[v6.1] possible deadlock in get_partial_node (3)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 8e6e2188d949 Linux 6.1.157
git tree: linux-6.1.y
console output: https://syzkaller.appspot.com/x/log.txt?x=10435de2580000
kernel config: https://syzkaller.appspot.com/x/.config?x=7eb38bd5021fec61
dashboard link: https://syzkaller.appspot.com/bug?extid=36547da81cd9e30aff85
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/18845d0cccdc/disk-8e6e2188.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/a65d29c3a1da/vmlinux-8e6e2188.xz
kernel image: https://storage.googleapis.com/syzbot-assets/f8120e905229/bzImage-8e6e2188.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+36547d...@syzkaller.appspotmail.com

======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
syz.7.347/5606 is trying to acquire lock:
ffff8880174433d8 (&n->list_lock){-.-.}-{2:2}, at: get_partial_node+0x36/0x470 mm/slub.c:2215

but task is already holding lock:
ffff8880591ec238 (&trie->lock){..-.}-{2:2}, at: trie_update_elem+0xc4/0xe90 kernel/bpf/lpm_trie.c:335

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (&trie->lock){..-.}-{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
trie_delete_elem+0x90/0x690 kernel/bpf/lpm_trie.c:467
bpf_prog_12666aae6518557f+0x26/0x3e
bpf_dispatcher_nop_func include/linux/bpf.h:1012 [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:2285 [inline]
bpf_trace_run2+0x1cd/0x3b0 kernel/trace/bpf_trace.c:2324
trace_contention_end+0x13f/0x190 include/trace/events/lock.h:122
__pv_queued_spin_lock_slowpath+0x7e8/0x9c0 kernel/locking/qspinlock.c:560
pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:591 [inline]
queued_spin_lock_slowpath+0x43/0x50 arch/x86/include/asm/qspinlock.h:51
queued_spin_lock include/asm-generic/qspinlock.h:114 [inline]
do_raw_spin_lock+0x217/0x280 kernel/locking/spinlock_debug.c:115
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:111 [inline]
_raw_spin_lock_irqsave+0xb0/0xf0 kernel/locking/spinlock.c:162
__unfreeze_partials+0x71/0x200 mm/slub.c:2555
put_cpu_partial+0x17c/0x250 mm/slub.c:2667
qlink_free mm/kasan/quarantine.c:168 [inline]
qlist_free_all+0x76/0xe0 mm/kasan/quarantine.c:187
kasan_quarantine_reduce+0x144/0x160 mm/kasan/quarantine.c:294
__kasan_slab_alloc+0x1e/0x80 mm/kasan/common.c:305
kasan_slab_alloc include/linux/kasan.h:201 [inline]
slab_post_alloc_hook+0x4b/0x480 mm/slab.h:737
slab_alloc_node mm/slub.c:3359 [inline]
slab_alloc mm/slub.c:3367 [inline]
__kmem_cache_alloc_lru mm/slub.c:3374 [inline]
kmem_cache_alloc+0x123/0x2f0 mm/slub.c:3383
mt_alloc_one lib/maple_tree.c:152 [inline]
mas_alloc_nodes+0x2ec/0x890 lib/maple_tree.c:1277
mas_node_count_gfp lib/maple_tree.c:1359 [inline]
mas_preallocate+0x161/0x3c0 lib/maple_tree.c:5807
__mmap_region mm/mmap.c:2765 [inline]
mmap_region+0xd8a/0x1c70 mm/mmap.c:2916
do_mmap+0x958/0xfd0 mm/mmap.c:1436
vm_mmap_pgoff+0x1b2/0x2b0 mm/util.c:520
elf_map+0x19e/0x2f0 fs/binfmt_elf.c:375
load_elf_interp+0x46d/0xd40 fs/binfmt_elf.c:664
load_elf_binary+0x19cd/0x26d0 fs/binfmt_elf.c:1272
search_binary_handler fs/exec.c:1764 [inline]
exec_binprm fs/exec.c:1805 [inline]
bprm_execve+0xb10/0x18a0 fs/exec.c:1874
kernel_execve+0x8b9/0x9c0 fs/exec.c:2039
call_usermodehelper_exec_async+0x207/0x350 kernel/umh.c:113
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295

