syzbot

======================================================
WARNING: possible circular locking dependency detected
6.1.90-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor216/3563 is trying to acquire lock:
ffff888028970e68 (&htab->buckets[i].lock){+.-.}-{2:2}, at: sock_hash_delete_elem+0x177/0x400 net/core/sock_map.c:938

but task is already holding lock:
ffff88807b06f3b8 (clock-AF_UNIX){+...}-{2:2}, at: sk_psock_init+0x32/0x6d0 net/core/skmsg.c:704

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (clock-AF_UNIX){+...}-{2:2}:
       lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662
       __raw_write_lock_bh include/linux/rwlock_api_smp.h:202 [inline]
       _raw_write_lock_bh+0x31/0x40 kernel/locking/spinlock.c:334
       sk_psock_drop+0x30/0x500 net/core/skmsg.c:836
       sock_hash_delete_elem+0x388/0x400 net/core/sock_map.c:942
       bpf_prog_2c29ac5cdc6b1842+0x2a/0x3e
       bpf_dispatcher_nop_func include/linux/bpf.h:989 [inline]
       __bpf_prog_run include/linux/filter.h:603 [inline]
       bpf_prog_run include/linux/filter.h:610 [inline]
       __bpf_trace_run kernel/trace/bpf_trace.c:2273 [inline]
       bpf_trace_run4+0x253/0x470 kernel/trace/bpf_trace.c:2314
       __bpf_trace_mm_page_alloc+0xba/0xe0 include/trace/events/kmem.h:177
       trace_mm_page_alloc include/trace/events/kmem.h:177 [inline]
       __alloc_pages+0x717/0x770 mm/page_alloc.c:5569
       __folio_alloc+0xf/0x30 mm/page_alloc.c:5579
       vma_alloc_folio+0x486/0x990 mm/mempolicy.c:2243
       alloc_page_vma include/linux/gfp.h:284 [inline]
       wp_page_copy+0x291/0x18c0 mm/memory.c:3134
       handle_pte_fault mm/memory.c:5031 [inline]
       __handle_mm_fault mm/memory.c:5155 [inline]
       handle_mm_fault+0x2525/0x5340 mm/memory.c:5276
       do_user_addr_fault arch/x86/mm/fault.c:1371 [inline]
       handle_page_fault arch/x86/mm/fault.c:1462 [inline]
       exc_page_fault+0x26f/0x660 arch/x86/mm/fault.c:1518
       asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:570

-> #0 (&htab->buckets[i].lock){+.-.}-{2:2}:
       check_prev_add kernel/locking/lockdep.c:3090 [inline]
       check_prevs_add kernel/locking/lockdep.c:3209 [inline]
       validate_chain+0x1661/0x5950 kernel/locking/lockdep.c:3825
       __lock_acquire+0x125b/0x1f80 kernel/locking/lockdep.c:5049
       lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662
       __raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline]
       _raw_spin_lock_bh+0x31/0x40 kernel/locking/spinlock.c:178
       sock_hash_delete_elem+0x177/0x400 net/core/sock_map.c:938
       bpf_prog_2c29ac5cdc6b1842+0x3a/0x3e
       bpf_dispatcher_nop_func include/linux/bpf.h:989 [inline]
       __bpf_prog_run include/linux/filter.h:603 [inline]
       bpf_prog_run include/linux/filter.h:610 [inline]
       __bpf_trace_run kernel/trace/bpf_trace.c:2273 [inline]
       bpf_trace_run4+0x253/0x470 kernel/trace/bpf_trace.c:2314
       __bpf_trace_mm_page_alloc+0xba/0xe0 include/trace/events/kmem.h:177
       __traceiter_mm_page_alloc+0x35/0x50 include/trace/events/kmem.h:177
       trace_mm_page_alloc include/trace/events/kmem.h:177 [inline]
       __alloc_pages+0x717/0x770 mm/page_alloc.c:5569
       alloc_slab_page+0x6a/0x150 mm/slub.c:1794
       allocate_slab mm/slub.c:1939 [inline]
       new_slab+0x84/0x2d0 mm/slub.c:1992
       ___slab_alloc+0xc20/0x1270 mm/slub.c:3180
       __slab_alloc mm/slub.c:3279 [inline]
       slab_alloc_node mm/slub.c:3364 [inline]
       __kmem_cache_alloc_node+0x19f/0x260 mm/slub.c:3437
       kmalloc_node_trace+0x23/0xe0 mm/slab_common.c:1058
       kmalloc_node include/linux/slab.h:578 [inline]
       kzalloc_node include/linux/slab.h:703 [inline]
       sk_psock_init+0x114/0x6d0 net/core/skmsg.c:716
       sock_map_link+0x767/0xe30 net/core/sock_map.c:277
       sock_hash_update_common+0xd1/0xa30 net/core/sock_map.c:996
       sock_map_update_elem_sys+0x5a0/0x910 net/core/sock_map.c:586
       map_update_elem+0x503/0x680 kernel/bpf/syscall.c:1448
       __sys_bpf+0x337/0x6c0 kernel/bpf/syscall.c:4993
       __do_sys_bpf kernel/bpf/syscall.c:5109 [inline]
       __se_sys_bpf kernel/bpf/syscall.c:5107 [inline]
       __x64_sys_bpf+0x78/0x90 kernel/bpf/syscall.c:5107
       do_syscall_x64 arch/x86/entry/common.c:51 [inline]
       do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81
       entry_SYSCALL_64_after_hwframe+0x68/0xd2

other info that might help us debug this:

