[syzbot] [bluetooth?] KASAN: slab-use-after-free Write in sk_skb_reason_drop

[syzbot <syzbot+0fd4135ebd713ba973dc@syzkaller.appspotmail.com>]

Hello,

syzbot found the following issue on:

HEAD commit:    da4373fbcf00 Merge tag 'thermal-6.12-rc7' of git://git.ker..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=10679e30580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=20d60fe605153ebe
dashboard link: https://syzkaller.appspot.com/bug?extid=0fd4135ebd713ba973dc
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/c048ef220197/disk-da4373fb.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/72888da151fb/vmlinux-da4373fb.xz
kernel image: https://storage.googleapis.com/syzbot-assets/5b8d553e33fe/bzImage-da4373fb.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+0fd4135ebd713ba973dc@syzkaller.appspotmail.com

Bluetooth: Unexpected start frame (len 30)
Bluetooth: hci0: ACL packet for unknown connection handle 201
Bluetooth: Unexpected start frame (len 30)
Bluetooth: Unexpected start frame (len 30)
==================================================================
BUG: KASAN: slab-use-after-free in instrument_atomic_read_write include/linux/instrumented.h:96 [inline]
BUG: KASAN: slab-use-after-free in atomic_fetch_sub_release include/linux/atomic/atomic-instrumented.h:400 [inline]
BUG: KASAN: slab-use-after-free in __refcount_sub_and_test include/linux/refcount.h:264 [inline]
BUG: KASAN: slab-use-after-free in __refcount_dec_and_test include/linux/refcount.h:307 [inline]
BUG: KASAN: slab-use-after-free in refcount_dec_and_test include/linux/refcount.h:325 [inline]
BUG: KASAN: slab-use-after-free in skb_unref include/linux/skbuff.h:1232 [inline]
BUG: KASAN: slab-use-after-free in __sk_skb_reason_drop net/core/skbuff.c:1213 [inline]
BUG: KASAN: slab-use-after-free in sk_skb_reason_drop+0x3d/0x1a0 net/core/skbuff.c:1241
Write of size 4 at addr ffff888061a885e4 by task kworker/u9:3/5829

CPU: 0 UID: 0 PID: 5829 Comm: kworker/u9:3 Not tainted 6.12.0-rc6-syzkaller-00272-gda4373fbcf00 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/30/2024
Workqueue: hci1 hci_rx_work
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: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_write include/linux/instrumented.h:96 [inline]
 atomic_fetch_sub_release include/linux/atomic/atomic-instrumented.h:400 [inline]
 __refcount_sub_and_test include/linux/refcount.h:264 [inline]
 __refcount_dec_and_test include/linux/refcount.h:307 [inline]
 refcount_dec_and_test include/linux/refcount.h:325 [inline]
 skb_unref include/linux/skbuff.h:1232 [inline]
 __sk_skb_reason_drop net/core/skbuff.c:1213 [inline]
 sk_skb_reason_drop+0x3d/0x1a0 net/core/skbuff.c:1241
 kfree_skb_reason include/linux/skbuff.h:1262 [inline]
 kfree_skb include/linux/skbuff.h:1271 [inline]
 l2cap_recv_reset net/bluetooth/l2cap_core.c:7465 [inline]
 l2cap_recv_acldata+0x129/0xb70 net/bluetooth/l2cap_core.c:7489
 hci_acldata_packet net/bluetooth/hci_core.c:3799 [inline]
 hci_rx_work+0xb1c/0x16c0 net/bluetooth/hci_core.c:4036
 process_one_work+0x9c5/0x1ba0 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
 </TASK>

