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

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

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    7271b2a53042 Add linux-next specific files for 20230818
git tree:       linux-next
console+strace: https://syzkaller.appspot.com/x/log.txt?x=13404b6ba80000
kernel config:  https://syzkaller.appspot.com/x/.config?x=1936af09cdef7dd6
dashboard link: https://syzkaller.appspot.com/bug?extid=a0c80b06ae2cb8895bc4
compiler:       gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=13506923a80000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=147569efa80000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/d81109bc02c1/disk-7271b2a5.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/4b3bf8e2a4f7/vmlinux-7271b2a5.xz
kernel image: https://storage.googleapis.com/syzbot-assets/6404cd473c1e/bzImage-7271b2a5.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+a0c80b06ae2cb8895bc4@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: slab-use-after-free in hci_send_acl+0xdf4/0xf30 net/bluetooth/hci_core.c:3228
Read of size 8 at addr ffff888025635618 by task kworker/1:1/27

CPU: 1 PID: 27 Comm: kworker/1:1 Not tainted 6.5.0-rc6-next-20230818-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/26/2023
Workqueue: events l2cap_info_timeout
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
 hci_send_acl+0xdf4/0xf30 net/bluetooth/hci_core.c:3228
 l2cap_send_cmd+0x6dd/0x920 net/bluetooth/l2cap_core.c:977
 l2cap_send_conn_req+0x1e5/0x260 net/bluetooth/l2cap_core.c:1286
 l2cap_start_connection+0x11e/0x420 net/bluetooth/l2cap_core.c:1514
 l2cap_conn_start+0x7ae/0xa40 net/bluetooth/l2cap_core.c:1661
 process_one_work+0x887/0x15d0 kernel/workqueue.c:2630
 process_scheduled_works kernel/workqueue.c:2703 [inline]
 worker_thread+0x8bb/0x1290 kernel/workqueue.c:2784
 kthread+0x33a/0x430 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:304
 </TASK>

Allocated by task 5046:
 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]
 hci_chan_create+0xa6/0x3a0 net/bluetooth/hci_conn.c:2691
 l2cap_conn_add.part.0+0x1a/0xdf0 net/bluetooth/l2cap_core.c:7841
 l2cap_conn_add include/net/bluetooth/l2cap.h:866 [inline]
 l2cap_chan_connect+0x15b9/0x2140 net/bluetooth/l2cap_core.c:8053
 bt_6lowpan_connect net/bluetooth/6lowpan.c:894 [inline]
 lowpan_control_write+0x3d6/0x730 net/bluetooth/6lowpan.c:1129
 full_proxy_write+0x124/0x190 fs/debugfs/file.c:236
 vfs_write+0x2a4/0xe40 fs/read_write.c:582
 ksys_write+0x12f/0x250 fs/read_write.c:637
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x38/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

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+0xb8/0x2f0 mm/slub.c:3822
 hci_chan_list_flush+0x81/0xf0 net/bluetooth/hci_conn.c:2731
 hci_conn_cleanup net/bluetooth/hci_conn.c:152 [inline]
 hci_conn_del+0x1fc/0xd10 net/bluetooth/hci_conn.c:1140
 hci_abort_conn_sync+0xacb/0xe20 net/bluetooth/hci_sync.c:5432
 abort_conn_sync+0x18e/0x3a0 net/bluetooth/hci_conn.c:2878
 hci_cmd_sync_work+0x1a4/0x3c0 net/bluetooth/hci_sync.c:306
 process_one_work+0x887/0x15d0 kernel/workqueue.c:2630
 process_scheduled_works kernel/workqueue.c:2703 [inline]
 worker_thread+0x8bb/0x1290 kernel/workqueue.c:2784
 kthread+0x33a/0x430 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:304

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
 kvfree_call_rcu+0x70/0xbe0 kernel/rcu/tree.c:3373
 kernfs_unlink_open_file+0x3b6/0x4b0 fs/kernfs/file.c:633
 kernfs_fop_release+0xec/0x1e0 fs/kernfs/file.c:805
 __fput+0x3f7/0xa70 fs/file_table.c:384
 __fput_sync+0x47/0x50 fs/file_table.c:465
 __do_sys_close fs/open.c:1572 [inline]
 __se_sys_close fs/open.c:1557 [inline]
 __x64_sys_close+0x87/0xf0 fs/open.c:1557
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x38/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

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
 kvfree_call_rcu+0x70/0xbe0 kernel/rcu/tree.c:3373
 kernfs_unlink_open_file+0x3b6/0x4b0 fs/kernfs/file.c:633
 kernfs_fop_release+0xec/0x1e0 fs/kernfs/file.c:805
 __fput+0x3f7/0xa70 fs/file_table.c:384
 __fput_sync+0x47/0x50 fs/file_table.c:465
 __do_sys_close fs/open.c:1572 [inline]
 __se_sys_close fs/open.c:1557 [inline]
 __x64_sys_close+0x87/0xf0 fs/open.c:1557
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x38/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

The buggy address belongs to the object at ffff888025635600
 which belongs to the cache kmalloc-128 of size 128
The buggy address is located 24 bytes inside of
 freed 128-byte region [ffff888025635600, ffff888025635680)

The buggy address belongs to the physical page:
page:ffffea0000958d40 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x25635
flags: 0xfff00000000800(slab|node=0|zone=1|lastcpupid=0x7ff)
page_type: 0xffffffff()
raw: 00fff00000000800 ffff888012c418c0 dead000000000100 dead000000000122
raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x12cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY), pid 4500, tgid 4500 (udevd), ts 28013160887, free_ts 27864795775
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook+0x2cf/0x340 mm/page_alloc.c:1536
 prep_new_page mm/page_alloc.c:1543 [inline]
 get_page_from_freelist+0x10d7/0x31b0 mm/page_alloc.c:3219
 __alloc_pages+0x1d0/0x4a0 mm/page_alloc.c:4475
 alloc_pages+0x1a9/0x270 mm/mempolicy.c:2298
 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+0x8be/0x1570 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+0x137/0x350 mm/slub.c:3517
 kmalloc_trace+0x25/0xe0 mm/slab_common.c:1095
 kmalloc include/linux/slab.h:600 [inline]
 kzalloc include/linux/slab.h:721 [inline]
 kernfs_get_open_node fs/kernfs/file.c:572 [inline]
 kernfs_fop_open+0xad1/0xe00 fs/kernfs/file.c:740
 do_dentry_open+0x88b/0x1730 fs/open.c:929
 do_open fs/namei.c:3636 [inline]
 path_openat+0x19af/0x29c0 fs/namei.c:3793
 do_filp_open+0x1de/0x430 fs/namei.c:3820
 do_sys_openat2+0x176/0x1e0 fs/open.c:1422
 do_sys_open fs/open.c:1437 [inline]
 __do_sys_openat fs/open.c:1453 [inline]
 __se_sys_openat fs/open.c:1448 [inline]
 __x64_sys_openat+0x175/0x210 fs/open.c:1448
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x38/0xb0 arch/x86/entry/common.c:80
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1136 [inline]
 free_unref_page_prepare+0x476/0xa40 mm/page_alloc.c:2348
 free_unref_page+0x33/0x3b0 mm/page_alloc.c:2441
 qlink_free mm/kasan/quarantine.c:166 [inline]
 qlist_free_all+0x6a/0x170 mm/kasan/quarantine.c:185
 kasan_quarantine_reduce+0x18b/0x1d0 mm/kasan/quarantine.c:292
 __kasan_slab_alloc+0x65/0x90 mm/kasan/common.c:305
 kasan_slab_alloc include/linux/kasan.h:188 [inline]
 slab_post_alloc_hook mm/slab.h:762 [inline]
 slab_alloc_node mm/slub.c:3478 [inline]
 slab_alloc mm/slub.c:3486 [inline]
 __kmem_cache_alloc_lru mm/slub.c:3493 [inline]
 kmem_cache_alloc+0x172/0x3b0 mm/slub.c:3502
 getname_flags.part.0+0x50/0x4d0 fs/namei.c:140
 getname_flags include/linux/audit.h:319 [inline]
 getname+0x90/0xe0 fs/namei.c:219
 do_sys_openat2+0x100/0x1e0 fs/open.c:1416
 do_sys_open fs/open.c:1437 [inline]
 __do_sys_openat fs/open.c:1453 [inline]
 __se_sys_openat fs/open.c:1448 [inline]
 __x64_sys_openat+0x175/0x210 fs/open.c:1448
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x38/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

Memory state around the buggy address:
 ffff888025635500: 00 00 00 00 00 00 00 00 00 00 00 00 00 fc fc fc
 ffff888025635580: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff888025635600: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                            ^
 ffff888025635680: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888025635700: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================


---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzkaller@googlegroups.com.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

If the bug is already fixed, let syzbot know by replying with:
#syz fix: exact-commit-title

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.

