============================================ WARNING: possible recursive locking detected 6.13.0-rc4-syzkaller-00004-gf07044dd0df0 #0 Not tainted -------------------------------------------- kworker/u32:1/12 is trying to acquire lock: ffff888032f13a68 (&trie->lock){-.-.}-{2:2}, at: trie_delete_elem+0xb0/0x7f0 kernel/bpf/lpm_trie.c:480 but task is already holding lock: ffff88803547c268 (&trie->lock){-.-.}-{2:2}, at: trie_delete_elem+0xb0/0x7f0 kernel/bpf/lpm_trie.c:480 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(&trie->lock); lock(&trie->lock); *** DEADLOCK *** May be due to missing lock nesting notation 9 locks held by kworker/u32:1/12: #0: ffff888020318148 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x1293/0x1ba0 kernel/workqueue.c:3204 #1: ffffc900000f7d80 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x921/0x1ba0 kernel/workqueue.c:3205 #2: ffff88802ac2a0e0 (&type->s_umount_key#51){++++}-{4:4}, at: super_trylock_shared+0x1e/0xf0 fs/super.c:562 #3: ffff88802ac2eb98 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: do_writepages+0x1b3/0x820 mm/page-writeback.c:2702 #4: ffff88802aba6958 (jbd2_handle){.+.+}-{0:0}, at: start_this_handle+0xf6c/0x1430 fs/jbd2/transaction.c:448 #5: ffff888035814a48 (&xa->xa_lock#10){..-.}-{3:3}, at: __folio_start_writeback+0x440/0xa90 mm/page-writeback.c:3135 #6: ffffffff8e1bb900 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline] #6: ffffffff8e1bb900 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #6: ffffffff8e1bb900 (rcu_read_lock){....}-{1:3}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2361 [inline] #6: ffffffff8e1bb900 (rcu_read_lock){....}-{1:3}, at: bpf_trace_run2+0x1c2/0x590 kernel/trace/bpf_trace.c:2403 #7: ffff88803547c268 (&trie->lock){-.-.}-{2:2}, at: trie_delete_elem+0xb0/0x7f0 kernel/bpf/lpm_trie.c:480 #8: ffffffff8e1bb900 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline] #8: ffffffff8e1bb900 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #8: ffffffff8e1bb900 (rcu_read_lock){....}-{1:3}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2361 [inline] #8: ffffffff8e1bb900 (rcu_read_lock){....}-{1:3}, at: bpf_trace_run2+0x1c2/0x590 kernel/trace/bpf_trace.c:2403 stack backtrace: CPU: 3 UID: 0 PID: 12 Comm: kworker/u32:1 Not tainted 6.13.0-rc4-syzkaller-00004-gf07044dd0df0 #0 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014 Workqueue: writeback wb_workfn (flush-8:0) Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120 print_deadlock_bug+0x2e3/0x410 kernel/locking/lockdep.c:3037 check_deadlock kernel/locking/lockdep.c:3089 [inline] validate_chain kernel/locking/lockdep.c:3891 [inline] __lock_acquire+0x2117/0x3c40 kernel/locking/lockdep.c:5226 lock_acquire.part.0+0x11b/0x380 kernel/locking/lockdep.c:5849 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x3a/0x60 kernel/locking/spinlock.c:162 trie_delete_elem+0xb0/0x7f0 kernel/bpf/lpm_trie.c:480 bpf_prog_2c29ac5cdc6b1842+0x43/0x47 bpf_dispatcher_nop_func include/linux/bpf.h:1290 [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:2362 [inline] bpf_trace_run2+0x231/0x590 kernel/trace/bpf_trace.c:2403 __bpf_trace_contention_end+0xca/0x110 include/trace/events/lock.h:122 __traceiter_contention_end+0x5a/0xa0 include/trace/events/lock.h:122 trace_contention_end.constprop.0+0xf0/0x170 include/trace/events/lock.h:122 __pv_queued_spin_lock_slowpath+0x27e/0xc90 kernel/locking/qspinlock.c:557 pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:584 [inline] queued_spin_lock_slowpath arch/x86/include/asm/qspinlock.h:51 [inline] queued_spin_lock include/asm-generic/qspinlock.h:114 [inline] do_raw_spin_lock+0x210/0x2c0 kernel/locking/spinlock_debug.c:116 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:111 [inline] _raw_spin_lock_irqsave+0x42/0x60 kernel/locking/spinlock.c:162 trie_delete_elem+0xb0/0x7f0 kernel/bpf/lpm_trie.c:480 bpf_prog_2c29ac5cdc6b1842+0x43/0x47 bpf_dispatcher_nop_func include/linux/bpf.h:1290 [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:2362 [inline] bpf_trace_run2+0x231/0x590 kernel/trace/bpf_trace.c:2403 __bpf_trace_contention_end+0xca/0x110 include/trace/events/lock.h:122 __traceiter_contention_end+0x5a/0xa0 include/trace/events/lock.h:122 trace_contention_end.constprop.0+0xf0/0x170 include/trace/events/lock.h:122 __pv_queued_spin_lock_slowpath+0x27e/0xc90 kernel/locking/qspinlock.c:557 pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:584 [inline] queued_spin_lock_slowpath arch/x86/include/asm/qspinlock.h:51 [inline] queued_spin_lock include/asm-generic/qspinlock.h:114 [inline] do_raw_spin_lock+0x210/0x2c0 kernel/locking/spinlock_debug.c:116 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:111 [inline] _raw_spin_lock_irqsave+0x42/0x60 kernel/locking/spinlock.c:162 __folio_start_writeback+0x440/0xa90 mm/page-writeback.c:3135 ext4_bio_write_folio+0x5cf/0x1da0 fs/ext4/page-io.c:556 mpage_submit_folio+0x1c0/0x350 fs/ext4/inode.c:1932 mpage_map_and_submit_buffers+0x590/0xae0 fs/ext4/inode.c:2178 mpage_map_and_submit_extent fs/ext4/inode.c:2310 [inline] ext4_do_writepages+0x1b07/0x32d0 fs/ext4/inode.c:2735 ext4_writepages+0x303/0x730 fs/ext4/inode.c:2824 do_writepages+0x1b3/0x820 mm/page-writeback.c:2702 __writeback_single_inode+0x166/0xfa0 fs/fs-writeback.c:1680 writeback_sb_inodes+0x606/0xfa0 fs/fs-writeback.c:1976 __writeback_inodes_wb+0xff/0x2e0 fs/fs-writeback.c:2047 wb_writeback+0x803/0xb80 fs/fs-writeback.c:2158 wb_check_background_flush fs/fs-writeback.c:2228 [inline] wb_do_writeback fs/fs-writeback.c:2316 [inline] wb_workfn+0x730/0xbc0 fs/fs-writeback.c:2343 process_one_work+0x9c5/0x1ba0 kernel/workqueue.c:3229 process_scheduled_works kernel/workqueue.c:3310 [inline] worker_thread+0x6c8/0xf00 kernel/workqueue.c:3391 kthread+0x2c1/0x3a0 kernel/kthread.c:389 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244