[v5.15] inconsistent lock state in htab_map_delete_elem

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: cc5ec8769306 Linux 5.15.196
git tree: linux-5.15.y
console output: https://syzkaller.appspot.com/x/log.txt?x=10c830c2580000
kernel config: https://syzkaller.appspot.com/x/.config?x=e1bb6d24ef2164eb
dashboard link: https://syzkaller.appspot.com/bug?extid=33a29bcf8af10436a5c7
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=15dee112580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=16a03f42580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/ed7568bc5bb4/disk-cc5ec876.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/e343e0aaac77/vmlinux-cc5ec876.xz
kernel image: https://storage.googleapis.com/syzbot-assets/089870f2a980/bzImage-cc5ec876.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+33a29b...@syzkaller.appspotmail.com

================================
WARNING: inconsistent lock state
syzkaller #0 Not tainted
--------------------------------
inconsistent {INITIAL USE} -> {IN-NMI} usage.
syz.0.17/4355 [HC1[1]:SC0[0]:HE0:SE1] takes:
ffff8880798d61d0 (&htab->lockdep_key){....}-{2:2}, at: htab_lock_bucket kernel/bpf/hashtab.c:183 [inline]
ffff8880798d61d0 (&htab->lockdep_key){....}-{2:2}, at: htab_map_delete_elem+0x1b2/0x520 kernel/bpf/hashtab.c:1361
{INITIAL USE} state was registered at:
lock_acquire+0x197/0x3f0 kernel/locking/lockdep.c:5623
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
_raw_spin_lock_irqsave+0xa4/0xf0 kernel/locking/spinlock.c:162
htab_lock_bucket kernel/bpf/hashtab.c:183 [inline]
htab_map_delete_elem+0x1b2/0x520 kernel/bpf/hashtab.c:1361
bpf_prog_653fb3e4a9309dc2+0x42/0x5d0
bpf_dispatcher_nop_func include/linux/bpf.h:888 [inline]
__bpf_prog_run include/linux/filter.h:628 [inline]
bpf_prog_run include/linux/filter.h:635 [inline]
bpf_overflow_handler+0x1c4/0x4c0 kernel/events/core.c:10297
__perf_event_overflow+0x364/0x530 kernel/events/core.c:9515
perf_swevent_overflow kernel/events/core.c:9591 [inline]
perf_swevent_event+0x4ad/0x530 kernel/events/core.c:9629
perf_bp_event+0x224/0x290 kernel/events/core.c:10484
hw_breakpoint_handler arch/x86/kernel/hw_breakpoint.c:555 [inline]
hw_breakpoint_exceptions_notify+0x152/0x470 arch/x86/kernel/hw_breakpoint.c:586
notifier_call_chain kernel/notifier.c:83 [inline]
atomic_notifier_call_chain+0x15d/0x280 kernel/notifier.c:198
notify_die+0x12d/0x180 kernel/notifier.c:529
notify_debug+0x20/0x30 arch/x86/kernel/traps.c:872
exc_debug_user arch/x86/kernel/traps.c:998 [inline]
noist_exc_debug+0x73/0x120 arch/x86/kernel/traps.c:1035
asm_exc_debug+0x2f/0x40 arch/x86/include/asm/idtentry.h:642
irq event stamp: 2560
hardirqs last enabled at (2559): [<ffffffff89a949f6>] exc_debug_kernel arch/x86/kernel/traps.c:947 [inline]
hardirqs last enabled at (2559): [<ffffffff89a949f6>] exc_debug+0xe6/0x130 arch/x86/kernel/traps.c:1029
hardirqs last disabled at (2560): [<ffffffff89a9497e>] exc_debug_kernel arch/x86/kernel/traps.c:893 [inline]
hardirqs last disabled at (2560): [<ffffffff89a9497e>] exc_debug+0x6e/0x130 arch/x86/kernel/traps.c:1029
softirqs last enabled at (2288): [<ffffffff81856560>] bpf_prog_load+0x1150/0x1550 kernel/bpf/syscall.c:2380
softirqs last disabled at (2286): [<ffffffff8183c969>] spin_lock_bh include/linux/spinlock.h:369 [inline]
softirqs last disabled at (2286): [<ffffffff8183c969>] bpf_ksym_add+0x29/0x340 kernel/bpf/core.c:633

other info that might help us debug this:
Possible unsafe locking scenario:

CPU0
----
lock(&htab->lockdep_key);
<Interrupt>
lock(&htab->lockdep_key);

*** DEADLOCK ***

no locks held by syz.0.17/4355.

