[syzbot] [serial?] KASAN: slab-use-after-free Read in uart_write

syzbot
2024-12-02T16:33:29Z

Hello,

syzbot found the following issue on:

HEAD commit: b86545e02e8c Merge tag 'acpi-6.13-rc1-2' of git://git.kern..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=17f91f5f980000
kernel config: https://syzkaller.appspot.com/x/.config?x=89e59b772d80e74b
dashboard link: https://syzkaller.appspot.com/bug?extid=7e89e4811726b862fd98
compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
userspace arch: i386

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

Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/7feb34a89c2a/non_bootable_disk-b86545e0.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/547617924f85/vmlinux-b86545e0.xz
kernel image: https://storage.googleapis.com/syzbot-assets/c2157113e5b9/bzImage-b86545e0.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+7e89e4811726b862fd98@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: slab-use-after-free in uart_write+0x9ff/0xb30 drivers/tty/serial/serial_core.c:614
Read of size 8 at addr ffff888065d185f8 by task aoe_tx0/1412

CPU: 0 UID: 0 PID: 1412 Comm: aoe_tx0 Not tainted 6.12.0-syzkaller-10553-gb86545e02e8c #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
print_address_description mm/kasan/report.c:378 [inline]
print_report+0xc3/0x620 mm/kasan/report.c:489
kasan_report+0xd9/0x110 mm/kasan/report.c:602
uart_write+0x9ff/0xb30 drivers/tty/serial/serial_core.c:614
handle_tx+0x203/0x630 drivers/net/caif/caif_serial.c:236
__netdev_start_xmit include/linux/netdevice.h:5002 [inline]
netdev_start_xmit include/linux/netdevice.h:5011 [inline]
xmit_one net/core/dev.c:3590 [inline]
dev_hard_start_xmit+0x9a/0x7b0 net/core/dev.c:3606
__dev_queue_xmit+0x7f0/0x43e0 net/core/dev.c:4434
dev_queue_xmit include/linux/netdevice.h:3168 [inline]
tx+0xcc/0x190 drivers/block/aoe/aoenet.c:62
kthread+0x1e7/0x3c0 drivers/block/aoe/aoecmd.c:1237
kthread+0x2c1/0x3a0 kernel/kthread.c:389
ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
</TASK>

Allocated by task 10254:
kasan_save_stack+0x33/0x60 mm/kasan/common.c:47
kasan_save_track+0x14/0x30 mm/kasan/common.c:68
poison_kmalloc_redzone mm/kasan/common.c:377 [inline]
__kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:394
kmalloc_noprof include/linux/slab.h:901 [inline]
kzalloc_noprof include/linux/slab.h:1037 [inline]
alloc_tty_struct+0x98/0x8d0 drivers/tty/tty_io.c:3116
tty_init_dev.part.0+0x1e/0x660 drivers/tty/tty_io.c:1409
tty_init_dev include/linux/err.h:67 [inline]
tty_open_by_driver drivers/tty/tty_io.c:2082 [inline]
tty_open+0xac1/0xf80 drivers/tty/tty_io.c:2129
chrdev_open+0x237/0x6a0 fs/char_dev.c:414
do_dentry_open+0xf59/0x1ea0 fs/open.c:945
vfs_open+0x82/0x3f0 fs/open.c:1075
do_open fs/namei.c:3828 [inline]
path_openat+0x1e6a/0x2d60 fs/namei.c:3987
do_filp_open+0x20c/0x470 fs/namei.c:4014
do_sys_openat2+0x17a/0x1e0 fs/open.c:1402
do_sys_open fs/open.c:1417 [inline]
__do_compat_sys_openat fs/open.c:1479 [inline]
__se_compat_sys_openat fs/open.c:1477 [inline]
__ia32_compat_sys_openat+0x16e/0x210 fs/open.c:1477
do_syscall_32_irqs_on arch/x86/entry/common.c:165 [inline]
__do_fast_syscall_32+0x73/0x120 arch/x86/entry/common.c:386
do_fast_syscall_32+0x32/0x80 arch/x86/entry/common.c:411
entry_SYSENTER_compat_after_hwframe+0x84/0x8e

