====================================================== WARNING: possible circular locking dependency detected 5.15.186-syzkaller #0 Not tainted ------------------------------------------------------ syz.1.44/5485 is trying to acquire lock: ffff88807391aaa0 (&htab->lockdep_key#25){....}-{2:2}, at: htab_lock_bucket kernel/bpf/hashtab.c:183 [inline] ffff88807391aaa0 (&htab->lockdep_key#25){....}-{2:2}, at: htab_map_delete_elem+0x1b2/0x520 kernel/bpf/hashtab.c:1361 but task is already holding lock: ffff888075902c20 (&htab->lockdep_key#26){....}-{2:2}, at: htab_lock_bucket kernel/bpf/hashtab.c:183 [inline] ffff888075902c20 (&htab->lockdep_key#26){....}-{2:2}, at: htab_map_update_elem+0x225/0xa40 kernel/bpf/hashtab.c:1082 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&htab->lockdep_key#26){....}-{2:2}: __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xa4/0xf0 kernel/locking/spinlock.c:162 htab_lock_bucket kernel/bpf/hashtab.c:183 [inline] htab_map_delete_elem+0x1b2/0x520 kernel/bpf/hashtab.c:1361 bpf_prog_2c29ac5cdc6b1842+0x3a/0xb04 bpf_dispatcher_nop_func include/linux/bpf.h:790 [inline] __bpf_prog_run include/linux/filter.h:628 [inline] bpf_prog_run include/linux/filter.h:635 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:1878 [inline] bpf_trace_run4+0x188/0x330 kernel/trace/bpf_trace.c:1917 __bpf_trace_mm_page_alloc+0xbf/0xf0 include/trace/events/kmem.h:201 __traceiter_mm_page_alloc+0x35/0x50 include/trace/events/kmem.h:201 trace_mm_page_alloc include/trace/events/kmem.h:201 [inline] __alloc_pages+0x449/0x470 mm/page_alloc.c:5496 __alloc_pages_node include/linux/gfp.h:570 [inline] alloc_pages_node include/linux/gfp.h:584 [inline] kmalloc_large_node+0x7d/0x190 mm/slub.c:4421 __kmalloc_node+0x232/0x3b0 mm/slub.c:4437 kmalloc_node include/linux/slab.h:627 [inline] bpf_map_kmalloc_node+0xba/0x140 kernel/bpf/syscall.c:430 alloc_htab_elem+0x28f/0x980 kernel/bpf/hashtab.c:973 htab_map_update_elem+0x3c3/0xa40 kernel/bpf/hashtab.c:1106 bpf_map_update_value+0x591/0x670 kernel/bpf/syscall.c:221 map_update_elem+0x626/0x770 kernel/bpf/syscall.c:1188 __sys_bpf+0x3fb/0x670 kernel/bpf/syscall.c:4639 __do_sys_bpf kernel/bpf/syscall.c:4755 [inline] __se_sys_bpf kernel/bpf/syscall.c:4753 [inline] __x64_sys_bpf+0x78/0x90 kernel/bpf/syscall.c:4753 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 -> #0 (&htab->lockdep_key#25){....}-{2:2}: check_prev_add kernel/locking/lockdep.c:3053 [inline] check_prevs_add kernel/locking/lockdep.c:3172 [inline] validate_chain kernel/locking/lockdep.c:3788 [inline] __lock_acquire+0x2c33/0x7c60 kernel/locking/lockdep.c:5012 lock_acquire+0x197/0x3f0 kernel/locking/lockdep.c:5623 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xa4/0xf0 kernel/locking/spinlock.c:162 htab_lock_bucket kernel/bpf/hashtab.c:183 [inline] htab_map_delete_elem+0x1b2/0x520 kernel/bpf/hashtab.c:1361 bpf_prog_2c29ac5cdc6b1842+0x3a/0x1c0 bpf_dispatcher_nop_func include/linux/bpf.h:790 [inline] __bpf_prog_run include/linux/filter.h:628 [inline] bpf_prog_run include/linux/filter.h:635 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:1878 [inline] bpf_trace_run4+0x188/0x330 kernel/trace/bpf_trace.c:1917 __bpf_trace_mm_page_alloc+0xbf/0xf0 include/trace/events/kmem.h:201 __traceiter_mm_page_alloc+0x35/0x50 include/trace/events/kmem.h:201 trace_mm_page_alloc include/trace/events/kmem.h:201 [inline] __alloc_pages+0x449/0x470 mm/page_alloc.c:5496 __alloc_pages_node include/linux/gfp.h:570 [inline] alloc_pages_node include/linux/gfp.h:584 [inline] kmalloc_large_node+0x7d/0x190 mm/slub.c:4421 __kmalloc_node+0x232/0x3b0 mm/slub.c:4437 