KASAN: use-after-free Read in kfree_skbmem

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: aea8526e Linux 4.14.133
git tree: linux-4.14.y
console output: https://syzkaller.appspot.com/x/log.txt?x=15ce9010600000
kernel config: https://syzkaller.appspot.com/x/.config?x=5dfccef5a159766b
dashboard link: https://syzkaller.appspot.com/bug?extid=1ade2df1f5580cc09203
compiler: gcc (GCC) 9.0.0 20181231 (experimental)

Unfortunately, I don't have any reproducer for this crash yet.

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+1ade2d...@syzkaller.appspotmail.com

Bluetooth: Invalid header checksum
Bluetooth: Invalid header checksum
Bluetooth: Invalid header checksum
Bluetooth: Invalid header checksum
==================================================================
BUG: KASAN: use-after-free in kfree_skbmem+0x105/0x120
/net/core/skbuff.c:584
Read of size 1 at addr ffff88808a1df28e by task syz-executor.5/10550

CPU: 0 PID: 10550 Comm: syz-executor.5 Not tainted 4.14.133 #28
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
Call Trace:
__dump_stack /lib/dump_stack.c:17 [inline]
dump_stack+0x138/0x19c /lib/dump_stack.c:53
print_address_description.cold+0x7c/0x1dc /mm/kasan/report.c:252
kasan_report_error /mm/kasan/report.c:351 [inline]
kasan_report /mm/kasan/report.c:409 [inline]
kasan_report.cold+0xa9/0x2af /mm/kasan/report.c:393
__asan_report_load1_noabort+0x14/0x20 /mm/kasan/report.c:427
kfree_skbmem+0x105/0x120 /net/core/skbuff.c:584
__kfree_skb /net/core/skbuff.c:646 [inline]
kfree_skb+0xbd/0x340 /net/core/skbuff.c:663
Bluetooth: Invalid header checksum
h5_reset_rx+0x4c/0x100 /drivers/bluetooth/hci_h5.c:499
h5_rx_3wire_hdr+0x2af/0x370 /drivers/bluetooth/hci_h5.c:409
h5_recv+0x25c/0x3f0 /drivers/bluetooth/hci_h5.c:532
hci_uart_tty_receive+0x1f4/0x4d0 /drivers/bluetooth/hci_ldisc.c:603
tiocsti /drivers/tty/tty_io.c:2186 [inline]
tty_ioctl+0xded/0x1320 /drivers/tty/tty_io.c:2572
vfs_ioctl /fs/ioctl.c:46 [inline]
file_ioctl /fs/ioctl.c:500 [inline]
do_vfs_ioctl+0x7ae/0x1060 /fs/ioctl.c:684
SYSC_ioctl /fs/ioctl.c:701 [inline]
SyS_ioctl+0x8f/0xc0 /fs/ioctl.c:692
do_syscall_64+0x1e8/0x640 /arch/x86/entry/common.c:292
entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x459819
RSP: 002b:00007f3a1b517c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000459819
RDX: 0000000020000080 RSI: 0000000000005412 RDI: 0000000000000004
RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f3a1b5186d4
R13: 00000000004c408a R14: 00000000004d7ff0 R15: 00000000ffffffff

