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xfree86: Change displays array to pointers array to fix invalid pointer issues after table reallocation 

There are rare cases when xf86SetDepthBpp is resizing displays array in confScreen.
As that array is shared between set of ScrnInfoRec's then realloc might invalidate chached DispPtr display values in
otheres ScrnInfoRec objects.

If we will change displays array as an array of pointers to DispRec then cached DispRec pointers in ScrnInfoRec
won't be invalid after reallocation of displays array.

Signed-off-by: Łukasz Spintzyk <lukasz.spintzyk@synaptics.com>
(cherry picked from commit f8a6be04d0)
This commit is contained in:
Łukasz Spintzyk 2021-06-08 20:02:21 +02:00
parent 22449f6300
commit a4210fe07a
3 changed files with 26 additions and 23 deletions
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10
hw/xfree86/common/xf86Config.c
View File

@ -1760,7 +1760,7 @@ configScreen(confScreenPtr screenp, XF86ConfScreenPtr conf_screen, int scrnum,
count++;
dispptr = (XF86ConfDisplayPtr) dispptr->list.next;
}
screenp->displays = xnfallocarray(count, sizeof(DispRec));
screenp->displays = xnfallocarray(count, sizeof(DispPtr));
screenp->numdisplays = count;
/* Fill in the default Virtual size, if any */
@ -1768,8 +1768,9 @@ configScreen(confScreenPtr screenp, XF86ConfScreenPtr conf_screen, int scrnum,
for (count = 0, dispptr = conf_screen->scrn_display_lst;
dispptr;
dispptr = (XF86ConfDisplayPtr) dispptr->list.next, count++) {
screenp->displays[count].virtualX = conf_screen->scrn_virtualX;
screenp->displays[count].virtualY = conf_screen->scrn_virtualY;
screenp->displays[count] = xnfcalloc(1, sizeof(DispRec));
screenp->displays[count]->virtualX = conf_screen->scrn_virtualX;
screenp->displays[count]->virtualY = conf_screen->scrn_virtualY;
}
}
@ -1777,7 +1778,7 @@ configScreen(confScreenPtr screenp, XF86ConfScreenPtr conf_screen, int scrnum,
count = 0;
dispptr = conf_screen->scrn_display_lst;
while (dispptr) {
configDisplay(&(screenp->displays[count]), dispptr);
configDisplay(screenp->displays[count], dispptr);
count++;
dispptr = (XF86ConfDisplayPtr) dispptr->list.next;
}
@ -1785,6 +1786,7 @@ configScreen(confScreenPtr screenp, XF86ConfScreenPtr conf_screen, int scrnum,
/*
* figure out how many videoadaptor references there are and fill them in
*/
count = 0;
conf_adaptor = conf_screen->scrn_adaptor_lst;
while (conf_adaptor) {
count++;

37
hw/xfree86/common/xf86Helper.c
View File

@ -525,8 +525,8 @@ xf86SetDepthBpp(ScrnInfoPtr scrp, int depth, int dummy, int fbbpp,
* Find the Display subsection matching the depth/fbbpp and initialise
* scrp->display with it.
*/
for (i = 0, disp = scrp->confScreen->displays;
i < scrp->confScreen->numdisplays; i++, disp++) {
for (i = 0; i < scrp->confScreen->numdisplays; i++) {
disp = scrp->confScreen->displays[i];
if ((disp->depth == scrp->depth && disp->fbbpp == scrp->bitsPerPixel)
|| (disp->depth == scrp->depth && disp->fbbpp <= 0)
|| (disp->fbbpp == scrp->bitsPerPixel && disp->depth <= 0)) {
@ -540,8 +540,8 @@ xf86SetDepthBpp(ScrnInfoPtr scrp, int depth, int dummy, int fbbpp,
* depth or fbbpp specified.
*/
if (i == scrp->confScreen->numdisplays) {
for (i = 0, disp = scrp->confScreen->displays;
i < scrp->confScreen->numdisplays; i++, disp++) {
for (i = 0; i < scrp->confScreen->numdisplays; i++) {
disp = scrp->confScreen->displays[i];
if (disp->depth <= 0 && disp->fbbpp <= 0) {
scrp->display = disp;
break;
@ -556,24 +556,25 @@ xf86SetDepthBpp(ScrnInfoPtr scrp, int depth, int dummy, int fbbpp,
scrp->confScreen->numdisplays++;
scrp->confScreen->displays =
xnfreallocarray(scrp->confScreen->displays,
scrp->confScreen->numdisplays, sizeof(DispRec));
scrp->confScreen->numdisplays, sizeof(DispPtr));
xf86DrvMsg(scrp->scrnIndex, X_INFO,
"Creating default Display subsection in Screen section\n"
"\t\"%s\" for depth/fbbpp %d/%d\n",
scrp->confScreen->id, scrp->depth, scrp->bitsPerPixel);
memset(&scrp->confScreen->displays[i], 0, sizeof(DispRec));
scrp->confScreen->displays[i].blackColour.red = -1;
scrp->confScreen->displays[i].blackColour.green = -1;
scrp->confScreen->displays[i].blackColour.blue = -1;
scrp->confScreen->displays[i].whiteColour.red = -1;
scrp->confScreen->displays[i].whiteColour.green = -1;
scrp->confScreen->displays[i].whiteColour.blue = -1;
scrp->confScreen->displays[i].defaultVisual = -1;
scrp->confScreen->displays[i].modes = xnfalloc(sizeof(char *));
scrp->confScreen->displays[i].modes[0] = NULL;
scrp->confScreen->displays[i].depth = depth;
scrp->confScreen->displays[i].fbbpp = fbbpp;
scrp->display = &scrp->confScreen->displays[i];
scrp->confScreen->displays[i] = xnfcalloc(1, sizeof(DispRec));
memset(scrp->confScreen->displays[i], 0, sizeof(DispRec));
scrp->confScreen->displays[i]->blackColour.red = -1;
scrp->confScreen->displays[i]->blackColour.green = -1;
scrp->confScreen->displays[i]->blackColour.blue = -1;
scrp->confScreen->displays[i]->whiteColour.red = -1;
scrp->confScreen->displays[i]->whiteColour.green = -1;
scrp->confScreen->displays[i]->whiteColour.blue = -1;
scrp->confScreen->displays[i]->defaultVisual = -1;
scrp->confScreen->displays[i]->modes = xnfalloc(sizeof(char *));
scrp->confScreen->displays[i]->modes[0] = NULL;
scrp->confScreen->displays[i]->depth = depth;
scrp->confScreen->displays[i]->fbbpp = fbbpp;
scrp->display = scrp->confScreen->displays[i];
}
/*

2
hw/xfree86/common/xf86str.h
View File

@ -349,7 +349,7 @@ typedef struct _confscreenrec {
MonPtr monitor;
GDevPtr device;
int numdisplays;
DispPtr displays;
DispPtr *displays;
int numxvadaptors;
confXvAdaptorPtr xvadaptors;
void *options;