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

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: d67978318827 Merge tag 'x86_cpu_for_v6.11_rc1' of git://gi..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=17409785980000
kernel config: https://syzkaller.appspot.com/x/.config?x=c27e4a218c759511
dashboard link: https://syzkaller.appspot.com/bug?extid=430996d5d5a2ca4b7d07
compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/4c2b69e5e6e3/disk-d6797831.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/4723bc702146/vmlinux-d6797831.xz
kernel image: https://storage.googleapis.com/syzbot-assets/ad0798383ba0/bzImage-d6797831.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+430996...@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: slab-use-after-free in instrument_atomic_read include/linux/instrumented.h:68 [inline]
BUG: KASAN: slab-use-after-free in atomic_read include/linux/atomic/atomic-instrumented.h:32 [inline]
BUG: KASAN: slab-use-after-free in refcount_read include/linux/refcount.h:136 [inline]
BUG: KASAN: slab-use-after-free in skb_unref include/linux/skbuff.h:1222 [inline]
BUG: KASAN: slab-use-after-free in __kfree_skb_reason net/core/skbuff.c:1195 [inline]
BUG: KASAN: slab-use-after-free in kfree_skb_reason+0x36/0x210 net/core/skbuff.c:1222
Read of size 4 at addr ffff888067541c24 by task kworker/u9:2/5086

CPU: 0 PID: 5086 Comm: kworker/u9:2 Not tainted 6.10.0-syzkaller-01155-gd67978318827 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/07/2024
Workqueue: hci0 hci_cmd_work
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:114
print_address_description mm/kasan/report.c:377 [inline]
print_report+0xc3/0x620 mm/kasan/report.c:488
kasan_report+0xd9/0x110 mm/kasan/report.c:601
check_region_inline mm/kasan/generic.c:183 [inline]
kasan_check_range+0xef/0x1a0 mm/kasan/generic.c:189
instrument_atomic_read include/linux/instrumented.h:68 [inline]
atomic_read include/linux/atomic/atomic-instrumented.h:32 [inline]
refcount_read include/linux/refcount.h:136 [inline]
skb_unref include/linux/skbuff.h:1222 [inline]
__kfree_skb_reason net/core/skbuff.c:1195 [inline]
kfree_skb_reason+0x36/0x210 net/core/skbuff.c:1222
kfree_skb include/linux/skbuff.h:1257 [inline]
hci_send_cmd_sync net/bluetooth/hci_core.c:4090 [inline]
hci_cmd_work+0x63e/0x710 net/bluetooth/hci_core.c:4111
process_one_work+0x9c5/0x1b40 kernel/workqueue.c:3231
process_scheduled_works kernel/workqueue.c:3312 [inline]
worker_thread+0x6c8/0xf20 kernel/workqueue.c:3390
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 5086:
kasan_save_stack+0x33/0x60 mm/kasan/common.c:47
kasan_save_track+0x14/0x30 mm/kasan/common.c:68
unpoison_slab_object mm/kasan/common.c:312 [inline]
__kasan_slab_alloc+0x89/0x90 mm/kasan/common.c:338
kasan_slab_alloc include/linux/kasan.h:201 [inline]
slab_post_alloc_hook mm/slub.c:3940 [inline]
slab_alloc_node mm/slub.c:4002 [inline]
kmem_cache_alloc_noprof+0x121/0x2f0 mm/slub.c:4009
skb_clone+0x190/0x3f0 net/core/skbuff.c:2052
hci_send_cmd_sync net/bluetooth/hci_core.c:4091 [inline]
hci_cmd_work+0x66a/0x710 net/bluetooth/hci_core.c:4111
process_one_work+0x9c5/0x1b40 kernel/workqueue.c:3231
process_scheduled_works kernel/workqueue.c:3312 [inline]
worker_thread+0x6c8/0xf20 kernel/workqueue.c:3390
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

Freed by task 12745:
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:579
poison_slab_object+0xf7/0x160 mm/kasan/common.c:240
__kasan_slab_free+0x32/0x50 mm/kasan/common.c:256
kasan_slab_free include/linux/kasan.h:184 [inline]
slab_free_hook mm/slub.c:2196 [inline]
slab_free mm/slub.c:4438 [inline]
kmem_cache_free+0x12f/0x3a0 mm/slub.c:4513
kfree_skbmem+0x10e/0x200 net/core/skbuff.c:1131
__kfree_skb net/core/skbuff.c:1188 [inline]
kfree_skb_reason+0x138/0x210 net/core/skbuff.c:1223
kfree_skb include/linux/skbuff.h:1257 [inline]
__hci_req_sync+0x61d/0x980 net/bluetooth/hci_request.c:184
hci_req_sync+0x97/0xd0 net/bluetooth/hci_request.c:206
hci_inquiry+0x3ea/0x950 net/bluetooth/hci_core.c:383
hci_sock_ioctl+0x2bb/0x880 net/bluetooth/hci_sock.c:1153
sock_do_ioctl+0x116/0x280 net/socket.c:1222
sock_ioctl+0x22e/0x6c0 net/socket.c:1341
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:907 [inline]
__se_sys_ioctl fs/ioctl.c:893 [inline]
__x64_sys_ioctl+0x193/0x220 fs/ioctl.c:893
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff888067541b40
which belongs to the cache skbuff_head_cache of size 240
The buggy address is located 228 bytes inside of
freed 240-byte region [ffff888067541b40, ffff888067541c30)

