Message-ID: <677b9c97.050a0220.a40f5.0003.GAE@google.com>
Date: Mon, 06 Jan 2025 01:04:23 -0800
From: syzbot <syzbot+31c2f641b850a348a734@...kaller.appspotmail.com>
To: johan.hedberg@...il.com, linux-bluetooth@...r.kernel.org, 
	linux-kernel@...r.kernel.org, luiz.dentz@...il.com, marcel@...tmann.org, 
	syzkaller-bugs@...glegroups.com
Subject: Re: [syzbot] [bluetooth?] KASAN: slab-use-after-free Read in l2cap_send_cmd

syzbot has found a reproducer for the following issue on:

HEAD commit:    ab75170520d4 Merge tag 'linux-watchdog-6.13-rc6' of git://..
git tree:       upstream
console+strace: https://syzkaller.appspot.com/x/log.txt?x=17f4330f980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=1c541fa8af5c9cc7
dashboard link: https://syzkaller.appspot.com/bug?extid=31c2f641b850a348a734
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=11261edf980000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=17fa36f8580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/1740fef78c43/disk-ab751705.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/a74d1ace549b/vmlinux-ab751705.xz
kernel image: https://storage.googleapis.com/syzbot-assets/524d100d5187/bzImage-ab751705.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+31c2f641b850a348a734@...kaller.appspotmail.com

BUG: KASAN: slab-use-after-free in l2cap_build_cmd net/bluetooth/l2cap_core.c:2964 [inline]
BUG: KASAN: slab-use-after-free in l2cap_send_cmd+0x187/0x8d0 net/bluetooth/l2cap_core.c:954
Read of size 8 at addr ffff8880271a4000 by task kworker/u9:2/5837

CPU: 0 UID: 0 PID: 5837 Comm: kworker/u9:2 Not tainted 6.13.0-rc5-syzkaller-00163-gab75170520d4 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Workqueue: hci1 hci_rx_work
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0x169/0x550 mm/kasan/report.c:489
 kasan_report+0x143/0x180 mm/kasan/report.c:602
 l2cap_build_cmd net/bluetooth/l2cap_core.c:2964 [inline]
 l2cap_send_cmd+0x187/0x8d0 net/bluetooth/l2cap_core.c:954
 l2cap_sig_send_rej net/bluetooth/l2cap_core.c:5502 [inline]
 l2cap_sig_channel net/bluetooth/l2cap_core.c:5538 [inline]
 l2cap_recv_frame+0x221f/0x10db0 net/bluetooth/l2cap_core.c:6817
 hci_acldata_packet net/bluetooth/hci_core.c:3797 [inline]
 hci_rx_work+0x508/0xdb0 net/bluetooth/hci_core.c:4040
 process_one_work kernel/workqueue.c:3229 [inline]
 process_scheduled_works+0xa66/0x1840 kernel/workqueue.c:3310
 worker_thread+0x870/0xd30 kernel/workqueue.c:3391
 kthread+0x2f0/0x390 kernel/kthread.c:389
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>

Allocated by task 5837:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
 poison_kmalloc_redzone mm/kasan/common.c:377 [inline]
 __kasan_kmalloc+0x98/0xb0 mm/kasan/common.c:394
 kasan_kmalloc include/linux/kasan.h:260 [inline]
 __kmalloc_cache_noprof+0x243/0x390 mm/slub.c:4329
 kmalloc_noprof include/linux/slab.h:901 [inline]
 kzalloc_noprof include/linux/slab.h:1037 [inline]
 l2cap_conn_add+0xa9/0x8e0 net/bluetooth/l2cap_core.c:6860
 l2cap_connect_cfm+0x115/0x1090 net/bluetooth/l2cap_core.c:7239
 hci_connect_cfm include/net/bluetooth/hci_core.h:2057 [inline]
 hci_remote_features_evt+0x68e/0xac0 net/bluetooth/hci_event.c:3726
 hci_event_func net/bluetooth/hci_event.c:7473 [inline]
 hci_event_packet+0xac2/0x1540 net/bluetooth/hci_event.c:7525
 hci_rx_work+0x3f3/0xdb0 net/bluetooth/hci_core.c:4035
 process_one_work kernel/workqueue.c:3229 [inline]
 process_scheduled_works+0xa66/0x1840 kernel/workqueue.c:3310
 worker_thread+0x870/0xd30 kernel/workqueue.c:3391
 kthread+0x2f0/0x390 kernel/kthread.c:389
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

Freed by task 54:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
 kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:582
 poison_slab_object mm/kasan/common.c:247 [inline]
 __kasan_slab_free+0x59/0x70 mm/kasan/common.c:264
 kasan_slab_free include/linux/kasan.h:233 [inline]
 slab_free_hook mm/slub.c:2353 [inline]
 slab_free mm/slub.c:4613 [inline]
 kfree+0x196/0x430 mm/slub.c:4761
 l2cap_connect_cfm+0xcc/0x1090 net/bluetooth/l2cap_core.c:7235
 hci_connect_cfm include/net/bluetooth/hci_core.h:2057 [inline]
 hci_conn_failed+0x287/0x400 net/bluetooth/hci_conn.c:1266
 hci_abort_conn_sync+0x56c/0x11f0 net/bluetooth/hci_sync.c:5603
 hci_cmd_sync_work+0x22b/0x400 net/bluetooth/hci_sync.c:332
 process_one_work kernel/workqueue.c:3229 [inline]
 process_scheduled_works+0xa66/0x1840 kernel/workqueue.c:3310
 worker_thread+0x870/0xd30 kernel/workqueue.c:3391
 kthread+0x2f0/0x390 kernel/kthread.c:389
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

