[syzbot] [bluetooth?] KASAN: slab-use-after-free Read in l2cap_connect

From: syzbot
Date: Wed Nov 15 2023 - 00:44:16 EST

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Hello,

syzbot found the following issue on:

HEAD commit: be3ca57cfb77 Merge tag 'media/v6.7-1' of git://git.kernel...
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1256c787680000
kernel config: https://syzkaller.appspot.com/x/.config?x=1ffa1cec3b40f3ce
dashboard link: https://syzkaller.appspot.com/bug?extid=c23a22651335aa864a7a
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/09ea6e07e1d4/disk-be3ca57c.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/acd288df0801/vmlinux-be3ca57c.xz
kernel image: https://storage.googleapis.com/syzbot-assets/40e81640103b/bzImage-be3ca57c.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+c23a22651335aa864a7a@xxxxxxxxxxxxxxxxxxxxxxxxx

==================================================================
BUG: KASAN: slab-use-after-free in l2cap_connect+0x10a5/0x1280 net/bluetooth/l2cap_core.c:4145
Read of size 8 at addr ffff88802a57b800 by task kworker/u5:7/5111

CPU: 0 PID: 5111 Comm: kworker/u5:7 Not tainted 6.6.0-syzkaller-15029-gbe3ca57cfb77 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/09/2023
Workqueue: hci5 hci_rx_work
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0xd9/0x1b0 lib/dump_stack.c:106
print_address_description mm/kasan/report.c:364 [inline]
print_report+0xc4/0x620 mm/kasan/report.c:475
kasan_report+0xda/0x110 mm/kasan/report.c:588
l2cap_connect+0x10a5/0x1280 net/bluetooth/l2cap_core.c:4145
l2cap_connect_req net/bluetooth/l2cap_core.c:4287 [inline]
l2cap_bredr_sig_cmd net/bluetooth/l2cap_core.c:5738 [inline]
l2cap_sig_channel net/bluetooth/l2cap_core.c:6523 [inline]
l2cap_recv_frame+0x3074/0x9440 net/bluetooth/l2cap_core.c:7802
l2cap_recv_acldata+0xa3d/0xbf0 net/bluetooth/l2cap_core.c:8520
hci_acldata_packet net/bluetooth/hci_core.c:3875 [inline]
hci_rx_work+0xaa7/0x1610 net/bluetooth/hci_core.c:4110
process_one_work+0x884/0x15c0 kernel/workqueue.c:2630
process_scheduled_works kernel/workqueue.c:2703 [inline]
worker_thread+0x8b9/0x1290 kernel/workqueue.c:2784
kthread+0x33c/0x440 kernel/kthread.c:388
ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:242
</TASK>

Allocated by task 50:
kasan_save_stack+0x33/0x50 mm/kasan/common.c:45
kasan_set_track+0x25/0x30 mm/kasan/common.c:52
____kasan_kmalloc mm/kasan/common.c:374 [inline]
__kasan_kmalloc+0xa2/0xb0 mm/kasan/common.c:383
kmalloc include/linux/slab.h:600 [inline]
kzalloc include/linux/slab.h:721 [inline]
l2cap_conn_add.part.0+0x60/0xdf0 net/bluetooth/l2cap_core.c:7845
l2cap_conn_add net/bluetooth/l2cap_core.c:71 [inline]
l2cap_connect_cfm+0x424/0xfb0 net/bluetooth/l2cap_core.c:8242
hci_connect_cfm include/net/bluetooth/hci_core.h:1959 [inline]
hci_remote_features_evt+0x565/0xa70 net/bluetooth/hci_event.c:3765
hci_event_func net/bluetooth/hci_event.c:7677 [inline]
hci_event_packet+0x9d3/0x1160 net/bluetooth/hci_event.c:7729
hci_rx_work+0x2c4/0x1610 net/bluetooth/hci_core.c:4105
process_one_work+0x884/0x15c0 kernel/workqueue.c:2630
process_scheduled_works kernel/workqueue.c:2703 [inline]
worker_thread+0x8b9/0x1290 kernel/workqueue.c:2784
kthread+0x33c/0x440 kernel/kthread.c:388
ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:242

Freed by task 50:
kasan_save_stack+0x33/0x50 mm/kasan/common.c:45
kasan_set_track+0x25/0x30 mm/kasan/common.c:52
kasan_save_free_info+0x2b/0x40 mm/kasan/generic.c:522
____kasan_slab_free mm/kasan/common.c:236 [inline]
____kasan_slab_free+0x15b/0x1b0 mm/kasan/common.c:200
kasan_slab_free include/linux/kasan.h:164 [inline]
slab_free_hook mm/slub.c:1800 [inline]
slab_free_freelist_hook+0x114/0x1e0 mm/slub.c:1826
slab_free mm/slub.c:3809 [inline]
__kmem_cache_free+0xc0/0x180 mm/slub.c:3822
l2cap_conn_free net/bluetooth/l2cap_core.c:1949 [inline]
kref_put include/linux/kref.h:65 [inline]
l2cap_conn_put net/bluetooth/l2cap_core.c:1961 [inline]
l2cap_conn_del+0x592/0x740 net/bluetooth/l2cap_core.c:1941
l2cap_connect_cfm+0xa10/0xfb0 net/bluetooth/l2cap_core.c:8238
hci_connect_cfm include/net/bluetooth/hci_core.h:1959 [inline]
hci_conn_failed+0x1c3/0x370 net/bluetooth/hci_conn.c:1283
hci_abort_conn_sync+0x758/0xb50 net/bluetooth/hci_sync.c:5424
abort_conn_sync+0x187/0x390 net/bluetooth/hci_conn.c:2957
hci_cmd_sync_work+0x1a4/0x410 net/bluetooth/hci_sync.c:306
process_one_work+0x884/0x15c0 kernel/workqueue.c:2630
process_scheduled_works kernel/workqueue.c:2703 [inline]
worker_thread+0x8b9/0x1290 kernel/workqueue.c:2784
kthread+0x33c/0x440 kernel/kthread.c:388
ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:242

