[syzbot] [bluetooth?] KASAN: slab-use-after-free Read in hci_sent_cmd_data

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 0d8395707651 Merge tag 'soc-fixes-7.2-2' of git://git.kern..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=117f8132580000
kernel config: https://syzkaller.appspot.com/x/.config?x=30772517ee66ef58
dashboard link: https://syzkaller.appspot.com/bug?extid=5456069b73569089f7e8
compiler: gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/6cacf03defdd/disk-0d839570.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/c376f093c1c8/vmlinux-0d839570.xz
kernel image: https://storage.googleapis.com/syzbot-assets/396434a79317/bzImage-0d839570.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+545606...@syzkaller.appspotmail.com

Bluetooth: hci5: unexpected cc 0x0c03 length: 249 > 1
==================================================================
BUG: KASAN: slab-use-after-free in hci_cmd_data net/bluetooth/hci_core.c:3119 [inline]
BUG: KASAN: slab-use-after-free in hci_sent_cmd_data net/bluetooth/hci_core.c:3134 [inline]
BUG: KASAN: slab-use-after-free in hci_sent_cmd_data+0x2c2/0x2d0 net/bluetooth/hci_core.c:3126
Read of size 2 at addr ffff8880657f8d08 by task kworker/u9:3/18543

CPU: 0 UID: 0 PID: 18543 Comm: kworker/u9:3 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
Workqueue: hci5 hci_rx_work
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
print_address_description mm/kasan/report.c:378 [inline]
print_report+0x13d/0x4b0 mm/kasan/report.c:482
kasan_report+0xdf/0x1c0 mm/kasan/report.c:595
hci_cmd_data net/bluetooth/hci_core.c:3119 [inline]
hci_sent_cmd_data net/bluetooth/hci_core.c:3134 [inline]
hci_sent_cmd_data+0x2c2/0x2d0 net/bluetooth/hci_core.c:3126
hci_req_cmd_complete+0x4c/0x7f0 net/bluetooth/hci_core.c:3934
hci_cmd_complete_evt+0x433/0xa20 net/bluetooth/hci_event.c:4297
hci_event_func net/bluetooth/hci_event.c:7781 [inline]
hci_event_packet+0x51c/0xcd0 net/bluetooth/hci_event.c:7835
hci_rx_work+0x451/0xfc0 net/bluetooth/hci_core.c:4039
process_one_work+0xa23/0x1940 kernel/workqueue.c:3322
process_scheduled_works kernel/workqueue.c:3405 [inline]
worker_thread+0x5ef/0xe50 kernel/workqueue.c:3486
kthread+0x370/0x450 kernel/kthread.c:436
ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
</TASK>

Allocated by task 18491:
kasan_save_stack+0x30/0x50 mm/kasan/common.c:57
kasan_save_track+0x14/0x30 mm/kasan/common.c:78
unpoison_slab_object mm/kasan/common.c:340 [inline]
__kasan_slab_alloc+0x89/0x90 mm/kasan/common.c:366
kasan_slab_alloc include/linux/kasan.h:253 [inline]
slab_post_alloc_hook mm/slub.c:4584 [inline]
slab_alloc_node mm/slub.c:4917 [inline]
kmem_cache_alloc_node_noprof+0x27d/0x6b0 mm/slub.c:4989
kmalloc_reserve+0x148/0x350 net/core/skbuff.c:615
__alloc_skb+0x185/0x710 net/core/skbuff.c:715
alloc_skb include/linux/skbuff.h:1384 [inline]
bt_skb_alloc include/net/bluetooth/bluetooth.h:517 [inline]
hci_cmd_sync_alloc+0x39/0x3d0 net/bluetooth/hci_sync.c:58
hci_cmd_sync_add net/bluetooth/hci_sync.c:99 [inline]
__hci_cmd_sync_sk+0x151/0xcf0 net/bluetooth/hci_sync.c:168
__hci_cmd_sync_status_sk+0x48/0x190 net/bluetooth/hci_sync.c:263
__hci_cmd_sync_status net/bluetooth/hci_sync.c:287 [inline]
hci_reset_sync net/bluetooth/hci_sync.c:3787 [inline]
hci_init1_sync net/bluetooth/hci_sync.c:3873 [inline]
hci_init_sync net/bluetooth/hci_sync.c:5065 [inline]
hci_dev_init_sync net/bluetooth/hci_sync.c:5257 [inline]
hci_dev_open_sync+0xce9/0x25c0 net/bluetooth/hci_sync.c:5335
hci_dev_do_open+0x2a/0xb0 net/bluetooth/hci_core.c:428
hci_power_on+0x131/0x630 net/bluetooth/hci_core.c:920
process_one_work+0xa23/0x1940 kernel/workqueue.c:3322
process_scheduled_works kernel/workqueue.c:3405 [inline]
worker_thread+0x5ef/0xe50 kernel/workqueue.c:3486
kthread+0x370/0x450 kernel/kthread.c:436
ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