If you want to overwrite bug's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)

If the bug is a duplicate of another bug, reply with:
#syz dup: exact-subject-of-another-report

If you want to undo deduplication, reply with:
#syz undup

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

[syzbot]

syzbot has bisected this issue to:

commit 45c37c4e9c9aab5bb1cf5778d8e5ebd9f9ad820a
Author: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Date:   Wed Aug 9 23:49:33 2023 +0000

    Bluetooth: hci_sync: Fix UAF in hci_disconnect_all_sync

bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=1042c5ffa80000
start commit:   7271b2a53042 Add linux-next specific files for 20230818
git tree:       linux-next
final oops:     https://syzkaller.appspot.com/x/report.txt?x=1242c5ffa80000
console output: https://syzkaller.appspot.com/x/log.txt?x=1442c5ffa80000
kernel config:  https://syzkaller.appspot.com/x/.config?x=1936af09cdef7dd6
dashboard link: https://syzkaller.appspot.com/bug?extid=a0c80b06ae2cb8895bc4
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=13506923a80000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=147569efa80000

Reported-by: syzbot+a0c80b06ae2cb8895bc4@syzkaller.appspotmail.com
Fixes: 45c37c4e9c9a ("Bluetooth: hci_sync: Fix UAF in hci_disconnect_all_sync")

For information about bisection process see: https://goo.gl/tpsmEJ#bisection

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

[syzbot]

syzbot suspects this issue was fixed by commit:

commit 181a42edddf51d5d9697ecdf365d72ebeab5afb0
Author: Ziyang Xuan <william.xuanziyang@huawei.com>
Date:   Wed Oct 11 09:57:31 2023 +0000

    Bluetooth: Make handle of hci_conn be unique

bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=127944c1e80000
start commit:   4b2b606075e5 ipv4/fib: send notify when delete source addr..
git tree:       net
kernel config:  https://syzkaller.appspot.com/x/.config?x=d594086f139d167
dashboard link: https://syzkaller.appspot.com/bug?extid=a0c80b06ae2cb8895bc4
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=138aad9e680000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=125e0b92680000

If the result looks correct, please mark the issue as fixed by replying with:

#syz fix: Bluetooth: Make handle of hci_conn be unique

For information about bisection process see: https://goo.gl/tpsmEJ#bisection

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

[syzbot]

Hello,

syzbot has tested the proposed patch and the reproducer did not trigger any issue:

Reported-and-tested-by: syzbot+a0c80b06ae2cb8895bc4@syzkaller.appspotmail.com

Tested on:

commit:         62dc2425 Bluetooth: ISO: Fix invalid context error
git tree:       git://git.kernel.org/pub/scm/linux/kernel/git/bluetooth/bluetooth-next.git master
console output: https://syzkaller.appspot.com/x/log.txt?x=12897062680000
kernel config:  https://syzkaller.appspot.com/x/.config?x=3d83e69abefedb6e
dashboard link: https://syzkaller.appspot.com/bug?extid=a0c80b06ae2cb8895bc4
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
userspace arch: arm64
patch:          https://syzkaller.appspot.com/x/patch.diff?x=14a7711a680000

Note: testing is done by a robot and is best-effort only.

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

[syzbot]

Hello,

syzbot has tested the proposed patch and the reproducer did not trigger any issue:

Reported-and-tested-by: syzbot+a0c80b06ae2cb8895bc4@syzkaller.appspotmail.com

Tested on:

commit:         7271b2a5 Add linux-next specific files for 20230818
git tree:       https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git
console output: https://syzkaller.appspot.com/x/log.txt?x=1032fd40680000
kernel config:  https://syzkaller.appspot.com/x/.config?x=1936af09cdef7dd6
dashboard link: https://syzkaller.appspot.com/bug?extid=a0c80b06ae2cb8895bc4
compiler:       gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
patch:          https://syzkaller.appspot.com/x/patch.diff?x=1496adb7a80000

Note: testing is done by a robot and is best-effort only.

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

[syzbot]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
KASAN: slab-use-after-free Read in l2cap_chan_del

==================================================================
BUG: KASAN: slab-use-after-free in hci_conn_drop include/net/bluetooth/hci_core.h:1549 [inline]
BUG: KASAN: slab-use-after-free in hci_conn_drop include/net/bluetooth/hci_core.h:1519 [inline]
BUG: KASAN: slab-use-after-free in l2cap_chan_del+0xa0b/0xa70 net/bluetooth/l2cap_core.c:668
Read of size 8 at addr ffff888073cb0718 by task kworker/1:0/23

CPU: 1 PID: 23 Comm: kworker/1:0 Not tainted 6.5.0-rc6-next-20230818-syzkaller-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/26/2023
Workqueue: events l2cap_chan_timeout
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
 hci_conn_drop include/net/bluetooth/hci_core.h:1549 [inline]
 hci_conn_drop include/net/bluetooth/hci_core.h:1519 [inline]
 l2cap_chan_del+0xa0b/0xa70 net/bluetooth/l2cap_core.c:668
 l2cap_chan_close+0xff/0xa20 net/bluetooth/l2cap_core.c:851
 l2cap_chan_timeout+0x17d/0x2f0 net/bluetooth/l2cap_core.c:452
 process_one_work+0x887/0x15d0 kernel/workqueue.c:2630
 process_scheduled_works kernel/workqueue.c:2703 [inline]
 worker_thread+0x8bb/0x1290 kernel/workqueue.c:2784
 kthread+0x33a/0x430 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:304
 </TASK>

Allocated by task 78:
 kasan_save_stack+0x33/0x50 mm/kasan/common.c:45
 kasan_set_track+0x25/0x30 mm/kasan/common.c:52
 __kasan_slab_alloc+0x81/0x90 mm/kasan/common.c:328
 kasan_slab_alloc include/linux/kasan.h:188 [inline]
 slab_post_alloc_hook mm/slab.h:762 [inline]
 slab_alloc_node mm/slub.c:3478 [inline]
 kmem_cache_alloc_node+0x185/0x3f0 mm/slub.c:3523
 kmalloc_reserve+0x167/0x270 net/core/skbuff.c:559
 pskb_expand_head+0x236/0x1170 net/core/skbuff.c:2087
 netlink_trim+0x1eb/0x240 net/netlink/af_netlink.c:1324
 netlink_broadcast_filtered+0xc5/0xf00 net/netlink/af_netlink.c:1531
 netlink_broadcast+0x39/0x50 net/netlink/af_netlink.c:1576
 nlmsg_multicast include/net/netlink.h:1079 [inline]
 genlmsg_multicast_netns include/net/genetlink.h:454 [inline]
 devlink_trap_notify net/devlink/leftover.c:8813 [inline]
 devlink_trap_notify+0x1a9/0x240 net/devlink/leftover.c:8791
 devlink_trap_unregister+0x127/0x3a0 net/devlink/leftover.c:8871
 devl_traps_unregister+0x233/0x2f0 net/devlink/leftover.c:8978
 nsim_dev_traps_exit+0x53/0x170 drivers/net/netdevsim/dev.c:936
 nsim_dev_reload_destroy+0x1e0/0x560 drivers/net/netdevsim/dev.c:1663
 nsim_dev_reload_down+0x6e/0xd0 drivers/net/netdevsim/dev.c:965
 devlink_reload+0x11c/0x450 net/devlink/dev.c:363
 devlink_pernet_pre_exit+0x1ce/0x2a0 net/devlink/core.c:282
 ops_pre_exit_list net/core/net_namespace.c:160 [inline]
 cleanup_net+0x46c/0xb20 net/core/net_namespace.c:602
 process_one_work+0x887/0x15d0 kernel/workqueue.c:2630
 process_scheduled_works kernel/workqueue.c:2703 [inline]
 worker_thread+0x8bb/0x1290 kernel/workqueue.c:2784
 kthread+0x33a/0x430 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:304