Allocated by task 5829:
 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:319 [inline]
 __kasan_slab_alloc+0x89/0x90 mm/kasan/common.c:345
 kasan_slab_alloc include/linux/kasan.h:247 [inline]
 slab_post_alloc_hook mm/slub.c:4085 [inline]
 slab_alloc_node mm/slub.c:4134 [inline]
 kmem_cache_alloc_node_noprof+0x153/0x310 mm/slub.c:4186
 __alloc_skb+0x2b1/0x380 net/core/skbuff.c:668
 alloc_skb include/linux/skbuff.h:1322 [inline]
 bt_skb_alloc include/net/bluetooth/bluetooth.h:494 [inline]
 l2cap_recv_frag+0x13d/0x2b0 net/bluetooth/l2cap_core.c:7412
 l2cap_recv_acldata+0x2a1/0xb70 net/bluetooth/l2cap_core.c:7520
 hci_acldata_packet net/bluetooth/hci_core.c:3799 [inline]
 hci_rx_work+0xb1c/0x16c0 net/bluetooth/hci_core.c:4036
 process_one_work+0x9c5/0x1ba0 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

Freed by task 10810:
 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 mm/kasan/common.c:247 [inline]
 __kasan_slab_free+0x51/0x70 mm/kasan/common.c:264
 kasan_slab_free include/linux/kasan.h:230 [inline]
 slab_free_hook mm/slub.c:2342 [inline]
 slab_free mm/slub.c:4579 [inline]
 kmem_cache_free+0x152/0x4b0 mm/slub.c:4681
 kfree_skbmem+0x1a4/0x1f0 net/core/skbuff.c:1148
 __kfree_skb net/core/skbuff.c:1205 [inline]
 sk_skb_reason_drop+0x136/0x1a0 net/core/skbuff.c:1242
 kfree_skb_reason include/linux/skbuff.h:1262 [inline]
 kfree_skb include/linux/skbuff.h:1271 [inline]
 l2cap_conn_del+0xa5/0x730 net/bluetooth/l2cap_core.c:1760
 l2cap_connect_cfm+0x9e6/0xf80 net/bluetooth/l2cap_core.c:7233
 hci_connect_cfm include/net/bluetooth/hci_core.h:1960 [inline]
 hci_conn_failed+0x1c3/0x340 net/bluetooth/hci_conn.c:1265
 hci_abort_conn_sync+0x75a/0xb50 net/bluetooth/hci_sync.c:5596
 hci_disconnect_all_sync.constprop.0+0x104/0x3c0 net/bluetooth/hci_sync.c:5619
 hci_suspend_sync+0x772/0xab0 net/bluetooth/hci_sync.c:6096
 hci_suspend_dev+0x30a/0x510 net/bluetooth/hci_core.c:2832
 hci_suspend_notifier+0x28d/0x2f0 net/bluetooth/hci_core.c:2412
 notifier_call_chain+0xb9/0x410 kernel/notifier.c:93
 notifier_call_chain_robust kernel/notifier.c:128 [inline]
 blocking_notifier_call_chain_robust kernel/notifier.c:353 [inline]
 blocking_notifier_call_chain_robust+0xc9/0x170 kernel/notifier.c:341
 pm_notifier_call_chain_robust+0x27/0x60 kernel/power/main.c:102
 snapshot_open+0x189/0x2b0 kernel/power/user.c:77
 misc_open+0x35a/0x420 drivers/char/misc.c:165
 chrdev_open+0x237/0x6a0 fs/char_dev.c:414
 do_dentry_open+0x6ca/0x1530 fs/open.c:958
 vfs_open+0x82/0x3f0 fs/open.c:1088
 do_open fs/namei.c:3774 [inline]
 path_openat+0x1e6a/0x2d60 fs/namei.c:3933
 do_filp_open+0x1dc/0x430 fs/namei.c:3960
 do_sys_openat2+0x17a/0x1e0 fs/open.c:1415
 do_sys_open fs/open.c:1430 [inline]
 __do_sys_openat fs/open.c:1446 [inline]
 __se_sys_openat fs/open.c:1441 [inline]
 __x64_sys_openat+0x175/0x210 fs/open.c:1441
 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 ffff888061a88500
 which belongs to the cache skbuff_head_cache of size 240
The buggy address is located 228 bytes inside of
 freed 240-byte region [ffff888061a88500, ffff888061a885f0)