Freed by task 1327:
kasan_save_stack+0x33/0x60 mm/kasan/common.c:47
kasan_save_track+0x14/0x30 mm/kasan/common.c:68
kasan_save_free_info+0x3b/0x60 mm/kasan/generic.c:582
poison_slab_object mm/kasan/common.c:247 [inline]
__kasan_slab_free+0x51/0x70 mm/kasan/common.c:264
kasan_slab_free include/linux/kasan.h:233 [inline]
slab_free_hook mm/slub.c:2338 [inline]
slab_free mm/slub.c:4598 [inline]
kfree+0x14f/0x4b0 mm/slub.c:4746
process_one_work+0x958/0x1b30 kernel/workqueue.c:3229
process_scheduled_works kernel/workqueue.c:3310 [inline]
worker_thread+0x6c8/0xf00 kernel/workqueue.c:3391
kthread+0x2c1/0x3a0 kernel/kthread.c:389
ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

Last potentially related work creation:
kasan_save_stack+0x33/0x60 mm/kasan/common.c:47
__kasan_record_aux_stack+0xba/0xd0 mm/kasan/generic.c:544
insert_work+0x36/0x230 kernel/workqueue.c:2183
__queue_work+0x97e/0x1080 kernel/workqueue.c:2339
queue_work_on+0x11a/0x140 kernel/workqueue.c:2390
kref_put include/linux/kref.h:65 [inline]
tty_kref_put drivers/tty/tty_io.c:1566 [inline]
tty_kref_put drivers/tty/tty_io.c:1563 [inline]
release_tty+0x4de/0x5d0 drivers/tty/tty_io.c:1602
tty_release_struct+0xb7/0xe0 drivers/tty/tty_io.c:1701
tty_release+0xe25/0x1410 drivers/tty/tty_io.c:1861
__fput+0x3f8/0xb60 fs/file_table.c:450
task_work_run+0x14e/0x250 kernel/task_work.c:239
exit_task_work include/linux/task_work.h:43 [inline]
do_exit+0xadd/0x2d70 kernel/exit.c:938
do_group_exit+0xd3/0x2a0 kernel/exit.c:1087
get_signal+0x2576/0x2610 kernel/signal.c:3016
arch_do_signal_or_restart+0x90/0x7e0 arch/x86/kernel/signal.c:337
exit_to_user_mode_loop kernel/entry/common.c:111 [inline]
exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline]
__syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
syscall_exit_to_user_mode+0x150/0x2a0 kernel/entry/common.c:218
__do_fast_syscall_32+0x80/0x120 arch/x86/entry/common.c:389
do_fast_syscall_32+0x32/0x80 arch/x86/entry/common.c:411
entry_SYSENTER_compat_after_hwframe+0x84/0x8e

The buggy address belongs to the object at ffff888065d18000
which belongs to the cache kmalloc-cg-2k of size 2048
The buggy address is located 1528 bytes inside of
freed 2048-byte region [ffff888065d18000, ffff888065d18800)