Freed by task 78:
 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+0xf0/0x480 mm/slub.c:3831
 skb_kfree_head net/core/skbuff.c:937 [inline]
 skb_kfree_head net/core/skbuff.c:934 [inline]
 skb_free_head+0x17f/0x1b0 net/core/skbuff.c:951
 skb_release_data+0x5ba/0x870 net/core/skbuff.c:981
 skb_release_all net/core/skbuff.c:1047 [inline]
 __kfree_skb net/core/skbuff.c:1061 [inline]
 consume_skb net/core/skbuff.c:1277 [inline]
 consume_skb+0xd2/0x170 net/core/skbuff.c:1271
 netlink_broadcast_filtered+0x3d4/0xf00 net/netlink/af_netlink.c:1554
 netlink_broadcast+0x39/0x50 net/netlink/af_netlink.c:1576
 nlmsg_multicast include/net/netlink.h:1079 [inline]
 genlmsg_multicast_netns include/net/genetlink.h:454 [inline]
 devlink_trap_notify net/devlink/leftover.c:8813 [inline]
 devlink_trap_notify+0x1a9/0x240 net/devlink/leftover.c:8791
 devlink_trap_unregister+0x127/0x3a0 net/devlink/leftover.c:8871
 devl_traps_unregister+0x233/0x2f0 net/devlink/leftover.c:8978
 nsim_dev_traps_exit+0x53/0x170 drivers/net/netdevsim/dev.c:936
 nsim_dev_reload_destroy+0x1e0/0x560 drivers/net/netdevsim/dev.c:1663
 nsim_dev_reload_down+0x6e/0xd0 drivers/net/netdevsim/dev.c:965
 devlink_reload+0x11c/0x450 net/devlink/dev.c:363
 devlink_pernet_pre_exit+0x1ce/0x2a0 net/devlink/core.c:282
 ops_pre_exit_list net/core/net_namespace.c:160 [inline]
 cleanup_net+0x46c/0xb20 net/core/net_namespace.c:602
 process_one_work+0x887/0x15d0 kernel/workqueue.c:2630
 process_scheduled_works kernel/workqueue.c:2703 [inline]
 worker_thread+0x8bb/0x1290 kernel/workqueue.c:2784
 kthread+0x33a/0x430 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:304

The buggy address belongs to the object at ffff888073cb0600
 which belongs to the cache skbuff_small_head of size 640
The buggy address is located 280 bytes inside of
 freed 640-byte region [ffff888073cb0600, ffff888073cb0880)

The buggy address belongs to the physical page:
page:ffffea0001cf2c00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x73cb0
head:ffffea0001cf2c00 order:2 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0xfff00000000840(slab|head|node=0|zone=1|lastcpupid=0x7ff)
page_type: 0xffffffff()
raw: 00fff00000000840 ffff888019a6a8c0 dead000000000122 0000000000000000
raw: 0000000000000000 0000000000150015 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 2, migratetype Unmovable, gfp_mask 0x1d28c0(GFP_NOWAIT|__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL), pid 78, tgid 78 (kworker/u4:5), ts 454224323940, free_ts 453753622092
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook+0x2cf/0x340 mm/page_alloc.c:1536
 prep_new_page mm/page_alloc.c:1543 [inline]
 get_page_from_freelist+0x10d7/0x31b0 mm/page_alloc.c:3219
 __alloc_pages+0x1d0/0x4a0 mm/page_alloc.c:4475
 alloc_pages+0x1a9/0x270 mm/mempolicy.c:2298
 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+0x8be/0x1570 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+0x137/0x3f0 mm/slub.c:3523
 kmalloc_reserve+0x167/0x270 net/core/skbuff.c:559
 pskb_expand_head+0x236/0x1170 net/core/skbuff.c:2087
 netlink_trim+0x1eb/0x240 net/netlink/af_netlink.c:1324
 netlink_broadcast_filtered+0xc5/0xf00 net/netlink/af_netlink.c:1531
 netlink_broadcast+0x39/0x50 net/netlink/af_netlink.c:1576
 nlmsg_multicast include/net/netlink.h:1079 [inline]
 genlmsg_multicast_netns include/net/genetlink.h:454 [inline]
 devlink_trap_notify net/devlink/leftover.c:8813 [inline]
 devlink_trap_notify+0x1a9/0x240 net/devlink/leftover.c:8791
 devlink_trap_unregister+0x127/0x3a0 net/devlink/leftover.c:8871
 devl_traps_unregister+0x233/0x2f0 net/devlink/leftover.c:8978
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1136 [inline]
 free_unref_page_prepare+0x476/0xa40 mm/page_alloc.c:2348
 free_unref_page+0x33/0x3b0 mm/page_alloc.c:2441
 __stack_depot_save+0x193/0x510 lib/stackdepot.c:443
 kasan_save_stack+0x43/0x50 mm/kasan/common.c:46
 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]
 nf_nat_masq_schedule.part.0+0x290/0x610 net/netfilter/nf_nat_masquerade.c:118
 nf_nat_masq_schedule net/netfilter/nf_nat_masquerade.c:108 [inline]
 masq_device_event+0xee/0x120 net/netfilter/nf_nat_masquerade.c:162
 notifier_call_chain+0xb6/0x3b0 kernel/notifier.c:93
 call_netdevice_notifiers_info+0xb9/0x130 net/core/dev.c:1970
 call_netdevice_notifiers_extack net/core/dev.c:2008 [inline]
 call_netdevice_notifiers net/core/dev.c:2022 [inline]
 dev_close_many+0x305/0x640 net/core/dev.c:1563
 unregister_netdevice_many_notify+0x41b/0x1a20 net/core/dev.c:10908
 unregister_netdevice_many net/core/dev.c:10991 [inline]
 unregister_netdevice_queue+0x2e5/0x3c0 net/core/dev.c:10871
 unregister_netdevice include/linux/netdevice.h:3106 [inline]
 __tun_detach+0x116f/0x1470 drivers/net/tun.c:684
 tun_detach drivers/net/tun.c:700 [inline]
 tun_chr_close+0xc8/0x240 drivers/net/tun.c:3496
 __fput+0x3f7/0xa70 fs/file_table.c:384

Memory state around the buggy address:
 ffff888073cb0600: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888073cb0680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888073cb0700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                            ^
 ffff888073cb0780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888073cb0800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================


Tested on:

commit:         7271b2a5 Add linux-next specific files for 20230818
git tree:       https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git
console output: https://syzkaller.appspot.com/x/log.txt?x=1372b89fa80000
kernel config:  https://syzkaller.appspot.com/x/.config?x=1936af09cdef7dd6
dashboard link: https://syzkaller.appspot.com/bug?extid=a0c80b06ae2cb8895bc4
compiler:       gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
patch:          https://syzkaller.appspot.com/x/patch.diff?x=11e1e55ba80000

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

[syzbot]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
KASAN: use-after-free Read in hci_get_route

==================================================================
BUG: KASAN: use-after-free in instrument_atomic_read include/linux/instrumented.h:68 [inline]
BUG: KASAN: use-after-free in _test_bit include/asm-generic/bitops/instrumented-non-atomic.h:141 [inline]
BUG: KASAN: use-after-free in hci_get_route+0x1cc/0x510 net/bluetooth/hci_conn.c:1156
Read of size 8 at addr ffff888068d1c0a8 by task syz-executor.0/5857

CPU: 0 PID: 5857 Comm: syz-executor.0 Not tainted 6.5.0-rc6-next-20230818-syzkaller-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/26/2023
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
 check_region_inline mm/kasan/generic.c:181 [inline]
 kasan_check_range+0xef/0x190 mm/kasan/generic.c:187
 instrument_atomic_read include/linux/instrumented.h:68 [inline]
 _test_bit include/asm-generic/bitops/instrumented-non-atomic.h:141 [inline]
 hci_get_route+0x1cc/0x510 net/bluetooth/hci_conn.c:1156
 get_l2cap_conn.constprop.0+0xe9/0x6b0 net/bluetooth/6lowpan.c:968
 lowpan_control_write+0x1ba/0x730 net/bluetooth/6lowpan.c:1100
 full_proxy_write+0x124/0x190 fs/debugfs/file.c:236
 vfs_write+0x2a4/0xe40 fs/read_write.c:582
 ksys_write+0x12f/0x250 fs/read_write.c:637
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x38/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f728f47cae9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f72900ee0c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f728f59bf80 RCX: 00007f728f47cae9
RDX: 000000000000001b RSI: 0000000020000280 RDI: 0000000000000003
RBP: 00007f728f4c847a R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000000b R14: 00007f728f59bf80 R15: 00007ffd19482978
 </TASK>

