[syzbot] [mm?] BUG: sleeping function called from invalid context in kvm_mmu_notifier_invalidate_range_start

[syzbot <syzbot+c3178b6b512446632bac@syzkaller.appspotmail.com>]

Hello,

syzbot found the following issue on:

HEAD commit:    37bb2e7217b0 Merge tag 'staging-6.19-rc1' of git://git.ker..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=159b2992580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=8750900a7c493a0b
dashboard link: https://syzkaller.appspot.com/bug?extid=c3178b6b512446632bac
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/461486e4058d/disk-37bb2e72.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/844c0aeb98b9/vmlinux-37bb2e72.xz
kernel image: https://storage.googleapis.com/syzbot-assets/20fb43a5a012/bzImage-37bb2e72.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+c3178b6b512446632bac@syzkaller.appspotmail.com

BUG: sleeping function called from invalid context at kernel/locking/spinlock_rt.c:48
in_atomic(): 0, irqs_disabled(): 0, non_block: 1, pid: 39, name: oom_reaper
preempt_count: 0, expected: 0
RCU nest depth: 0, expected: 0
4 locks held by oom_reaper/39:
 #0: ffff888030a29070 (&mm->mmap_lock){++++}-{4:4}, at: mmap_read_trylock include/linux/mmap_lock.h:410 [inline]
 #0: ffff888030a29070 (&mm->mmap_lock){++++}-{4:4}, at: oom_reap_task_mm mm/oom_kill.c:582 [inline]
 #0: ffff888030a29070 (&mm->mmap_lock){++++}-{4:4}, at: oom_reap_task mm/oom_kill.c:625 [inline]
 #0: ffff888030a29070 (&mm->mmap_lock){++++}-{4:4}, at: oom_reaper+0x27e/0xa90 mm/oom_kill.c:666
 #1: ffffffff8d6ce600 (mmu_notifier_invalidate_range_start){+.+.}-{0:0}, at: mmu_notifier_invalidate_range_start_nonblock include/linux/mmu_notifier.h:456 [inline]
 #1: ffffffff8d6ce600 (mmu_notifier_invalidate_range_start){+.+.}-{0:0}, at: __oom_reap_task_mm+0x268/0x490 mm/oom_kill.c:558
 #2: ffffffff8d6ce658 (srcu){.+.+}-{0:0}, at: srcu_lock_acquire include/linux/srcu.h:185 [inline]
 #2: ffffffff8d6ce658 (srcu){.+.+}-{0:0}, at: srcu_read_lock include/linux/srcu.h:277 [inline]
 #2: ffffffff8d6ce658 (srcu){.+.+}-{0:0}, at: mn_hlist_invalidate_range_start mm/mmu_notifier.c:468 [inline]
 #2: ffffffff8d6ce658 (srcu){.+.+}-{0:0}, at: __mmu_notifier_invalidate_range_start+0x30b/0x840 mm/mmu_notifier.c:533
 #3: ffff8880276bcaf8 (&kvm->mn_invalidate_lock){+.+.}-{3:3}, at: spin_lock include/linux/spinlock_rt.h:44 [inline]
 #3: ffff8880276bcaf8 (&kvm->mn_invalidate_lock){+.+.}-{3:3}, at: kvm_mmu_notifier_invalidate_range_start+0x1bd/0xae0 virt/kvm/kvm_main.c:750
CPU: 1 UID: 0 PID: 39 Comm: oom_reaper Tainted: G             L      syzkaller #0 PREEMPT_{RT,(full)} 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
 __might_resched+0x44b/0x5d0 kernel/sched/core.c:8827
 __rt_spin_lock kernel/locking/spinlock_rt.c:48 [inline]
 rt_spin_lock+0xc7/0x3e0 kernel/locking/spinlock_rt.c:57
 spin_lock include/linux/spinlock_rt.h:44 [inline]
 kvm_mmu_notifier_invalidate_range_start+0x1bd/0xae0 virt/kvm/kvm_main.c:750
 mn_hlist_invalidate_range_start mm/mmu_notifier.c:478 [inline]
 __mmu_notifier_invalidate_range_start+0x440/0x840 mm/mmu_notifier.c:533
 mmu_notifier_invalidate_range_start_nonblock include/linux/mmu_notifier.h:459 [inline]
 __oom_reap_task_mm+0x2cb/0x490 mm/oom_kill.c:558
 oom_reap_task_mm mm/oom_kill.c:601 [inline]
 oom_reap_task mm/oom_kill.c:625 [inline]
 oom_reaper+0x3aa/0xa90 mm/oom_kill.c:666
 kthread+0x711/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x599/0xb30 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
 </TASK>
oom_reaper: reaped process 20496 (syz.8.2014), now anon-rss:24kB, file-rss:21692kB, shmem-rss:128kB


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