Re: [syzbot] INFO: task hung in hci_power_on

From: syzbot
Date: Thu Jun 02 2022 - 04:41:13 EST

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Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
KASAN: use-after-free Read in hci_cmd_timeout

==================================================================
BUG: KASAN: use-after-free in hci_cmd_timeout+0x68/0x1e0 net/bluetooth/hci_core.c:1473
Read of size 8 at addr ffff88801a28d358 by task kworker/1:7/4369

CPU: 1 PID: 4369 Comm: kworker/1:7 Not tainted 5.18.0-syzkaller-10643-g9d004b2f4fea-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: events hci_cmd_timeout
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106
print_address_description+0x65/0x4b0 mm/kasan/report.c:313
print_report+0xf4/0x210 mm/kasan/report.c:429
kasan_report+0xfb/0x130 mm/kasan/report.c:491
hci_cmd_timeout+0x68/0x1e0 net/bluetooth/hci_core.c:1473
process_one_work+0x81c/0xd10 kernel/workqueue.c:2289
worker_thread+0xb14/0x1330 kernel/workqueue.c:2436
kthread+0x266/0x300 kernel/kthread.c:376
ret_from_fork+0x1f/0x30
</TASK>

Allocated by task 3611:
kasan_save_stack mm/kasan/common.c:38 [inline]
kasan_set_track mm/kasan/common.c:45 [inline]
set_alloc_info mm/kasan/common.c:436 [inline]
__kasan_slab_alloc+0xb2/0xe0 mm/kasan/common.c:469
kasan_slab_alloc include/linux/kasan.h:224 [inline]
slab_post_alloc_hook mm/slab.h:750 [inline]
slab_alloc_node mm/slub.c:3214 [inline]
slab_alloc mm/slub.c:3222 [inline]
__kmem_cache_alloc_lru mm/slub.c:3229 [inline]
kmem_cache_alloc+0x199/0x2f0 mm/slub.c:3239
skb_clone+0x1aa/0x370 net/core/skbuff.c:1515
hci_cmd_work+0xbc/0x360 net/bluetooth/hci_core.c:3854
process_one_work+0x81c/0xd10 kernel/workqueue.c:2289
worker_thread+0xb14/0x1330 kernel/workqueue.c:2436
kthread+0x266/0x300 kernel/kthread.c:376
ret_from_fork+0x1f/0x30

Freed by task 4083:
kasan_save_stack mm/kasan/common.c:38 [inline]
kasan_set_track+0x4c/0x70 mm/kasan/common.c:45
kasan_set_free_info+0x1f/0x40 mm/kasan/generic.c:370
____kasan_slab_free+0xd8/0x110 mm/kasan/common.c:366
kasan_slab_free include/linux/kasan.h:200 [inline]
slab_free_hook mm/slub.c:1727 [inline]
slab_free_freelist_hook+0x12e/0x1a0 mm/slub.c:1753
slab_free mm/slub.c:3507 [inline]
kmem_cache_free+0xc7/0x270 mm/slub.c:3524
kfree_skb include/linux/skbuff.h:1375 [inline]
hci_dev_open_sync+0x107e/0x1340 net/bluetooth/hci_sync.c:4052
hci_dev_do_open net/bluetooth/hci_core.c:482 [inline]
hci_power_on+0x180/0x650 net/bluetooth/hci_core.c:963
process_one_work+0x81c/0xd10 kernel/workqueue.c:2289
worker_thread+0xb14/0x1330 kernel/workqueue.c:2436
kthread+0x266/0x300 kernel/kthread.c:376
ret_from_fork+0x1f/0x30

The buggy address belongs to the object at ffff88801a28d280
which belongs to the cache skbuff_head_cache of size 240
The buggy address is located 216 bytes inside of
240-byte region [ffff88801a28d280, ffff88801a28d370)