The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x65d18
head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
memcg:ffff88804a2b0e01
flags: 0x4fff00000000040(head|node=1|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 04fff00000000040 ffff88801ac50140 ffffea0001377600 dead000000000002
raw: 0000000000000000 0000000000080008 00000001f5000000 ffff88804a2b0e01
head: 04fff00000000040 ffff88801ac50140 ffffea0001377600 dead000000000002
head: 0000000000000000 0000000000080008 00000001f5000000 ffff88804a2b0e01
head: 04fff00000000003 ffffea0001974601 ffffffffffffffff 0000000000000000
head: 0000000000000008 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 8425, tgid 8425 (syz-executor), ts 105968917948, free_ts 105959451209
set_page_owner include/linux/page_owner.h:32 [inline]
post_alloc_hook+0x2d1/0x350 mm/page_alloc.c:1556
prep_new_page mm/page_alloc.c:1564 [inline]
get_page_from_freelist+0xfce/0x2f80 mm/page_alloc.c:3474
__alloc_pages_noprof+0x223/0x25a0 mm/page_alloc.c:4751
alloc_pages_mpol_noprof+0x2c9/0x610 mm/mempolicy.c:2265
alloc_slab_page mm/slub.c:2408 [inline]
allocate_slab mm/slub.c:2574 [inline]
new_slab+0x2c9/0x410 mm/slub.c:2627
___slab_alloc+0xd1d/0x16e0 mm/slub.c:3815
__slab_alloc.constprop.0+0x56/0xb0 mm/slub.c:3905
__slab_alloc_node mm/slub.c:3980 [inline]
slab_alloc_node mm/slub.c:4141 [inline]
__do_kmalloc_node mm/slub.c:4282 [inline]
__kmalloc_node_track_caller_noprof+0x2ee/0x520 mm/slub.c:4302
kmemdup_noprof+0x29/0x60 mm/util.c:135
neigh_sysctl_register+0xb3/0x640 net/core/neighbour.c:3734
addrconf_sysctl_register+0xb9/0x1f0 net/ipv6/addrconf.c:7265
ipv6_add_dev+0xa1a/0x13e0 net/ipv6/addrconf.c:456
addrconf_notify+0x53e/0x19c0 net/ipv6/addrconf.c:3655
notifier_call_chain+0xb7/0x410 kernel/notifier.c:85
call_netdevice_notifiers_info+0xbe/0x140 net/core/dev.c:1996
call_netdevice_notifiers_extack net/core/dev.c:2034 [inline]
call_netdevice_notifiers net/core/dev.c:2048 [inline]
register_netdevice+0x1728/0x1e20 net/core/dev.c:10626
page last free pid 8425 tgid 8425 stack trace:
reset_page_owner include/linux/page_owner.h:25 [inline]
free_pages_prepare mm/page_alloc.c:1127 [inline]
free_unref_page+0x661/0x1080 mm/page_alloc.c:2657
__put_partials+0x14c/0x170 mm/slub.c:3142
qlink_free mm/kasan/quarantine.c:163 [inline]
qlist_free_all+0x4e/0x120 mm/kasan/quarantine.c:179
kasan_quarantine_reduce+0x195/0x1e0 mm/kasan/quarantine.c:286
__kasan_slab_alloc+0x69/0x90 mm/kasan/common.c:329
kasan_slab_alloc include/linux/kasan.h:250 [inline]
slab_post_alloc_hook mm/slub.c:4104 [inline]
slab_alloc_node mm/slub.c:4153 [inline]
kmem_cache_alloc_node_noprof+0x1ca/0x3b0 mm/slub.c:4205
__alloc_skb+0x2b3/0x380 net/core/skbuff.c:668
alloc_skb include/linux/skbuff.h:1323 [inline]
nlmsg_new include/net/netlink.h:1018 [inline]
netlink_ack+0x164/0xb20 net/netlink/af_netlink.c:2478
netlink_rcv_skb+0x327/0x410 net/netlink/af_netlink.c:2547
netlink_unicast_kernel net/netlink/af_netlink.c:1321 [inline]
netlink_unicast+0x53c/0x7f0 net/netlink/af_netlink.c:1347
netlink_sendmsg+0x8b8/0xd70 net/netlink/af_netlink.c:1891
sock_sendmsg_nosec net/socket.c:711 [inline]
__sock_sendmsg net/socket.c:726 [inline]
__sys_sendto+0x488/0x4f0 net/socket.c:2197
__do_compat_sys_socketcall+0x5e2/0x700 net/compat.c:475
do_syscall_32_irqs_on arch/x86/entry/common.c:165 [inline]
__do_fast_syscall_32+0x73/0x120 arch/x86/entry/common.c:386
do_fast_syscall_32+0x32/0x80 arch/x86/entry/common.c:411
entry_SYSENTER_compat_after_hwframe+0x84/0x8e

Memory state around the buggy address:
ffff888065d18480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff888065d18500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888065d18580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff888065d18600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff888065d18680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================

---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzkaller@googlegroups.com.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title

If you want to overwrite report's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)

If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report

If you want to undo deduplication, reply with:
#syz undup