The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x67541
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
page_type: 0xffffefff(slab)
raw: 00fff00000000000 ffff88801929a780 ffffea0001fe0ac0 dead000000000004
raw: 0000000000000000 00000000000c000c 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 0x152820(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_HARDWALL), pid 11673, tgid 11673 (syz-executor), ts 518110047408, free_ts 516558045102
set_page_owner include/linux/page_owner.h:32 [inline]
post_alloc_hook+0x2d1/0x350 mm/page_alloc.c:1473
prep_new_page mm/page_alloc.c:1481 [inline]
get_page_from_freelist+0x1353/0x2e50 mm/page_alloc.c:3425
__alloc_pages_noprof+0x22b/0x2460 mm/page_alloc.c:4683
__alloc_pages_node_noprof include/linux/gfp.h:269 [inline]
alloc_pages_node_noprof include/linux/gfp.h:296 [inline]
alloc_slab_page+0x56/0x110 mm/slub.c:2265
allocate_slab mm/slub.c:2428 [inline]
new_slab+0x84/0x260 mm/slub.c:2481
___slab_alloc+0xdac/0x1870 mm/slub.c:3667
__slab_alloc.constprop.0+0x56/0xb0 mm/slub.c:3757
__slab_alloc_node mm/slub.c:3810 [inline]
slab_alloc_node mm/slub.c:3990 [inline]
kmem_cache_alloc_noprof+0x2a7/0x2f0 mm/slub.c:4009
skb_clone+0x190/0x3f0 net/core/skbuff.c:2052
__netlink_deliver_tap_skb net/netlink/af_netlink.c:300 [inline]
__netlink_deliver_tap net/netlink/af_netlink.c:325 [inline]
netlink_deliver_tap+0xab3/0xd90 net/netlink/af_netlink.c:338
netlink_deliver_tap_kernel net/netlink/af_netlink.c:347 [inline]
netlink_unicast_kernel net/netlink/af_netlink.c:1334 [inline]
netlink_unicast+0x604/0x820 net/netlink/af_netlink.c:1361
netlink_sendmsg+0x8b8/0xd70 net/netlink/af_netlink.c:1905
sock_sendmsg_nosec net/socket.c:730 [inline]
__sock_sendmsg net/socket.c:745 [inline]
__sys_sendto+0x47f/0x4e0 net/socket.c:2204
__do_sys_sendto net/socket.c:2216 [inline]
__se_sys_sendto net/socket.c:2212 [inline]
__x64_sys_sendto+0xe0/0x1c0 net/socket.c:2212
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
page last free pid 12063 tgid 12059 stack trace:
reset_page_owner include/linux/page_owner.h:25 [inline]
free_pages_prepare mm/page_alloc.c:1093 [inline]
free_unref_folios+0x991/0x1310 mm/page_alloc.c:2637
folios_put_refs+0x487/0x6d0 mm/swap.c:1024
free_pages_and_swap_cache+0x45f/0x510 mm/swap_state.c:332
__tlb_batch_free_encoded_pages+0xf9/0x290 mm/mmu_gather.c:136
tlb_batch_pages_flush mm/mmu_gather.c:149 [inline]
tlb_flush_mmu_free mm/mmu_gather.c:366 [inline]
tlb_flush_mmu mm/mmu_gather.c:373 [inline]
tlb_finish_mmu+0x168/0x7b0 mm/mmu_gather.c:465
exit_mmap+0x3d1/0xb20 mm/mmap.c:3354
__mmput+0x12a/0x480 kernel/fork.c:1340
mmput+0x62/0x70 kernel/fork.c:1362
exit_mm kernel/exit.c:567 [inline]
do_exit+0x9b7/0x2ba0 kernel/exit.c:863
do_group_exit+0xd3/0x2a0 kernel/exit.c:1025
get_signal+0x25fb/0x2770 kernel/signal.c:2917
arch_do_signal_or_restart+0x90/0x7e0 arch/x86/kernel/signal.c:310
exit_to_user_mode_loop kernel/entry/common.c:111 [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+0x150/0x2a0 kernel/entry/common.c:218
do_syscall_64+0xda/0x250 arch/x86/entry/common.c:89
entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
ffff888067541b00: fc fc fc fc fc fc fc fc fa fb fb fb fb fb fb fb
ffff888067541b80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888067541c00: fb fb fb fb fb fb fc fc fc fc fc fc fc fc fc fc
^
ffff888067541c80: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff888067541d00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fc fc
==================================================================


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[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.