From 03acb0c5ac46b1aa5f3015f1e01243aff9e08600 Mon Sep 17 00:00:00 2001 From: Xiyu Yang Date: Sat, 17 Jul 2021 18:17:22 +0800 Subject: [PATCH] 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: Dimitri Sivanich Signed-off-by: Xiyu Yang Signed-off-by: Xin Tan Link: https://lore.kernel.org/r/1626517043-42696-1-git-send-email-xiyuyang19@fudan.edu.cn Signed-off-by: Greg Kroah-Hartman --- drivers/misc/sgi-gru/grumain.c | 6 +++--- drivers/misc/sgi-gru/grutables.h | 3 ++- 2 files changed, 5 insertions(+), 4 deletions(-) diff --git a/drivers/misc/sgi-gru/grumain.c b/drivers/misc/sgi-gru/grumain.c index 40ac59d..9afda47 100644 --- a/drivers/misc/sgi-gru/grumain.c +++ b/drivers/misc/sgi-gru/grumain.c @@ -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(>s->ts_refcnt) == 0) { + if (gts && refcount_dec_and_test(>s->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(>s->ts_refcnt, 1); + refcount_set(>s->ts_refcnt, 1); mutex_init(>s->ts_ctxlock); gts->ts_cbr_au_count = cbr_au_count; gts->ts_dsr_au_count = dsr_au_count; @@ -888,7 +888,7 @@ again: gts->ts_gru = gru; gts->ts_blade = gru->gs_blade_id; gts->ts_ctxnum = gru_assign_context_number(gru); - atomic_inc(>s->ts_refcnt); + refcount_inc(>s->ts_refcnt); gru->gs_gts[gts->ts_ctxnum] = gts; spin_unlock(&gru->gs_lock); diff --git a/drivers/misc/sgi-gru/grutables.h b/drivers/misc/sgi-gru/grutables.h index 5ce8f30..e4c067c 100644 --- a/drivers/misc/sgi-gru/grutables.h +++ b/drivers/misc/sgi-gru/grutables.h @@ -129,6 +129,7 @@ * */ +#include #include #include #include @@ -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 -- 2.7.4