Last potentially related work creation:
kasan_save_stack+0x33/0x50 mm/kasan/common.c:45
__kasan_record_aux_stack+0xbc/0xd0 mm/kasan/generic.c:492
insert_work+0x38/0x230 kernel/workqueue.c:1647
__queue_work+0x5d0/0x1050 kernel/workqueue.c:1799
call_timer_fn+0x193/0x580 kernel/time/timer.c:1700
expire_timers kernel/time/timer.c:1746 [inline]
__run_timers+0x585/0xb10 kernel/time/timer.c:2022
run_timer_softirq+0x58/0xd0 kernel/time/timer.c:2035
__do_softirq+0x21a/0x968 kernel/softirq.c:553

Second to last potentially related work creation:
kasan_save_stack+0x33/0x50 mm/kasan/common.c:45
__kasan_record_aux_stack+0xbc/0xd0 mm/kasan/generic.c:492
insert_work+0x38/0x230 kernel/workqueue.c:1647
__queue_work+0xb77/0x1050 kernel/workqueue.c:1803
queue_work_on+0xed/0x110 kernel/workqueue.c:1834
queue_work include/linux/workqueue.h:562 [inline]
l2cap_conn_ready net/bluetooth/l2cap_core.c:1779 [inline]
l2cap_connect_cfm+0x9f3/0xfb0 net/bluetooth/l2cap_core.c:8283
hci_connect_cfm include/net/bluetooth/hci_core.h:1959 [inline]
hci_remote_features_evt+0x565/0xa70 net/bluetooth/hci_event.c:3765
hci_event_func net/bluetooth/hci_event.c:7677 [inline]
hci_event_packet+0x9d3/0x1160 net/bluetooth/hci_event.c:7729
hci_rx_work+0x2c4/0x1610 net/bluetooth/hci_core.c:4105
process_one_work+0x884/0x15c0 kernel/workqueue.c:2630
process_scheduled_works kernel/workqueue.c:2703 [inline]
worker_thread+0x8b9/0x1290 kernel/workqueue.c:2784
kthread+0x33c/0x440 kernel/kthread.c:388
ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:242

The buggy address belongs to the object at ffff88802a57b800
which belongs to the cache kmalloc-1k of size 1024
The buggy address is located 0 bytes inside of
freed 1024-byte region [ffff88802a57b800, ffff88802a57bc00)

The buggy address belongs to the physical page:
page:ffffea0000a95e00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x2a578
head:ffffea0000a95e00 order:3 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0xfff00000000840(slab|head|node=0|zone=1|lastcpupid=0x7ff)
page_type: 0xffffffff()
raw: 00fff00000000840 ffff888013041dc0 ffffea00006f5200 dead000000000002
raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 1, tgid 1 (swapper/0), ts 29439741396, free_ts 0
set_page_owner include/linux/page_owner.h:31 [inline]
post_alloc_hook+0x2cf/0x340 mm/page_alloc.c:1537
prep_new_page mm/page_alloc.c:1544 [inline]
get_page_from_freelist+0xa25/0x36c0 mm/page_alloc.c:3312
__alloc_pages+0x1d0/0x4a0 mm/page_alloc.c:4568
alloc_pages_mpol+0x258/0x5f0 mm/mempolicy.c:2133
alloc_slab_page mm/slub.c:1870 [inline]
allocate_slab+0x251/0x380 mm/slub.c:2017
new_slab mm/slub.c:2070 [inline]
___slab_alloc+0x8c7/0x1580 mm/slub.c:3223
__slab_alloc.constprop.0+0x56/0xa0 mm/slub.c:3322
__slab_alloc_node mm/slub.c:3375 [inline]
slab_alloc_node mm/slub.c:3468 [inline]
__kmem_cache_alloc_node+0x131/0x310 mm/slub.c:3517
__do_kmalloc_node mm/slab_common.c:1006 [inline]
__kmalloc_node_track_caller+0x50/0x100 mm/slab_common.c:1027
__do_krealloc mm/slab_common.c:1395 [inline]
krealloc+0x5d/0x100 mm/slab_common.c:1428
add_sysfs_param+0xca/0x960 kernel/params.c:652
kernel_add_sysfs_param kernel/params.c:813 [inline]
param_sysfs_builtin kernel/params.c:852 [inline]
param_sysfs_builtin_init+0x2ca/0x450 kernel/params.c:986
do_one_initcall+0x11c/0x640 init/main.c:1236
do_initcall_level init/main.c:1298 [inline]
do_initcalls init/main.c:1314 [inline]
do_basic_setup init/main.c:1333 [inline]
kernel_init_freeable+0x5c2/0x900 init/main.c:1551
kernel_init+0x1c/0x2a0 init/main.c:1441
ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
page_owner free stack trace missing

Memory state around the buggy address:
ffff88802a57b700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff88802a57b780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88802a57b800: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff88802a57b880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88802a57b900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================

---
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Next message: Srikar Dronamraju: "Re: [PATCH v4 1/5] powerpc/smp: Enable Asym packing for cores on shared processor"
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