[syzbot] [bpf?] possible deadlock in get_partial_node

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 4b377b4868ef kprobe/ftrace: fix build error due to bad fun..
git tree: net-next
console output: https://syzkaller.appspot.com/x/log.txt?x=1295df6c980000
kernel config: https://syzkaller.appspot.com/x/.config?x=17ffd15f654c98ba
dashboard link: https://syzkaller.appspot.com/bug?extid=9045c0a3d5a7f1b119f7
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/6f4c61bc9252/disk-4b377b48.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/841f1b24d3a1/vmlinux-4b377b48.xz
kernel image: https://storage.googleapis.com/syzbot-assets/017b655dca3d/bzImage-4b377b48.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+9045c0...@syzkaller.appspotmail.com

======================================================
WARNING: possible circular locking dependency detected
6.9.0-syzkaller-08544-g4b377b4868ef #0 Not tainted
------------------------------------------------------
syz-executor.0/10441 is trying to acquire lock:
ffff88801504e318 (&n->list_lock){-.-.}-{2:2}, at: get_partial_node+0x36/0x280 mm/slub.c:2601

but task is already holding lock:
ffff88802b82c9f8 (&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: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
0xffffffffa0001fe2
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_run2+0x2ec/0x540 kernel/trace/bpf_trace.c:2444
trace_contention_end+0x114/0x140 include/trace/events/lock.h:122
__pv_queued_spin_lock_slowpath+0xb81/0xdc0 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
__put_partials+0x61/0x130 mm/slub.c:2900
put_cpu_partial+0x17c/0x250 mm/slub.c:2995
__slab_free+0x2ea/0x3d0 mm/slub.c:4224
qlink_free mm/kasan/quarantine.c:163 [inline]
qlist_free_all+0x5e/0xc0 mm/kasan/quarantine.c:179
kasan_quarantine_reduce+0x14f/0x170 mm/kasan/quarantine.c:286
__kasan_slab_alloc+0x23/0x80 mm/kasan/common.c:322
kasan_slab_alloc include/linux/kasan.h:201 [inline]
slab_post_alloc_hook mm/slub.c:3871 [inline]
slab_alloc_node mm/slub.c:3918 [inline]
kmem_cache_alloc_node+0x194/0x390 mm/slub.c:3961
__alloc_skb+0x1c3/0x440 net/core/skbuff.c:656
alloc_skb include/linux/skbuff.h:1308 [inline]
sock_wmalloc+0xab/0x120 net/core/sock.c:2643
l2tp_ip_sendmsg+0x1b1/0x1670 net/l2tp/l2tp_ip.c:439
sock_sendmsg_nosec net/socket.c:730 [inline]
__sock_sendmsg+0x1a6/0x270 net/socket.c:745
____sys_sendmsg+0x525/0x7d0 net/socket.c:2584
___sys_sendmsg net/socket.c:2638 [inline]
__sys_sendmmsg+0x3b2/0x740 net/socket.c:2724
__do_sys_sendmmsg net/socket.c:2753 [inline]
__se_sys_sendmmsg net/socket.c:2750 [inline]
__x64_sys_sendmmsg+0xa0/0xb0 net/socket.c:2750
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 (&n->list_lock){-.-.}-{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
get_partial_node+0x36/0x280 mm/slub.c:2601
get_partial mm/slub.c:2715 [inline]
___slab_alloc+0xa81/0x12e0 mm/slub.c:3572
__slab_alloc mm/slub.c:3682 [inline]
__slab_alloc_node mm/slub.c:3735 [inline]
slab_alloc_node mm/slub.c:3908 [inline]
__do_kmalloc_node mm/slub.c:4038 [inline]
__kmalloc_node+0x2db/0x4f0 mm/slub.c:4046
kmalloc_node include/linux/slab.h:648 [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
generic_map_update_batch+0x60d/0x900 kernel/bpf/syscall.c:1889
bpf_map_do_batch+0x3e0/0x690 kernel/bpf/syscall.c:5196
__sys_bpf+0x377/0x810
__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:

Possible unsafe locking scenario:

CPU0 CPU1
---- ----
lock(&trie->lock);
lock(&n->list_lock);
lock(&trie->lock);
lock(&n->list_lock);

*** DEADLOCK ***

2 locks held by syz-executor.0/10441:
#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: ffff88802b82c9f8 (&trie->lock){-.-.}-{2:2}, at: trie_update_elem+0xc8/0xc00 kernel/bpf/lpm_trie.c:333

stack backtrace:
CPU: 1 PID: 10441 Comm: syz-executor.0 Not tainted 6.9.0-syzkaller-08544-g4b377b4868ef #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
get_partial_node+0x36/0x280 mm/slub.c:2601
get_partial mm/slub.c:2715 [inline]
___slab_alloc+0xa81/0x12e0 mm/slub.c:3572
__slab_alloc mm/slub.c:3682 [inline]
__slab_alloc_node mm/slub.c:3735 [inline]
slab_alloc_node mm/slub.c:3908 [inline]
__do_kmalloc_node mm/slub.c:4038 [inline]
__kmalloc_node+0x2db/0x4f0 mm/slub.c:4046
kmalloc_node include/linux/slab.h:648 [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
generic_map_update_batch+0x60d/0x900 kernel/bpf/syscall.c:1889
bpf_map_do_batch+0x3e0/0x690 kernel/bpf/syscall.c:5196
__sys_bpf+0x377/0x810
__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: 0033:0x7f9c7b07cee9
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:00007f9c7bd5e0c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000141
RAX: ffffffffffffffda RBX: 00007f9c7b1ac050 RCX: 00007f9c7b07cee9
RDX: 0000000000000038 RSI: 0000000020000240 RDI: 000000000000001a
RBP: 00007f9c7b0c949e R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000006e R14: 00007f9c7b1ac050 R15: 00007fffe20416d8
</TASK>


---
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