Hello, syzbot found the following issue on: HEAD commit: 989a29cfed9b libbpf: Fix possible compiler warnings in has.. git tree: bpf-next console output: https://syzkaller.appspot.com/x/log.txt?x=116c5440580000 kernel config: https://syzkaller.appspot.com/x/.config?x=f95955e3f7b5790c dashboard link: https://syzkaller.appspot.com/bug?extid=b12149f7ab5a8751740f compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40 Unfortunately, I don't have any reproducer for this issue yet. Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/628a969b8618/disk-989a29cf.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/20c58ef873dc/vmlinux-989a29cf.xz kernel image: https://storage.googleapis.com/syzbot-assets/cda8b348a2ce/bzImage-989a29cf.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+b12149f7ab5a8751740f@xxxxxxxxxxxxxxxxxxxxxxxxx ====================================================== WARNING: possible circular locking dependency detected 6.12.0-rc1-syzkaller-00176-g989a29cfed9b #0 Not tainted ------------------------------------------------------ syz.1.55/5474 is trying to acquire lock: ffffffff9a614a58 (&obj_hash[i].lock){-.-.}-{2:2}, at: __debug_check_no_obj_freed lib/debugobjects.c:978 [inline] ffffffff9a614a58 (&obj_hash[i].lock){-.-.}-{2:2}, at: debug_check_no_obj_freed+0x234/0x580 lib/debugobjects.c:1019 but task is already holding lock: ffff88805c781a00 (&trie->lock){-.-.}-{2:2}, at: trie_update_elem+0xc8/0xc00 kernel/bpf/lpm_trie.c:333 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&trie->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 trie_delete_elem+0x96/0x6a0 kernel/bpf/lpm_trie.c:462 0xffffffffa000492e bpf_dispatcher_nop_func include/linux/bpf.h:1257 [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:2318 [inline] bpf_trace_run2+0x2ec/0x540 kernel/trace/bpf_trace.c:2359 trace_contention_end+0x114/0x140 include/trace/events/lock.h:122 __pv_queued_spin_lock_slowpath+0xb7e/0xdb0 kernel/locking/qspinlock.c:557 pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:584 [inline] queued_spin_lock_slowpath+0x42/0x50 arch/x86/include/asm/qspinlock.h:51 queued_spin_lock include/asm-generic/qspinlock.h:114 [inline] do_raw_spin_lock+0x272/0x370 kernel/locking/spinlock_debug.c:116 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:111 [inline] _raw_spin_lock_irqsave+0xe1/0x120 kernel/locking/spinlock.c:162 debug_object_active_state+0x15d/0x360 lib/debugobjects.c:936 debug_rcu_head_unqueue kernel/rcu/rcu.h:233 [inline] rcu_do_batch kernel/rcu/tree.c:2559 [inline] rcu_core+0xa21/0x17a0 kernel/rcu/tree.c:2823 handle_softirqs+0x2c5/0x980 kernel/softirq.c:554 run_ksoftirqd+0xca/0x130 kernel/softirq.c:927 smpboot_thread_fn+0x544/0xa30 kernel/smpboot.c:164 kthread+0x2f0/0x390 kernel/kthread.c:389 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 (&obj_hash[i].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_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xd5/0x120 kernel/locking/spinlock.c:162 __debug_check_no_obj_freed lib/debugobjects.c:978 [inline] debug_check_no_obj_freed+0x234/0x580 lib/debugobjects.c:1019 free_pages_prepare mm/page_alloc.c:1115 [inline] free_unref_page+0x41b/0xf20 mm/page_alloc.c:2638 stack_depot_save_flags+0x6f6/0x830 lib/stackdepot.c:666 kasan_save_stack mm/kasan/common.c:48 [inline] kasan_save_track+0x51/0x80 mm/kasan/common.c:68 poison_kmalloc_redzone mm/kasan/common.c:377 [inline] __kasan_kmalloc+0x98/0xb0 mm/kasan/common.c:394 kasan_kmalloc include/linux/kasan.h:257 [inline] __do_kmalloc_node mm/slub.c:4265 [inline] __kmalloc_node_noprof+0x22a/0x440 mm/slub.c:4271 kmalloc_array_node_noprof include/linux/slab.h:995 [inline] alloc_slab_obj_exts mm/slub.c:1969 [inline] account_slab mm/slub.c:2542 [inline] allocate_slab+0xb6/0x2f0 mm/slub.c:2597 new_slab mm/slub.c:2632 [inline] ___slab_alloc+0xcd1/0x14b0 mm/slub.c:3819 __slab_alloc+0x58/0xa0 mm/slub.c:3909 __slab_alloc_node mm/slub.c:3962 [inline] slab_alloc_node mm/slub.c:4123 [inline] __do_kmalloc_node mm/slub.c:4264 [inline] __kmalloc_node_noprof+0x286/0x440 mm/slub.c:4271 kmalloc_node_noprof include/linux/slab.h:905 [inline] bpf_map_kmalloc_node+0xd3/0x1c0 