KASAN: slab-use-after-free Write in hci_conn_drop (2)

Status: upstream: reported C repro on 2023/11/02 22:01
Subsystems: bluetooth
[Documentation on labels]
First crash: 134d, last: 5d22h
Cause bisection: introduced by (bisect log) :
commit 456561ba8e495e9320c1f304bf1cd3d1043cbe7b
Author: Jonas Dreßler <>
Date: Tue Feb 6 11:08:13 2024 +0000

  Bluetooth: hci_conn: Only do ACL connections sequentially

Crash: KASAN: slab-use-after-free Write in __hci_acl_create_connection_sync (log)
Repro: C syz .config
Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [bluetooth?] KASAN: slab-use-after-free Write in hci_conn_drop (2) 2 (13) 2024/02/18 08:44
Similar bugs (1)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KASAN: slab-use-after-free Write in hci_conn_drop bluetooth 1 281d 276d 0/26 auto-obsoleted due to no activity on 2023/08/25 20:26
Last patch testing requests (12)
Created Duration User Patch Repo Result
2024/02/18 08:44 0m patch 2c3b09aac00d error OK
2024/02/17 10:58 22m patch master error OK
2024/01/30 16:25 24m retest repro git:// for-kernelci OK log
2023/11/17 00:38 18m retest repro git:// for-kernelci report log
2023/11/04 05:40 19m patch git:// 8de1e7afcc1c report log
2023/11/04 04:47 18m patch git:// 8de1e7afcc1c report log
2023/11/04 03:23 11m patch git:// 8de1e7afcc1c error OK
2023/11/03 12:18 24m patch master OK log
2023/11/03 08:00 9m patch git:// 8de1e7afcc1c error OK
2023/11/03 07:01 9m patch git:// 8de1e7afcc1c error OK
2023/11/03 05:13 9m patch git:// 8de1e7afcc1c error OK
2023/11/03 01:01 9m patch git:// 8de1e7afcc1c error OK

Sample crash report:
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_dec_and_test include/linux/atomic/atomic-instrumented.h:1375 [inline]
BUG: KASAN: slab-use-after-free in hci_conn_drop+0x34/0x2c0 include/net/bluetooth/hci_core.h:1574
Write of size 4 at addr ffff8880781d6010 by task syz-executor409/22560

CPU: 0 PID: 22560 Comm: syz-executor409 Not tainted 6.8.0-rc4-next-20240214-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024
Call Trace:
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:114
 print_address_description mm/kasan/report.c:377 [inline]
 print_report+0x169/0x550 mm/kasan/report.c:488
 kasan_report+0x143/0x180 mm/kasan/report.c:601
 kasan_check_range+0x282/0x290 mm/kasan/generic.c:189
 instrument_atomic_read_write include/linux/instrumented.h:96 [inline]
 atomic_dec_and_test include/linux/atomic/atomic-instrumented.h:1375 [inline]
 hci_conn_drop+0x34/0x2c0 include/net/bluetooth/hci_core.h:1574
 __sco_sock_close+0x37b/0x570 net/bluetooth/sco.c:445
 sco_sock_close net/bluetooth/sco.c:470 [inline]
 sco_sock_release+0xb3/0x320 net/bluetooth/sco.c:1247
 __sock_release net/socket.c:659 [inline]
 sock_close+0xbc/0x240 net/socket.c:1421
 __fput+0x429/0x8a0 fs/file_table.c:411
 __do_sys_close fs/open.c:1557 [inline]
 __se_sys_close fs/open.c:1542 [inline]
 __x64_sys_close+0x7f/0x110 fs/open.c:1542
RIP: 0033:0x7f53a414802a
Code: 48 3d 00 f0 ff ff 77 48 c3 0f 1f 80 00 00 00 00 48 83 ec 18 89 7c 24 0c e8 f3 64 02 00 8b 7c 24 0c 89 c2 b8 03 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 36 89 d7 89 44 24 0c e8 53 65 02 00 8b 44 24
RSP: 002b:00007ffcd1d20920 EFLAGS: 00000293 ORIG_RAX: 0000000000000003
RAX: ffffffffffffffda RBX: 0000000000000005 RCX: 00007f53a414802a
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000004
RBP: 0000000000000003 R08: 00007ffcd1d209c4 R09: 00007ffcd1d209c4
R10: 0000000000000000 R11: 0000000000000293 R12: 0000555557478370
R13: 0000000000000011 R14: 00007ffcd1d20968 R15: 00007ffcd1d209c0

