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

[Sean Christopherson <seanjc@google.com>]

On Mon, May 04, 2026, syzbot wrote:
> syzbot has found a reproducer for the following issue on:
> 
> HEAD commit:    b9303e6bff70 Add linux-next specific files for 20260430
> git tree:       linux-next
> console output: https://syzkaller.appspot.com/x/log.txt?x=13745dba580000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=5474e13c6d20d45c
> dashboard link: https://syzkaller.appspot.com/bug?extid=c3178b6b512446632bac
> compiler:       Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=125dd748580000
> 
> Downloadable assets:
> disk image: https://storage.googleapis.com/syzbot-assets/b3a0a2e50f73/disk-b9303e6b.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/d3d481b220d4/vmlinux-b9303e6b.xz
> kernel image: https://storage.googleapis.com/syzbot-assets/d6e012913960/bzImage-b9303e6b.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

This is a known issue:

https://lore.kernel.org/all/20260429222502.25414-1-shaikhkamal2012@gmail.com

> in_atomic(): 0, irqs_disabled(): 0, non_block: 1, pid: 40, name: oom_reaper
> preempt_count: 0, expected: 0
> RCU nest depth: 0, expected: 0
> 4 locks held by oom_reaper/40:
>  #0: ffff8880335ed1b0 (&mm->mmap_lock){++++}-{4:4}, at: mmap_read_trylock include/linux/mmap_lock.h:611 [inline]
>  #0: ffff8880335ed1b0 (&mm->mmap_lock){++++}-{4:4}, at: oom_reap_task_mm mm/oom_kill.c:566 [inline]
>  #0: ffff8880335ed1b0 (&mm->mmap_lock){++++}-{4:4}, at: oom_reap_task mm/oom_kill.c:609 [inline]
>  #0: ffff8880335ed1b0 (&mm->mmap_lock){++++}-{4:4}, at: oom_reaper+0x2bb/0xc10 mm/oom_kill.c:650
>  #1: ffffffff8e3066c0 (mmu_notifier_invalidate_range_start){+.+.}-{0:0}, at: mmu_notifier_invalidate_range_start_nonblock include/linux/mmu_notifier.h:495 [inline]
>  #1: ffffffff8e3066c0 (mmu_notifier_invalidate_range_start){+.+.}-{0:0}, at: zap_vma_for_reaping+0x193/0x380 mm/memory.c:2119
>  #2: ffffffff8e306718 (srcu){.+.+}-{0:0}, at: srcu_lock_acquire include/linux/srcu.h:187 [inline]
>  #2: ffffffff8e306718 (srcu){.+.+}-{0:0}, at: srcu_read_lock include/linux/srcu.h:294 [inline]
>  #2: ffffffff8e306718 (srcu){.+.+}-{0:0}, at: mn_hlist_invalidate_range_start mm/mmu_notifier.c:515 [inline]
>  #2: ffffffff8e306718 (srcu){.+.+}-{0:0}, at: __mmu_notifier_invalidate_range_start+0x5a1/0xb60 mm/mmu_notifier.c:580
>  #3: ffff88803996caf8 (&kvm->mn_invalidate_lock){+.+.}-{3:3}, at: spin_lock include/linux/spinlock_rt.h:45 [inline]
>  #3: ffff88803996caf8 (&kvm->mn_invalidate_lock){+.+.}-{3:3}, at: kvm_mmu_notifier_invalidate_range_start+0x1b7/0xc00 virt/kvm/kvm_main.c:744
> CPU: 0 UID: 0 PID: 40 Comm: oom_reaper Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
> Call Trace:
>  <TASK>
>  dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
>  __might_resched+0x329/0x480 kernel/sched/core.c:9163
>  __rt_spin_lock kernel/locking/spinlock_rt.c:48 [inline]
>  rt_spin_lock+0xc2/0x400 kernel/locking/spinlock_rt.c:57
>  spin_lock include/linux/spinlock_rt.h:45 [inline]
>  kvm_mmu_notifier_invalidate_range_start+0x1b7/0xc00 virt/kvm/kvm_main.c:744
>  mn_hlist_invalidate_range_start mm/mmu_notifier.c:525 [inline]
