[syzbot] [mm?] WARNING: locking bug in __percpu_counter_limited_add

[syzbot <syzbot+57a2bb6f53fad29bd29c@syzkaller.appspotmail.com>]

Hello,

syzbot found the following issue on:

HEAD commit:    94619ea2d933 Merge tag 'ipsec-next-2025-07-23' of git://gi..
git tree:       net-next
console output: https://syzkaller.appspot.com/x/log.txt?x=1327c0a2580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=ceda48240b85ec34
dashboard link: https://syzkaller.appspot.com/bug?extid=57a2bb6f53fad29bd29c
compiler:       Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/afd64d9816ee/disk-94619ea2.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/e1755ce1f83b/vmlinux-94619ea2.xz
kernel image: https://storage.googleapis.com/syzbot-assets/2061dff2fbf4/bzImage-94619ea2.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+57a2bb6f53fad29bd29c@syzkaller.appspotmail.com

------------[ cut here ]------------
DEBUG_LOCKS_WARN_ON(!test_bit(class_idx, lock_classes_in_use))
WARNING: CPU: 0 PID: 20124 at kernel/locking/lockdep.c:5210 __lock_acquire+0xc0c/0xd20 kernel/locking/lockdep.c:5210
Modules linked in:
CPU: 0 UID: 0 PID: 20124 Comm: syz.3.4335 Not tainted 6.16.0-rc6-syzkaller-01673-g94619ea2d933 #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:__lock_acquire+0xc0c/0xd20 kernel/locking/lockdep.c:5210
Code: ff ff 90 e8 36 ad 1e 03 85 c0 74 22 83 3d 2f 14 04 0e 00 75 19 90 48 c7 c7 1d b7 b8 8d 48 c7 c6 ff 5b a0 8d e8 25 cb e5 ff 90 <0f> 0b 90 90 90 e9 8f 00 00 00 90 0f 0b 90 e9 8d fe ff ff 90 e8 fb
RSP: 0018:ffffc9000524f5c0 EFLAGS: 00010046
RAX: b837b7aac7381900 RBX: 0000000000000003 RCX: 0000000000080000
RDX: ffffc90011215000 RSI: 000000000000cba4 RDI: 000000000000cba5
RBP: 0000000000000000 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffffbfff1bfaa6c R12: 0000000000000004
R13: 0000000000000002 R14: ffff8880251d4768 R15: 0000000000000000
FS:  00007f1c62b736c0(0000) GS:ffff888125c15000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000020000003e000 CR3: 0000000075eea000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5871
 __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline]
 _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154
 __percpu_counter_limited_add+0x22d/0x710 lib/percpu_counter.c:351
 percpu_counter_limited_add include/linux/percpu_counter.h:77 [inline]
 shmem_inode_acct_blocks+0x187/0x470 mm/shmem.c:233
 shmem_alloc_and_add_folio+0x8bc/0xf60 mm/shmem.c:1920
 shmem_get_folio_gfp+0x59d/0x1660 mm/shmem.c:2536
 shmem_get_folio mm/shmem.c:2642 [inline]
 shmem_write_begin+0xf7/0x2b0 mm/shmem.c:3292
 generic_perform_write+0x2c7/0x910 mm/filemap.c:4112
 shmem_file_write_iter+0xf8/0x120 mm/shmem.c:3467
 new_sync_write fs/read_write.c:593 [inline]
 vfs_write+0x548/0xa90 fs/read_write.c:686
 ksys_write+0x145/0x250 fs/read_write.c:738
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f1c61d8e9a9
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:00007f1c62b73038 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f1c61fb6160 RCX: 00007f1c61d8e9a9
RDX: 00000000ffffffc1 RSI: 0000200000000200 RDI: 000000000000000a
RBP: 00007f1c61e10d69 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f1c61fb6160 R15: 00007ffe8452d7f8
 </TASK>


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