The buggy address belongs to the physical page:
page:ffffea0001a34700 refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x68d1c
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
page_type: 0xffffffff()
raw: 00fff00000000000 ffffea00008a6e08 ffff8880b9842670 0000000000000000
raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as freed
page last allocated via order 2, migratetype Unmovable, gfp_mask 0x140dc0(GFP_USER|__GFP_COMP|__GFP_ZERO), pid 5393, tgid 5393 (syz-executor.0), ts 86181654329, free_ts 106465252737
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook+0x2cf/0x340 mm/page_alloc.c:1536
 prep_new_page mm/page_alloc.c:1543 [inline]
 get_page_from_freelist+0x10d7/0x31b0 mm/page_alloc.c:3219
 __alloc_pages+0x1d0/0x4a0 mm/page_alloc.c:4475
 __alloc_pages_node include/linux/gfp.h:237 [inline]
 alloc_pages_node include/linux/gfp.h:260 [inline]
 __kmalloc_large_node+0x87/0x1c0 mm/slab_common.c:1145
 __do_kmalloc_node mm/slab_common.c:992 [inline]
 __kmalloc.cold+0xb/0xe0 mm/slab_common.c:1017
 kmalloc include/linux/slab.h:604 [inline]
 kzalloc include/linux/slab.h:721 [inline]
 hci_alloc_dev_priv+0x1d/0x2770 net/bluetooth/hci_core.c:2467
 hci_alloc_dev include/net/bluetooth/hci_core.h:1598 [inline]
 __vhci_create_device+0xf7/0x800 drivers/bluetooth/hci_vhci.c:402
 vhci_create_device drivers/bluetooth/hci_vhci.c:475 [inline]
 vhci_get_user drivers/bluetooth/hci_vhci.c:532 [inline]
 vhci_write+0x2c7/0x470 drivers/bluetooth/hci_vhci.c:612
 call_write_iter include/linux/fs.h:1983 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x650/0xe40 fs/read_write.c:584
 ksys_write+0x12f/0x250 fs/read_write.c:637
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x38/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1136 [inline]
 free_unref_page_prepare+0x476/0xa40 mm/page_alloc.c:2348
 free_unref_page+0x33/0x3b0 mm/page_alloc.c:2441
 bt_host_release+0x87/0xb0 net/bluetooth/hci_sysfs.c:95
 device_release+0xa1/0x240 drivers/base/core.c:2484
 kobject_cleanup lib/kobject.c:689 [inline]
 kobject_release lib/kobject.c:720 [inline]
 kref_put include/linux/kref.h:65 [inline]
 kobject_put+0x1f7/0x5b0 lib/kobject.c:737
 put_device+0x1f/0x30 drivers/base/core.c:3731
 hci_dev_put include/net/bluetooth/hci_core.h:1558 [inline]
 hci_conn_timeout+0x215/0x2d0 net/bluetooth/hci_conn.c:633
 process_one_work+0x887/0x15d0 kernel/workqueue.c:2630
 process_scheduled_works kernel/workqueue.c:2703 [inline]
 worker_thread+0x8bb/0x1290 kernel/workqueue.c:2784
 kthread+0x33a/0x430 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:304

Memory state around the buggy address:
 ffff888068d1bf80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff888068d1c000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff888068d1c080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                                  ^
 ffff888068d1c100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff888068d1c180: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================


Tested on:

commit:         7271b2a5 Add linux-next specific files for 20230818
git tree:       https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git
console output: https://syzkaller.appspot.com/x/log.txt?x=11425db7a80000
kernel config:  https://syzkaller.appspot.com/x/.config?x=1936af09cdef7dd6
dashboard link: https://syzkaller.appspot.com/bug?extid=a0c80b06ae2cb8895bc4
compiler:       gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
patch:          https://syzkaller.appspot.com/x/patch.diff?x=170c63a7a80000

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

[syzbot]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
KASAN: use-after-free Read in hci_cmd_sync_queue

==================================================================
BUG: KASAN: use-after-free in instrument_atomic_read include/linux/instrumented.h:68 [inline]
BUG: KASAN: use-after-free in _test_bit include/asm-generic/bitops/instrumented-non-atomic.h:141 [inline]
BUG: KASAN: use-after-free in hci_cmd_sync_queue+0x31/0xa0 net/bluetooth/hci_sync.c:736
Read of size 8 at addr ffff88806a2f00a8 by task kworker/u4:3/48

CPU: 0 PID: 48 Comm: kworker/u4:3 Not tainted 6.5.0-rc6-next-20230818-syzkaller-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/26/2023
Workqueue: events_unbound hci_conn_timeout
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
 check_region_inline mm/kasan/generic.c:181 [inline]
 kasan_check_range+0xef/0x190 mm/kasan/generic.c:187
 instrument_atomic_read include/linux/instrumented.h:68 [inline]
 _test_bit include/asm-generic/bitops/instrumented-non-atomic.h:141 [inline]
 hci_cmd_sync_queue+0x31/0xa0 net/bluetooth/hci_sync.c:736
 hci_abort_conn+0x15b/0x330 net/bluetooth/hci_conn.c:2912
 hci_conn_timeout+0x1a9/0x210 net/bluetooth/hci_conn.c:631
 process_one_work+0x887/0x15d0 kernel/workqueue.c:2630
 process_scheduled_works kernel/workqueue.c:2703 [inline]
 worker_thread+0x8bb/0x1290 kernel/workqueue.c:2784
 kthread+0x33a/0x430 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:304
 </TASK>

The buggy address belongs to the physical page:
page:ffffea0001a8bc00 refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x6a2f0
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
page_type: 0xffffffff()
raw: 00fff00000000000 ffffea0001957c08 ffffea0001a25708 0000000000000000
raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as freed
page last allocated via order 2, migratetype Unmovable, gfp_mask 0x5c2cc0(GFP_USER|__GFP_NOWARN|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_ACCOUNT), pid 4708, tgid 4708 (dhcpcd), ts 454062019777, free_ts 454066820991
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook+0x2cf/0x340 mm/page_alloc.c:1536
 prep_new_page mm/page_alloc.c:1543 [inline]
 get_page_from_freelist+0x10d7/0x31b0 mm/page_alloc.c:3219
 __alloc_pages+0x1d0/0x4a0 mm/page_alloc.c:4475
 __alloc_pages_node include/linux/gfp.h:237 [inline]
 alloc_pages_node include/linux/gfp.h:260 [inline]
 __kmalloc_large_node+0x87/0x1c0 mm/slab_common.c:1145
 __do_kmalloc_node mm/slab_common.c:992 [inline]
 __kmalloc_node_track_caller.cold+0x5/0xdd mm/slab_common.c:1024
 kmalloc_reserve+0xef/0x270 net/core/skbuff.c:575
 __alloc_skb+0x12b/0x330 net/core/skbuff.c:644
 alloc_skb include/linux/skbuff.h:1286 [inline]
 alloc_skb_with_frags+0xe4/0x710 net/core/skbuff.c:6274
 sock_alloc_send_pskb+0x7c8/0x950 net/core/sock.c:2794
 unix_dgram_sendmsg+0x455/0x1c30 net/unix/af_unix.c:1953
 sock_sendmsg_nosec net/socket.c:730 [inline]
 sock_sendmsg+0xd9/0x180 net/socket.c:753
 sock_write_iter+0x29b/0x3d0 net/socket.c:1140
 call_write_iter include/linux/fs.h:1983 [inline]
 do_iter_readv_writev+0x21e/0x3c0 fs/read_write.c:735
 do_iter_write+0x17f/0x830 fs/read_write.c:860
 vfs_writev+0x221/0x700 fs/read_write.c:933
 do_writev+0x285/0x370 fs/read_write.c:976
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1136 [inline]
 free_unref_page_prepare+0x476/0xa40 mm/page_alloc.c:2348
 free_unref_page+0x33/0x3b0 mm/page_alloc.c:2441
 skb_kfree_head net/core/skbuff.c:939 [inline]
 skb_free_head+0x110/0x1b0 net/core/skbuff.c:951
 skb_release_data+0x5ba/0x870 net/core/skbuff.c:981
 skb_release_all net/core/skbuff.c:1047 [inline]
 __kfree_skb net/core/skbuff.c:1061 [inline]
 consume_skb net/core/skbuff.c:1277 [inline]
 consume_skb+0xd2/0x170 net/core/skbuff.c:1271
 __unix_dgram_recvmsg+0x814/0xe50 net/unix/af_unix.c:2442
 unix_dgram_recvmsg+0xc3/0xf0 net/unix/af_unix.c:2459
 sock_recvmsg_nosec net/socket.c:1026 [inline]
 sock_recvmsg+0xe2/0x170 net/socket.c:1048
 sock_read_iter+0x2c3/0x3c0 net/socket.c:1118
 call_read_iter include/linux/fs.h:1977 [inline]
 do_iter_readv_writev+0x2f2/0x3c0 fs/read_write.c:733
 do_iter_read+0x315/0x870 fs/read_write.c:795
 vfs_readv+0x12d/0x1a0 fs/read_write.c:915
 do_readv+0x285/0x370 fs/read_write.c:952
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x38/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

