[moderation] [v9fs?] KASAN: slab-use-after-free Read in p9_client_destroy

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 11cb68ad52ac Add linux-next specific files for 20240408
git tree: linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=155f2915180000
kernel config: https://syzkaller.appspot.com/x/.config?x=727d5608101b5d77
dashboard link: https://syzkaller.appspot.com/bug?extid=a2dc80815276e9a84583
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
CC: [asma...@codewreck.org eri...@kernel.org linux-...@vger.kernel.org linux-...@vger.kernel.org linu...@crudebyte.com lu...@ionkov.net v9...@lists.linux.dev]

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/4e90f2d3b1ef/disk-11cb68ad.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/d886b454e2cc/vmlinux-11cb68ad.xz
kernel image: https://storage.googleapis.com/syzbot-assets/ed94857c6f92/bzImage-11cb68ad.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+a2dc80...@syzkaller.appspotmail.com

9pnet: Found fid 1 not clunked
==================================================================
BUG: KASAN: slab-use-after-free in p9_fid_destroy net/9p/client.c:885 [inline]
BUG: KASAN: slab-use-after-free in p9_client_destroy+0x183/0x660 net/9p/client.c:1071
Read of size 8 at addr ffff88802099a680 by task syz-executor.4/11655

CPU: 1 PID: 11655 Comm: syz-executor.4 Not tainted 6.9.0-rc3-next-20240408-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x241/0x360 lib/dump_stack.c:114
print_address_description mm/kasan/report.c:377 [inline]
print_report+0x169/0x550 mm/kasan/report.c:488
kasan_report+0x143/0x180 mm/kasan/report.c:601
p9_fid_destroy net/9p/client.c:885 [inline]
p9_client_destroy+0x183/0x660 net/9p/client.c:1071
v9fs_session_close+0x51/0x210 fs/9p/v9fs.c:506
v9fs_kill_super+0x5c/0x90 fs/9p/vfs_super.c:196
deactivate_locked_super+0xc4/0x130 fs/super.c:472
cleanup_mnt+0x426/0x4c0 fs/namespace.c:1267
task_work_run+0x24f/0x310 kernel/task_work.c:180
resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
exit_to_user_mode_loop kernel/entry/common.c:114 [inline]
exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline]
__syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
syscall_exit_to_user_mode+0x168/0x370 kernel/entry/common.c:218
do_syscall_64+0x10a/0x240 arch/x86/entry/common.c:89
entry_SYSCALL_64_after_hwframe+0x72/0x7a
RIP: 0033:0x7fa65687f197
Code: b0 ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 0f 1f 44 00 00 31 f6 e9 09 00 00 00 66 0f 1f 84 00 00 00 00 00 b8 a6 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 01 c3 48 c7 c2 b0 ff ff ff f7 d8 64 89 02 b8
RSP: 002b:00007ffd3bc295f8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 00007fa65687f197
RDX: 0000000000000000 RSI: 000000000000000a RDI: 00007ffd3bc296b0
RBP: 00007ffd3bc296b0 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000ffffffff R11: 0000000000000246 R12: 00007ffd3bc2a770
R13: 00007fa6568c93b9 R14: 00000000000d0c49 R15: 000000000000000c
</TASK>

Allocated by task 26720:
kasan_save_stack mm/kasan/common.c:47 [inline]
kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
poison_kmalloc_redzone mm/kasan/common.c:370 [inline]
__kasan_kmalloc+0x98/0xb0 mm/kasan/common.c:387
kasan_kmalloc include/linux/kasan.h:211 [inline]
kmalloc_trace_noprof+0x19c/0x2b0 mm/slub.c:4109
kmalloc_noprof include/linux/slab.h:660 [inline]
kzalloc_noprof include/linux/slab.h:775 [inline]
p9_fid_create+0x4f/0x230 net/9p/client.c:854
p9_client_walk+0x103/0x690 net/9p/client.c:1155
clone_fid fs/9p/fid.h:23 [inline]
v9fs_fid_clone fs/9p/fid.h:33 [inline]
v9fs_file_open+0x285/0xa60 fs/9p/vfs_file.c:56
do_dentry_open+0x907/0x15f0 fs/open.c:955
do_open fs/namei.c:3642 [inline]
path_openat+0x289f/0x3280 fs/namei.c:3799
do_filp_open+0x235/0x490 fs/namei.c:3826
do_sys_openat2+0x13e/0x1d0 fs/open.c:1406
do_sys_open fs/open.c:1421 [inline]
__do_sys_creat fs/open.c:1497 [inline]
__se_sys_creat fs/open.c:1491 [inline]
__x64_sys_creat+0x123/0x170 fs/open.c:1491
do_syscall_64+0xfb/0x240
entry_SYSCALL_64_after_hwframe+0x72/0x7a