-> #0 (&n->list_lock){-.-.}-{2:2}:
check_prev_add kernel/locking/lockdep.c:3090 [inline]
check_prevs_add kernel/locking/lockdep.c:3209 [inline]
validate_chain kernel/locking/lockdep.c:3825 [inline]
__lock_acquire+0x2cf8/0x7c50 kernel/locking/lockdep.c:5049
lock_acquire+0x1b4/0x490 kernel/locking/lockdep.c:5662
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
_raw_spin_lock_irqsave+0xa4/0xf0 kernel/locking/spinlock.c:162
get_partial_node+0x36/0x470 mm/slub.c:2215
get_partial mm/slub.c:2330 [inline]
___slab_alloc+0x968/0x1230 mm/slub.c:3131
__slab_alloc mm/slub.c:3240 [inline]
slab_alloc_node mm/slub.c:3325 [inline]
__kmem_cache_alloc_node+0x1a0/0x260 mm/slub.c:3398
__do_kmalloc_node mm/slab_common.c:935 [inline]
__kmalloc_node+0xa0/0x240 mm/slab_common.c:943
kmalloc_node include/linux/slab.h:589 [inline]
bpf_map_kmalloc_node+0xb8/0x1a0 kernel/bpf/syscall.c:454
lpm_trie_node_alloc kernel/bpf/lpm_trie.c:291 [inline]
trie_update_elem+0x160/0xe90 kernel/bpf/lpm_trie.c:338
bpf_map_update_value+0x59e/0x670 kernel/bpf/syscall.c:228
generic_map_update_batch+0x569/0x850 kernel/bpf/syscall.c:1709
bpf_map_do_batch+0x466/0x600 kernel/bpf/syscall.c:-1
__sys_bpf+0x65f/0x6d0 kernel/bpf/syscall.c:-1
__do_sys_bpf kernel/bpf/syscall.c:5131 [inline]
__se_sys_bpf kernel/bpf/syscall.c:5129 [inline]
__x64_sys_bpf+0x78/0x90 kernel/bpf/syscall.c:5129
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x4c/0xa0 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(&trie->lock);
lock(&n->list_lock);
lock(&trie->lock);
lock(&n->list_lock);

*** DEADLOCK ***

2 locks held by syz.7.347/5606:
#0: ffffffff8cb2aca0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
#0: ffffffff8cb2aca0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline]
#0: ffffffff8cb2aca0 (rcu_read_lock){....}-{1:2}, at: bpf_map_update_value+0x375/0x670 kernel/bpf/syscall.c:227
#1: ffff8880591ec238 (&trie->lock){..-.}-{2:2}, at: trie_update_elem+0xc4/0xe90 kernel/bpf/lpm_trie.c:335

stack backtrace:
CPU: 0 PID: 5606 Comm: syz.7.347 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
Call Trace:
<TASK>
dump_stack_lvl+0x168/0x22e lib/dump_stack.c:106
check_noncircular+0x274/0x310 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 kernel/locking/lockdep.c:3825 [inline]
__lock_acquire+0x2cf8/0x7c50 kernel/locking/lockdep.c:5049
lock_acquire+0x1b4/0x490 kernel/locking/lockdep.c:5662
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
_raw_spin_lock_irqsave+0xa4/0xf0 kernel/locking/spinlock.c:162
get_partial_node+0x36/0x470 mm/slub.c:2215
get_partial mm/slub.c:2330 [inline]
___slab_alloc+0x968/0x1230 mm/slub.c:3131
__slab_alloc mm/slub.c:3240 [inline]
slab_alloc_node mm/slub.c:3325 [inline]
__kmem_cache_alloc_node+0x1a0/0x260 mm/slub.c:3398
__do_kmalloc_node mm/slab_common.c:935 [inline]
__kmalloc_node+0xa0/0x240 mm/slab_common.c:943
kmalloc_node include/linux/slab.h:589 [inline]
bpf_map_kmalloc_node+0xb8/0x1a0 kernel/bpf/syscall.c:454
lpm_trie_node_alloc kernel/bpf/lpm_trie.c:291 [inline]
trie_update_elem+0x160/0xe90 kernel/bpf/lpm_trie.c:338
bpf_map_update_value+0x59e/0x670 kernel/bpf/syscall.c:228
generic_map_update_batch+0x569/0x850 kernel/bpf/syscall.c:1709
bpf_map_do_batch+0x466/0x600 kernel/bpf/syscall.c:-1
__sys_bpf+0x65f/0x6d0 kernel/bpf/syscall.c:-1
__do_sys_bpf kernel/bpf/syscall.c:5131 [inline]
__se_sys_bpf kernel/bpf/syscall.c:5129 [inline]
__x64_sys_bpf+0x78/0x90 kernel/bpf/syscall.c:5129
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fd7b878efc9
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:00007fd7b9543038 EFLAGS: 00000246 ORIG_RAX: 0000000000000141
RAX: ffffffffffffffda RBX: 00007fd7b89e6090 RCX: 00007fd7b878efc9
RDX: 0000000000000038 RSI: 0000200000000240 RDI: 000000000000001a
RBP: 00007fd7b8811f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fd7b89e6128 R14: 00007fd7b89e6090 R15: 00007ffc68af33d8
</TASK>


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