Allocated by task 22560:
 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:370 [inline]
 __kasan_kmalloc+0x98/0xb0 mm/kasan/common.c:387
 kasan_kmalloc include/linux/kasan.h:211 [inline]
 kmalloc_trace+0x1d9/0x360 mm/slub.c:4013
 kmalloc include/linux/slab.h:590 [inline]
 kzalloc include/linux/slab.h:711 [inline]
 hci_conn_add+0xc7/0x13a0 net/bluetooth/hci_conn.c:914
 hci_conn_add_unset net/bluetooth/hci_conn.c:1016 [inline]
 hci_connect_sco+0xc9/0x350 net/bluetooth/hci_conn.c:1701
 sco_connect net/bluetooth/sco.c:266 [inline]
 sco_sock_connect+0x2fc/0x990 net/bluetooth/sco.c:592
 __sys_connect_file net/socket.c:2048 [inline]
 __sys_connect+0x2df/0x310 net/socket.c:2065
 __do_sys_connect net/socket.c:2075 [inline]
 __se_sys_connect net/socket.c:2072 [inline]
 __x64_sys_connect+0x7a/0x90 net/socket.c:2072

Freed by task 5084:
 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:586
 poison_slab_object+0xa6/0xe0 mm/kasan/common.c:240
 __kasan_slab_free+0x37/0x60 mm/kasan/common.c:256
 kasan_slab_free include/linux/kasan.h:184 [inline]
 slab_free_hook mm/slub.c:2122 [inline]
 slab_free mm/slub.c:4296 [inline]
 kfree+0x14a/0x380 mm/slub.c:4406
 kobject_cleanup lib/kobject.c:689 [inline]
 kobject_release lib/kobject.c:720 [inline]
 kref_put include/linux/kref.h:65 [inline]
 kobject_put+0x22f/0x480 lib/kobject.c:737
 hci_conn_cleanup net/bluetooth/hci_conn.c:176 [inline]
 hci_conn_del+0x8f0/0xc70 net/bluetooth/hci_conn.c:1126
 hci_abort_conn_sync+0x583/0xde0 net/bluetooth/hci_sync.c:5361
 hci_cmd_sync_work+0x22b/0x400 net/bluetooth/hci_sync.c:306
 process_one_work kernel/workqueue.c:3146 [inline]
 process_scheduled_works+0x9d7/0x1730 kernel/workqueue.c:3226
 worker_thread+0x86d/0xd70 kernel/workqueue.c:3307
 kthread+0x2f0/0x390 kernel/kthread.c:388
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:242

The buggy address belongs to the object at ffff8880781d6000
 which belongs to the cache kmalloc-4k of size 4096
The buggy address is located 16 bytes inside of
 freed 4096-byte region [ffff8880781d6000, ffff8880781d7000)