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(clock-AF_UNIX);
                               lock(&htab->buckets[i].lock);
                               lock(clock-AF_UNIX);
  lock(&htab->buckets[i].lock);

 *** DEADLOCK ***

4 locks held by syz-executor216/3563:
 #0: ffff88807b06f130 (sk_lock-AF_UNIX){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1748 [inline]
 #0: ffff88807b06f130 (sk_lock-AF_UNIX){+.+.}-{0:0}, at: sock_map_sk_acquire net/core/sock_map.c:119 [inline]
 #0: ffff88807b06f130 (sk_lock-AF_UNIX){+.+.}-{0:0}, at: sock_map_update_elem_sys+0x1c8/0x910 net/core/sock_map.c:580
 #1: ffffffff8d12ac80 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
 #1: ffffffff8d12ac80 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline]
 #1: ffffffff8d12ac80 (rcu_read_lock){....}-{1:2}, at: sock_map_sk_acquire net/core/sock_map.c:120 [inline]
 #1: ffffffff8d12ac80 (rcu_read_lock){....}-{1:2}, at: sock_map_update_elem_sys+0x1d4/0x910 net/core/sock_map.c:580
 #2: ffff88807b06f3b8 (clock-AF_UNIX){+...}-{2:2}, at: sk_psock_init+0x32/0x6d0 net/core/skmsg.c:704
 #3: ffffffff8d12ac80 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
 #3: ffffffff8d12ac80 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline]
 #3: ffffffff8d12ac80 (rcu_read_lock){....}-{1:2}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2272 [inline]
 #3: ffffffff8d12ac80 (rcu_read_lock){....}-{1:2}, at: bpf_trace_run4+0x16a/0x470 kernel/trace/bpf_trace.c:2314

stack backtrace:
CPU: 0 PID: 3563 Comm: syz-executor216 Not tainted 6.1.90-syzkaller #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+0x1e3/0x2cb lib/dump_stack.c:106
 check_noncircular+0x2fa/0x3b0 kernel/locking/lockdep.c:2170
 check_prev_add kernel/locking/lockdep.c:3090 [inline]
 check_prevs_add kernel/locking/lockdep.c:3209 [inline]
 validate_chain+0x1661/0x5950 kernel/locking/lockdep.c:3825
 __lock_acquire+0x125b/0x1f80 kernel/locking/lockdep.c:5049
 lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662
 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline]
 _raw_spin_lock_bh+0x31/0x40 kernel/locking/spinlock.c:178
 sock_hash_delete_elem+0x177/0x400 net/core/sock_map.c:938
 bpf_prog_2c29ac5cdc6b1842+0x3a/0x3e
 bpf_dispatcher_nop_func include/linux/bpf.h:989 [inline]
 __bpf_prog_run include/linux/filter.h:603 [inline]
 bpf_prog_run include/linux/filter.h:610 [inline]
 __bpf_trace_run kernel/trace/bpf_trace.c:2273 [inline]
 bpf_trace_run4+0x253/0x470 kernel/trace/bpf_trace.c:2314
 __bpf_trace_mm_page_alloc+0xba/0xe0 include/trace/events/kmem.h:177
 __traceiter_mm_page_alloc+0x35/0x50 include/trace/events/kmem.h:177
 trace_mm_page_alloc include/trace/events/kmem.h:177 [inline]
 __alloc_pages+0x717/0x770 mm/page_alloc.c:5569
 alloc_slab_page+0x6a/0x150 mm/slub.c:1794
 allocate_slab mm/slub.c:1939 [inline]
 new_slab+0x84/0x2d0 mm/slub.c:1992
 ___slab_alloc+0xc20/0x1270 mm/slub.c:3180
 __slab_alloc mm/slub.c:3279 [inline]
 slab_alloc_node mm/slub.c:3364 [inline]
 __kmem_cache_alloc_node+0x19f/0x260 mm/slub.c:3437
 kmalloc_node_trace+0x23/0xe0 mm/slab_common.c:1058
 kmalloc_node include/linux/slab.h:578 [inline]
 kzalloc_node include/linux/slab.h:703 [inline]
 sk_psock_init+0x114/0x6d0 net/core/skmsg.c:716
 sock_map_link+0x767/0xe30 net/core/sock_map.c:277
 sock_hash_update_common+0xd1/0xa30 net/core/sock_map.c:996
 sock_map_update_elem_sys+0x5a0/0x910 net/core/sock_map.c:586
 map_update_elem+0x503/0x680 kernel/bpf/syscall.c:1448
 __sys_bpf+0x337/0x6c0 kernel/bpf/syscall.c:4993
 __do_sys_bpf kernel/bpf/syscall.c:5109 [inline]
 __se_sys_bpf kernel/bpf/syscall.c:5107 [inline]
 __x64_sys_bpf+0x78/0x90 kernel/bpf/syscall.c:5107
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fb9a55d2029
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 c1 17 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffcf66fee78 EFLAGS: 00000246 ORIG_RAX: 0000000000000141
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fb9a55d2029
RDX: 0000000000000020 RSI: 0000000020000180 RDI: 0000000000000002
RBP: 0000000000000000 R08: 00000000000000a0 R09: 00000000000000a0
R10: 00000000000000a0 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
 </TASK>