The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x61a88
memcg:ffff888032bbc881
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000000 ffff88801ea91780 dead000000000100 dead000000000122
raw: 0000000000000000 00000000000c000c 00000001f5000000 ffff888032bbc881
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x52820(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP), pid 8566, tgid 8562 (syz.0.484), ts 331157518755, free_ts 327767117142
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x2d1/0x350 mm/page_alloc.c:1537
 prep_new_page mm/page_alloc.c:1545 [inline]
 get_page_from_freelist+0xf7d/0x2d10 mm/page_alloc.c:3457
 __alloc_pages_noprof+0x223/0x25a0 mm/page_alloc.c:4733
 alloc_pages_mpol_noprof+0x2c9/0x610 mm/mempolicy.c:2265
 alloc_slab_page mm/slub.c:2412 [inline]
 allocate_slab mm/slub.c:2578 [inline]
 new_slab+0x2c9/0x410 mm/slub.c:2631
 ___slab_alloc+0xdac/0x1880 mm/slub.c:3818
 __slab_alloc.constprop.0+0x56/0xb0 mm/slub.c:3908
 __slab_alloc_node mm/slub.c:3961 [inline]
 slab_alloc_node mm/slub.c:4122 [inline]
 kmem_cache_alloc_node_noprof+0xed/0x310 mm/slub.c:4186
 __alloc_skb+0x2b1/0x380 net/core/skbuff.c:668
 skb_copy+0x1c9/0x3a0 net/core/skbuff.c:2159
 mac80211_hwsim_tx_frame_no_nl.isra.0+0xb7f/0x12f0 drivers/net/wireless/virtual/mac80211_hwsim.c:1866
 mac80211_hwsim_tx_frame+0x1eb/0x2a0 drivers/net/wireless/virtual/mac80211_hwsim.c:2215
 __mac80211_hwsim_beacon_tx drivers/net/wireless/virtual/mac80211_hwsim.c:2232 [inline]
 mac80211_hwsim_beacon_tx+0x592/0xa00 drivers/net/wireless/virtual/mac80211_hwsim.c:2315
 __iterate_interfaces+0x2d0/0x5d0 net/mac80211/util.c:774
 ieee80211_iterate_active_interfaces_atomic+0x71/0x1b0 net/mac80211/util.c:810
 mac80211_hwsim_beacon+0x105/0x200 drivers/net/wireless/virtual/mac80211_hwsim.c:2345
page last free pid 5200 tgid 5200 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1108 [inline]
 free_unref_page+0x5f4/0xdc0 mm/page_alloc.c:2638
 __put_partials+0x14c/0x170 mm/slub.c:3145
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x4e/0x120 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x192/0x1e0 mm/kasan/quarantine.c:286
 __kasan_slab_alloc+0x69/0x90 mm/kasan/common.c:329
 kasan_slab_alloc include/linux/kasan.h:247 [inline]
 slab_post_alloc_hook mm/slub.c:4085 [inline]
 slab_alloc_node mm/slub.c:4134 [inline]
 kmem_cache_alloc_noprof+0x121/0x2f0 mm/slub.c:4141
 getname_flags.part.0+0x4c/0x550 fs/namei.c:139
 getname_flags+0x93/0xf0 include/linux/audit.h:322
 vfs_fstatat+0x86/0x160 fs/stat.c:340
 __do_sys_newfstatat+0xa2/0x130 fs/stat.c:505
 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

Memory state around the buggy address:
 ffff888061a88480: fb fb fb fb fb fb fc fc fc fc fc fc fc fc fc fc
 ffff888061a88500: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888061a88580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fc fc
                                                       ^
 ffff888061a88600: fc fc fc fc fc fc fc fc fa fb fb fb fb fb fb fb
 ffff888061a88680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================


---
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