stack backtrace:
CPU: 1 PID: 4355 Comm: syz.0.17 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
Call Trace:
<#DB>
dump_stack_lvl+0x168/0x230 lib/dump_stack.c:106
lock_acquire+0x2b2/0x3f0 kernel/locking/lockdep.c:5614
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
_raw_spin_lock_irqsave+0xa4/0xf0 kernel/locking/spinlock.c:162
htab_lock_bucket kernel/bpf/hashtab.c:183 [inline]
htab_map_delete_elem+0x1b2/0x520 kernel/bpf/hashtab.c:1361
bpf_prog_653fb3e4a9309dc2+0x42/0x5d0
bpf_dispatcher_nop_func include/linux/bpf.h:888 [inline]
__bpf_prog_run include/linux/filter.h:628 [inline]
bpf_prog_run include/linux/filter.h:635 [inline]
bpf_overflow_handler+0x1c4/0x4c0 kernel/events/core.c:10297
__perf_event_overflow+0x364/0x530 kernel/events/core.c:9515
perf_swevent_overflow kernel/events/core.c:9591 [inline]
perf_swevent_event+0x4ad/0x530 kernel/events/core.c:9629
perf_bp_event+0x224/0x290 kernel/events/core.c:10484
hw_breakpoint_handler arch/x86/kernel/hw_breakpoint.c:555 [inline]
hw_breakpoint_exceptions_notify+0x152/0x470 arch/x86/kernel/hw_breakpoint.c:586
notifier_call_chain kernel/notifier.c:83 [inline]
atomic_notifier_call_chain+0x15d/0x280 kernel/notifier.c:198
notify_die+0x12d/0x180 kernel/notifier.c:529
notify_debug+0x20/0x30 arch/x86/kernel/traps.c:872
exc_debug_kernel arch/x86/kernel/traps.c:929 [inline]
exc_debug+0xcf/0x130 arch/x86/kernel/traps.c:1029
asm_exc_debug+0x1a/0x40 arch/x86/include/asm/idtentry.h:642
RIP: 0010:copy_user_generic_unrolled+0xa2/0xc0 arch/x86/lib/copy_user_64.S:102
Code: ff c9 75 b6 89 d1 83 e2 07 c1 e9 03 74 12 4c 8b 06 4c 89 07 48 8d 76 08 48 8d 7f 08 ff c9 75 ee 21 d2 74 10 89 d1 8a 06 88 07 <48> ff c6 48 ff c7 ff c9 75 f2 31 c0 0f 01 ca c3 90 90 90 90 90 90
RSP: 0018:ffffc9000333f0f8 EFLAGS: 00040202
RAX: ffffffff83daee20 RBX: 0000000000000004 RCX: 0000000000000002
RDX: 0000000000000004 RSI: ffff88807ccb466e RDI: 0000200000000302
RBP: 0000000000000000 R08: dffffc0000000000 R09: ffffed100f9968ce
R10: ffffed100f9968ce R11: 1ffff1100f9968cd R12: 00007ffffffff000
R13: 0000200000000304 R14: ffff88807ccb466c R15: 0000200000000300
</#DB>
<TASK>
copy_user_generic arch/x86/include/asm/uaccess_64.h:37 [inline]
raw_copy_to_user arch/x86/include/asm/uaccess_64.h:58 [inline]
_copy_to_user+0xf0/0x130 lib/usercopy.c:40
copy_to_user include/linux/uaccess.h:200 [inline]
bpf_verifier_vlog+0x1b5/0x350 kernel/bpf/verifier.c:303
verbose+0x1dc/0x2a0 kernel/bpf/verifier.c:348
do_check+0x4785/0xeac0 kernel/bpf/verifier.c:11266
do_check_common+0xe67/0x16c0 kernel/bpf/verifier.c:13506
do_check_main kernel/bpf/verifier.c:13569 [inline]
bpf_check+0x31f3/0xf090 kernel/bpf/verifier.c:14140
bpf_prog_load+0x1043/0x1550 kernel/bpf/syscall.c:2354
__sys_bpf+0x4c2/0x670 kernel/bpf/syscall.c:4657
__do_sys_bpf kernel/bpf/syscall.c:4761 [inline]
__se_sys_bpf kernel/bpf/syscall.c:4759 [inline]
__x64_sys_bpf+0x78/0x90 kernel/bpf/syscall.c:4759
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f32fa1ce749
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:00007fffdab375e8 EFLAGS: 00000246 ORIG_RAX: 0000000000000141
RAX: ffffffffffffffda RBX: 00007f32fa424fa0 RCX: 00007f32fa1ce749
RDX: 0000000000000048 RSI: 0000200000000240 RDI: 0000000000000005
RBP: 00007f32fa252f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f32fa424fa0 R14: 00007f32fa424fa0 R15: 0000000000000003
</TASK>
----------------
Code disassembly (best guess):
0: ff c9 dec %ecx
2: 75 b6 jne 0xffffffba
4: 89 d1 mov %edx,%ecx
6: 83 e2 07 and $0x7,%edx
9: c1 e9 03 shr $0x3,%ecx
c: 74 12 je 0x20
e: 4c 8b 06 mov (%rsi),%r8
11: 4c 89 07 mov %r8,(%rdi)
14: 48 8d 76 08 lea 0x8(%rsi),%rsi
18: 48 8d 7f 08 lea 0x8(%rdi),%rdi
1c: ff c9 dec %ecx
1e: 75 ee jne 0xe
20: 21 d2 and %edx,%edx
22: 74 10 je 0x34
24: 89 d1 mov %edx,%ecx
26: 8a 06 mov (%rsi),%al
28: 88 07 mov %al,(%rdi)
* 2a: 48 ff c6 inc %rsi <-- trapping instruction
2d: 48 ff c7 inc %rdi
30: ff c9 dec %ecx
32: 75 f2 jne 0x26
34: 31 c0 xor %eax,%eax
36: 0f 01 ca clac
39: c3 ret
3a: 90 nop
3b: 90 nop
3c: 90 nop
3d: 90 nop
3e: 90 nop
3f: 90 nop


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