The buggy address belongs to the object at ffff8880657f8d00
which belongs to the cache skbuff_small_head of size 704
The buggy address is located 8 bytes inside of
freed 704-byte region [ffff8880657f8d00, ffff8880657f8fc0)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x657f8
head: order:2 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000040 ffff888140487b40 dead000000000100 dead000000000122
raw: 0000000000000000 0000000800130013 00000000f5000000 0000000000000000
head: 00fff00000000040 ffff888140487b40 dead000000000100 dead000000000122
head: 0000000000000000 0000000800130013 00000000f5000000 0000000000000000
head: 00fff00000000002 ffffffffffffff01 00000000ffffffff 00000000ffffffff
head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000004
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 2, migratetype Unmovable, gfp_mask 0xd2820(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 18482, tgid 18482 (syz-executor), ts 853476511834, free_ts 851474883257
set_page_owner include/linux/page_owner.h:32 [inline]
post_alloc_hook+0xfd/0x120 mm/page_alloc.c:1859
prep_new_page mm/page_alloc.c:1867 [inline]
get_page_from_freelist+0xf48/0x3530 mm/page_alloc.c:3946
__alloc_frozen_pages_noprof+0x299/0x2dc0 mm/page_alloc.c:5304
alloc_slab_page mm/slub.c:3266 [inline]
allocate_slab mm/slub.c:3380 [inline]
new_slab+0xa2/0x640 mm/slub.c:3426
refill_objects+0xe3/0x410 mm/slub.c:7310
refill_sheaf mm/slub.c:2804 [inline]
__pcs_replace_empty_main+0x376/0x680 mm/slub.c:4675
alloc_from_pcs mm/slub.c:4773 [inline]
slab_alloc_node mm/slub.c:4905 [inline]
kmem_cache_alloc_node_noprof+0x52c/0x6b0 mm/slub.c:4989
kmalloc_reserve+0x148/0x350 net/core/skbuff.c:615
__alloc_skb+0x185/0x710 net/core/skbuff.c:715
skb_copy+0x1ca/0x3a0 net/core/skbuff.c:2191
mac80211_hwsim_tx_frame_no_nl+0xc7f/0x1830 drivers/net/wireless/virtual/mac80211_hwsim_main.c:2020
mac80211_hwsim_tx_frame+0x1b7/0x250 drivers/net/wireless/virtual/mac80211_hwsim_main.c:2417
__mac80211_hwsim_beacon_tx drivers/net/wireless/virtual/mac80211_hwsim_main.c:2430 [inline]
mac80211_hwsim_beacon_tx+0x56c/0xa00 drivers/net/wireless/virtual/mac80211_hwsim_main.c:2493
__iterate_interfaces+0x2e6/0x650 net/mac80211/util.c:775
ieee80211_iterate_active_interfaces_atomic+0x71/0x1b0 net/mac80211/util.c:811
mac80211_hwsim_beacon+0xe5/0x2a0 drivers/net/wireless/virtual/mac80211_hwsim_main.c:2525
page last free pid 190 tgid 190 stack trace:
reset_page_owner include/linux/page_owner.h:25 [inline]
__free_pages_prepare mm/page_alloc.c:1406 [inline]
__free_frozen_pages+0x79f/0x1090 mm/page_alloc.c:2950
kasan_depopulate_vmalloc_pte+0x5d/0x80 mm/kasan/shadow.c:484
apply_to_pte_range mm/memory.c:3338 [inline]
apply_to_pmd_range mm/memory.c:3382 [inline]
apply_to_pud_range mm/memory.c:3418 [inline]
apply_to_p4d_range mm/memory.c:3454 [inline]
__apply_to_page_range+0xb1d/0x1520 mm/memory.c:3490
__kasan_release_vmalloc+0xd7/0xe0 mm/kasan/shadow.c:602
kasan_release_vmalloc include/linux/kasan.h:593 [inline]
kasan_release_vmalloc_node mm/vmalloc.c:2284 [inline]
purge_vmap_node+0x210/0xb40 mm/vmalloc.c:2306
__purge_vmap_area_lazy+0x90a/0xc00 mm/vmalloc.c:2396
drain_vmap_area_work+0x27/0x40 mm/vmalloc.c:2430
process_one_work+0xa23/0x1940 kernel/workqueue.c:3322
process_scheduled_works kernel/workqueue.c:3405 [inline]
worker_thread+0x5ef/0xe50 kernel/workqueue.c:3486
kthread+0x370/0x450 kernel/kthread.c:436
ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Memory state around the buggy address:
ffff8880657f8c00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8880657f8c80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff8880657f8d00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff8880657f8d80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8880657f8e00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
Bluetooth: hci5: unexpected event for opcode 0x0c03
Bluetooth: hci5: unexpected cc 0x0c03 length: 249 > 1
Bluetooth: hci7: command 0x0406 tx timeout


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