[v6.6] INFO: rcu detected stall in mount

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: a1153c0deb44 Linux 6.6.147
git tree: linux-6.6.y
console output: https://syzkaller.appspot.com/x/log.txt?x=17913632580000
kernel config: https://syzkaller.appspot.com/x/.config?x=f0bc3d90c30838b5
dashboard link: https://syzkaller.appspot.com/bug?extid=26ab649e6c65b6925289
compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/9f646bfa1b52/disk-a1153c0d.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/a2aec2e8f0fd/vmlinux-a1153c0d.xz
kernel image: https://storage.googleapis.com/syzbot-assets/a7abe1f87405/bzImage-a1153c0d.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+26ab64...@syzkaller.appspotmail.com

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P11615/1:b..l
rcu: (detected by 0, t=10502 jiffies, g=62877, q=234 ncpus=1)
task:syz.1.1838 state:R running task stack:23176 pid:11615 ppid:5774 flags:0x00004002
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5382 [inline]
__schedule+0x15ae/0x4660 kernel/sched/core.c:6701
preempt_schedule_irq+0xbf/0x150 kernel/sched/core.c:7011
irqentry_exit+0x67/0x70 kernel/entry/common.c:438
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
RIP: 0010:__sanitizer_cov_trace_pc+0x42/0x60 kernel/kcov.c:221
Code: e2 00 01 ff 00 74 11 81 fa 00 01 00 00 75 35 83 b9 1c 16 00 00 00 74 2c 8b 91 f8 15 00 00 83 fa 02 75 21 48 8b 91 00 16 00 00 <48> 8b 32 48 8d 7e 01 8b 89 fc 15 00 00 48 39 cf 73 08 48 89 3a 48
RSP: 0018:ffffc9000345f228 EFLAGS: 00000246
RAX: ffffffff812fb319 RBX: ffffc9000345f2c8 RCX: ffff888021e25a00
RDX: ffffc9000d9db000 RSI: 0000000000025e99 RDI: 0000000000025e9a
RBP: ffffc9000345f2f0 R08: ffffc9000345f327 R09: 0000000000000000
R10: ffffc9000345f2c8 R11: fffff5200068be65 R12: ffffc9000345f268
R13: ffffc9000345f2e8 R14: ffffc9000345f2e8 R15: ffff888021e25a00
get_stack_info+0x29/0x170 arch/x86/kernel/dumpstack_64.c:194
__unwind_start+0x406/0x730 arch/x86/kernel/unwind_orc.c:729
unwind_start arch/x86/include/asm/unwind.h:64 [inline]
arch_stack_walk+0xf8/0x190 arch/x86/kernel/stacktrace.c:24
stack_trace_save+0xaa/0x100 kernel/stacktrace.c:122
save_stack+0x125/0x230 mm/page_owner.c:128
__reset_page_owner+0x4e/0x190 mm/page_owner.c:149
reset_page_owner include/linux/page_owner.h:24 [inline]
free_pages_prepare mm/page_alloc.c:1182 [inline]
free_unref_page_prepare+0x7d7/0x8f0 mm/page_alloc.c:2366
free_unref_page+0x32/0x2e0 mm/page_alloc.c:2459
__slab_free+0x35a/0x400 mm/slub.c:3736
qlink_free mm/kasan/quarantine.c:166 [inline]
qlist_free_all+0x75/0xd0 mm/kasan/quarantine.c:185
kasan_quarantine_reduce+0x143/0x160 mm/kasan/quarantine.c:292
__kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:306
kasan_slab_alloc include/linux/kasan.h:188 [inline]
slab_post_alloc_hook+0x6a/0x4d0 mm/slab.h:770
slab_alloc_node mm/slub.c:3495 [inline]
slab_alloc mm/slub.c:3503 [inline]
__kmem_cache_alloc_lru mm/slub.c:3510 [inline]
kmem_cache_alloc+0x17e/0x2c0 mm/slub.c:3519
kmem_cache_zalloc include/linux/slab.h:711 [inline]
alloc_buffer_head+0x2d/0x280 fs/buffer.c:3031
folio_alloc_buffers+0x39b/0x9c0 fs/buffer.c:935
grow_dev_page fs/buffer.c:1072 [inline]
grow_buffers fs/buffer.c:1118 [inline]
__getblk_slow fs/buffer.c:1145 [inline]
__getblk_gfp+0x2d5/0x620 fs/buffer.c:1439
__bread_gfp+0x2a/0x330 fs/buffer.c:1473
sb_bread include/linux/buffer_head.h:326 [inline]
fat_fill_super+0x1dc4/0x50c0 fs/fat/inode.c:1645
mount_bdev+0x21c/0x2c0 fs/super.c:1643
legacy_get_tree+0xea/0x180 fs/fs_context.c:662
vfs_get_tree+0x8c/0x280 fs/super.c:1764
do_new_mount+0x24a/0xa40 fs/namespace.c:3386
do_mount fs/namespace.c:3726 [inline]
__do_sys_mount fs/namespace.c:3935 [inline]
__se_sys_mount+0x2e7/0x3d0 fs/namespace.c:3912
do_syscall_x64 arch/x86/entry/common.c:46 [inline]
do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f1b7359f28a
RSP: 002b:00007f1b743dee58 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f1b743deee0 RCX: 00007f1b7359f28a
RDX: 0000200000000300 RSI: 0000200000000180 RDI: 00007f1b743deea0
RBP: 0000200000000300 R08: 00007f1b743deee0 R09: 0000000000800000
R10: 0000000000800000 R11: 0000000000000246 R12: 0000200000000180
R13: 00007f1b743deea0 R14: 000000000000037f R15: 0000200000000200
</TASK>


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