linux-kernel - Re: [syzbot] [mm?] WARNING in xfs_init_fs

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Message-ID: <68d973fc.a00a0220.102ee.002b.GAE@google.com>
Date: Sun, 28 Sep 2025 10:44:28 -0700
From: syzbot <syzbot+359a67b608de1ef72f65@...kaller.appspotmail.com>
To: akpm@...ux-foundation.org, apopple@...dia.com, baohua@...nel.org, 
	byungchul@...com, cem@...nel.org, david@...morbit.com, david@...hat.com, 
	gourry@...rry.net, harry.yoo@...cle.com, joshua.hahnjy@...il.com, 
	linux-kernel@...r.kernel.org, linux-mm@...ck.org, linux-xfs@...r.kernel.org, 
	matthew.brost@...el.com, mhocko@...e.com, penguin-kernel@...ove.sakura.ne.jp, 
	rakie.kim@...com, syzkaller-bugs@...glegroups.com, vbabka@...e.cz, 
	willy@...radead.org, ying.huang@...ux.alibaba.com, ziy@...dia.com
Subject: Re: [syzbot] [mm?] WARNING in xfs_init_fs_context

syzbot has found a reproducer for the following issue on:

HEAD commit:    51a24b7deaae Merge tag 'trace-tools-v6.17-rc5' of git://gi..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1268bf12580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=bf99f2510ef92ba5
dashboard link: https://syzkaller.appspot.com/bug?extid=359a67b608de1ef72f65
compiler:       Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=11a20334580000

Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/d900f083ada3/non_bootable_disk-51a24b7d.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/2d2422223a2d/vmlinux-51a24b7d.xz
kernel image: https://storage.googleapis.com/syzbot-assets/3f33b7e0feca/bzImage-51a24b7d.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/345ccb8f827e/mount_8.gz
  fsck result: failed (log: https://syzkaller.appspot.com/x/fsck.log?x=161e6ae2580000)

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+359a67b608de1ef72f65@...kaller.appspotmail.com

loop0: detected capacity change from 0 to 32768
------------[ cut here ]------------
WARNING: CPU: 0 PID: 6463 at mm/page_alloc.c:4619 __alloc_pages_slowpath+0xcb3/0xce0 mm/page_alloc.c:4619
Modules linked in:
CPU: 0 UID: 0 PID: 6463 Comm: syz.0.279 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
RIP: 0010:__alloc_pages_slowpath+0xcb3/0xce0 mm/page_alloc.c:4619
Code: d8 48 c1 e8 03 0f b6 04 08 84 c0 75 2e f6 43 01 08 48 8b 14 24 0f 84 a2 f3 ff ff 90 0f 0b 90 e9 99 f3 ff ff e8 3e 9e 64 09 90 <0f> 0b 90 f7 c5 00 04 00 00 75 bc 90 0f 0b 90 eb b6 89 d9 80 e1 07
RSP: 0018:ffffc9000e2ff8f0 EFLAGS: 00010246
RAX: 97af8c55b4e88b00 RBX: 0000000000000002 RCX: dffffc0000000000
RDX: ffffc9000e2ffa00 RSI: 0000000000000002 RDI: 0000000000048cc0
RBP: 0000000000048cc0 R08: ffff88805ffd7297 R09: 1ffff1100bffae52
R10: dffffc0000000000 R11: ffffed100bffae53 R12: ffffc9000e2ffa00
R13: 1ffff92001c5ff3c R14: 0000000000048cc0 R15: dffffc0000000000
FS:  00007fb4ec9696c0(0000) GS:ffff88808d007000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fb4ebb72b60 CR3: 00000000516af000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 __alloc_frozen_pages_noprof+0x319/0x370 mm/page_alloc.c:5161
 alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2416
 alloc_slab_page mm/slub.c:2492 [inline]
 allocate_slab+0xd9/0x370 mm/slub.c:2668
 new_slab mm/slub.c:2714 [inline]
 ___slab_alloc+0xbeb/0x1420 mm/slub.c:3901
 __slab_alloc mm/slub.c:3992 [inline]
 __slab_alloc_node mm/slub.c:4067 [inline]
 slab_alloc_node mm/slub.c:4228 [inline]
 __kmalloc_cache_noprof+0x296/0x3d0 mm/slub.c:4402
 kmalloc_noprof include/linux/slab.h:905 [inline]
 kzalloc_noprof include/linux/slab.h:1039 [inline]
 xfs_init_fs_context+0x54/0x500 fs/xfs/xfs_super.c:2278
 alloc_fs_context+0x64e/0x7d0 fs/fs_context.c:318
 do_new_mount+0x16f/0x9e0 fs/namespace.c:3787
 do_mount fs/namespace.c:4136 [inline]
 __do_sys_mount fs/namespace.c:4347 [inline]
 __se_sys_mount+0x317/0x410 fs/namespace.c:4324
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fb4ebb9066a
Code: d8 64 89 02 48 c7 c0 ff ff ff ff eb a6 e8 de 1a 00 00 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 49 89 ca b8 a5 00 00 00 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:00007fb4ec968e68 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007fb4ec968ef0 RCX: 00007fb4ebb9066a
RDX: 0000200000009600 RSI: 0000200000009640 RDI: 00007fb4ec968eb0
RBP: 0000200000009600 R08: 00007fb4ec968ef0 R09: 0000000000200800
R10: 0000000000200800 R11: 0000000000000246 R12: 0000200000009640
R13: 00007fb4ec968eb0 R14: 0000000000009644 R15: 00002000000002c0
 </TASK>


---
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.