>  __mmu_notifier_invalidate_range_start+0x6e4/0xb60 mm/mmu_notifier.c:580
>  mmu_notifier_invalidate_range_start_nonblock include/linux/mmu_notifier.h:498 [inline]
>  zap_vma_for_reaping+0x1f7/0x380 mm/memory.c:2119
>  __oom_reap_task_mm mm/oom_kill.c:548 [inline]
>  oom_reap_task_mm mm/oom_kill.c:585 [inline]
>  oom_reap_task mm/oom_kill.c:609 [inline]
>  oom_reaper+0x51e/0xc10 mm/oom_kill.c:650
>  kthread+0x388/0x470 kernel/kthread.c:436
>  ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
>  ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
>  </TASK>
> BUG: sleeping function called from invalid context at kernel/locking/spinlock_rt.c:48
> in_atomic(): 0, irqs_disabled(): 0, non_block: 1, pid: 40, name: oom_reaper
> preempt_count: 0, expected: 0
> RCU nest depth: 0, expected: 0
> 4 locks held by oom_reaper/40:
>  #0: ffff8880335ed1b0 (&mm->mmap_lock){++++}-{4:4}, at: mmap_read_trylock include/linux/mmap_lock.h:611 [inline]
>  #0: ffff8880335ed1b0 (&mm->mmap_lock){++++}-{4:4}, at: oom_reap_task_mm mm/oom_kill.c:566 [inline]
>  #0: ffff8880335ed1b0 (&mm->mmap_lock){++++}-{4:4}, at: oom_reap_task mm/oom_kill.c:609 [inline]
>  #0: ffff8880335ed1b0 (&mm->mmap_lock){++++}-{4:4}, at: oom_reaper+0x2bb/0xc10 mm/oom_kill.c:650
>  #1: ffffffff8e3066c0 (mmu_notifier_invalidate_range_start){+.+.}-{0:0}, at: __mmu_notifier_invalidate_range_end+0x67/0x400 mm/mmu_notifier.c:611
>  #2: ffffffff8e306718 (srcu){.+.+}-{0:0}, at: __mmu_notifier_invalidate_range_end+0x67/0x400 mm/mmu_notifier.c:611
>  #3: ffff88803996caf8 (&kvm->mn_invalidate_lock){+.+.}-{3:3}, at: spin_lock include/linux/spinlock_rt.h:45 [inline]
>  #3: ffff88803996caf8 (&kvm->mn_invalidate_lock){+.+.}-{3:3}, at: kvm_mmu_notifier_invalidate_range_end+0x1d6/0x3d0 virt/kvm/kvm_main.c:814
> CPU: 0 UID: 0 PID: 40 Comm: oom_reaper Tainted: G        W           syzkaller #0 PREEMPT_{RT,(full)} 
> Tainted: [W]=WARN
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
> Call Trace:
>  <TASK>
>  dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
>  __might_resched+0x329/0x480 kernel/sched/core.c:9163
>  __rt_spin_lock kernel/locking/spinlock_rt.c:48 [inline]
>  rt_spin_lock+0xc2/0x400 kernel/locking/spinlock_rt.c:57
>  spin_lock include/linux/spinlock_rt.h:45 [inline]
>  kvm_mmu_notifier_invalidate_range_end+0x1d6/0x3d0 virt/kvm/kvm_main.c:814
>  mn_hlist_invalidate_end mm/mmu_notifier.c:597 [inline]
>  __mmu_notifier_invalidate_range_end+0x23b/0x400 mm/mmu_notifier.c:616
>  mmu_notifier_invalidate_range_end include/linux/mmu_notifier.h:511 [inline]
>  zap_vma_for_reaping+0x2d9/0x380 mm/memory.c:2124
>  __oom_reap_task_mm mm/oom_kill.c:548 [inline]
>  oom_reap_task_mm mm/oom_kill.c:585 [inline]
>  oom_reap_task mm/oom_kill.c:609 [inline]
>  oom_reaper+0x51e/0xc10 mm/oom_kill.c:650
>  kthread+0x388/0x470 kernel/kthread.c:436
>  ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
>  ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
>  </TASK>
> oom_reaper: reaped process 6034 (syz.0.24), now anon-rss:0kB, file-rss:64kB, shmem-rss:0kB
> 
> 
> ---
> If you want syzbot to run the reproducer, reply with:
> #syz test: git://repo/address.git branch-or-commit-hash
> If you attach or paste a git patch, syzbot will apply it before testing.