Last potentially related work creation:
 kasan_save_stack+0x3f/0x60 mm/kasan/common.c:47
 __kasan_record_aux_stack+0xac/0xc0 mm/kasan/generic.c:544
 insert_work+0x3e/0x330 kernel/workqueue.c:2183
 __queue_work+0xc8b/0xf50 kernel/workqueue.c:2339
 call_timer_fn+0x187/0x650 kernel/time/timer.c:1793
 expire_timers kernel/time/timer.c:1839 [inline]
 __run_timers kernel/time/timer.c:2418 [inline]
 __run_timer_base+0x695/0x8e0 kernel/time/timer.c:2430
 run_timer_base kernel/time/timer.c:2439 [inline]
 run_timer_softirq+0xb7/0x170 kernel/time/timer.c:2449
 handle_softirqs+0x2d4/0x9b0 kernel/softirq.c:561
 __do_softirq kernel/softirq.c:595 [inline]
 invoke_softirq kernel/softirq.c:435 [inline]
 __irq_exit_rcu+0xf7/0x220 kernel/softirq.c:662
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:678
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1049 [inline]
 sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1049
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702

Second to last potentially related work creation:
 kasan_save_stack+0x3f/0x60 mm/kasan/common.c:47
 __kasan_record_aux_stack+0xac/0xc0 mm/kasan/generic.c:544
 insert_work+0x3e/0x330 kernel/workqueue.c:2183
 __queue_work+0xb66/0xf50 kernel/workqueue.c:2343
 queue_work_on+0x1c2/0x380 kernel/workqueue.c:2390
 queue_work include/linux/workqueue.h:662 [inline]
 l2cap_conn_ready net/bluetooth/l2cap_core.c:1640 [inline]
 l2cap_connect_cfm+0xdd5/0x1090 net/bluetooth/l2cap_core.c:7280
 hci_connect_cfm include/net/bluetooth/hci_core.h:2057 [inline]
 hci_remote_features_evt+0x68e/0xac0 net/bluetooth/hci_event.c:3726
 hci_event_func net/bluetooth/hci_event.c:7473 [inline]
 hci_event_packet+0xac2/0x1540 net/bluetooth/hci_event.c:7525
 hci_rx_work+0x3f3/0xdb0 net/bluetooth/hci_core.c:4035
 process_one_work kernel/workqueue.c:3229 [inline]
 process_scheduled_works+0xa66/0x1840 kernel/workqueue.c:3310
 worker_thread+0x870/0xd30 kernel/workqueue.c:3391
 kthread+0x2f0/0x390 kernel/kthread.c:389
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

The buggy address belongs to the object at ffff8880271a4000
 which belongs to the cache kmalloc-1k of size 1024
The buggy address is located 0 bytes inside of
 freed 1024-byte region [ffff8880271a4000, ffff8880271a4400)

The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x271a0
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 ffff88801ac41dc0 ffffea0001c09800 dead000000000002
raw: 0000000000000000 0000000000100010 00000001f5000000 0000000000000000
head: 00fff00000000040 ffff88801ac41dc0 ffffea0001c09800 dead000000000002
head: 0000000000000000 0000000000100010 00000001f5000000 0000000000000000
head: 00fff00000000003 ffffea00009c6801 ffffffffffffffff 0000000000000000
head: 0000000000000008 0000000000000000 00000000ffffffff 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 0x252800(GFP_NOWAIT|__GFP_NORETRY|__GFP_COMP|__GFP_THISNODE), pid 12, tgid 12 (kworker/u8:1), ts 7179124429, free_ts 0
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x1f3/0x230 mm/page_alloc.c:1558
 prep_new_page mm/page_alloc.c:1566 [inline]
 get_page_from_freelist+0x365c/0x37a0 mm/page_alloc.c:3476
 __alloc_pages_noprof+0x292/0x710 mm/page_alloc.c:4753
 __alloc_pages_node_noprof include/linux/gfp.h:269 [inline]
 alloc_slab_page+0x59/0x110 mm/slub.c:2425
 allocate_slab+0x5a/0x2b0 mm/slub.c:2589
 new_slab mm/slub.c:2642 [inline]
 ___slab_alloc+0xc27/0x14a0 mm/slub.c:3830
 __slab_alloc+0x58/0xa0 mm/slub.c:3920
 __slab_alloc_node mm/slub.c:3995 [inline]
 slab_alloc_node mm/slub.c:4156 [inline]
 __kmalloc_cache_node_noprof+0x294/0x3a0 mm/slub.c:4337
 kmalloc_node_noprof include/linux/slab.h:924 [inline]
 blk_mq_alloc_hctx block/blk-mq.c:3935 [inline]
 blk_mq_alloc_and_init_hctx+0x17f/0xd50 block/blk-mq.c:4443
 blk_mq_realloc_hw_ctxs+0x19c/0xb00 block/blk-mq.c:4476
 blk_mq_init_allocated_queue+0x3f6/0x14c0 block/blk-mq.c:4530
 blk_mq_alloc_queue+0x1d3/0x2f0 block/blk-mq.c:4343
 scsi_alloc_sdev+0x76c/0xb80 drivers/scsi/scsi_scan.c:337
 scsi_probe_and_add_lun+0x1d4/0x4bd0 drivers/scsi/scsi_scan.c:1210
 __scsi_scan_target+0x205/0x1080 drivers/scsi/scsi_scan.c:1757
 scsi_scan_channel drivers/scsi/scsi_scan.c:1845 [inline]
 scsi_scan_host_selected+0x37e/0x690 drivers/scsi/scsi_scan.c:1874
page_owner free stack trace missing

Memory state around the buggy address:
 ffff8880271a3f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8880271a3f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff8880271a4000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                   ^
 ffff8880271a4080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8880271a4100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================


---
If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.

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