general protection fault in perf_output_read

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: cbfa1702 Linux 4.14.198
git tree: linux-4.14.y
console output: https://syzkaller.appspot.com/x/log.txt?x=16dde4a0500000
kernel config: https://syzkaller.appspot.com/x/.config?x=3990958d85b55e59
dashboard link: https://syzkaller.appspot.com/bug?extid=f8020e7926a3d6347903
compiler: gcc (GCC) 10.1.0-syz 20200507
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1619f6cf900000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=114a4e78500000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+f8020e...@syzkaller.appspotmail.com

kasan: CONFIG_KASAN_INLINE enabled
kasan: GPF could be caused by NULL-ptr deref or user memory access
general protection fault: 0000 [#1] PREEMPT SMP KASAN
Modules linked in:
CPU: 0 PID: 9335 Comm: syz-executor129 Not tainted 4.14.198-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff888094b2c580 task.stack: ffff8880956d0000
RIP: 0010:primary_event_id kernel/events/core.c:1318 [inline]
RIP: 0010:perf_output_read_group kernel/events/core.c:5893 [inline]
RIP: 0010:perf_output_read+0x659/0x1090 kernel/events/core.c:5928
RSP: 0018:ffff8880956d7290 EFLAGS: 00010203
RAX: 0000000020000091 RBX: 00000000ffffffff RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffff8880941b3d50 RDI: 000000010000048f
RBP: 0000000000000000 R08: 0000000000000001 R09: ffffed10128aa3b3
R10: ffff888094551d9f R11: 0000005a72d84bff R12: dffffc0000000000
R13: ffffed1012adaeaa R14: ffff8880956d7528 R15: ffff8880941b3d50
FS: 00007fc3a2587700(0000) GS:ffff8880aea00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000800000001 CR3: 00000000976eb000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
perf_output_sample+0xa28/0x16f0 kernel/events/core.c:5970
__perf_event_output kernel/events/core.c:6283 [inline]
perf_event_output_forward+0xf8/0x1f0 kernel/events/core.c:6296
__perf_event_overflow+0x113/0x310 kernel/events/core.c:7541
perf_swevent_overflow kernel/events/core.c:7617 [inline]
perf_swevent_event+0x299/0x460 kernel/events/core.c:7645
do_perf_sw_event kernel/events/core.c:7758 [inline]
___perf_sw_event+0x2a1/0x480 kernel/events/core.c:7789
__perf_sw_event+0x4f/0x100 kernel/events/core.c:7801
perf_sw_event include/linux/perf_event.h:1046 [inline]
__do_page_fault+0x6c1/0xb50 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:ffff8880956d7a78 EFLAGS: 00010206
RAX: ffffed1014fd8000 RBX: 0000000000008000 RCX: 0000000000004acb
RDX: 0000000000008000 RSI: 0000000020e39000 RDI: ffff8880a7ebb535
RBP: 0000000020e35acb R08: 0000000000000001 R09: ffffed1014fd7fff
R10: ffff8880a7ebffff R11: 0000000000000000 R12: ffff8880a7eb8000
R13: 00007ffffffff000 R14: 0000000020e3dacb R15: ffff8880a7eb8000
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: 0033:0x4498a9
RSP: 002b:00007fc3a2586da8 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 00000000006dec48 RCX: 00000000004498a9
RDX: ffffffffffffffef RSI: 0000000020d7cfcb RDI: 0000000000000004
RBP: 00000000006dec40 R08: 0000000000000000 R09: 0000000000000053
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000006dec4c
R13: 00007ffe3412617f R14: 00007fc3a25879c0 R15: 0000000000000064
Code: 00 0f 85 f8 09 00 00 48 8b 44 24 08 48 8b 98 b8 02 00 00 48 85 db 74 25 e8 b5 a7 f1 ff 48 8d bb 90 04 00 00 48 89 f8 48 c1 e8 03 <42> 80 3c 20 00 0f 85 d3 09 00 00 48 8b ab 90 04 00 00 e8 90 a7
RIP: primary_event_id kernel/events/core.c:1318 [inline] RSP: ffff8880956d7290
RIP: perf_output_read_group kernel/events/core.c:5893 [inline] RSP: ffff8880956d7290
RIP: perf_output_read+0x659/0x1090 kernel/events/core.c:5928 RSP: ffff8880956d7290
---[ end trace 3b21a5e10669da16 ]---


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