kernel/bpf/syscall.c:422 lpm_trie_node_alloc kernel/bpf/lpm_trie.c:299 [inline] trie_update_elem+0x1cd/0xc00 kernel/bpf/lpm_trie.c:342 bpf_map_update_value+0x4d3/0x540 kernel/bpf/syscall.c:203 map_update_elem+0x51a/0x6f0 kernel/bpf/syscall.c:1626 __sys_bpf+0x76f/0x810 kernel/bpf/syscall.c:5622 __do_sys_bpf kernel/bpf/syscall.c:5741 [inline] __se_sys_bpf kernel/bpf/syscall.c:5739 [inline] __x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:5739 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: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&trie->lock); lock(&obj_hash[i].lock); lock(&trie->lock); lock(&obj_hash[i].lock); *** DEADLOCK *** 2 locks held by syz.1.55/5474: #0: ffffffff8e937de0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline] #0: ffffffff8e937de0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #0: ffffffff8e937de0 (rcu_read_lock){....}-{1:2}, at: bpf_map_update_value+0x3c4/0x540 kernel/bpf/syscall.c:202 #1: ffff88805c781a00 (&trie->lock){-.-.}-{2:2}, at: trie_update_elem+0xc8/0xc00 kernel/bpf/lpm_trie.c:333 stack backtrace: CPU: 1 UID: 0 PID: 5474 Comm: syz.1.55 Not tainted 6.12.0-rc1-syzkaller-00176-g989a29cfed9b #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 Call Trace: <TASK> __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_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xd5/0x120 kernel/locking/spinlock.c:162 __debug_check_no_obj_freed lib/debugobjects.c:978 [inline] debug_check_no_obj_freed+0x234/0x580 lib/debugobjects.c:1019 free_pages_prepare mm/page_alloc.c:1115 [inline] free_unref_page+0x41b/0xf20 mm/page_alloc.c:2638 stack_depot_save_flags+0x6f6/0x830 lib/stackdepot.c:666 kasan_save_stack mm/kasan/common.c:48 [inline] kasan_save_track+0x51/0x80 mm/kasan/common.c:68 poison_kmalloc_redzone mm/kasan/common.c:377 [inline] __kasan_kmalloc+0x98/0xb0 mm/kasan/common.c:394 kasan_kmalloc include/linux/kasan.h:257 [inline] __do_kmalloc_node mm/slub.c:4265 [inline] __kmalloc_node_noprof+0x22a/0x440 mm/slub.c:4271 kmalloc_array_node_noprof include/linux/slab.h:995 [inline] alloc_slab_obj_exts mm/slub.c:1969 [inline] account_slab mm/slub.c:2542 [inline] allocate_slab+0xb6/0x2f0 mm/slub.c:2597 new_slab mm/slub.c:2632 [inline] ___slab_alloc+0xcd1/0x14b0 mm/slub.c:3819 __slab_alloc+0x58/0xa0 mm/slub.c:3909 __slab_alloc_node mm/slub.c:3962 [inline] slab_alloc_node mm/slub.c:4123 [inline] __do_kmalloc_node mm/slub.c:4264 [inline] __kmalloc_node_noprof+0x286/0x440 mm/slub.c:4271 kmalloc_node_noprof include/linux/slab.h:905 [inline] bpf_map_kmalloc_node+0xd3/0x1c0 kernel/bpf/syscall.c:422 lpm_trie_node_alloc kernel/bpf/lpm_trie.c:299 [inline] trie_update_elem+0x1cd/0xc00 kernel/bpf/lpm_trie.c:342 bpf_map_update_value+0x4d3/0x540 kernel/bpf/syscall.c:203 map_update_elem+0x51a/0x6f0 kernel/bpf/syscall.c:1626 __sys_bpf+0x76f/0x810 kernel/bpf/syscall.c:5622 __do_sys_bpf kernel/bpf/syscall.c:5741 [inline] __se_sys_bpf kernel/bpf/syscall.c:5739 [inline] __x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:5739 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: 0033:0x7f93def7dff9 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:00007f93dfe48038 EFLAGS: 00000246 ORIG_RAX: 0000000000000141 RAX: ffffffffffffffda RBX: 00007f93df135f80 RCX: 00007f93def7dff9 RDX: 0000000000000020 RSI: 00000000200004c0 RDI: 0000000000000002 RBP: 00007f93deff0296 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f93df135f80 R15: 00007fff24bc8458 </TASK> --- This report is generated by a bot. It may contain errors. See https://goo.gl/tpsmEJ for more information about syzbot. syzbot engineers can be reached at syzkaller@xxxxxxxxxxxxxxxx. syzbot will keep track of this issue. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot. If the report is already addressed, let syzbot know by replying with: #syz fix: exact-commit-title If you want to overwrite report's subsystems, reply with: #syz set subsystems: new-subsystem (See the list of subsystem names on the web dashboard) If the report is a duplicate of another one, reply with: #syz dup: exact-subject-of-another-report If you want to undo deduplication, reply with: #syz undup
