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

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 70c8a7ec6715 Add linux-next specific files for 20260422
git tree: linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=1586ae6a580000
kernel config: https://syzkaller.appspot.com/x/.config?x=d941ac7f11ceb230
dashboard link: https://syzkaller.appspot.com/bug?extid=98bfe400bc653d89958c
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/a920efda9ff7/disk-70c8a7ec.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/7d7626f0c3dc/vmlinux-70c8a7ec.xz
kernel image: https://storage.googleapis.com/syzbot-assets/261effff1138/bzImage-70c8a7ec.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+98bfe4...@syzkaller.appspotmail.com

BUG: sleeping function called from invalid context at mm/mmu_gather.c:142
in_atomic(): 0, irqs_disabled(): 0, non_block: 0, pid: 5808, name: udevd
preempt_count: 0, expected: 0
RCU nest depth: 1, expected: 0
2 locks held by udevd/5808:
#0: ffff8880387090b0 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock include/linux/mmap_lock.h:536 [inline]
#0: ffff8880387090b0 (&mm->mmap_lock){++++}-{4:4}, at: exit_mmap+0x2c2/0x9e0 mm/mmap.c:1308
#1: ffffffff8dfc81c0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#1: ffffffff8dfc81c0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline]
#1: ffffffff8dfc81c0 (rcu_read_lock){....}-{1:3}, at: folio_lruvec_lock_irqsave+0x24/0x540 mm/memcontrol.c:1452
CPU: 0 UID: 0 PID: 5808 Comm: udevd 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:9162
__tlb_batch_free_encoded_pages mm/mmu_gather.c:142 [inline]
tlb_batch_pages_flush mm/mmu_gather.c:151 [inline]
tlb_flush_mmu_free mm/mmu_gather.c:417 [inline]
tlb_flush_mmu+0x6f2/0xa30 mm/mmu_gather.c:424
tlb_finish_mmu+0xf9/0x230 mm/mmu_gather.c:549
exit_mmap+0x498/0x9e0 mm/mmap.c:1313
__mmput+0xcb/0x3e0 kernel/fork.c:1178
exit_mm+0x18e/0x250 kernel/exit.c:581
do_exit+0x6a2/0x22c0 kernel/exit.c:963
do_group_exit+0x21b/0x2d0 kernel/exit.c:1117
__do_sys_exit_group kernel/exit.c:1128 [inline]
__se_sys_exit_group kernel/exit.c:1126 [inline]
__x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1126
x64_sys_call+0x221a/0x2240 arch/x86/include/generated/asm/syscalls_64.h:232
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f62bcd8c6c5
Code: Unable to access opcode bytes at 0x7f62bcd8c69b.
RSP: 002b:00007fff29267f78 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 000055dbfa9391d0 RCX: 00007f62bcd8c6c5
RDX: 00000000000000e7 RSI: fffffffffffffe68 RDI: 0000000000000000
RBP: 000055dbfa6da910 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fff29267fc0 R14: 0000000000000000 R15: 0000000000000000
</TASK>

=============================
[ BUG: Invalid wait context ]
syzkaller #0 Tainted: G W
-----------------------------
udevd/5808 is trying to lock:
ffff8880406438b8 (&sb->s_type->i_mutex_key#13){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:1029 [inline]
ffff8880406438b8 (&sb->s_type->i_mutex_key#13){+.+.}-{4:4}, at: __sock_release+0x89/0x250 net/socket.c:725
other info that might help us debug this:
context-{5:5}
1 lock held by udevd/5808:
#0: ffffffff8dfc81c0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#0: ffffffff8dfc81c0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline]
#0: ffffffff8dfc81c0 (rcu_read_lock){....}-{1:3}, at: folio_lruvec_lock_irqsave+0x24/0x540 mm/memcontrol.c:1452
stack backtrace:
CPU: 0 UID: 0 PID: 5808 Comm: udevd 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
print_lock_invalid_wait_context kernel/locking/lockdep.c:4832 [inline]
check_wait_context kernel/locking/lockdep.c:4904 [inline]
__lock_acquire+0xec1/0x2cf0 kernel/locking/lockdep.c:5189
lock_acquire+0x106/0x350 kernel/locking/lockdep.c:5870
down_write+0x3a/0x50 kernel/locking/rwsem.c:1625
inode_lock include/linux/fs.h:1029 [inline]
__sock_release+0x89/0x250 net/socket.c:725
sock_close+0x1c/0x30 net/socket.c:1529
__fput+0x461/0xa70 fs/file_table.c:510
task_work_run+0x1d9/0x270 kernel/task_work.c:233
exit_task_work include/linux/task_work.h:40 [inline]
do_exit+0x70f/0x22c0 kernel/exit.c:975
do_group_exit+0x21b/0x2d0 kernel/exit.c:1117
__do_sys_exit_group kernel/exit.c:1128 [inline]
__se_sys_exit_group kernel/exit.c:1126 [inline]
__x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1126
x64_sys_call+0x221a/0x2240 arch/x86/include/generated/asm/syscalls_64.h:232
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f62bcd8c6c5
Code: Unable to access opcode bytes at 0x7f62bcd8c69b.
RSP: 002b:00007fff29267f78 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 000055dbfa9391d0 RCX: 00007f62bcd8c6c5
RDX: 00000000000000e7 RSI: fffffffffffffe68 RDI: 0000000000000000
RBP: 000055dbfa6da910 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fff29267fc0 R14: 0000000000000000 R15: 0000000000000000
</TASK>


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