============================================ WARNING: possible recursive locking detected 6.12.0-rc6-next-20241106-syzkaller #0 Not tainted -------------------------------------------- syz.6.656/9526 is trying to acquire lock: ffff8880600cca00 (&trie->lock){....}-{3:3}, at: trie_delete_elem+0x96/0x6a0 kernel/bpf/lpm_trie.c:462 but task is already holding lock: ffff8880600cca00 (&trie->lock){....}-{3:3}, at: trie_update_elem+0xc8/0xc00 kernel/bpf/lpm_trie.c:333 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 3 locks held by syz.6.656/9526: #0: ffffffff8e93c160 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline] #0: ffffffff8e93c160 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #0: ffffffff8e93c160 (rcu_read_lock){....}-{1:3}, at: bpf_map_update_value+0x433/0x5c0 kernel/bpf/syscall.c:288 #1: ffff8880600cca00 (&trie->lock){....}-{3:3}, at: trie_update_elem+0xc8/0xc00 kernel/bpf/lpm_trie.c:333 #2: ffffffff8e93c160 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline] #2: ffffffff8e93c160 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #2: ffffffff8e93c160 (rcu_read_lock){....}-{1:3}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2339 [inline] #2: ffffffff8e93c160 (rcu_read_lock){....}-{1:3}, at: bpf_trace_run2+0x1fc/0x540 kernel/trace/bpf_trace.c:2381 stack backtrace: CPU: 0 UID: 0 PID: 9526 Comm: syz.6.656 Not tainted 6.12.0-rc6-next-20241106-syzkaller #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_deadlock_bug+0x483/0x620 kernel/locking/lockdep.c:3037 check_deadlock kernel/locking/lockdep.c:3089 [inline] validate_chain+0x15e2/0x5920 kernel/locking/lockdep.c:3891 __lock_acquire+0x1397/0x2100 kernel/locking/lockdep.c:5226 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xd5/0x120 kernel/locking/spinlock.c:162 trie_delete_elem+0x96/0x6a0 kernel/bpf/lpm_trie.c:462 bpf_prog_6aea58caec58c56e+0x43/0x4c 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:2340 [inline] bpf_trace_run2+0x2ec/0x540 kernel/trace/bpf_trace.c:2381 trace_kfree include/trace/events/kmem.h:94 [inline] kfree+0x378/0x420 mm/slub.c:4733 trie_update_elem+0x26c/0xc00 kernel/bpf/lpm_trie.c:436 bpf_map_update_value+0x533/0x5c0 kernel/bpf/syscall.c:289 map_update_elem+0x51a/0x6f0 kernel/bpf/syscall.c:1727 __sys_bpf+0x76f/0x810 kernel/bpf/syscall.c:5773 __do_sys_bpf kernel/bpf/syscall.c:5892 [inline] __se_sys_bpf kernel/bpf/syscall.c:5890 [inline] __x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:5890 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: 0033:0x7fd3f457e719 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:00007fd3f543d038 EFLAGS: 00000246 ORIG_RAX: 0000000000000141 RAX: ffffffffffffffda RBX: 00007fd3f4735f80 RCX: 00007fd3f457e719 RDX: 0000000000000020 RSI: 0000000020000300 RDI: 0000000000000002 RBP: 00007fd3f543d090 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 R13: 0000000000000000 R14: 00007fd3f4735f80 R15: 00007fffb6125618