[syzbot] [v9fs?] WARNING in p9_client_create (2)

syzbot
2024-09-22T12:10:22Z

Hello,

syzbot found the following issue on:

HEAD commit: bdf56c7580d2 Merge tag 'slab-for-6.12' of git://git.kernel..
git tree: upstream
console+strace: https://syzkaller.appspot.com/x/log.txt?x=152d7fc7980000
kernel config: https://syzkaller.appspot.com/x/.config?x=4540f5bcdd31e3de
dashboard link: https://syzkaller.appspot.com/bug?extid=3c5d43e97993e1fa612b
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=15c98b00580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=151424a9980000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/cec9f3c675f1/disk-bdf56c75.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/21e06ae5b159/vmlinux-bdf56c75.xz
kernel image: https://storage.googleapis.com/syzbot-assets/1e936c954b8b/bzImage-bdf56c75.xz

The issue was bisected to:

commit 4c39529663b93165953ecf9b1a9ea817358dcd06
Author: Pedro Falcato <pedro.falcato@gmail.com>
Date: Wed Aug 7 09:07:46 2024 +0000

slab: Warn on duplicate cache names when DEBUG_VM=y

bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=111f269f980000
final oops: https://syzkaller.appspot.com/x/report.txt?x=131f269f980000
console output: https://syzkaller.appspot.com/x/log.txt?x=151f269f980000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+3c5d43e97993e1fa612b@syzkaller.appspotmail.com
Fixes: 4c39529663b9 ("slab: Warn on duplicate cache names when DEBUG_VM=y")

------------[ cut here ]------------
kmem_cache of name '9p-fcall-cache' already exists
WARNING: CPU: 0 PID: 5221 at mm/slab_common.c:108 kmem_cache_sanity_check mm/slab_common.c:107 [inline]
WARNING: CPU: 0 PID: 5221 at mm/slab_common.c:108 __kmem_cache_create_args+0xa7/0x350 mm/slab_common.c:294
Modules linked in:
CPU: 0 UID: 0 PID: 5221 Comm: syz-executor647 Not tainted 6.11.0-syzkaller-04744-gbdf56c7580d2 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/06/2024
RIP: 0010:kmem_cache_sanity_check mm/slab_common.c:107 [inline]
RIP: 0010:__kmem_cache_create_args+0xa7/0x350 mm/slab_common.c:294
Code: 8e 48 8b 1b 48 39 eb 74 25 48 8b 7b f8 4c 89 fe e8 ae 72 d5 09 85 c0 75 e8 90 48 c7 c7 03 a5 08 8e 4c 89 fe e8 5a 36 7d ff 90 <0f> 0b 90 90 4c 89 ff be 20 00 00 00 e8 08 74 d5 09 48 85 c0 0f 85
RSP: 0018:ffffc90003c07788 EFLAGS: 00010246
RAX: 158c5a6442ad7f00 RBX: ffff88814cccd428 RCX: ffff88802c34bc00
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffffff8ea168a0 R08: ffffffff8155af72 R09: 1ffff92000780e8c
R10: dffffc0000000000 R11: fffff52000780e8d R12: 0000000000020018
R13: 0000000000000000 R14: ffffc90003c07860 R15: ffffffff8d2c41c0
FS: 0000555573dac380(0000) GS:ffff8880b8800000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020001000 CR3: 0000000075df4000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
kmem_cache_create_usercopy include/linux/slab.h:361 [inline]
p9_client_create+0xba5/0x1110 net/9p/client.c:1042
v9fs_session_init+0x1e4/0x1b80 fs/9p/v9fs.c:410
v9fs_mount+0xcf/0xaa0 fs/9p/vfs_super.c:122
legacy_get_tree+0xee/0x190 fs/fs_context.c:662
vfs_get_tree+0x90/0x2b0 fs/super.c:1800
do_new_mount+0x2be/0xb40 fs/namespace.c:3507
do_mount fs/namespace.c:3847 [inline]
__do_sys_mount fs/namespace.c:4055 [inline]
__se_sys_mount+0x2d6/0x3c0 fs/namespace.c:4032
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f29cf818069
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 c1 17 00 00 90 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffd4a6d8418 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f29cf8610e8 RCX: 00007f29cf818069
RDX: 00000000200002c0 RSI: 0000000020000080 RDI: 0000000000000000
RBP: 00000000000f4240 R08: 0000000020000380 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffd4a6d8430
R13: 00007ffd4a6d8450 R14: 00007ffd4a6d8530 R15: 0000000000000001
</TASK>

---
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