq->__lock); lock(krc.lock); lock(&pool->lock); *** DEADLOCK *** 3 locks held by syz.4.2526/15232: #0: ffffffff8e937da0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline] #0: ffffffff8e937da0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #0: ffffffff8e937da0 (rcu_read_lock){....}-{1:2}, at: bpf_map_update_value+0x3c4/0x540 kernel/bpf/syscall.c:202 #1: ffff8880b8729430 (krc.lock){..-.}-{2:2}, at: krc_this_cpu_lock kernel/rcu/tree.c:3312 [inline] #1: ffff8880b8729430 (krc.lock){..-.}-{2:2}, at: add_ptr_to_bulk_krc_lock kernel/rcu/tree.c:3725 [inline] #1: ffff8880b8729430 (krc.lock){..-.}-{2:2}, at: kvfree_call_rcu+0x18a/0x790 kernel/rcu/tree.c:3811 #2: ffffffff8e937da0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline] #2: ffffffff8e937da0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #2: ffffffff8e937da0 (rcu_read_lock){....}-{1:2}, at: try_to_grab_pending kernel/workqueue.c:2072 [inline] #2: ffffffff8e937da0 (rcu_read_lock){....}-{1:2}, at: work_grab_pending+0x1d3/0xae0 kernel/workqueue.c:2157 stack backtrace: CPU: 1 UID: 0 PID: 15232 Comm: syz.4.2526 Not tainted 6.12.0-rc5-syzkaller-01053-gdbb9a7ef3478 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120 print_circular_bug+0x13a/0x1b0 kernel/locking/lockdep.c:2074 check_noncircular+0x36a/0x4a0 kernel/locking/lockdep.c:2206 check_prev_add kernel/locking/lockdep.c:3161 [inline] check_prevs_add kernel/locking/lockdep.c:3280 [inline] validate_chain+0x18ef/0x5920 kernel/locking/lockdep.c:3904 __lock_acquire+0x1384/0x2050 kernel/locking/lockdep.c:5202 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5825 __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline] _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154 try_to_grab_pending kernel/workqueue.c:2081 [inline] work_grab_pending+0x294/0xae0 kernel/workqueue.c:2157 mod_delayed_work_on+0xd4/0x370 kernel/workqueue.c:2585 kvfree_call_rcu+0x47f/0x790 kernel/rcu/tree.c:3839 trie_update_elem+0x7e5/0xc00 kernel/bpf/lpm_trie.c:441 bpf_map_update_value+0x4d3/0x540 kernel/bpf/syscall.c:203 generic_map_update_batch+0x60d/0x900 kernel/bpf/syscall.c:1849 bpf_map_do_batch+0x39a/0x660 kernel/bpf/syscall.c:5162 __sys_bpf+0x377/0x810 __do_sys_bpf kernel/bpf/syscall.c:5760 [inline] __se_sys_bpf kernel/bpf/syscall.c:5758 [inline] __x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:5758 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fdcb177e719 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fdcb2645038 EFLAGS: 00000246 ORIG_RAX: 0000000000000141 RAX: ffffffffffffffda RBX: 00007fdcb1935f80 RCX: 00007fdcb177e719 RDX: 0000000000000038 RSI: 0000000020000000 RDI: 000000000000001a RBP: 00007fdcb17f132e R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007fdcb1935f80 R15: 00007ffe264ea148