Memory state around the buggy address:
 ffff88806a2eff80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88806a2f0000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff88806a2f0080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                                  ^
 ffff88806a2f0100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88806a2f0180: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================


Tested on:

commit:         7271b2a5 Add linux-next specific files for 20230818
git tree:       https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git
console output: https://syzkaller.appspot.com/x/log.txt?x=1005e760680000
kernel config:  https://syzkaller.appspot.com/x/.config?x=1936af09cdef7dd6
dashboard link: https://syzkaller.appspot.com/bug?extid=a0c80b06ae2cb8895bc4
compiler:       gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
patch:          https://syzkaller.appspot.com/x/patch.diff?x=145e5f5ba80000

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

[syzbot]

Hello,

syzbot has tested the proposed patch and the reproducer did not trigger any issue:

Reported-and-tested-by: syzbot+a0c80b06ae2cb8895bc4@syzkaller.appspotmail.com

Tested on:

commit:         2a05334d Bluetooth: btusb: Do not call kfree_skb() und..
git tree:       git://git.kernel.org/pub/scm/linux/kernel/git/bluetooth/bluetooth-next.git master
console output: https://syzkaller.appspot.com/x/log.txt?x=1521e55ba80000
kernel config:  https://syzkaller.appspot.com/x/.config?x=e532e371ba4b65ca
dashboard link: https://syzkaller.appspot.com/bug?extid=a0c80b06ae2cb8895bc4
compiler:       gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
patch:          https://syzkaller.appspot.com/x/patch.diff?x=11eaff5ba80000

Note: testing is done by a robot and is best-effort only.

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

[syzbot]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
INFO: task hung in l2cap_chan_timeout

INFO: task kworker/0:0:8 blocked for more than 143 seconds.
      Not tainted 6.5.0-rc6-next-20230818-syzkaller-dirty #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/0:0     state:D stack:26488 pid:8     ppid:2      flags:0x00004000
Workqueue: events l2cap_chan_timeout
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5382 [inline]
 __schedule+0xee1/0x59f0 kernel/sched/core.c:6695
 schedule+0xe7/0x1b0 kernel/sched/core.c:6771
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:6830
 __mutex_lock_common kernel/locking/mutex.c:679 [inline]
 __mutex_lock+0x967/0x1340 kernel/locking/mutex.c:747
 l2cap_chan_timeout+0x68/0x2f0 net/bluetooth/l2cap_core.c:438
 process_one_work+0x887/0x15d0 kernel/workqueue.c:2630
 process_scheduled_works kernel/workqueue.c:2703 [inline]
 worker_thread+0x8bb/0x1290 kernel/workqueue.c:2784
 kthread+0x33a/0x430 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:304
 </TASK>
INFO: task kworker/0:1:9 blocked for more than 143 seconds.
      Not tainted 6.5.0-rc6-next-20230818-syzkaller-dirty #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/0:1     state:D stack:28784 pid:9     ppid:2      flags:0x00004000
Workqueue: events l2cap_chan_timeout
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5382 [inline]
 __schedule+0xee1/0x59f0 kernel/sched/core.c:6695
 schedule+0xe7/0x1b0 kernel/sched/core.c:6771
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:6830
 __mutex_lock_common kernel/locking/mutex.c:679 [inline]
 __mutex_lock+0x967/0x1340 kernel/locking/mutex.c:747
 l2cap_chan_timeout+0x68/0x2f0 net/bluetooth/l2cap_core.c:438
 process_one_work+0x887/0x15d0 kernel/workqueue.c:2630
 process_scheduled_works kernel/workqueue.c:2703 [inline]
 worker_thread+0x8bb/0x1290 kernel/workqueue.c:2784
 kthread+0x33a/0x430 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:304
 </TASK>
INFO: task kworker/1:0:23 blocked for more than 143 seconds.
      Not tainted 6.5.0-rc6-next-20230818-syzkaller-dirty #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/1:0     state:D stack:25448 pid:23    ppid:2      flags:0x00004000
Workqueue: events l2cap_chan_timeout
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5382 [inline]
 __schedule+0xee1/0x59f0 kernel/sched/core.c:6695
 schedule+0xe7/0x1b0 kernel/sched/core.c:6771
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:6830
 __mutex_lock_common kernel/locking/mutex.c:679 [inline]
 __mutex_lock+0x967/0x1340 kernel/locking/mutex.c:747
 l2cap_chan_timeout+0x68/0x2f0 net/bluetooth/l2cap_core.c:438
 process_one_work+0x887/0x15d0 kernel/workqueue.c:2630
 process_scheduled_works kernel/workqueue.c:2703 [inline]
 worker_thread+0x8bb/0x1290 kernel/workqueue.c:2784
 kthread+0x33a/0x430 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:304
 </TASK>
INFO: task kworker/1:1:27 blocked for more than 143 seconds.
      Not tainted 6.5.0-rc6-next-20230818-syzkaller-dirty #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/1:1     state:D stack:25880 pid:27    ppid:2      flags:0x00004000
Workqueue: events l2cap_chan_timeout
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5382 [inline]
 __schedule+0xee1/0x59f0 kernel/sched/core.c:6695
 schedule+0xe7/0x1b0 kernel/sched/core.c:6771
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:6830
 __mutex_lock_common kernel/locking/mutex.c:679 [inline]
 __mutex_lock+0x967/0x1340 kernel/locking/mutex.c:747
 l2cap_chan_timeout+0x68/0x2f0 net/bluetooth/l2cap_core.c:438
 process_one_work+0x887/0x15d0 kernel/workqueue.c:2630
 process_scheduled_works kernel/workqueue.c:2703 [inline]
 worker_thread+0x8bb/0x1290 kernel/workqueue.c:2784
 kthread+0x33a/0x430 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:304
 </TASK>
INFO: task kworker/u5:0:50 blocked for more than 144 seconds.
      Not tainted 6.5.0-rc6-next-20230818-syzkaller-dirty #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u5:0    state:D stack:27704 pid:50    ppid:2      flags:0x00004000
Workqueue: hci0 hci_cmd_sync_work
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5382 [inline]
 __schedule+0xee1/0x59f0 kernel/sched/core.c:6695
 schedule+0xe7/0x1b0 kernel/sched/core.c:6771
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:6830
 __mutex_lock_common kernel/locking/mutex.c:679 [inline]
 __mutex_lock+0x967/0x1340 kernel/locking/mutex.c:747
 l2cap_chan_del+0x2b3/0xaa0 net/bluetooth/l2cap_core.c:659
 l2cap_conn_del+0x3ce/0x870 net/bluetooth/l2cap_core.c:1918
 l2cap_connect_cfm+0xa10/0xf90 net/bluetooth/l2cap_core.c:8232
 hci_connect_cfm include/net/bluetooth/hci_core.h:1933 [inline]
 hci_conn_failed+0x196/0x320 net/bluetooth/hci_conn.c:1235
 hci_abort_conn_sync+0xacb/0xe20 net/bluetooth/hci_sync.c:5432
 abort_conn_sync+0x18e/0x3a0 net/bluetooth/hci_conn.c:2878
 hci_cmd_sync_work+0x1a4/0x3c0 net/bluetooth/hci_sync.c:306
 process_one_work+0x887/0x15d0 kernel/workqueue.c:2630
 process_scheduled_works kernel/workqueue.c:2703 [inline]
 worker_thread+0x8bb/0x1290 kernel/workqueue.c:2784
 kthread+0x33a/0x430 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:304
 </TASK>
INFO: task kworker/0:2:54 blocked for more than 144 seconds.
      Not tainted 6.5.0-rc6-next-20230818-syzkaller-dirty #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/0:2     state:D stack:25568 pid:54    ppid:2      flags:0x00004000
Workqueue: events l2cap_chan_timeout
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5382 [inline]
 __schedule+0xee1/0x59f0 kernel/sched/core.c:6695
 schedule+0xe7/0x1b0 kernel/sched/core.c:6771
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:6830
 __mutex_lock_common kernel/locking/mutex.c:679 [inline]
 __mutex_lock+0x967/0x1340 kernel/locking/mutex.c:747
 l2cap_chan_del+0x2b3/0xaa0 net/bluetooth/l2cap_core.c:659
 l2cap_chan_close+0xff/0xa20 net/bluetooth/l2cap_core.c:844
 l2cap_chan_timeout+0x17d/0x2f0 net/bluetooth/l2cap_core.c:452
 process_one_work+0x887/0x15d0 kernel/workqueue.c:2630
 process_scheduled_works kernel/workqueue.c:2703 [inline]
 worker_thread+0x8bb/0x1290 kernel/workqueue.c:2784
 kthread+0x33a/0x430 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:304
 </TASK>
INFO: task kworker/1:2:780 blocked for more than 144 seconds.
      Not tainted 6.5.0-rc6-next-20230818-syzkaller-dirty #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/1:2     state:D stack:26504 pid:780   ppid:2      flags:0x00004000
Workqueue: events l2cap_chan_timeout
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5382 [inline]
 __schedule+0xee1/0x59f0 kernel/sched/core.c:6695
 schedule+0xe7/0x1b0 kernel/sched/core.c:6771
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:6830
 __mutex_lock_common kernel/locking/mutex.c:679 [inline]
 __mutex_lock+0x967/0x1340 kernel/locking/mutex.c:747
 l2cap_chan_timeout+0x68/0x2f0 net/bluetooth/l2cap_core.c:438
 process_one_work+0x887/0x15d0 kernel/workqueue.c:2630
 process_scheduled_works kernel/workqueue.c:2703 [inline]
 worker_thread+0x8bb/0x1290 kernel/workqueue.c:2784
 kthread+0x33a/0x430 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:304
 </TASK>
INFO: task kworker/1:3:4456 blocked for more than 144 seconds.
      Not tainted 6.5.0-rc6-next-20230818-syzkaller-dirty #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/1:3     state:D stack:28128 pid:4456  ppid:2      flags:0x00004000
Workqueue: events l2cap_chan_timeout
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5382 [inline]
 __schedule+0xee1/0x59f0 kernel/sched/core.c:6695
 schedule+0xe7/0x1b0 kernel/sched/core.c:6771
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:6830
 __mutex_lock_common kernel/locking/mutex.c:679 [inline]
 __mutex_lock+0x967/0x1340 kernel/locking/mutex.c:747
 l2cap_chan_timeout+0x68/0x2f0 net/bluetooth/l2cap_core.c:438
 process_one_work+0x887/0x15d0 kernel/workqueue.c:2630
 process_scheduled_works kernel/workqueue.c:2703 [inline]
 worker_thread+0x8bb/0x1290 kernel/workqueue.c:2784
 kthread+0x33a/0x430 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:304
 </TASK>
INFO: task kworker/1:4:5053 blocked for more than 145 seconds.
      Not tainted 6.5.0-rc6-next-20230818-syzkaller-dirty #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/1:4     state:D stack:25112 pid:5053  ppid:2      flags:0x00004000
Workqueue: events l2cap_chan_timeout
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5382 [inline]
 __schedule+0xee1/0x59f0 kernel/sched/core.c:6695
 schedule+0xe7/0x1b0 kernel/sched/core.c:6771
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:6830
 __mutex_lock_common kernel/locking/mutex.c:679 [inline]
 __mutex_lock+0x967/0x1340 kernel/locking/mutex.c:747
 l2cap_chan_timeout+0x68/0x2f0 net/bluetooth/l2cap_core.c:438
 process_one_work+0x887/0x15d0 kernel/workqueue.c:2630
 process_scheduled_works kernel/workqueue.c:2703 [inline]
 worker_thread+0x8bb/0x1290 kernel/workqueue.c:2784
 kthread+0x33a/0x430 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:304
 </TASK>
INFO: task kworker/0:4:5059 blocked for more than 145 seconds.
      Not tainted 6.5.0-rc6-next-20230818-syzkaller-dirty #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/0:4     state:D stack:27920 pid:5059  ppid:2      flags:0x00004000
Workqueue: events l2cap_chan_timeout
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5382 [inline]
 __schedule+0xee1/0x59f0 kernel/sched/core.c:6695
 schedule+0xe7/0x1b0 kernel/sched/core.c:6771
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:6830
 __mutex_lock_common kernel/locking/mutex.c:679 [inline]
 __mutex_lock+0x967/0x1340 kernel/locking/mutex.c:747
 l2cap_chan_timeout+0x68/0x2f0 net/bluetooth/l2cap_core.c:438
 process_one_work+0x887/0x15d0 kernel/workqueue.c:2630
 process_scheduled_works kernel/workqueue.c:2703 [inline]
 worker_thread+0x8bb/0x1290 kernel/workqueue.c:2784
 kthread+0x33a/0x430 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:304
 </TASK>
Future hung task reports are suppressed, see sysctl kernel.hung_task_warnings
INFO: lockdep is turned off.
NMI backtrace for cpu 0
CPU: 0 PID: 29 Comm: khungtaskd Not tainted 6.5.0-rc6-next-20230818-syzkaller-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/26/2023
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xd9/0x1b0 lib/dump_stack.c:106
 nmi_cpu_backtrace+0x277/0x380 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x299/0x300 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:222 [inline]
 watchdog+0xfac/0x1230 kernel/hung_task.c:379
 kthread+0x33a/0x430 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:304
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1 skipped: idling at native_safe_halt arch/x86/include/asm/irqflags.h:48 [inline]
NMI backtrace for cpu 1 skipped: idling at arch_safe_halt arch/x86/include/asm/irqflags.h:86 [inline]
NMI backtrace for cpu 1 skipped: idling at acpi_safe_halt+0x1b/0x20 drivers/acpi/processor_idle.c:112


