[PATCH 3/3] drm/msm: Fix task dump in gpu recovery

[Sharat Masetty <smasetty-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org>]

The current recovery code gets a pointer to the task struct and does a
few things all within the rcu_read_lock. This puts constraints on the
types of gfp flags that can be used within the rcu lock. This patch
instead gets a reference to the task within the rcu lock and releases
the lock immediately, this way the task stays afloat until we need it and
we also get to use the desired gfp flags.

Signed-off-by: Sharat Masetty <smasetty@codeaurora.org>
---
 drivers/gpu/drm/msm/msm_gpu.c | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/msm/msm_gpu.c b/drivers/gpu/drm/msm/msm_gpu.c
index da63d3d..ca573f6 100644
--- a/drivers/gpu/drm/msm/msm_gpu.c
+++ b/drivers/gpu/drm/msm/msm_gpu.c
@@ -438,10 +438,9 @@ static void recover_worker(struct work_struct *work)
 	if (submit) {
 		struct task_struct *task;
 
-		rcu_read_lock();
-		task = pid_task(submit->pid, PIDTYPE_PID);
+		task = get_pid_task(submit->pid, PIDTYPE_PID);
 		if (task) {
-			comm = kstrdup(task->comm, GFP_ATOMIC);
+			comm = kstrdup(task->comm, GFP_KERNEL);
 
 			/*
 			 * So slightly annoying, in other paths like
@@ -454,10 +453,10 @@ static void recover_worker(struct work_struct *work)
 			 * about the submit going away.
 			 */
 			mutex_unlock(&dev->struct_mutex);
-			cmd = kstrdup_quotable_cmdline(task, GFP_ATOMIC);
+			cmd = kstrdup_quotable_cmdline(task, GFP_KERNEL);
+			put_task_struct(task);
 			mutex_lock(&dev->struct_mutex);
 		}
-		rcu_read_unlock();
 
 		if (comm && cmd) {
 			dev_err(dev->dev, "%s: offending task: %s (%s)\n",
-- 
1.9.1

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