WARNING in perf_trace_buf_alloc

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: 666c420f FROMLIST: ANDROID: binder: Add BINDER_GET_NODE_IN..
git tree: android-4.14
console output: https://syzkaller.appspot.com/x/log.txt?x=16e121f1400000
kernel config: https://syzkaller.appspot.com/x/.config?x=89d929f317ea847c
dashboard link: https://syzkaller.appspot.com/bug?extid=a1824c1624a3ea722ff1
compiler: gcc (GCC) 8.0.1 20180413 (experimental)
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=176d6511400000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1577321a400000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+a1824c...@syzkaller.appspotmail.com

random: sshd: uninitialized urandom read (32 bytes read)
audit: type=1400 audit(1537530110.754:7): avc: denied { map } for
pid=1800 comm="syz-executor339" path="/root/syz-executor339185019"
dev="sda1" ino=16481 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023
tcontext=unconfined_u:object_r:user_home_t:s0 tclass=file permissive=1
audit: type=1400 audit(1537530110.804:8): avc: denied { map_create } for
pid=1801 comm="syz-executor339"
scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023
tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=bpf
permissive=1
perf buffer not large enough
------------[ cut here ]------------
WARNING: CPU: 0 PID: 1801 at kernel/trace/trace_event_perf.c:274
perf_trace_buf_alloc.cold.2+0x18/0x2b kernel/trace/trace_event_perf.c:273
Kernel panic - not syncing: panic_on_warn set ...

CPU: 0 PID: 1801 Comm: syz-executor339 Not tainted 4.14.71+ #8
Call Trace:
__dump_stack lib/dump_stack.c:17 [inline]
dump_stack+0xb9/0x11b lib/dump_stack.c:53
panic+0x1bf/0x3a4 kernel/panic.c:181
__warn.cold.7+0x148/0x185 kernel/panic.c:542
report_bug+0x1f7/0x26c lib/bug.c:186
fixup_bug arch/x86/kernel/traps.c:177 [inline]
do_error_trap+0x1ba/0x2c0 arch/x86/kernel/traps.c:295
invalid_op+0x18/0x40 arch/x86/entry/entry_64.S:944
RIP: 0010:perf_trace_buf_alloc.cold.2+0x18/0x2b
kernel/trace/trace_event_perf.c:273
RSP: 0018:ffff8801cfbd7c28 EFLAGS: 00010282
RAX: 000000000000001c RBX: ffff8801d6897180 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000297
RBP: 0000000000000b44 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffff8801cfbd7cc0
R13: ffff8801cfbd7d00 R14: 0000000000000b11 R15: 0000000000000000
perf_trace_bpf_map_keyval+0x1d2/0x720 include/trace/events/bpf.h:228
trace_bpf_map_update_elem include/trace/events/bpf.h:274 [inline]
map_update_elem kernel/bpf/syscall.c:658 [inline]
SYSC_bpf kernel/bpf/syscall.c:1576 [inline]
SyS_bpf+0x2ec7/0x3640 kernel/bpf/syscall.c:1547
do_syscall_64+0x19b/0x4b0 arch/x86/entry/common.c:289
entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x440f29
RSP: 002b:00007ffca67af668 EFLAGS: 00000217 ORIG_RAX: 0000000000000141
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000440f29
RDX: 0000000000000020 RSI: 0000000020000140 RDI: 0000000000000002
RBP: 0000000000000000 R08: 00000000004002c8 R09: 00000000004002c8
R10: 00000000004002c8 R11: 0000000000000217 R12: 0000000000401e70
R13: 0000000000401f00 R14: 0000000000000000 R15: 0000000000000000
Kernel Offset: 0x11000000 from 0xffffffff81000000 (relocation range:
0xffffffff80000000-0xffffffffbfffffff)
Rebooting in 86400 seconds..


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