Allocated by task 2269:
save_stack_trace+0x16/0x20 /arch/x86/kernel/stacktrace.c:59
save_stack+0x45/0xd0 /mm/kasan/kasan.c:447
set_track /mm/kasan/kasan.c:459 [inline]
kasan_kmalloc /mm/kasan/kasan.c:551 [inline]
kasan_kmalloc+0xce/0xf0 /mm/kasan/kasan.c:529
kasan_slab_alloc+0xf/0x20 /mm/kasan/kasan.c:489
kmem_cache_alloc_node+0x144/0x780 /mm/slab.c:3642
__alloc_skb+0x9c/0x500 /net/core/skbuff.c:193
alloc_skb /./include/linux/skbuff.h:980 [inline]
bt_skb_alloc /./include/net/bluetooth/bluetooth.h:336 [inline]
h5_rx_pkt_start+0xc2/0x260 /drivers/bluetooth/hci_h5.c:443
h5_recv+0x25c/0x3f0 /drivers/bluetooth/hci_h5.c:532
hci_uart_tty_receive+0x1f4/0x4d0 /drivers/bluetooth/hci_ldisc.c:603
tty_ldisc_receive_buf+0x14d/0x1a0 /drivers/tty/tty_buffer.c:459
tty_port_default_receive_buf+0x73/0xa0 /drivers/tty/tty_port.c:37
receive_buf /drivers/tty/tty_buffer.c:475 [inline]
flush_to_ldisc+0x1ec/0x400 /drivers/tty/tty_buffer.c:527
process_one_work+0x863/0x1600 /kernel/workqueue.c:2114
worker_thread+0x5d9/0x1050 /kernel/workqueue.c:2248
kthread+0x319/0x430 /kernel/kthread.c:232
ret_from_fork+0x24/0x30 /arch/x86/entry/entry_64.S:404

Freed by task 2269:
save_stack_trace+0x16/0x20 /arch/x86/kernel/stacktrace.c:59
save_stack+0x45/0xd0 /mm/kasan/kasan.c:447
set_track /mm/kasan/kasan.c:459 [inline]
kasan_slab_free+0x75/0xc0 /mm/kasan/kasan.c:524
__cache_free /mm/slab.c:3496 [inline]
kmem_cache_free+0x83/0x2b0 /mm/slab.c:3758
kfree_skbmem /net/core/skbuff.c:586 [inline]
kfree_skbmem+0xac/0x120 /net/core/skbuff.c:580
__kfree_skb /net/core/skbuff.c:646 [inline]
kfree_skb+0xbd/0x340 /net/core/skbuff.c:663
h5_reset_rx+0x4c/0x100 /drivers/bluetooth/hci_h5.c:499
h5_rx_3wire_hdr+0x2af/0x370 /drivers/bluetooth/hci_h5.c:409
h5_recv+0x25c/0x3f0 /drivers/bluetooth/hci_h5.c:532
hci_uart_tty_receive+0x1f4/0x4d0 /drivers/bluetooth/hci_ldisc.c:603
tty_ldisc_receive_buf+0x14d/0x1a0 /drivers/tty/tty_buffer.c:459
tty_port_default_receive_buf+0x73/0xa0 /drivers/tty/tty_port.c:37
receive_buf /drivers/tty/tty_buffer.c:475 [inline]
flush_to_ldisc+0x1ec/0x400 /drivers/tty/tty_buffer.c:527
process_one_work+0x863/0x1600 /kernel/workqueue.c:2114
worker_thread+0x5d9/0x1050 /kernel/workqueue.c:2248
kthread+0x319/0x430 /kernel/kthread.c:232
ret_from_fork+0x24/0x30 /arch/x86/entry/entry_64.S:404

The buggy address belongs to the object at ffff88808a1df200
which belongs to the cache skbuff_head_cache of size 232
The buggy address is located 142 bytes inside of
232-byte region [ffff88808a1df200, ffff88808a1df2e8)
The buggy address belongs to the page:
page:ffffea00022877c0 count:1 mapcount:0 mapping:ffff88808a1df0c0 index:0x0
flags: 0x1fffc0000000100(slab)
raw: 01fffc0000000100 ffff88808a1df0c0 0000000000000000 000000010000000c
raw: ffffea00025a9fa0 ffffea0001ca10e0 ffff88821b719240 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
ffff88808a1df180: fb fb fb fb fb fc fc fc fc fc fc fc fc fc fc fc
ffff88808a1df200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> ffff88808a1df280: fb fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc
^
ffff88808a1df300: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb
ffff88808a1df380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================


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[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.