syzbot

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BUG: KASAN: slab-use-after-free in l2cap_sock_ready_cb+0xd5/0x140 net/bluetooth/l2cap_sock.c:1684
Read of size 8 at addr ffff888030ff5188 by task kworker/u9:0/55

CPU: 0 UID: 0 PID: 55 Comm: kworker/u9:0 Not tainted 6.15.0-rc3-syzkaller-00283-gf1a3944c860b #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/19/2025
Workqueue: hci2 hci_rx_work
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:408 [inline]
 print_report+0xb4/0x290 mm/kasan/report.c:521
 kasan_report+0x118/0x150 mm/kasan/report.c:634
 l2cap_sock_ready_cb+0xd5/0x140 net/bluetooth/l2cap_sock.c:1684
 l2cap_chan_ready net/bluetooth/l2cap_core.c:1263 [inline]
 l2cap_le_start+0xb0d/0x13b0 net/bluetooth/l2cap_core.c:1375
 l2cap_conn_ready net/bluetooth/l2cap_core.c:1627 [inline]
 l2cap_connect_cfm+0x6be/0x1040 net/bluetooth/l2cap_core.c:7279
 hci_connect_cfm+0x95/0x140 include/net/bluetooth/hci_core.h:2054
 le_conn_complete_evt+0xcd3/0x1220 net/bluetooth/hci_event.c:5779
 hci_le_conn_complete_evt+0x187/0x450 net/bluetooth/hci_event.c:5805
 hci_event_func net/bluetooth/hci_event.c:7490 [inline]
 hci_event_packet+0x7a5/0x1270 net/bluetooth/hci_event.c:7545
 hci_rx_work+0x46a/0xe80 net/bluetooth/hci_core.c:4020
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0xade/0x17a0 kernel/workqueue.c:3319
 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3400
 kthread+0x711/0x8a0 kernel/kthread.c:464
 ret_from_fork+0x4e/0x80 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>

