Re: [syzbot] [fs?] [mm?] WARNING: bad unlock balance in hugetlb_vmdelete_list

[syzbot <syzbot+62edf7e27b2e8f754525@syzkaller.appspotmail.com>]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
WARNING in hugetlb_vma_assert_locked

------------[ cut here ]------------
WARNING: mm/hugetlb.c:368 at hugetlb_vma_assert_locked+0x1dd/0x250 mm/hugetlb.c:368, CPU#0: syz.0.41/6582
Modules linked in:
CPU: 0 UID: 0 PID: 6582 Comm: syz.0.41 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
RIP: 0010:hugetlb_vma_assert_locked+0x1dd/0x250 mm/hugetlb.c:368
Code: 2e e8 e7 42 a1 ff eb 0c e8 e0 42 a1 ff eb 05 e8 d9 42 a1 ff 5b 41 5c 41 5d 41 5e 41 5f 5d e9 9a a0 6a 09 cc e8 c4 42 a1 ff 90 <0f> 0b 90 eb e5 e8 b9 42 a1 ff 90 0f 0b 90 eb da 48 c7 c1 70 b5 e4
RSP: 0018:ffffc9000217f388 EFLAGS: 00010293
RAX: ffffffff821f540c RBX: 0000000000000000 RCX: ffff88807af68000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000001 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff5200042fe74 R12: ffff88805df6aa00
R13: 1ffff110064fdfc4 R14: dffffc0000000000 R15: 0000000000000080
FS:  00007fc7b46136c0(0000) GS:ffff8881257be000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fc7b45f2d58 CR3: 0000000077790000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 huge_pmd_unshare+0x2c8/0x540 mm/hugetlb.c:7622
 __unmap_hugepage_range+0x6e3/0x1aa0 mm/hugetlb.c:5901
 unmap_hugepage_range+0x32e/0x410 mm/hugetlb.c:6089
 hugetlb_vmdelete_list+0x171/0x1c0 fs/hugetlbfs/inode.c:494
 hugetlb_vmtruncate fs/hugetlbfs/inode.c:641 [inline]
 hugetlbfs_setattr+0x4d1/0x6d0 fs/hugetlbfs/inode.c:879
 notify_change+0xc1a/0xf40 fs/attr.c:546
 do_truncate+0x1a4/0x220 fs/open.c:68
 handle_truncate fs/namei.c:3596 [inline]
 do_open fs/namei.c:3979 [inline]
 path_openat+0x306c/0x3830 fs/namei.c:4134
 do_filp_open+0x1fa/0x410 fs/namei.c:4161
 do_sys_openat2+0x121/0x1c0 fs/open.c:1437
 do_sys_open fs/open.c:1452 [inline]
 __do_sys_open fs/open.c:1460 [inline]
 __se_sys_open fs/open.c:1456 [inline]
 __x64_sys_open+0x11e/0x150 fs/open.c:1456
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fc7b378eec9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fc7b4613038 EFLAGS: 00000246 ORIG_RAX: 0000000000000002
RAX: ffffffffffffffda RBX: 00007fc7b39e5fa0 RCX: 00007fc7b378eec9
RDX: 0000000000000100 RSI: 000000000014927e RDI: 0000200000000340
RBP: 00007fc7b3811f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fc7b39e6038 R14: 00007fc7b39e5fa0 R15: 00007ffc872255b8
 </TASK>


Tested on:

commit:         b5a4da2c Add linux-next specific files for 20250924
git tree:       linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=10f02f12580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=841973c5ab4f4157
dashboard link: https://syzkaller.appspot.com/bug?extid=62edf7e27b2e8f754525
compiler:       Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
patch:          https://syzkaller.appspot.com/x/patch.diff?x=1581ed34580000