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authorJeremy Kerr <jk@ozlabs.org>2008-08-14 14:59:12 +1000
committerJeremy Kerr <jk@ozlabs.org>2008-08-14 14:59:12 +1000
commit8d5636fbca202f61fdb808fc9e20c0142291d802 (patch)
treee6d9d9375f0f7894931749b687e66a19e5dffa84 /arch/powerpc/platforms
parentd9dd421fd6ed17af55d27c8d93a9f561be0ff50f (diff)
downloadlinaro-lsk-8d5636fbca202f61fdb808fc9e20c0142291d802.tar.gz
powerpc/spufs: reference context while dropping state mutex in scheduler
Based on an original patch from Christoph Hellwig <hch@lst.de>. Currently, there is a possible reference-after-free in the spusched code - contexts may be freed after we have released their state_mutex in spusched_tick and find_victim. This change takes a reference to the context before releasing the mutex, so that the context doesn't get destroyed. Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Diffstat (limited to 'arch/powerpc/platforms')
-rw-r--r--arch/powerpc/platforms/cell/spufs/sched.c9
1 files changed, 8 insertions, 1 deletions
diff --git a/arch/powerpc/platforms/cell/spufs/sched.c b/arch/powerpc/platforms/cell/spufs/sched.c
index 2deeeba7ecc..4b6b0c3a8c9 100644
--- a/arch/powerpc/platforms/cell/spufs/sched.c
+++ b/arch/powerpc/platforms/cell/spufs/sched.c
@@ -641,8 +641,10 @@ static struct spu *find_victim(struct spu_context *ctx)
if (tmp && tmp->prio > ctx->prio &&
!(tmp->flags & SPU_CREATE_NOSCHED) &&
- (!victim || tmp->prio > victim->prio))
+ (!victim || tmp->prio > victim->prio)) {
victim = spu->ctx;
+ get_spu_context(victim);
+ }
}
mutex_unlock(&cbe_spu_info[node].list_mutex);
@@ -658,6 +660,7 @@ static struct spu *find_victim(struct spu_context *ctx)
* look at another context or give up after X retries.
*/
if (!mutex_trylock(&victim->state_mutex)) {
+ put_spu_context(victim);
victim = NULL;
goto restart;
}
@@ -670,6 +673,7 @@ static struct spu *find_victim(struct spu_context *ctx)
* restart the search.
*/
mutex_unlock(&victim->state_mutex);
+ put_spu_context(victim);
victim = NULL;
goto restart;
}
@@ -687,6 +691,7 @@ static struct spu *find_victim(struct spu_context *ctx)
spu_add_to_rq(victim);
mutex_unlock(&victim->state_mutex);
+ put_spu_context(victim);
return spu;
}
@@ -985,9 +990,11 @@ static int spusched_thread(void *unused)
struct spu_context *ctx = spu->ctx;
if (ctx) {
+ get_spu_context(ctx);
mutex_unlock(mtx);
spusched_tick(ctx);
mutex_lock(mtx);
+ put_spu_context(ctx);
}
}
mutex_unlock(mtx);