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Commit bbdbc138 authored by Vamsi krishna Gattupalli's avatar Vamsi krishna Gattupalli Committed by vgattupa
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msm: ADSPRPC: Fix deadlock during SSR 



Deadlock is happening because map_mutex and smd_mutex lock is
acquired before fastrpc_mmap_remove_ssr() call and inside again
in get_args() and fastrpc_invoke_send() respectively. Added
lock only to critical sections in need.

Change-Id: I900e44790ec0285b7b156542bf599092479dc864
Signed-off-by: default avatarVamsi krishna Gattupalli <vgattupa@codeaurora.org>
parent 9cdeb30a

drivers/char/adsprpc.c

+8 −3
Original line number Diff line number Diff line
@@ -3191,13 +3191,18 @@ static int fastrpc_mmap_remove_ssr(struct fastrpc_file *fl) 
					kfree(ramdump_segments_rh);

				}

			}

			mutex_lock(&fl->map_mutex);

			fastrpc_mmap_free(match, 0);

			mutex_unlock(&fl->map_mutex);

		}

	} while (match);

	me->enable_ramdump = false;

bail:

	if (err && match)

	if (err && match) {

		mutex_lock(&fl->map_mutex);

		fastrpc_mmap_add(match);

		mutex_unlock(&fl->map_mutex);

	}

	return err;

}
@@ -4006,13 +4011,13 @@ static int fastrpc_channel_open(struct fastrpc_file *fl) 


	if (cid == ADSP_DOMAIN_ID && me->channel[cid].ssrcount !=

			 me->channel[cid].prevssrcount) {

		mutex_lock(&fl->map_mutex);

		mutex_unlock(&me->channel[cid].smd_mutex);

		err = fastrpc_mmap_remove_ssr(fl);

		if (err)

			pr_warn("adsprpc: %s: %s: failed to unmap remote heap for %s (err %d)\n",

					__func__, current->comm,

					me->channel[cid].subsys, err);

		mutex_unlock(&fl->map_mutex);

		mutex_lock(&me->channel[cid].smd_mutex);

		me->channel[cid].prevssrcount =

					me->channel[cid].ssrcount;

	}