[v5.15] BUG: corrupted list in fscache_free_cookie

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 458ce51d0356 Linux 5.15.149
git tree: linux-5.15.y
console output: https://syzkaller.appspot.com/x/log.txt?x=10c0dd9a180000
kernel config: https://syzkaller.appspot.com/x/.config?x=72292cff014cb054
dashboard link: https://syzkaller.appspot.com/bug?extid=e1c1e6e68c2c44511424
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
userspace arch: arm64

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/5e02146c6560/disk-458ce51d.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/267e4c48f387/vmlinux-458ce51d.xz
kernel image: https://storage.googleapis.com/syzbot-assets/e46fd8f3e04b/Image-458ce51d.gz.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+e1c1e6...@syzkaller.appspotmail.com

------------[ cut here ]------------
kernel BUG at lib/list_debug.c:50!
Internal error: Oops - BUG: 00000000f2000800 [#1] PREEMPT SMP
Modules linked in:

CPU: 1 PID: 20963 Comm: syz-executor.3 Not tainted 5.15.149-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024
pstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : __list_del_entry_valid+0xe0/0x150 lib/list_debug.c:49
lr : __list_del_entry_valid+0xe0/0x150 lib/list_debug.c:49
sp : ffff8000258575d0
x29: ffff8000258575d0
x28: 0000000000000000
x27: 000000000000001a

x26: ffff0000dcbe5d00
x25: 0000000000000065 x24: ffff000131d2874a
x23: dfff800000000000 x22: 0000000000000000 x21: dfff800000000000
x20: 0000000000000000 x19: ffff000131d286d8 x18: ffff800025856c00
x17: 0000000000000002 x16: ffff80001198bc54 x15: 0000000000034b45
x14: ffff800016f53500 x13: dfff800000000000 x12: 0000000000040000
x11: 000000000001f7ad x10: ffff80002040a000 x9 : 841b51647bf70300
x8 : 841b51647bf70300 x7 : 0000000000000000 x6 : 0000000000000000
x5 : 0000000000000020 x4 : 0000000000000000 x3 : ffff80000a9604c0
x2 : ffff0001b4813d10 x1 : 0000000000000001 x0 : 0000000000000033
Call trace:
__list_del_entry_valid+0xe0/0x150 lib/list_debug.c:49
__list_del_entry include/linux/list.h:132 [inline]
list_del include/linux/list.h:146 [inline]
fscache_free_cookie+0x68/0x240 fs/fscache/cookie.c:71
fscache_alloc_cookie+0x45c/0x5d4 fs/fscache/cookie.c:195
__fscache_acquire_cookie+0x14c/0x878 fs/fscache/cookie.c:296
fscache_acquire_cookie include/linux/fscache.h:334 [inline]
v9fs_cache_session_get_cookie+0x1ac/0x240 fs/9p/cache.c:60
v9fs_session_init+0x1170/0x1504 fs/9p/v9fs.c:473
v9fs_mount+0x88/0x780 fs/9p/vfs_super.c:126
legacy_get_tree+0xd4/0x16c fs/fs_context.c:611
vfs_get_tree+0x90/0x274 fs/super.c:1517
do_new_mount+0x278/0x8fc fs/namespace.c:3005
path_mount+0x594/0x101c fs/namespace.c:3335
do_mount fs/namespace.c:3348 [inline]
__do_sys_mount fs/namespace.c:3556 [inline]
__se_sys_mount fs/namespace.c:3533 [inline]
__arm64_sys_mount+0x510/0x5e0 fs/namespace.c:3533
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52
el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181
el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:608
el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:626
el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584
Code: d003ae80 91038000 aa1303e1 95bf1c10 (d4210000)
---[ end trace d8e0fb9184dfc824 ]---


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[syzbot]

syzbot has found a reproducer for the following issue on:

HEAD commit: 458ce51d0356 Linux 5.15.149
git tree: linux-5.15.y

console output: https://syzkaller.appspot.com/x/log.txt?x=105ae874180000

kernel config: https://syzkaller.appspot.com/x/.config?x=72292cff014cb054
dashboard link: https://syzkaller.appspot.com/bug?extid=e1c1e6e68c2c44511424
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
userspace arch: arm64

syz repro: https://syzkaller.appspot.com/x/repro.syz?x=15a110e4180000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=15a456ac180000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/5e02146c6560/disk-458ce51d.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/267e4c48f387/vmlinux-458ce51d.xz
kernel image: https://storage.googleapis.com/syzbot-assets/e46fd8f3e04b/Image-458ce51d.gz.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+e1c1e6...@syzkaller.appspotmail.com

el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:608
el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:626
el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584

list_del corruption, ffff0000c0b48860->next is NULL

------------[ cut here ]------------
kernel BUG at lib/list_debug.c:50!
Internal error: Oops - BUG: 00000000f2000800 [#1] PREEMPT SMP
Modules linked in:

CPU: 1 PID: 3967 Comm: syz-executor126 Not tainted 5.15.149-syzkaller #0

Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024
pstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : __list_del_entry_valid+0xe0/0x150 lib/list_debug.c:49
lr : __list_del_entry_valid+0xe0/0x150 lib/list_debug.c:49

sp : ffff80001a3675d0
x29: ffff80001a3675d0 x28: 0000000000000000 x27: 000000000000001a
x26: ffff0000c7a71400 x25: 0000000000000065 x24: ffff0000c0b488d2

x23: dfff800000000000 x22: 0000000000000000 x21: dfff800000000000

x20: 0000000000000000 x19: ffff0000c0b48860 x18: 0000000000000002
x17: 0000000000000000 x16: ffff800008333ac0 x15: 00000000ffffffff
x14: ffff0000c8863680 x13: 0000000000000001 x12: 0000000000000001
x11: 0000000000000001 x10: 0000000000000000 x9 : ea5fb83aa34b7800
x8 : ea5fb83aa34b7800 x7 : 0000000000000001 x6 : 0000000000000001
x5 : ffff80001a366d38 x4 : ffff8000149ff9a0 x3 : ffff800008333c0c
x2 : 0000000000000001 x1 : 0000000100000001 x0 : 0000000000000033

---[ end trace 0263a6a54822108f ]---


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