[syzbot] [mm?] WARNING in vma_mark_detached

syzbot
2026-04-20T21:14:29Z

Hello,

syzbot found the following issue on:

HEAD commit: 43cfbdda5af6 Merge tag 'for-linus-iommufd' of git://git.ke..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=17711906580000
kernel config: https://syzkaller.appspot.com/x/.config?x=8195c5b22e79c2cf
dashboard link: https://syzkaller.appspot.com/bug?extid=db390288d141a1dccf96
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=14cd78ce580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=161f82d2580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/848e46852283/disk-43cfbdda.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/24283dbdc318/vmlinux-43cfbdda.xz
kernel image: https://storage.googleapis.com/syzbot-assets/f91b3fadd31d/bzImage-43cfbdda.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+db390288d141a1dccf96@syzkaller.appspotmail.com

RDX: bbdccba4532b703b RSI: 0000200000000000 RDI: 0000000000000000
RBP: 00007ffcde93cf30 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 00007fa5dec15fac R14: 00007fa5dec15fa0 R15: 00007fa5dec15fa0
</TASK>
HugeTLB: unable to allocate vma specific lock
------------[ cut here ]------------
!vma_is_attached(vma)
WARNING: ./include/linux/mmap_lock.h:435 at vma_assert_attached include/linux/mmap_lock.h:435 [inline], CPU#0: syz.0.17/6011
WARNING: ./include/linux/mmap_lock.h:435 at vma_mark_detached+0x198/0x260 include/linux/mmap_lock.h:455, CPU#0: syz.0.17/6011
Modules linked in:
CPU: 0 UID: 0 PID: 6011 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
RIP: 0010:vma_assert_attached include/linux/mmap_lock.h:435 [inline]
RIP: 0010:vma_mark_detached+0x198/0x260 include/linux/mmap_lock.h:455
Code: 01 00 00 00 89 ee e8 57 5f a4 ff 85 ed 7e 4b e8 0e 5b a4 ff 48 89 df 5b 41 5c 41 5e 41 5f 5d e9 7e db f3 ff e8 f9 5a a4 ff 90 <0f> 0b 90 eb 95 e8 ee 5a a4 ff 90 0f 0b 90 e9 04 ff ff ff e8 e0 5a
RSP: 0018:ffffc90003396df0 EFLAGS: 00010293
RAX: ffffffff8220ba17 RBX: ffff8880536f8500 RCX: ffff88802baf3d80
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: ffff8880536f8583 R09: 1ffff1100a6df0b0
R10: dffffc0000000000 R11: ffffed100a6df0b1 R12: dffffc0000000000
R13: ffffc90003397130 R14: ffff8880536f8580 R15: 0000000000000001
FS: 000055555c863500(0000) GS:ffff88812522b000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2fb63fff CR3: 00000000325d8000 CR4: 00000000003526f0
Call Trace:
<TASK>
vms_gather_munmap_vmas+0x6ab/0x1380 mm/vma.c:1458
do_vmi_align_munmap+0x2b4/0x4b0 mm/vma.c:1595
do_vmi_munmap+0x252/0x2d0 mm/vma.c:1652
do_munmap+0xf9/0x170 mm/mmap.c:1067
mmap_action_finish mm/util.c:1422 [inline]
mmap_action_complete+0x480/0x590 mm/util.c:1491
compat_vma_mmap+0x243/0x2c0 mm/util.c:1280
vfs_mmap include/linux/fs.h:2072 [inline]
shm_mmap+0xda/0x200 ipc/shm.c:607
vfs_mmap include/linux/fs.h:2074 [inline]
mmap_file mm/internal.h:168 [inline]
__mmap_new_file_vma mm/vma.c:2496 [inline]
__mmap_new_vma mm/vma.c:2562 [inline]
__mmap_region mm/vma.c:2771 [inline]
mmap_region+0x1ab2/0x2280 mm/vma.c:2856
do_mmap+0xc39/0x10c0 mm/mmap.c:560
do_shmat+0x8d8/0xc10 ipc/shm.c:1662
__do_sys_shmat ipc/shm.c:1698 [inline]
__se_sys_shmat ipc/shm.c:1693 [inline]
__x64_sys_shmat+0x9c/0xf0 ipc/shm.c:1693
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: 0033:0x7fa5de99c819
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffcde93cec8 EFLAGS: 00000246 ORIG_RAX: 000000000000001e
RAX: ffffffffffffffda RBX: 00007fa5dec15fa0 RCX: 00007fa5de99c819
RDX: bbdccba4532b703b RSI: 0000200000000000 RDI: 0000000000000000
RBP: 00007ffcde93cf30 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 00007fa5dec15fac R14: 00007fa5dec15fa0 R15: 00007fa5dec15fa0
</TASK>

---
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