The buggy address belongs to the physical page:
page:ffffea000068a340 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1a28d
flags: 0xfff00000000200(slab|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000200 ffffea0000682640 dead000000000005 ffff888140a57500
raw: 0000000000000000 00000000000c000c 00000001ffffffff 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 0x112cc0(GFP_USER|__GFP_NOWARN|__GFP_NORETRY), pid 51, tgid 51 (kworker/u4:2), ts 58236376345, free_ts 58226454515
prep_new_page mm/page_alloc.c:2456 [inline]
get_page_from_freelist+0x72b/0x7a0 mm/page_alloc.c:4198
__alloc_pages+0x259/0x560 mm/page_alloc.c:5426
alloc_slab_page+0x70/0xf0 mm/slub.c:1797
allocate_slab+0x5e/0x520 mm/slub.c:1942
new_slab mm/slub.c:2002 [inline]
___slab_alloc+0x41e/0xcd0 mm/slub.c:3002
__slab_alloc mm/slub.c:3089 [inline]
slab_alloc_node mm/slub.c:3180 [inline]
kmem_cache_alloc_node+0x287/0x340 mm/slub.c:3264
__alloc_skb+0xd5/0x660 net/core/skbuff.c:414
alloc_skb include/linux/skbuff.h:1426 [inline]
nlmsg_new include/net/netlink.h:953 [inline]
inet6_netconf_notify_devconf+0xf8/0x1b0 net/ipv6/addrconf.c:581
__addrconf_sysctl_unregister net/ipv6/addrconf.c:7112 [inline]
addrconf_sysctl_unregister net/ipv6/addrconf.c:7136 [inline]
addrconf_ifdown+0x18a2/0x1bc0 net/ipv6/addrconf.c:3903
addrconf_notify+0x403/0xf80
notifier_call_chain kernel/notifier.c:84 [inline]
raw_notifier_call_chain+0xe7/0x170 kernel/notifier.c:392
call_netdevice_notifiers_info net/core/dev.c:1943 [inline]
call_netdevice_notifiers_extack net/core/dev.c:1981 [inline]
call_netdevice_notifiers net/core/dev.c:1995 [inline]
unregister_netdevice_many+0xeee/0x1950 net/core/dev.c:10834
default_device_exit_batch+0x660/0x6d0 net/core/dev.c:11328
ops_exit_list net/core/net_namespace.c:167 [inline]
cleanup_net+0x80c/0xc50 net/core/net_namespace.c:594
process_one_work+0x81c/0xd10 kernel/workqueue.c:2289
worker_thread+0xb14/0x1330 kernel/workqueue.c:2436
page last free stack trace:
reset_page_owner include/linux/page_owner.h:24 [inline]
free_pages_prepare mm/page_alloc.c:1371 [inline]
free_pcp_prepare+0x812/0x900 mm/page_alloc.c:1421
free_unref_page_prepare mm/page_alloc.c:3343 [inline]
free_unref_page+0x7d/0x390 mm/page_alloc.c:3438
mm_free_pgd kernel/fork.c:737 [inline]
__mmdrop+0xae/0x3f0 kernel/fork.c:788
mmdrop include/linux/sched/mm.h:50 [inline]
mmdrop_sched include/linux/sched/mm.h:78 [inline]
finish_task_switch+0x221/0x610 kernel/sched/core.c:5021
context_switch kernel/sched/core.c:5119 [inline]
__schedule+0x95f/0xec0 kernel/sched/core.c:6431
schedule+0xeb/0x1b0 kernel/sched/core.c:6503
do_wait+0x7a4/0x9d0 kernel/exit.c:1537
kernel_wait4+0x29c/0x3e0 kernel/exit.c:1681
__do_sys_wait4 kernel/exit.c:1709 [inline]
__se_sys_wait4 kernel/exit.c:1705 [inline]
__x64_sys_wait4+0x130/0x1e0 kernel/exit.c:1705
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x46/0xb0

Memory state around the buggy address:
ffff88801a28d200: fb fb fb fb fb fb fc fc fc fc fc fc fc fc fc fc
ffff88801a28d280: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88801a28d300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fc fc
^
ffff88801a28d380: fc fc fc fc fc fc fc fc fa fb fb fb fb fb fb fb
ffff88801a28d400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================

Tested on:

commit: 9d004b2f Merge tag 'cxl-for-5.19' of git://git.kernel...
git tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
console output: https://syzkaller.appspot.com/x/log.txt?x=11b24b8ff00000
kernel config: https://syzkaller.appspot.com/x/.config?x=3c367f7c347f1679
dashboard link: https://syzkaller.appspot.com/bug?extid=8d7b9ced2a99394b0a50
compiler: Debian clang version 13.0.1-++20220126092033+75e33f71c2da-1~exp1~20220126212112.63, GNU ld (GNU Binutils for Debian) 2.35.2
patch: https://syzkaller.appspot.com/x/patch.diff?x=11b72613f00000

Next message: David Hildenbrand: "Re: [PATCH 2/3] mm/swapfile: avoid confusing swap cache statistics"
Previous message: Maxime Ripard: "Re: [PATCH] drm: bridge: adv7511: Add check for mipi_dsi_driver_register"
In reply to: syzbot: "Re: [syzbot] INFO: task hung in hci_power_on"
Next in thread: syzbot: "Re: [syzbot] INFO: task hung in hci_power_on"
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