syzbot

======================================================
WARNING: possible circular locking dependency detected
6.9.0-syzkaller-09429-g61307b7be41a #0 Not tainted
------------------------------------------------------
syz-executor.0/16579 is trying to acquire lock:
ffff88813fffece0 (&pgdat->kswapd_wait){....}-{2:2}, at: __wake_up_common_lock+0x25/0x1e0 kernel/sched/wait.c:105

but task is already holding lock:
ffff88804abf71f8 (&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:

-> #3 (&trie->lock){..-.}-{2:2}:
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5754
       __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
       0xffffffffa000085a
       bpf_dispatcher_nop_func include/linux/bpf.h:1243 [inline]
       __bpf_prog_run include/linux/filter.h:691 [inline]
       bpf_prog_run include/linux/filter.h:698 [inline]
       __bpf_trace_run kernel/trace/bpf_trace.c:2403 [inline]
       bpf_trace_run4+0x336/0x590 kernel/trace/bpf_trace.c:2446
       __traceiter_sched_switch+0x9a/0xd0 include/trace/events/sched.h:222
       trace_sched_switch include/trace/events/sched.h:222 [inline]
       __schedule+0x2587/0x4a50 kernel/sched/core.c:6742
       preempt_schedule_irq+0xfb/0x1c0 kernel/sched/core.c:7067
       irqentry_exit+0x5e/0x90 kernel/entry/common.c:354
       asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:707
       debug_object_active_state+0xa5/0x360 lib/debugobjects.c:926
       debug_rcu_head_queue kernel/rcu/rcu.h:228 [inline]
       __call_rcu_common kernel/rcu/tree.c:3057 [inline]
       call_rcu+0xb5/0xa70 kernel/rcu/tree.c:3176
       release_probes kernel/tracepoint.c:164 [inline]
       tracepoint_add_func+0x620/0x9e0 kernel/tracepoint.c:386
       tracepoint_probe_register_prio_may_exist+0x122/0x190 kernel/tracepoint.c:482
       bpf_raw_tp_link_attach+0x48b/0x6e0 kernel/bpf/syscall.c:3874
       bpf_raw_tracepoint_open+0x1c2/0x240 kernel/bpf/syscall.c:3905
       __sys_bpf+0x3c0/0x810 kernel/bpf/syscall.c:5729
       __do_sys_bpf kernel/bpf/syscall.c:5794 [inline]
       __se_sys_bpf kernel/bpf/syscall.c:5792 [inline]
       __x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:5792
       do_syscall_x64 arch/x86/entry/common.c:52 [inline]
       do_syscall_64+0xf5/0x240 arch/x86/entry/common.c:83
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #2 (&rq->__lock){-.-.}-{2:2}:
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5754
       _raw_spin_lock_nested+0x31/0x40 kernel/locking/spinlock.c:378
       raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:559
       raw_spin_rq_lock kernel/sched/sched.h:1406 [inline]
       rq_lock kernel/sched/sched.h:1702 [inline]
       task_fork_fair+0x61/0x1e0 kernel/sched/fair.c:12709
       sched_cgroup_fork+0x37e/0x410 kernel/sched/core.c:4844
       copy_process+0x2217/0x3dc0 kernel/fork.c:2499
       kernel_clone+0x226/0x8f0 kernel/fork.c:2797
       user_mode_thread+0x132/0x1a0 kernel/fork.c:2875
       rest_init+0x23/0x300 init/main.c:707
       start_kernel+0x47a/0x500 init/main.c:1084
       x86_64_start_reservations+0x2a/0x30 arch/x86/kernel/head64.c:507
       x86_64_start_kernel+0x99/0xa0 arch/x86/kernel/head64.c:488
       common_startup_64+0x13e/0x147