kmalloc_node include/linux/slab.h:627 [inline] bpf_map_kmalloc_node+0xba/0x140 kernel/bpf/syscall.c:430 alloc_htab_elem+0x28f/0x980 kernel/bpf/hashtab.c:973 htab_map_update_elem+0x3c3/0xa40 kernel/bpf/hashtab.c:1106 bpf_map_update_value+0x591/0x670 kernel/bpf/syscall.c:221 map_update_elem+0x626/0x770 kernel/bpf/syscall.c:1188 __sys_bpf+0x3fb/0x670 kernel/bpf/syscall.c:4639 __do_sys_bpf kernel/bpf/syscall.c:4755 [inline] __se_sys_bpf kernel/bpf/syscall.c:4753 [inline] __x64_sys_bpf+0x78/0x90 kernel/bpf/syscall.c:4753 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&htab->lockdep_key#26); lock(&htab->lockdep_key#25); lock(&htab->lockdep_key#26); lock(&htab->lockdep_key#25); *** DEADLOCK *** 3 locks held by syz.1.44/5485: #0: ffffffff8c11bfa0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x5/0x30 include/linux/rcupdate.h:311 #1: ffff888075902c20 (&htab->lockdep_key#26){....}-{2:2}, at: htab_lock_bucket kernel/bpf/hashtab.c:183 [inline] #1: ffff888075902c20 (&htab->lockdep_key#26){....}-{2:2}, at: htab_map_update_elem+0x225/0xa40 kernel/bpf/hashtab.c:1082 #2: ffffffff8c11bfa0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x5/0x30 include/linux/rcupdate.h:311 stack backtrace: CPU: 1 PID: 5485 Comm: syz.1.44 Not tainted 5.15.186-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 Call Trace: dump_stack_lvl+0x168/0x230 lib/dump_stack.c:106 check_noncircular+0x274/0x310 kernel/locking/lockdep.c:2133 check_prev_add kernel/locking/lockdep.c:3053 [inline] check_prevs_add kernel/locking/lockdep.c:3172 [inline] validate_chain kernel/locking/lockdep.c:3788 [inline] __lock_acquire+0x2c33/0x7c60 kernel/locking/lockdep.c:5012 lock_acquire+0x197/0x3f0 kernel/locking/lockdep.c:5623 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xa4/0xf0 kernel/locking/spinlock.c:162 htab_lock_bucket kernel/bpf/hashtab.c:183 [inline] htab_map_delete_elem+0x1b2/0x520 kernel/bpf/hashtab.c:1361 bpf_prog_2c29ac5cdc6b1842+0x3a/0x1c0 bpf_dispatcher_nop_func include/linux/bpf.h:790 [inline] __bpf_prog_run include/linux/filter.h:628 [inline] bpf_prog_run include/linux/filter.h:635 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:1878 [inline] bpf_trace_run4+0x188/0x330 kernel/trace/bpf_trace.c:1917 __bpf_trace_mm_page_alloc+0xbf/0xf0 include/trace/events/kmem.h:201 __traceiter_mm_page_alloc+0x35/0x50 include/trace/events/kmem.h:201 trace_mm_page_alloc include/trace/events/kmem.h:201 [inline] __alloc_pages+0x449/0x470 mm/page_alloc.c:5496 __alloc_pages_node include/linux/gfp.h:570 [inline] alloc_pages_node include/linux/gfp.h:584 [inline] kmalloc_large_node+0x7d/0x190 mm/slub.c:4421 __kmalloc_node+0x232/0x3b0 mm/slub.c:4437 kmalloc_node include/linux/slab.h:627 [inline] bpf_map_kmalloc_node+0xba/0x140 kernel/bpf/syscall.c:430 alloc_htab_elem+0x28f/0x980 kernel/bpf/hashtab.c:973 htab_map_update_elem+0x3c3/0xa40 kernel/bpf/hashtab.c:1106 bpf_map_update_value+0x591/0x670 kernel/bpf/syscall.c:221 map_update_elem+0x626/0x770 kernel/bpf/syscall.c:1188 __sys_bpf+0x3fb/0x670 kernel/bpf/syscall.c:4639 __do_sys_bpf kernel/bpf/syscall.c:4755 [inline] __se_sys_bpf kernel/bpf/syscall.c:4753 [inline] __x64_sys_bpf+0x78/0x90 kernel/bpf/syscall.c:4753 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7f9eff1b3d29 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:00007f9efe42c038 EFLAGS: 00000246 ORIG_RAX: 0000000000000141 RAX: ffffffffffffffda RBX: 00007f9eff3a3fa0 RCX: 00007f9eff1b3d29 RDX: 0000000000000020 RSI: 0000000020000280 RDI: 0000000000000002 RBP: 00007f9eff22fb08 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f9eff3a3fa0 R15: 00007fffd051ba78