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Commit 3acc958e authored by Yao Jiang's avatar Yao Jiang Committed by Gerrit - the friendly Code Review server
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soc: qcom: hab: replace kref_get with kref_get_unless_zero 



If refcount was 0 before increment, it maybe has a race condition that
this kref is freeing by some other thread right now. In this case we should
not increments refcount, so replace with kref_get_unless_zero.

Change-Id: Ic15eaefc111770a966094d05b19eca2a04d52fc2
Signed-off-by: default avatarYao Jiang <yaojia@codeaurora.org>
parent 3b8fc0b7

drivers/soc/qcom/hab/hab.c

+9 −1
Original line number Original line Diff line number Diff line
@@ -218,7 +218,15 @@ struct virtual_channel *hab_get_vchan_fromvcid(int32_t vcid, 
	read_lock(&ctx->ctx_lock);

	read_lock(&ctx->ctx_lock);

	list_for_each_entry(vchan, &ctx->vchannels, node) {

	list_for_each_entry(vchan, &ctx->vchannels, node) {

		if (vcid == vchan->id) {

		if (vcid == vchan->id) {

			kref_get(&vchan->refcount);

			if (vchan->otherend_closed || vchan->closed ||

				!kref_get_unless_zero(&vchan->refcount)) {

				pr_debug("failed to inc vcid %x remote %x session %d refcnt %d close_flg remote %d local %d\n",

					vchan->id, vchan->otherend_id,

					vchan->session_id,

					get_refcnt(vchan->refcount),

					vchan->otherend_closed, vchan->closed);

				vchan = NULL;

			}

			read_unlock(&ctx->ctx_lock);

			read_unlock(&ctx->ctx_lock);

			return vchan;

			return vchan;

		}

		}