Commit 9acdfe4e authored Apr 15, 2018 by Jiri Olsa Committed by Greg Kroah-Hartman Apr 29, 2018

perf: Return proper values for user stack errors



commit 78b562fbfa2cf0a9fcb23c3154756b690f4905c1 upstream.

Return immediately when we find issue in the user stack checks. The
error value could get overwritten by following check for
PERF_SAMPLE_REGS_INTR.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: syzkaller-bugs@googlegroups.com
Cc: x86@kernel.org
Fixes: 60e2364e ("perf: Add ability to sample machine state on interrupt")
Link: http://lkml.kernel.org/r/20180415092352.12403-1-jolsa@kernel.org


Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent ac6f0cb3

kernel/events/core.c

+2 −2

Original line number	Original line	Diff line number	Diff line
	@@ -9456,9 +9456,9 @@ static int perf_copy_attr(struct perf_event_attr __user *uattr,
	* __u16 sample size limit.		* __u16 sample size limit.
	*/		*/
	if (attr->sample_stack_user >= USHRT_MAX)		if (attr->sample_stack_user >= USHRT_MAX)
	ret = -EINVAL;		return -EINVAL;
	else if (!IS_ALIGNED(attr->sample_stack_user, sizeof(u64)))		else if (!IS_ALIGNED(attr->sample_stack_user, sizeof(u64)))
	ret = -EINVAL;		return -EINVAL;
	}		}

	if (attr->sample_type & PERF_SAMPLE_REGS_INTR)		if (attr->sample_type & PERF_SAMPLE_REGS_INTR)