============================================ WARNING: possible recursive locking detected 6.13.0-rc1-syzkaller-00182-gb8f52214c61a #0 Not tainted -------------------------------------------- syz.0.387/7009 is trying to acquire lock: ffff888023051a00 (&trie->lock){..-.}-{3:3}, at: trie_delete_elem+0xb0/0x820 kernel/bpf/lpm_trie.c:462 but task is already holding lock: ffff888067ebc200 (&trie->lock){..-.}-{3:3}, at: trie_update_elem+0xc7/0xdb0 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.0.387/7009: #0: ffffffff8ddba940 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline] #0: ffffffff8ddba940 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #0: ffffffff8ddba940 (rcu_read_lock){....}-{1:3}, at: bpf_map_update_value+0x5da/0xce0 kernel/bpf/syscall.c:288 #1: ffff888067ebc200 (&trie->lock){..-.}-{3:3}, at: trie_update_elem+0xc7/0xdb0 kernel/bpf/lpm_trie.c:333 #2: ffffffff8ddba940 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline] #2: ffffffff8ddba940 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #2: ffffffff8ddba940 (rcu_read_lock){....}-{1:3}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2350 [inline] #2: ffffffff8ddba940 (rcu_read_lock){....}-{1:3}, at: bpf_trace_run2+0x1c2/0x590 kernel/trace/bpf_trace.c:2392 stack backtrace: CPU: 1 UID: 0 PID: 7009 Comm: syz.0.387 Not tainted 6.13.0-rc1-syzkaller-00182-gb8f52214c61a #0 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014 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+0xb0/0x820 kernel/bpf/lpm_trie.c:462 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:2351 [inline] bpf_trace_run2+0x231/0x590 kernel/trace/bpf_trace.c:2392 __traceiter_kfree+0x2d/0x50 include/trace/events/kmem.h:94 trace_kfree include/trace/events/kmem.h:94 [inline] kfree+0x258/0x4b0 mm/slub.c:4733 trie_update_elem+0x816/0xdb0 kernel/bpf/lpm_trie.c:436 bpf_map_update_value+0x659/0xce0 kernel/bpf/syscall.c:289 generic_map_update_batch+0x454/0x5f0 kernel/bpf/syscall.c:1950 bpf_map_do_batch+0x576/0x640 kernel/bpf/syscall.c:5298 __sys_bpf+0x1c9f/0x57a0 kernel/bpf/syscall.c:5854 __do_sys_bpf kernel/bpf/syscall.c:5897 [inline] __se_sys_bpf kernel/bpf/syscall.c:5895 [inline] __ia32_sys_bpf+0x76/0xe0 kernel/bpf/syscall.c:5895 do_syscall_32_irqs_on arch/x86/entry/common.c:165 [inline] __do_fast_syscall_32+0x73/0x120 arch/x86/entry/common.c:386 do_fast_syscall_32+0x32/0x80 arch/x86/entry/common.c:411 entry_SYSENTER_compat_after_hwframe+0x84/0x8e RIP: 0023:0xf7f20579 Code: 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 00 00 00 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:00000000f50a657c EFLAGS: 00000292 ORIG_RAX: 0000000000000165 RAX: ffffffffffffffda RBX: 000000000000001a RCX: 0000000020000240 RDX: 0000000000000038 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000296 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 ---------------- Code disassembly (best guess), 2 bytes skipped: 0: 10 06 adc %al,(%rsi) 2: 03 74 b4 01 add 0x1(%rsp,%rsi,4),%esi 6: 10 07 adc %al,(%rdi) 8: 03 74 b0 01 add 0x1(%rax,%rsi,4),%esi c: 10 08 adc %cl,(%rax) e: 03 74 d8 01 add 0x1(%rax,%rbx,8),%esi 1e: 00 51 52 add %dl,0x52(%rcx) 21: 55 push %rbp 22: 89 e5 mov %esp,%ebp 24: 0f 34 sysenter 26: cd 80 int $0x80 * 28: 5d pop %rbp <-- trapping instruction 29: 5a pop %rdx 2a: 59 pop %rcx 2b: c3 ret 2c: 90 nop 2d: 90 nop 2e: 90 nop 2f: 90 nop 30: 8d b4 26 00 00 00 00 lea 0x0(%rsi,%riz,1),%esi 37: 8d b4 26 00 00 00 00 lea 0x0(%rsi,%riz,1),%esi