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23 October 2021, 00:29:24 UTC
Revision e94bd1736f1f60e916a85a80c0b0ebeaae36cce5 authored by Michel Dänzer on 30 November 2016, 08:30:01 UTC, committed by Daniel Vetter on 30 November 2016, 09:13:00 UTC 
drm: Don't call drm_for_each_crtc with a non-KMS driver
 
Fixes oops if userspace calls DRM_IOCTL_GET_CAP for
 DRM_CAP_PAGE_FLIP_TARGET on a non-KMS device node. (Normal userspace
doesn't do that, discovered by syzkaller)

Reported-by: Dmitry Vyukov <dvyukov@google.com>
Fixes: f837297ad824 ("drm: Add DRM_MODE_PAGE_FLIP_TARGET_ABSOLUTE/RELATIVE flags v2")
Cc: stable@vger.kernel.org
Signed-off-by: Michel Dänzer <michel.daenzer@amd.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/20161130083002.1520-1-michel@daenzer.net
1 parent e5517c2
Raw File
Tip revision: e94bd1736f1f60e916a85a80c0b0ebeaae36cce5 authored by Michel Dänzer on 30 November 2016, 08:30:01 UTC
drm: Don't call drm_for_each_crtc with a non-KMS driver
Tip revision: e94bd17
lcm.c 
#include <linux/compiler.h>
#include <linux/gcd.h>
#include <linux/export.h>
#include <linux/lcm.h>

/* Lowest common multiple */
unsigned long lcm(unsigned long a, unsigned long b)
{
	if (a && b)
		return (a / gcd(a, b)) * b;
	else
		return 0;
}
EXPORT_SYMBOL_GPL(lcm);

unsigned long lcm_not_zero(unsigned long a, unsigned long b)
{
	unsigned long l = lcm(a, b);

	if (l)
		return l;

	return (b ? : a);
}
EXPORT_SYMBOL_GPL(lcm_not_zero);
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