perf/ring-buffer: Undefined behaviour in kernel/events/ring_buffer.c:685:22

From	Sasha Levin <sasha.levin@oracle.com>
Newsgroups	linux.kernel
Subject	perf/ring-buffer: Undefined behaviour in kernel/events/ring_buffer.c:685:22
Date	2016-01-10 22:00 +0100
Message-ID	<qPvfI-Ou-11@gated-at.bofh.it> (permalink)
Organization	linux.* mail to news gateway

Show all headers | View raw

Hi all,

While fuzzing with trinity inside a KVM tools guest, running the latest -next
kernel, I've hit the following warning:

[ 3494.030114] UBSAN: Undefined behaviour in kernel/events/ring_buffer.c:685:22
[ 3494.030647] shift exponent -1 is negative
[ 3494.031025] CPU: 1 PID: 28506 Comm: kworker/1:2 Not tainted 4.4.0-rc8-next-20160108-sasha-00024-gaaecb9a #2780
[ 3494.032861] Workqueue: events rb_free_work
[ 3494.033195]  1ffff10018bb2f1b 0000000025cc19e7 ffff8800c5d97958 ffffffffa101a182
[ 3494.033871]  0000000041b58ab3 ffffffffac1b3838 ffffffffa101a0b7 ffff8800c5d97920
[ 3494.034469]  ffffffffae01db80 ffff8800c5d97940 0000000025cc19e7 ffffffffae01db80
[ 3494.035097] Call Trace:
[ 3494.035336]  [<ffffffffa101a182>] dump_stack+0xcb/0x149
[ 3494.036171]  [<ffffffffa1114296>] ubsan_epilogue+0x12/0x8f
[ 3494.036568]  [<ffffffffa1114e9a>] __ubsan_handle_shift_out_of_bounds+0x2a3/0x308
[ 3494.038670]  [<ffffffff9f6274ee>] rb_free_work+0xae/0x1a0
[ 3494.039491]  [<ffffffff9f3ac74c>] process_one_work+0xb6c/0x13d0
[ 3494.042924]  [<ffffffff9f3adce3>] worker_thread+0xd33/0x1150
[ 3494.043923]  [<ffffffff9f3c4239>] kthread+0x2f9/0x310


Thanks,
Sasha

Back to linux.kernel | Previous | Next | Find similar | Unroll thread

Thread

perf/ring-buffer: Undefined behaviour in  kernel/events/ring_buffer.c:685:22 Sasha Levin <sasha.levin@oracle.com> - 2016-01-10 22:00 +0100

csiph-web