From 482f96324a4e08818db7d75bb12beaaea6c9561d Mon Sep 17 00:00:00 2001
From: Sharat Masetty <smasetty@codeaurora.org>
Date: Fri, 12 Oct 2018 14:26:56 +0530
Subject: drm/msm: Fix task dump in gpu recovery
Git-commit: 482f96324a4e08818db7d75bb12beaaea6c9561d
Patch-mainline: v4.20-rc6
References: bsc#1113956

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>
Signed-off-by: Rob Clark <robdclark@gmail.com>
Signed-off-by: Sean Paul <seanpaul@chromium.org>
Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
---
 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 32d04a9b48cf..2b7c8946adba 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",
-- 
2.20.1