Tested on:

commit:         7271b2a5 Add linux-next specific files for 20230818
git tree:       https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git
console output: https://syzkaller.appspot.com/x/log.txt?x=109b2797a80000
kernel config:  https://syzkaller.appspot.com/x/.config?x=1936af09cdef7dd6
dashboard link: https://syzkaller.appspot.com/bug?extid=a0c80b06ae2cb8895bc4
compiler:       gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
patch:          https://syzkaller.appspot.com/x/patch.diff?x=146ec7cfa80000

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

[syzbot]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
WARNING in l2cap_chan_del

------------[ cut here ]------------
WARNING: CPU: 0 PID: 780 at kernel/workqueue.c:1725 __queue_work+0xb52/0x1060 kernel/workqueue.c:1724
Modules linked in:
CPU: 0 PID: 780 Comm: kworker/0:2 Not tainted 6.5.0-rc6-next-20230818-syzkaller-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/26/2023
Workqueue: events l2cap_chan_timeout
RIP: 0010:__queue_work+0xb52/0x1060 kernel/workqueue.c:1724
Code: 03 38 d0 7c 09 84 d2 74 05 e8 ea 54 87 00 8b 5b 2c 31 ff 83 e3 20 89 de e8 5b cf 31 00 85 db 0f 85 7f 01 00 00 e8 de d3 31 00 <0f> 0b e9 ca fa ff ff e8 d2 d3 31 00 0f 0b e9 76 fa ff ff e8 c6 d3
RSP: 0018:ffffc900046d7ac8 EFLAGS: 00010093
RAX: 0000000000000000 RBX: ffff888013650000 RCX: 0000000000000000
RDX: ffff88801d4d1dc0 RSI: ffffffff8155ff92 RDI: ffff888013650008
RBP: 0000000000000000 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000200000 R11: 0000000000000000 R12: ffff88806a634270
R13: ffffffff81dd2d93 R14: ffff88806a6342b8 R15: ffffffff81dd2d93
FS:  0000000000000000(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f98dec6b6c0 CR3: 000000000c976000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 __queue_delayed_work+0x1bf/0x260 kernel/workqueue.c:1950
 queue_delayed_work_on+0x106/0x130 kernel/workqueue.c:1986
 queue_delayed_work include/linux/workqueue.h:569 [inline]
 hci_conn_drop include/net/bluetooth/hci_core.h:1549 [inline]
 hci_conn_drop include/net/bluetooth/hci_core.h:1519 [inline]
 l2cap_chan_del+0x389/0x9b0 net/bluetooth/l2cap_core.c:659
 l2cap_chan_close+0xff/0xa20 net/bluetooth/l2cap_core.c:842
 l2cap_chan_timeout+0x17d/0x2f0 net/bluetooth/l2cap_core.c:452
 process_one_work+0x887/0x15d0 kernel/workqueue.c:2630
 process_scheduled_works kernel/workqueue.c:2703 [inline]
 worker_thread+0x8bb/0x1290 kernel/workqueue.c:2784
 kthread+0x33a/0x430 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:304
 </TASK>