Allocated by task 14092:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:68
 poison_kmalloc_redzone mm/kasan/common.c:377 [inline]
 __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:394
 kasan_kmalloc include/linux/kasan.h:260 [inline]
 __do_kmalloc_node mm/slub.c:4341 [inline]
 __kmalloc_noprof+0x27a/0x4f0 mm/slub.c:4353
 kmalloc_noprof include/linux/slab.h:909 [inline]
 sk_prot_alloc+0xe7/0x220 net/core/sock.c:2198
 sk_alloc+0x3a/0x370 net/core/sock.c:2254
 bt_sock_alloc+0x3b/0x310 net/bluetooth/af_bluetooth.c:148
 l2cap_sock_alloc net/bluetooth/l2cap_sock.c:1891 [inline]
 l2cap_sock_create+0x147/0x300 net/bluetooth/l2cap_sock.c:1933
 bt_sock_create+0x163/0x240 net/bluetooth/af_bluetooth.c:132
 __sock_create+0x4b3/0x9f0 net/socket.c:1541
 sock_create net/socket.c:1599 [inline]
 __sys_socket_create net/socket.c:1636 [inline]
 __sys_socket+0xd7/0x1b0 net/socket.c:1683
 __do_sys_socket net/socket.c:1697 [inline]
 __se_sys_socket net/socket.c:1695 [inline]
 __x64_sys_socket+0x7a/0x90 net/socket.c:1695
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xf6/0x210 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 14092:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:68
 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:576
 poison_slab_object mm/kasan/common.c:247 [inline]
 __kasan_slab_free+0x62/0x70 mm/kasan/common.c:264
 kasan_slab_free include/linux/kasan.h:233 [inline]
 slab_free_hook mm/slub.c:2398 [inline]
 slab_free mm/slub.c:4656 [inline]
 kfree+0x193/0x440 mm/slub.c:4855
 sk_prot_free net/core/sock.c:2237 [inline]
 __sk_destruct+0x4e1/0x660 net/core/sock.c:2332
 l2cap_sock_release+0x158/0x1d0 net/bluetooth/l2cap_sock.c:1435
 __sock_release net/socket.c:647 [inline]
 sock_close+0xc3/0x240 net/socket.c:1391
 __fput+0x44c/0xa70 fs/file_table.c:465
 task_work_run+0x1d4/0x260 kernel/task_work.c:227
 resume_user_mode_work+0x5e/0x80 include/linux/resume_user_mode.h:50
 exit_to_user_mode_loop kernel/entry/common.c:114 [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+0x9a/0x120 kernel/entry/common.c:218
 do_syscall_64+0x103/0x210 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff888030ff5000
 which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 392 bytes inside of
 freed 2048-byte region [ffff888030ff5000, ffff888030ff5800)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x30ff0
head: order:3 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 ffff88801a042000 ffffea000174be00 dead000000000002
raw: 0000000000000000 0000000080080008 00000000f5000000 0000000000000000
head: 00fff00000000040 ffff88801a042000 ffffea000174be00 dead000000000002
head: 0000000000000000 0000000080080008 00000000f5000000 0000000000000000
head: 00fff00000000003 ffffea0000c3fc01 00000000ffffffff 00000000ffffffff
head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000008
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Unmovable, gfp_mask 0x1d28c0(GFP_NOWAIT|__GFP_IO|__GFP_FS|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL), pid 52, tgid 52 (kworker/u8:3), ts 770102412039, free_ts 770062696618
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x1d8/0x230 mm/page_alloc.c:1718
 prep_new_page mm/page_alloc.c:1726 [inline]
 get_page_from_freelist+0x21ce/0x22b0 mm/page_alloc.c:3688
 __alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:4970
 alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2301
 alloc_slab_page mm/slub.c:2468 [inline]
 allocate_slab+0x8a/0x3b0 mm/slub.c:2632
 new_slab mm/slub.c:2686 [inline]
 ___slab_alloc+0xbfc/0x1480 mm/slub.c:3872
 __slab_alloc mm/slub.c:3962 [inline]
 __slab_alloc_node mm/slub.c:4037 [inline]
 slab_alloc_node mm/slub.c:4198 [inline]
 __do_kmalloc_node mm/slub.c:4340 [inline]
 __kmalloc_node_track_caller_noprof+0x2f8/0x4e0 mm/slub.c:4360
 kmalloc_reserve+0x136/0x290 net/core/skbuff.c:599
 pskb_expand_head+0x18f/0x1290 net/core/skbuff.c:2247
 netlink_trim+0x1d5/0x2e0 net/netlink/af_netlink.c:1295
 netlink_broadcast_filtered+0x80/0x1140 net/netlink/af_netlink.c:1501
 nlmsg_multicast_filtered include/net/netlink.h:1129 [inline]
 nlmsg_multicast include/net/netlink.h:1148 [inline]
 nlmsg_notify+0xf0/0x1a0 net/netlink/af_netlink.c:2577
 rtnl_notify net/core/rtnetlink.c:958 [inline]
 rtmsg_ifinfo_send net/core/rtnetlink.c:4429 [inline]
 rtmsg_ifinfo_event net/core/rtnetlink.c:4445 [inline]
 rtnetlink_event+0x224/0x270 net/core/rtnetlink.c:7015
 notifier_call_chain+0x1b6/0x3e0 kernel/notifier.c:85
 netdev_lower_state_changed+0xc6/0x140 net/core/dev.c:9135
 team_lower_state_changed drivers/net/team/team_core.c:91 [inline]
 team_refresh_port_linkup drivers/net/team/team_core.c:101 [inline]
 __team_port_change_send+0x1cc/0x4f0 drivers/net/team/team_core.c:2898
page last free pid 52 tgid 52 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1262 [inline]
 __free_frozen_pages+0xb0e/0xcd0 mm/page_alloc.c:2725
 discard_slab mm/slub.c:2730 [inline]
 __put_partials+0x161/0x1c0 mm/slub.c:3199
 put_cpu_partial+0x17c/0x250 mm/slub.c:3274
 __slab_free+0x2f7/0x400 mm/slub.c:4526
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x9a/0x140 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286
 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:329
 kasan_slab_alloc include/linux/kasan.h:250 [inline]
 slab_post_alloc_hook mm/slub.c:4161 [inline]
 slab_alloc_node mm/slub.c:4210 [inline]
 kmem_cache_alloc_node_noprof+0x1bb/0x3c0 mm/slub.c:4262
 __alloc_skb+0x112/0x2d0 net/core/skbuff.c:658
 alloc_skb include/linux/skbuff.h:1340 [inline]
 nlmsg_new include/net/netlink.h:1019 [inline]
 rtmsg_ifinfo_build_skb+0x84/0x260 net/core/rtnetlink.c:4400
 rtmsg_ifinfo_event net/core/rtnetlink.c:4442 [inline]
 rtmsg_ifinfo+0x8c/0x1a0 net/core/rtnetlink.c:4451
 dev_close_many+0x27f/0x410 net/core/dev.c:1730
 unregister_netdevice_many_notify+0x834/0x2330 net/core/dev.c:11952
 unregister_netdevice_many net/core/dev.c:12046 [inline]
 default_device_exit_batch+0x819/0x890 net/core/dev.c:12538
 ops_exit_list net/core/net_namespace.c:177 [inline]
 cleanup_net+0x7ac/0xbd0 net/core/net_namespace.c:654
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0xade/0x17a0 kernel/workqueue.c:3319

Memory state around the buggy address:
 ffff888030ff5080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888030ff5100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888030ff5180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                      ^
 ffff888030ff5200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888030ff5280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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