-> #1 (&p->pi_lock){-.-.}-{2:2}:
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5754
       __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
       _raw_spin_lock_irqsave+0xd5/0x120 kernel/locking/spinlock.c:162
       class_raw_spinlock_irqsave_constructor include/linux/spinlock.h:553 [inline]
       try_to_wake_up+0xb0/0x1470 kernel/sched/core.c:4262
       autoremove_wake_function+0x16/0x110 kernel/sched/wait.c:384
       __wake_up_common kernel/sched/wait.c:89 [inline]
       __wake_up_common_lock+0x132/0x1e0 kernel/sched/wait.c:106
       rmqueue mm/page_alloc.c:3004 [inline]
       get_page_from_freelist+0x2aaf/0x2ee0 mm/page_alloc.c:3399
       __alloc_pages_noprof+0x256/0x6c0 mm/page_alloc.c:4660
       alloc_pages_mpol_noprof+0x3e8/0x680 mm/mempolicy.c:2265
       shmem_alloc_folio mm/shmem.c:1628 [inline]
       shmem_alloc_and_add_folio+0x24d/0xdb0 mm/shmem.c:1668
       shmem_get_folio_gfp+0x82d/0x1f50 mm/shmem.c:2055
       shmem_get_folio mm/shmem.c:2160 [inline]
       shmem_write_begin+0x170/0x4d0 mm/shmem.c:2743
       generic_perform_write+0x324/0x640 mm/filemap.c:4015
       shmem_file_write_iter+0xfc/0x120 mm/shmem.c:2919
       call_write_iter include/linux/fs.h:2120 [inline]
       new_sync_write fs/read_write.c:497 [inline]
       vfs_write+0xa2f/0xc50 fs/read_write.c:590
       ksys_write+0x1a0/0x2c0 fs/read_write.c:643
       do_syscall_x64 arch/x86/entry/common.c:52 [inline]
       do_syscall_64+0xf5/0x240 arch/x86/entry/common.c:83
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #0 (&pgdat->kswapd_wait){....}-{2:2}:
       check_prev_add kernel/locking/lockdep.c:3134 [inline]
       check_prevs_add kernel/locking/lockdep.c:3253 [inline]
       validate_chain+0x18cb/0x58e0 kernel/locking/lockdep.c:3869
       __lock_acquire+0x1346/0x1fd0 kernel/locking/lockdep.c:5137
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5754
       __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
       _raw_spin_lock_irqsave+0xd5/0x120 kernel/locking/spinlock.c:162
       __wake_up_common_lock+0x25/0x1e0 kernel/sched/wait.c:105
       rmqueue mm/page_alloc.c:3004 [inline]
       get_page_from_freelist+0x2aaf/0x2ee0 mm/page_alloc.c:3399
       __alloc_pages_noprof+0x256/0x6c0 mm/page_alloc.c:4660
       __alloc_pages_node_noprof include/linux/gfp.h:244 [inline]
       alloc_pages_node_noprof include/linux/gfp.h:271 [inline]
       __kmalloc_large_node+0x91/0x1f0 mm/slub.c:4066
       __do_kmalloc_node mm/slub.c:4109 [inline]
       __kmalloc_node_noprof+0x2d7/0x450 mm/slub.c:4128
       kmalloc_node_noprof include/linux/slab.h:681 [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+0x4d5/0x540 kernel/bpf/syscall.c:203
       map_update_elem+0x53a/0x6f0 kernel/bpf/syscall.c:1654
       __sys_bpf+0x76f/0x810 kernel/bpf/syscall.c:5675
       __do_sys_bpf kernel/bpf/syscall.c:5794 [inline]
       __se_sys_bpf kernel/bpf/syscall.c:5792 [inline]
       __x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:5792
       do_syscall_x64 arch/x86/entry/common.c:52 [inline]
       do_syscall_64+0xf5/0x240 arch/x86/entry/common.c:83
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

other info that might help us debug this:

Chain exists of:
  &pgdat->kswapd_wait --> &rq->__lock --> &trie->lock

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&trie->lock);
                               lock(&rq->__lock);
                               lock(&trie->lock);
  lock(&pgdat->kswapd_wait);

 *** DEADLOCK ***

2 locks held by syz-executor.0/16579:
 #0: ffffffff8e333d20 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:329 [inline]
 #0: ffffffff8e333d20 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:781 [inline]
 #0: ffffffff8e333d20 (rcu_read_lock){....}-{1:2}, at: bpf_map_update_value+0x3c4/0x540 kernel/bpf/syscall.c:202
 #1: ffff88804abf71f8 (&trie->lock){..-.}-{2:2}, at: trie_update_elem+0xc8/0xc00 kernel/bpf/lpm_trie.c:333

stack backtrace:
CPU: 0 PID: 16579 Comm: syz-executor.0 Not tainted 6.9.0-syzkaller-09429-g61307b7be41a #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/02/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:114
 check_noncircular+0x36a/0x4a0 kernel/locking/lockdep.c:2187
 check_prev_add kernel/locking/lockdep.c:3134 [inline]
 check_prevs_add kernel/locking/lockdep.c:3253 [inline]
 validate_chain+0x18cb/0x58e0 kernel/locking/lockdep.c:3869
 __lock_acquire+0x1346/0x1fd0 kernel/locking/lockdep.c:5137
 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5754
 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
 _raw_spin_lock_irqsave+0xd5/0x120 kernel/locking/spinlock.c:162
 __wake_up_common_lock+0x25/0x1e0 kernel/sched/wait.c:105
 rmqueue mm/page_alloc.c:3004 [inline]
 get_page_from_freelist+0x2aaf/0x2ee0 mm/page_alloc.c:3399
 __alloc_pages_noprof+0x256/0x6c0 mm/page_alloc.c:4660
 __alloc_pages_node_noprof include/linux/gfp.h:244 [inline]
 alloc_pages_node_noprof include/linux/gfp.h:271 [inline]
 __kmalloc_large_node+0x91/0x1f0 mm/slub.c:4066
 __do_kmalloc_node mm/slub.c:4109 [inline]
 __kmalloc_node_noprof+0x2d7/0x450 mm/slub.c:4128
 kmalloc_node_noprof include/linux/slab.h:681 [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+0x4d5/0x540 kernel/bpf/syscall.c:203
 map_update_elem+0x53a/0x6f0 kernel/bpf/syscall.c:1654
 __sys_bpf+0x76f/0x810 kernel/bpf/syscall.c:5675
 __do_sys_bpf kernel/bpf/syscall.c:5794 [inline]
 __se_sys_bpf kernel/bpf/syscall.c:5792 [inline]
 __x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:5792
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf5/0x240 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f36b307cee9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 00 00 90 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 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f36b3df20c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000141
RAX: ffffffffffffffda RBX: 00007f36b31abf80 RCX: 00007f36b307cee9
RDX: 0000000000000020 RSI: 0000000020000000 RDI: 0000000000000002
RBP: 00007f36b30c949e R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000000b R14: 00007f36b31abf80 R15: 00007ffd75b57ff8
 </TASK>