KASAN: use-after-free Read in perf_output_read (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 7d7d1c0a Linux 4.14.232
git tree: linux-4.14.y
console output: https://syzkaller.appspot.com/x/log.txt?x=101df9b3d00000
kernel config: https://syzkaller.appspot.com/x/.config?x=17ee8a0e183900d8
dashboard link: https://syzkaller.appspot.com/bug?extid=59185e10718a4132bf32

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

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+59185e...@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: use-after-free in primary_event_id kernel/events/core.c:1316 [inline]
BUG: KASAN: use-after-free in perf_output_read_group kernel/events/core.c:5895 [inline]
BUG: KASAN: use-after-free in perf_output_read+0x1046/0x1090 kernel/events/core.c:5930
Read of size 8 at addr ffff8880abfceda0 by task syz-executor.0/18931

CPU: 1 PID: 18931 Comm: syz-executor.0 Not tainted 4.14.232-syzkaller #0
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+0x1b2/0x281 lib/dump_stack.c:58
print_address_description.cold+0x54/0x1d3 mm/kasan/report.c:252
kasan_report_error.cold+0x8a/0x191 mm/kasan/report.c:351
kasan_report mm/kasan/report.c:409 [inline]
__asan_report_load8_noabort+0x68/0x70 mm/kasan/report.c:430
primary_event_id kernel/events/core.c:1316 [inline]
perf_output_read_group kernel/events/core.c:5895 [inline]
perf_output_read+0x1046/0x1090 kernel/events/core.c:5930
perf_output_sample+0xa28/0x16f0 kernel/events/core.c:5972
__perf_event_output kernel/events/core.c:6285 [inline]
perf_event_output_forward+0xf8/0x1f0 kernel/events/core.c:6298
__perf_event_overflow+0x113/0x310 kernel/events/core.c:7547
perf_swevent_overflow kernel/events/core.c:7623 [inline]
perf_swevent_event+0x299/0x460 kernel/events/core.c:7651
do_perf_sw_event kernel/events/core.c:7764 [inline]
___perf_sw_event+0x2a1/0x480 kernel/events/core.c:7795
__perf_sw_event+0x4f/0x100 kernel/events/core.c:7807
perf_sw_event include/linux/perf_event.h:1046 [inline]
__do_page_fault+0x692/0xad0 arch/x86/mm/fault.c:1483
page_fault+0x25/0x50 arch/x86/entry/entry_64.S:1123
RIP: 0010:copy_user_enhanced_fast_string+0xe/0x20 arch/x86/lib/copy_user_64.S:181
RSP: 0018:ffff8880487a7a78 EFLAGS: 00010206
RAX: ffffed10091d8000 RBX: 0000000000008000 RCX: 0000000000000acb
RDX: 0000000000008000 RSI: 0000000020fad000 RDI: ffff888048ebf535
RBP: 0000000020fa5acb R08: 0000000000000001 R09: ffffed10091d7fff
R10: ffff888048ebffff R11: 0000000000000000 R12: ffff888048eb8000
R13: 00007ffffffff000 R14: 0000000020fadacb R15: ffff888048eb8000
copy_user_generic arch/x86/include/asm/uaccess_64.h:37 [inline]
raw_copy_from_user arch/x86/include/asm/uaccess_64.h:55 [inline]
copyin+0x99/0xc0 lib/iov_iter.c:146
_copy_from_iter_full+0x197/0x690 lib/iov_iter.c:608
copy_from_iter_full include/linux/uio.h:126 [inline]
skb_do_copy_data_nocache include/net/sock.h:1889 [inline]
skb_copy_to_page_nocache include/net/sock.h:1915 [inline]
tcp_sendmsg_locked+0x23fc/0x2ef0 net/ipv4/tcp.c:1360
tcp_sendmsg+0x2b/0x40 net/ipv4/tcp.c:1457
inet_sendmsg+0x11a/0x4e0 net/ipv4/af_inet.c:762
sock_sendmsg_nosec net/socket.c:646 [inline]
sock_sendmsg+0xb5/0x100 net/socket.c:656
SYSC_sendto net/socket.c:1763 [inline]
SyS_sendto+0x1c7/0x2c0 net/socket.c:1731
do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
entry_SYSCALL_64_after_hwframe+0x46/0xbb
RIP: 0033:0x4665d9
RSP: 002b:00007f7d61567188 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 000000000056bf60 RCX: 00000000004665d9
RDX: ffffffffffffffef RSI: 0000000020d7cfcb RDI: 0000000000000007
RBP: 00000000004bfcb9 R08: 0000000000000000 R09: 0000000000000053
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056bf60
R13: 00007ffd35e5e97f R14: 00007f7d61567300 R15: 0000000000022000