The buggy address belongs to the physical page:
page:ffffea0001e07400 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x781d0
head:ffffea0001e07400 order:3 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0xfff80000000840(slab|head|node=0|zone=1|lastcpupid=0xfff)
page_type: 0xffffffff()
raw: 00fff80000000840 ffff888014c42140 dead000000000100 dead000000000122
raw: 0000000000000000 0000000080040004 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 0xd2040(__GFP_IO|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 4486, tgid 4486 (mount), ts 16228925553, free_ts 14928891043
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook+0x1ea/0x210 mm/page_alloc.c:1533
 prep_new_page mm/page_alloc.c:1540 [inline]
 get_page_from_freelist+0x33ea/0x3580 mm/page_alloc.c:3311
 __alloc_pages+0x256/0x6a0 mm/page_alloc.c:4567
 __alloc_pages_node include/linux/gfp.h:238 [inline]
 alloc_pages_node include/linux/gfp.h:261 [inline]
 alloc_slab_page+0x5f/0x160 mm/slub.c:2191
 allocate_slab mm/slub.c:2354 [inline]
 new_slab+0x84/0x2f0 mm/slub.c:2407
 ___slab_alloc+0xc73/0x1260 mm/slub.c:3541
 __slab_alloc mm/slub.c:3626 [inline]
 __slab_alloc_node mm/slub.c:3679 [inline]
 slab_alloc_node mm/slub.c:3851 [inline]
 kmalloc_trace+0x267/0x360 mm/slub.c:4008
 kmalloc include/linux/slab.h:590 [inline]
 tomoyo_print_header security/tomoyo/audit.c:156 [inline]
 tomoyo_init_log+0x1ca/0x2050 security/tomoyo/audit.c:255
 tomoyo_supervisor+0x38a/0x11f0 security/tomoyo/common.c:2089
 tomoyo_audit_mount_log security/tomoyo/mount.c:32 [inline]
 tomoyo_mount_acl security/tomoyo/mount.c:166 [inline]
 tomoyo_mount_permission+0x792/0xb80 security/tomoyo/mount.c:237
 security_sb_mount+0x8f/0xd0 security/security.c:1459
 path_mount+0xb9/0xfb0 fs/namespace.c:3621
 do_mount fs/namespace.c:3692 [inline]
 __do_sys_mount fs/namespace.c:3898 [inline]
 __se_sys_mount+0x2d9/0x3c0 fs/namespace.c:3875
page last free pid 1 tgid 1 stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1140 [inline]
 free_unref_page_prepare+0x968/0xa90 mm/page_alloc.c:2346
 free_unref_page+0x37/0x3f0 mm/page_alloc.c:2486
 free_contig_range+0x9e/0x160 mm/page_alloc.c:6532
 destroy_args+0x8a/0x890 mm/debug_vm_pgtable.c:1028
 debug_vm_pgtable+0x4be/0x550 mm/debug_vm_pgtable.c:1408
 do_one_initcall+0x238/0x830 init/main.c:1233
 do_initcall_level+0x157/0x210 init/main.c:1295
 do_initcalls+0x3f/0x80 init/main.c:1311
 kernel_init_freeable+0x435/0x5d0 init/main.c:1543
 kernel_init+0x1d/0x2b0 init/main.c:1432
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:242

Memory state around the buggy address:
 ffff8880781d5f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8880781d5f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff8880781d6000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8880781d6080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8880781d6100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb

Crashes (6):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/02/17 02:09 linux-next 2c3b09aac00d 578f7538 .config console log report syz C [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root KASAN: slab-use-after-free Write in hci_conn_drop
2023/11/02 22:00 git:// for-kernelci 8de1e7afcc1c b5f07fd3 .config console log report syz [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 KASAN: slab-use-after-free Write in hci_conn_drop
2023/12/27 09:06 upstream fbafc3e621c3 fb427a07 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root KASAN: slab-use-after-free Write in hci_conn_drop
2023/11/17 22:32 git:// for-kernelci 8de1e7afcc1c cb976f63 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 KASAN: slab-use-after-free Write in hci_conn_drop
2023/11/02 21:16 git:// for-kernelci 8de1e7afcc1c b5f07fd3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 KASAN: slab-use-after-free Write in hci_conn_drop
2023/10/11 05:11 git:// for-kernelci 19af4a4ed414 83165b57 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 KASAN: slab-use-after-free Write in hci_conn_drop
* Struck through repros no longer work on HEAD.