Tested on:

commit:         7271b2a5 Add linux-next specific files for 20230818
git tree:       https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git
console output: https://syzkaller.appspot.com/x/log.txt?x=1333e4dfa80000
kernel config:  https://syzkaller.appspot.com/x/.config?x=1936af09cdef7dd6
dashboard link: https://syzkaller.appspot.com/bug?extid=a0c80b06ae2cb8895bc4
compiler:       gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
patch:          https://syzkaller.appspot.com/x/patch.diff?x=1361735ba80000

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

[syzbot]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
KASAN: slab-out-of-bounds Read in l2cap_chan_del

==================================================================
BUG: KASAN: slab-out-of-bounds in hci_conn_drop include/net/bluetooth/hci_core.h:1549 [inline]
BUG: KASAN: slab-out-of-bounds in hci_conn_drop include/net/bluetooth/hci_core.h:1519 [inline]
BUG: KASAN: slab-out-of-bounds in l2cap_chan_del+0xa0b/0xa70 net/bluetooth/l2cap_core.c:668
Read of size 8 at addr ffff888068778718 by task kworker/0:0/8

CPU: 0 PID: 8 Comm: kworker/0:0 Not tainted 6.5.0-rc6-next-20230818-syzkaller-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/26/2023
Workqueue: events l2cap_chan_timeout
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
 hci_conn_drop include/net/bluetooth/hci_core.h:1549 [inline]
 hci_conn_drop include/net/bluetooth/hci_core.h:1519 [inline]
 l2cap_chan_del+0xa0b/0xa70 net/bluetooth/l2cap_core.c:668
 l2cap_chan_close+0xff/0xa20 net/bluetooth/l2cap_core.c:851
 l2cap_chan_timeout+0x17d/0x2f0 net/bluetooth/l2cap_core.c:452
 process_one_work+0x887/0x15d0 kernel/workqueue.c:2630
 process_scheduled_works kernel/workqueue.c:2703 [inline]
 worker_thread+0x8bb/0x1290 kernel/workqueue.c:2784
 kthread+0x33a/0x430 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:304
 </TASK>

Allocated by task 4708:
 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
 kasan_kmalloc include/linux/kasan.h:198 [inline]
 __do_kmalloc_node mm/slab_common.c:1004 [inline]
 __kmalloc_node_track_caller+0x61/0x100 mm/slab_common.c:1024
 kmalloc_reserve+0xef/0x270 net/core/skbuff.c:575
 __alloc_skb+0x12b/0x330 net/core/skbuff.c:644
 alloc_skb include/linux/skbuff.h:1286 [inline]
 alloc_skb_with_frags+0xe4/0x710 net/core/skbuff.c:6274
 sock_alloc_send_pskb+0x7c8/0x950 net/core/sock.c:2794
 unix_dgram_sendmsg+0x455/0x1c30 net/unix/af_unix.c:1953
 sock_sendmsg_nosec net/socket.c:730 [inline]
 sock_sendmsg+0xd9/0x180 net/socket.c:753
 sock_write_iter+0x29b/0x3d0 net/socket.c:1140
 call_write_iter include/linux/fs.h:1983 [inline]
 do_iter_readv_writev+0x21e/0x3c0 fs/read_write.c:735
 do_iter_write+0x17f/0x830 fs/read_write.c:860
 vfs_writev+0x221/0x700 fs/read_write.c:933
 do_writev+0x285/0x370 fs/read_write.c:976
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x38/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

Freed by task 4707:
 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+0xb8/0x2f0 mm/slub.c:3822
 skb_kfree_head net/core/skbuff.c:939 [inline]
 skb_free_head+0x110/0x1b0 net/core/skbuff.c:951
 skb_release_data+0x5ba/0x870 net/core/skbuff.c:981
 skb_release_all net/core/skbuff.c:1047 [inline]
 __kfree_skb net/core/skbuff.c:1061 [inline]
 consume_skb net/core/skbuff.c:1277 [inline]
 consume_skb+0xd2/0x170 net/core/skbuff.c:1271
 __unix_dgram_recvmsg+0x814/0xe50 net/unix/af_unix.c:2442
 unix_dgram_recvmsg+0xc3/0xf0 net/unix/af_unix.c:2459
 sock_recvmsg_nosec net/socket.c:1026 [inline]
 sock_recvmsg+0xe2/0x170 net/socket.c:1048
 sock_read_iter+0x2c3/0x3c0 net/socket.c:1118
 call_read_iter include/linux/fs.h:1977 [inline]
 do_iter_readv_writev+0x2f2/0x3c0 fs/read_write.c:733
 do_iter_read+0x315/0x870 fs/read_write.c:795
 vfs_readv+0x12d/0x1a0 fs/read_write.c:915
 do_readv+0x285/0x370 fs/read_write.c:952
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x38/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

The buggy address belongs to the object at ffff888068778400
 which belongs to the cache kmalloc-cg-512 of size 512
The buggy address is located 280 bytes to the right of
 allocated 512-byte region [ffff888068778400, ffff888068778600)

The buggy address belongs to the physical page:
page:ffffea0001a1de00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x68778
head:ffffea0001a1de00 order:2 entire_mapcount:0 nr_pages_mapped:0 pincount:0
memcg:ffff88801937bc01
flags: 0xfff00000000840(slab|head|node=0|zone=1|lastcpupid=0x7ff)
page_type: 0xffffffff()
raw: 00fff00000000840 ffff888012c4f140 dead000000000122 0000000000000000
raw: 0000000000000000 0000000000100010 00000001ffffffff ffff88801937bc01
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 2, migratetype Unmovable, gfp_mask 0x1d20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL), pid 4708, tgid 4708 (dhcpcd), ts 448399025420, free_ts 448388778101
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook+0x2cf/0x340 mm/page_alloc.c:1536
 prep_new_page mm/page_alloc.c:1543 [inline]
 get_page_from_freelist+0x10d7/0x31b0 mm/page_alloc.c:3219
 __alloc_pages+0x1d0/0x4a0 mm/page_alloc.c:4475
 alloc_pages+0x1a9/0x270 mm/mempolicy.c:2298
 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+0x8be/0x1570 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+0x137/0x350 mm/slub.c:3517
 __do_kmalloc_node mm/slab_common.c:1003 [inline]
 __kmalloc_node_track_caller+0x50/0x100 mm/slab_common.c:1024
 kmalloc_reserve+0xef/0x270 net/core/skbuff.c:575
 __alloc_skb+0x12b/0x330 net/core/skbuff.c:644
 alloc_skb include/linux/skbuff.h:1286 [inline]
 alloc_skb_with_frags+0xe4/0x710 net/core/skbuff.c:6274
 sock_alloc_send_pskb+0x7c8/0x950 net/core/sock.c:2794
 unix_dgram_sendmsg+0x455/0x1c30 net/unix/af_unix.c:1953
 sock_sendmsg_nosec net/socket.c:730 [inline]
 sock_sendmsg+0xd9/0x180 net/socket.c:753
 sock_write_iter+0x29b/0x3d0 net/socket.c:1140
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1136 [inline]
 free_unref_page_prepare+0x476/0xa40 mm/page_alloc.c:2348
 free_unref_page+0x33/0x3b0 mm/page_alloc.c:2441
 skb_kfree_head net/core/skbuff.c:939 [inline]
 skb_free_head+0x110/0x1b0 net/core/skbuff.c:951
 skb_release_data+0x5ba/0x870 net/core/skbuff.c:981
 skb_release_all net/core/skbuff.c:1047 [inline]
 __kfree_skb net/core/skbuff.c:1061 [inline]
 consume_skb net/core/skbuff.c:1277 [inline]
 consume_skb+0xd2/0x170 net/core/skbuff.c:1271
 __unix_dgram_recvmsg+0x814/0xe50 net/unix/af_unix.c:2442
 unix_dgram_recvmsg+0xc3/0xf0 net/unix/af_unix.c:2459
 sock_recvmsg_nosec net/socket.c:1026 [inline]
 sock_recvmsg+0xe2/0x170 net/socket.c:1048
 sock_read_iter+0x2c3/0x3c0 net/socket.c:1118
 call_read_iter include/linux/fs.h:1977 [inline]
 do_iter_readv_writev+0x2f2/0x3c0 fs/read_write.c:733
 do_iter_read+0x315/0x870 fs/read_write.c:795
 vfs_readv+0x12d/0x1a0 fs/read_write.c:915
 do_readv+0x285/0x370 fs/read_write.c:952
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x38/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

