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

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

Acked-by: Dimitri Sivanich <sivanich@hpe.com>
Signed-off-by: Xiyu Yang <xiyuyang19@fudan.edu.cn>
Signed-off-by: Xin Tan <tanxin.ctf@gmail.com>
Link: https://lore.kernel.org/r/1626517043-42696-1-git-send-email-xiyuyang19@fudan.edu.cn
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Xiyu Yang 2021-07-17 18:17:22 +08:00 committed by Greg Kroah-Hartman
parent 07e913418c
commit 03acb0c5ac
2 changed files with 5 additions and 4 deletions
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6
drivers/misc/sgi-gru/grumain.c
View File

@ -282,7 +282,7 @@ static void gru_unload_mm_tracker(struct gru_state *gru,
*/ */
void gts_drop(struct gru_thread_state *gts) 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) if (gts->ts_gms)
gru_drop_mmu_notifier(gts->ts_gms); gru_drop_mmu_notifier(gts->ts_gms);
kfree(gts); kfree(gts);
@ -323,7 +323,7 @@ struct gru_thread_state *gru_alloc_gts(struct vm_area_struct *vma,
STAT(gts_alloc); STAT(gts_alloc);
memset(gts, 0, sizeof(struct gru_thread_state)); /* zero out header */ 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); mutex_init(&gts->ts_ctxlock);
gts->ts_cbr_au_count = cbr_au_count; gts->ts_cbr_au_count = cbr_au_count;
gts->ts_dsr_au_count = dsr_au_count; gts->ts_dsr_au_count = dsr_au_count;
@ -888,7 +888,7 @@ again:
gts->ts_gru = gru; gts->ts_gru = gru;
gts->ts_blade = gru->gs_blade_id; gts->ts_blade = gru->gs_blade_id;
gts->ts_ctxnum = gru_assign_context_number(gru); 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; gru->gs_gts[gts->ts_ctxnum] = gts;
spin_unlock(&gru->gs_lock); spin_unlock(&gru->gs_lock);

3
drivers/misc/sgi-gru/grutables.h
View File

@ -129,6 +129,7 @@
* *
*/ */
#include <linux/refcount.h>
#include <linux/rmap.h> #include <linux/rmap.h>
#include <linux/interrupt.h> #include <linux/interrupt.h>
#include <linux/mutex.h> #include <linux/mutex.h>
@ -358,7 +359,7 @@ struct gru_thread_state {
enabled */ enabled */
int ts_ctxnum; /* context number where the int ts_ctxnum; /* context number where the
context is loaded */ 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 unsigned char ts_dsr_au_count;/* Number of DSR resources
required for contest */ required for contest */
unsigned char ts_cbr_au_count;/* Number of CBR resources unsigned char ts_cbr_au_count;/* Number of CBR resources