[syzbot ci] Re: hugetlb: supports unmapping private mappings

[syzbot ci <syzbot+cid535899c573f38fa@syzkaller.appspotmail.com>]

syzbot ci has tested the following series

[v1] hugetlb: supports unmapping private mappings
https://lore.kernel.org/all/20261028041528.269829-1-eadavis@sina.com
* [PATCH] hugetlb: supports unmapping private mappings

and found the following issue:
WARNING: bad unlock balance in remove_inode_hugepages

Full report is available here:
https://ci.syzbot.org/series/bf349aec-df0c-48a8-ab82-9f71361a3830

***

WARNING: bad unlock balance in remove_inode_hugepages

tree:      mm-new
URL:       https://kernel.googlesource.com/pub/scm/linux/kernel/git/akpm/mm.git
base:      7d1f84f1b94e79cb95d974ab3ec54cb3a4d64f5b
arch:      amd64
compiler:  Debian clang version 22.1.8 (1~deb13u4), Debian LLD 22.1.8
config:    https://ci.syzbot.org/builds/7d19c5c0-63db-4726-978e-d863eedfb488/config

=====================================
WARNING: bad unlock balance detected!
syzkaller #0 Not tainted
-------------------------------------
syz.4.862/12304 is trying to release lock (&vma_lock->rw_sema) at:
[<ffffffff82b5a0e7>] remove_inode_hugepages+0xc57/0x1220
but there are no more locks to release!

other info that might help us debug this:
locks held by syz.4.862/12304: 4, last CPU#1:
 #0: ffff88810729e460 (sb_writers#12){.+.+}-{0:0}, at: vfs_fallocate+0x5e0/0x7e0
 #1: ffff8881aa537b00 (&sb->s_type->i_mutex_key#24){+.+.}-{4:4}, at: hugetlbfs_fallocate+0x3f7/0x11c0
 #2: ffff8881683dc638 (&hugetlb_fault_mutex_table[i]){+.+.}-{4:4}, at: remove_inode_hugepages+0x370/0x1220
 #3: ffff8881aa537da8 (&hugetlbfs_i_mmap_rwsem_key){+.+.}-{4:4}, at: remove_inode_hugepages+0xa44/0x1220

stack backtrace:
CPU: 1 UID: 0 PID: 12304 Comm: syz.4.862 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150
 print_unlock_imbalance_bug+0xdc/0xf0
 lock_release+0x252/0x3c0
 up_write+0x2d/0x4a0
 remove_inode_hugepages+0xc57/0x1220
 hugetlbfs_fallocate+0xc51/0x11c0
 vfs_fallocate+0x65a/0x7e0
 madvise_vma_behavior+0x2cf5/0x43b0
 madvise_walk_vmas+0x576/0xb00
 madvise_do_behavior+0x385/0x540
 do_madvise+0x327/0x3a0
 __x64_sys_madvise+0xa6/0xc0
 do_syscall_64+0x166/0x520
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f0c8dd9f559
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:00007f0c8bff6028 EFLAGS: 00000246 ORIG_RAX: 000000000000001c
RAX: ffffffffffffffda RBX: 00007f0c8e026450 RCX: 00007f0c8dd9f559
RDX: 0000000000000009 RSI: 0000000000c00000 RDI: 0000200000400000
RBP: 00007f0c8de36b20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f0c8e0264e8 R14: 00007f0c8e026450 R15: 00007ffc9fc94698
 </TASK>
------------[ cut here ]------------
DEBUG_RWSEMS_WARN_ON((rwsem_owner(sem) != current) && !rwsem_test_oflags(sem, RWSEM_NONSPINNABLE)): count = 0x0, magic = 0xffff88810b4c2608, owner = 0x0, curr 0xffff88816ff4bc00, list not empty
WARNING: kernel/locking/rwsem.c:1413 at up_write+0x35c/0x4a0, CPU#1: syz.4.862/12304
Modules linked in:
CPU: 1 UID: 0 PID: 12304 Comm: syz.4.862 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
RIP: 0010:up_write+0x40f/0x4a0
Code: 0d 8c 49 c7 c2 80 33 0d 8c 4c 0f 44 d0 48 8b 7c 24 10 48 c7 c6 20 36 0d 8c 48 8b 14 24 48 8b 4c 24 08 4d 89 e0 4d 89 f9 41 52 <67> 48 0f b9 3a 48 83 c4 08 e8 f3 6f 45 03 e9 d6 fc ff ff 48 c7 c1
RSP: 0018:ffffc900040cede0 EFLAGS: 00010246
RAX: ffffffff8c0d33a0 RBX: ffff88810b4c2608 RCX: ffff88810b4c2608
RDX: 0000000000000000 RSI: ffffffff8c0d3620 RDI: ffffffff917dda70
RBP: dffffc0000000000 R08: 0000000000000000 R09: ffff88816ff4bc00
R10: ffffffff8c0d33a0 R11: ffffed10216984c3 R12: 0000000000000000
R13: ffff88810b4c2610 R14: ffff88810b4c2660 R15: ffff88816ff4bc00
FS:  00007f0c8bff66c0(0000) GS:ffff8882a7c83000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f8981484378 CR3: 00000001ad2de000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 remove_inode_hugepages+0xc57/0x1220
 hugetlbfs_fallocate+0xc51/0x11c0
 vfs_fallocate+0x65a/0x7e0
 madvise_vma_behavior+0x2cf5/0x43b0
 madvise_walk_vmas+0x576/0xb00
 madvise_do_behavior+0x385/0x540
 do_madvise+0x327/0x3a0
 __x64_sys_madvise+0xa6/0xc0
 do_syscall_64+0x166/0x520
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f0c8dd9f559
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:00007f0c8bff6028 EFLAGS: 00000246 ORIG_RAX: 000000000000001c
RAX: ffffffffffffffda RBX: 00007f0c8e026450 RCX: 00007f0c8dd9f559
RDX: 0000000000000009 RSI: 0000000000c00000 RDI: 0000200000400000
RBP: 00007f0c8de36b20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f0c8e0264e8 R14: 00007f0c8e026450 R15: 00007ffc9fc94698
 </TASK>


***

If these findings have caused you to resend the series or submit a
separate fix, please add the following tag to your commit message:
  Tested-by: syzbot@syzkaller.appspotmail.com

---
This report is generated by a bot. It may contain errors.
syzbot ci engineers can be reached at syzkaller@googlegroups.com.

To test a fix for this bug, please reply with `#syz test`
(on a separate line) and attach the patch to the email.

Notes:
- The patch will be applied on top of the tested series (as an
  incremental fix).
- To test a new version of the whole series, please send it directly
  to syzbot@lists.linux.dev.
- Arguments like custom git repos and branches are not supported.