Memory state around the buggy address:
 ffff888068778600: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888068778680: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff888068778700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
                            ^
 ffff888068778780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888068778800: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================


Tested on:

commit:         7271b2a5 Add linux-next specific files for 20230818
git tree:       https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git
console output: https://syzkaller.appspot.com/x/log.txt?x=142e2cbda80000
kernel config:  https://syzkaller.appspot.com/x/.config?x=1936af09cdef7dd6
dashboard link: https://syzkaller.appspot.com/bug?extid=a0c80b06ae2cb8895bc4
compiler:       gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
patch:          https://syzkaller.appspot.com/x/patch.diff?x=12838e5ba80000

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

[syzbot]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
KASAN: slab-use-after-free Read in hci_send_acl

==================================================================
BUG: KASAN: slab-use-after-free in hci_send_acl+0xdf4/0xf30 net/bluetooth/hci_core.c:3228
Read of size 8 at addr ffff888069713618 by task kworker/0:4/5435

CPU: 0 PID: 5435 Comm: kworker/0:4 Not tainted 6.5.0-rc6-next-20230818-syzkaller-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/26/2023
Workqueue: events l2cap_info_timeout
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
 hci_send_acl+0xdf4/0xf30 net/bluetooth/hci_core.c:3228
 l2cap_send_cmd+0x6dd/0x920 net/bluetooth/l2cap_core.c:977
 l2cap_send_conn_req+0x1e5/0x260 net/bluetooth/l2cap_core.c:1286
 l2cap_start_connection+0x11e/0x420 net/bluetooth/l2cap_core.c:1514
 l2cap_conn_start+0x7ae/0xa40 net/bluetooth/l2cap_core.c:1661
 process_one_work+0x887/0x15d0 kernel/workqueue.c:2630
 process_scheduled_works kernel/workqueue.c:2703 [inline]
 worker_thread+0x8bb/0x1290 kernel/workqueue.c:2784
 kthread+0x33a/0x430 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:304
 </TASK>

Allocated by task 5466:
 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]
 hci_chan_create+0xa6/0x3a0 net/bluetooth/hci_conn.c:2691
 l2cap_conn_add.part.0+0x1a/0xdf0 net/bluetooth/l2cap_core.c:7839
 l2cap_conn_add include/net/bluetooth/l2cap.h:866 [inline]
 l2cap_chan_connect+0x15b9/0x2140 net/bluetooth/l2cap_core.c:8051
 bt_6lowpan_connect net/bluetooth/6lowpan.c:894 [inline]
 lowpan_control_write+0x3d6/0x730 net/bluetooth/6lowpan.c:1129
 full_proxy_write+0x124/0x190 fs/debugfs/file.c:236
 vfs_write+0x2a4/0xe40 fs/read_write.c:582
 ksys_write+0x12f/0x250 fs/read_write.c:637
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x38/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

Freed by task 5045:
 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+0xb8/0x2f0 mm/slub.c:3822
 hci_chan_list_flush+0x81/0xf0 net/bluetooth/hci_conn.c:2731
 hci_conn_cleanup net/bluetooth/hci_conn.c:152 [inline]
 hci_conn_del+0x1fc/0xd10 net/bluetooth/hci_conn.c:1140
 hci_abort_conn_sync+0xacb/0xe20 net/bluetooth/hci_sync.c:5432
 abort_conn_sync+0x18e/0x3a0 net/bluetooth/hci_conn.c:2878
 hci_cmd_sync_work+0x1a4/0x3c0 net/bluetooth/hci_sync.c:306
 process_one_work+0x887/0x15d0 kernel/workqueue.c:2630
 process_scheduled_works kernel/workqueue.c:2703 [inline]
 worker_thread+0x8bb/0x1290 kernel/workqueue.c:2784
 kthread+0x33a/0x430 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:304

The buggy address belongs to the object at ffff888069713600
 which belongs to the cache kmalloc-128 of size 128
The buggy address is located 24 bytes inside of
 freed 128-byte region [ffff888069713600, ffff888069713680)

The buggy address belongs to the physical page:
page:ffffea0001a5c4c0 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x69713
flags: 0xfff00000000800(slab|node=0|zone=1|lastcpupid=0x7ff)
page_type: 0xffffffff()
raw: 00fff00000000800 ffff888012c418c0 dead000000000122 0000000000000000
raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x112cc0(GFP_USER|__GFP_NOWARN|__GFP_NORETRY), pid 5400, tgid 5400 (syz-executor.0), ts 92397723620, free_ts 92397302327
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook+0x2cf/0x340 mm/page_alloc.c:1536
 prep_new_page mm/page_alloc.c:1543 [inline]
 get_page_from_freelist+0x10d7/0x31b0 mm/page_alloc.c:3219
 __alloc_pages+0x1d0/0x4a0 mm/page_alloc.c:4475
 __alloc_pages_node include/linux/gfp.h:237 [inline]
 alloc_slab_page mm/slub.c:1872 [inline]
 allocate_slab+0xa1/0x380 mm/slub.c:2017
 new_slab mm/slub.c:2070 [inline]
 ___slab_alloc+0x8be/0x1570 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+0x137/0x350 mm/slub.c:3517
 __do_kmalloc_node mm/slab_common.c:1003 [inline]
 __kmalloc_node+0x52/0x110 mm/slab_common.c:1011
 kmalloc_array_node include/linux/slab.h:698 [inline]
 kcalloc_node include/linux/slab.h:703 [inline]
 memcg_alloc_slab_cgroups+0xa9/0x170 mm/memcontrol.c:2895
 memcg_slab_post_alloc_hook+0xaa/0x390 mm/slab.h:530
 slab_post_alloc_hook mm/slab.h:770 [inline]
 slab_alloc_node mm/slub.c:3478 [inline]
 slab_alloc mm/slub.c:3486 [inline]
 __kmem_cache_alloc_lru mm/slub.c:3493 [inline]
 kmem_cache_alloc+0x1a7/0x3b0 mm/slub.c:3502
 prepare_creds+0x43/0x7b0 kernel/cred.c:263
 copy_creds+0xa7/0xe50 kernel/cred.c:368
 copy_process+0xeb6/0x7400 kernel/fork.c:2368
 kernel_clone+0xfd/0x930 kernel/fork.c:2916
 __do_sys_clone+0xba/0x100 kernel/fork.c:3059
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1136 [inline]
 free_unref_page_prepare+0x476/0xa40 mm/page_alloc.c:2348
 free_unref_page+0x33/0x3b0 mm/page_alloc.c:2441
 vfree+0x181/0x7a0 mm/vmalloc.c:2842
 __do_replace+0x7bf/0x9c0 net/ipv4/netfilter/arp_tables.c:937
 do_replace net/ipv6/netfilter/ip6_tables.c:1154 [inline]
 do_ip6t_set_ctl+0x93a/0xbd0 net/ipv6/netfilter/ip6_tables.c:1636
 nf_setsockopt+0x87/0xe0 net/netfilter/nf_sockopt.c:101
 ipv6_setsockopt+0x12b/0x190 net/ipv6/ipv6_sockglue.c:1017
 tcp_setsockopt+0x9d/0x100 net/ipv4/tcp.c:3677
 __sys_setsockopt+0x2cd/0x5b0 net/socket.c:2307
 __do_sys_setsockopt net/socket.c:2318 [inline]
 __se_sys_setsockopt net/socket.c:2315 [inline]
 __x64_sys_setsockopt+0xbd/0x150 net/socket.c:2315
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x38/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

Memory state around the buggy address:
 ffff888069713500: 00 00 00 00 00 00 00 00 00 00 00 00 00 fc fc fc
 ffff888069713580: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff888069713600: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                            ^
 ffff888069713680: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888069713700: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
==================================================================


Tested on:

commit:         7271b2a5 Add linux-next specific files for 20230818
git tree:       https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git
console output: https://syzkaller.appspot.com/x/log.txt?x=1555b1bba80000
kernel config:  https://syzkaller.appspot.com/x/.config?x=1936af09cdef7dd6
dashboard link: https://syzkaller.appspot.com/bug?extid=a0c80b06ae2cb8895bc4
compiler:       gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
patch:          https://syzkaller.appspot.com/x/patch.diff?x=1766e9bba80000