Allocated by task 12147:
save_stack mm/kasan/kasan.c:447 [inline]
set_track mm/kasan/kasan.c:459 [inline]
kasan_kmalloc+0xeb/0x160 mm/kasan/kasan.c:551
__do_kmalloc_node mm/slab.c:3682 [inline]
__kmalloc_node_track_caller+0x4c/0x70 mm/slab.c:3696
__kmalloc_reserve net/core/skbuff.c:137 [inline]
__alloc_skb+0x96/0x510 net/core/skbuff.c:205
alloc_skb include/linux/skbuff.h:980 [inline]
alloc_skb_with_frags+0x85/0x500 net/core/skbuff.c:5255
sock_alloc_send_pskb+0x577/0x6d0 net/core/sock.c:2083
bt_skb_send_alloc include/net/bluetooth/bluetooth.h:347 [inline]
l2cap_sock_alloc_skb_cb+0xa6/0x3c0 net/bluetooth/l2cap_sock.c:1398
l2cap_create_basic_pdu net/bluetooth/l2cap_core.c:2236 [inline]
l2cap_chan_send+0x25b/0x37f0 net/bluetooth/l2cap_core.c:2532
l2cap_sock_sendmsg+0x1cd/0x280 net/bluetooth/l2cap_sock.c:975
sock_sendmsg_nosec net/socket.c:646 [inline]
sock_sendmsg+0xb5/0x100 net/socket.c:656
___sys_sendmsg+0x326/0x800 net/socket.c:2062
__sys_sendmmsg+0x129/0x330 net/socket.c:2152
SYSC_sendmmsg net/socket.c:2183 [inline]
SyS_sendmmsg+0x2f/0x50 net/socket.c:2178
do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
entry_SYSCALL_64_after_hwframe+0x46/0xbb

Freed by task 14381:
save_stack mm/kasan/kasan.c:447 [inline]
set_track mm/kasan/kasan.c:459 [inline]
kasan_slab_free+0xc3/0x1a0 mm/kasan/kasan.c:524
__cache_free mm/slab.c:3496 [inline]
kfree+0xc9/0x250 mm/slab.c:3815
skb_free_head net/core/skbuff.c:563 [inline]
skb_release_data+0x5f6/0x820 net/core/skbuff.c:583
skb_release_all net/core/skbuff.c:640 [inline]
__kfree_skb net/core/skbuff.c:654 [inline]
kfree_skb+0xe7/0x390 net/core/skbuff.c:672
skb_queue_purge+0x14/0x30 net/core/skbuff.c:2870
hci_chan_del+0x12f/0x1e0 net/bluetooth/hci_conn.c:1578
l2cap_conn_del+0x426/0x690 net/bluetooth/l2cap_core.c:1739
l2cap_disconn_cfm net/bluetooth/l2cap_core.c:7441 [inline]
l2cap_disconn_cfm+0x7c/0xb0 net/bluetooth/l2cap_core.c:7434
hci_disconn_cfm include/net/bluetooth/hci_core.h:1226 [inline]
hci_conn_hash_flush+0x127/0x260 net/bluetooth/hci_conn.c:1393
hci_dev_do_close+0x535/0xca0 net/bluetooth/hci_core.c:1622
hci_unregister_dev+0x17f/0x8c0 net/bluetooth/hci_core.c:3193
vhci_release+0x70/0xe0 drivers/bluetooth/hci_vhci.c:354
__fput+0x25f/0x7a0 fs/file_table.c:210
task_work_run+0x11f/0x190 kernel/task_work.c:113
exit_task_work include/linux/task_work.h:22 [inline]
do_exit+0xa44/0x2850 kernel/exit.c:868
do_group_exit+0x100/0x2e0 kernel/exit.c:965
get_signal+0x38d/0x1ca0 kernel/signal.c:2423
do_signal+0x7c/0x1550 arch/x86/kernel/signal.c:792
exit_to_usermode_loop+0x160/0x200 arch/x86/entry/common.c:160
prepare_exit_to_usermode arch/x86/entry/common.c:199 [inline]
syscall_return_slowpath arch/x86/entry/common.c:270 [inline]
do_syscall_64+0x4a3/0x640 arch/x86/entry/common.c:297
entry_SYSCALL_64_after_hwframe+0x46/0xbb

The buggy address belongs to the object at ffff8880abfced40
which belongs to the cache kmalloc-512 of size 512
The buggy address is located 96 bytes inside of
512-byte region [ffff8880abfced40, ffff8880abfcef40)
The buggy address belongs to the page:
page:ffffea0002aff380 count:1 mapcount:0 mapping:ffff8880abfce0c0 index:0xffff8880abfced40
flags: 0xfff00000000100(slab)
raw: 00fff00000000100 ffff8880abfce0c0 ffff8880abfced40 0000000100000004
raw: ffffea00023ca0a0 ffffea0002ad52a0 ffff88813fe80940 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
ffff8880abfcec80: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
ffff8880abfced00: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb
>ffff8880abfced80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff8880abfcee00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8880abfcee80: 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.