Commit 03acb0c5 authored by Xiyu Yang's avatar Xiyu Yang Committed by Greg Kroah-Hartman
Browse files

misc: sgi-gru: Convert from atomic_t to refcount_t on gru_thread_state->ts_refcnt 



refcount_t type and corresponding API can protect refcounters from
accidental underflow and overflow and further use-after-free situations.

Acked-by: default avatarDimitri Sivanich <sivanich@hpe.com>
Signed-off-by: default avatarXiyu Yang <xiyuyang19@fudan.edu.cn>
Signed-off-by: default avatarXin Tan <tanxin.ctf@gmail.com>
Link: https://lore.kernel.org/r/1626517043-42696-1-git-send-email-xiyuyang19@fudan.edu.cn


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 07e91341

drivers/misc/sgi-gru/grumain.c

+3 −3
Original line number Diff line number Diff line
@@ -282,7 +282,7 @@ static void gru_unload_mm_tracker(struct gru_state *gru, 
 */

void gts_drop(struct gru_thread_state *gts)

{

	if (gts && atomic_dec_return(&gts->ts_refcnt) == 0) {

	if (gts && refcount_dec_and_test(&gts->ts_refcnt)) {

		if (gts->ts_gms)

			gru_drop_mmu_notifier(gts->ts_gms);

		kfree(gts);
@@ -323,7 +323,7 @@ struct gru_thread_state *gru_alloc_gts(struct vm_area_struct *vma, 


	STAT(gts_alloc);

	memset(gts, 0, sizeof(struct gru_thread_state)); /* zero out header */

	atomic_set(&gts->ts_refcnt, 1);

	refcount_set(&gts->ts_refcnt, 1);

	mutex_init(&gts->ts_ctxlock);

	gts->ts_cbr_au_count = cbr_au_count;

	gts->ts_dsr_au_count = dsr_au_count;
@@ -888,7 +888,7 @@ struct gru_state *gru_assign_gru_context(struct gru_thread_state *gts) 
		gts->ts_gru = gru;

		gts->ts_blade = gru->gs_blade_id;

		gts->ts_ctxnum = gru_assign_context_number(gru);

		atomic_inc(&gts->ts_refcnt);

		refcount_inc(&gts->ts_refcnt);

		gru->gs_gts[gts->ts_ctxnum] = gts;

		spin_unlock(&gru->gs_lock);

drivers/misc/sgi-gru/grutables.h

+2 −1
Original line number Diff line number Diff line
@@ -129,6 +129,7 @@ 
 *

 */



#include <linux/refcount.h>

#include <linux/rmap.h>

#include <linux/interrupt.h>

#include <linux/mutex.h>
@@ -358,7 +359,7 @@ struct gru_thread_state { 
						     enabled */

	int			ts_ctxnum;	/* context number where the

						   context is loaded */

	atomic_t		ts_refcnt;	/* reference count GTS */

	refcount_t		ts_refcnt;	/* reference count GTS */

	unsigned char		ts_dsr_au_count;/* Number of DSR resources

						   required for contest */

	unsigned char		ts_cbr_au_count;/* Number of CBR resources