Freed by task 19352:
kasan_save_stack mm/kasan/common.c:47 [inline]
kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:579
poison_slab_object+0xe0/0x150 mm/kasan/common.c:240
__kasan_slab_free+0x37/0x60 mm/kasan/common.c:256
kasan_slab_free include/linux/kasan.h:184 [inline]
slab_free_hook mm/slub.c:2190 [inline]
slab_free mm/slub.c:4393 [inline]
kfree+0x149/0x350 mm/slub.c:4514
p9_fid_destroy net/9p/client.c:890 [inline]
p9_client_clunk+0x1ce/0x260 net/9p/client.c:1457
netfs_free_request+0x244/0x5e0 fs/netfs/objects.c:133
netfs_write_collection_worker+0x5079/0x5630 fs/netfs/write_collect.c:706
process_one_work kernel/workqueue.c:3218 [inline]
process_scheduled_works+0xa2c/0x1830 kernel/workqueue.c:3299
worker_thread+0x86d/0xd70 kernel/workqueue.c:3380
kthread+0x2f0/0x390 kernel/kthread.c:388
ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:243

The buggy address belongs to the object at ffff88802099a680
which belongs to the cache kmalloc-96 of size 96
The buggy address is located 0 bytes inside of
freed 96-byte region [ffff88802099a680, ffff88802099a6e0)

The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x2099a
ksm flags: 0xfff80000000000(node=0|zone=1|lastcpupid=0xfff)
page_type: 0xffffefff(slab)
raw: 00fff80000000000 ffff888015041780 ffffea00006fb0c0 dead000000000003
raw: 0000000000000000 0000000000200020 00000001ffffefff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x112820(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_HARDWALL), pid 10, tgid -1888566726 (kworker/u8:0), ts 10, free_ts 79706592626
set_page_owner include/linux/page_owner.h:32 [inline]
post_alloc_hook+0x1f3/0x230 mm/page_alloc.c:1468
prep_new_page mm/page_alloc.c:1476 [inline]
get_page_from_freelist+0x2ce2/0x2d90 mm/page_alloc.c:3438
__alloc_pages_noprof+0x256/0x6c0 mm/page_alloc.c:4696
__alloc_pages_node_noprof include/linux/gfp.h:244 [inline]
alloc_pages_node_noprof include/linux/gfp.h:271 [inline]
alloc_slab_page+0x5f/0x120 mm/slub.c:2259
allocate_slab+0x5a/0x2e0 mm/slub.c:2422
new_slab mm/slub.c:2475 [inline]
___slab_alloc+0xcd1/0x14b0 mm/slub.c:3624
__slab_alloc+0x58/0xa0 mm/slub.c:3714
__slab_alloc_node mm/slub.c:3767 [inline]
slab_alloc_node mm/slub.c:3945 [inline]
kmalloc_trace_noprof+0x1d5/0x2b0 mm/slub.c:4104
kmalloc_noprof include/linux/slab.h:660 [inline]
dst_cow_metrics_generic+0x56/0x1c0 net/core/dst.c:178
dst_metrics_write_ptr include/net/dst.h:133 [inline]
dst_metric_set include/net/dst.h:194 [inline]
icmp6_dst_alloc+0x270/0x420 net/ipv6/route.c:3286
ndisc_send_skb+0x32a/0x1380 net/ipv6/ndisc.c:489
addrconf_dad_completed+0x76c/0xcd0 net/ipv6/addrconf.c:4358
addrconf_dad_work+0xdc2/0x16f0
process_one_work kernel/workqueue.c:3218 [inline]
process_scheduled_works+0xa2c/0x1830 kernel/workqueue.c:3299
worker_thread+0x86d/0xd70 kernel/workqueue.c:3380
kthread+0x2f0/0x390 kernel/kthread.c:388
page last free pid 5233 tgid 5233 stack trace:
reset_page_owner include/linux/page_owner.h:25 [inline]
free_pages_prepare mm/page_alloc.c:1088 [inline]
free_unref_page+0xd22/0xea0 mm/page_alloc.c:2601
tlb_batch_list_free mm/mmu_gather.c:159 [inline]
tlb_finish_mmu+0x11f/0x200 mm/mmu_gather.c:468
exit_mmap+0x44f/0xc80 mm/mmap.c:3325
__mmput+0x115/0x3c0 kernel/fork.c:1345
exit_mm+0x220/0x310 kernel/exit.c:569
do_exit+0x99e/0x27e0 kernel/exit.c:865
do_group_exit+0x207/0x2c0 kernel/exit.c:1027
__do_sys_exit_group kernel/exit.c:1038 [inline]
__se_sys_exit_group kernel/exit.c:1036 [inline]
__x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1036
do_syscall_64+0xfb/0x240
entry_SYSCALL_64_after_hwframe+0x72/0x7a

Memory state around the buggy address:
ffff88802099a580: 00 00 00 00 00 00 00 00 00 00 00 00 fc fc fc fc
ffff88802099a600: 00 00 00 00 00 00 00 00 00 01 fc fc fc fc fc fc
>ffff88802099a680: fa fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
^
ffff88802099a700: fa fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
ffff88802099a780: fa fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
==================================================================


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