[PATCH] drm/msm: Fix crash on dev file close

[Rob Clark]

From: Rob Clark <robdclark at chromium.org>

If the device file was opened prior to fw being available (such as from
initrd before rootfs is mounted, when the initrd does not contain GPU
fw), that would cause a later crash when the dev file is closed due to
unitialized submitqueues list:

   CPU: 4 PID: 263 Comm: plymouthd Tainted: G        W         5.15.0-rc2-next-20210924 #2
   Hardware name: LENOVO 81JL/LNVNB161216, BIOS 9UCN33WW(V2.06) 06/ 4/2019
   pstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
   pc : msm_submitqueue_close+0x30/0x190 [msm]
   lr : msm_postclose+0x54/0xf0 [msm]
   sp : ffff80001074bb80
   x29: ffff80001074bb80 x28: ffff03ad80c4db80 x27: ffff03ad80dc5ab0
   x26: 0000000000000000 x25: ffff03ad80dc5af8 x24: ffff03ad81e90800
   x23: 0000000000000000 x22: ffff03ad81e90800 x21: ffff03ad8b35e788
   x20: ffff03ad81e90878 x19: 0000000000000000 x18: 0000000000000000
   x17: 0000000000000000 x16: ffffda15f14f7940 x15: 0000000000000000
   x14: 0000000000000000 x13: 0000000000000001 x12: 0000000000000040
   x11: 0000000000000000 x10: 0000000000000000 x9 : ffffda15cd18ff88
   x8 : ffff03ad80c4db80 x7 : 0000000000000228 x6 : 0000000000000000
   x5 : 1793a4e807e636bd x4 : ffff03ad80c4db80 x3 : ffff03ad81e90878
   x2 : 0000000000000000 x1 : ffff03ad80c4db80 x0 : 0000000000000000
   Call trace:
    msm_submitqueue_close+0x30/0x190 [msm]
    msm_postclose+0x54/0xf0 [msm]
    drm_file_free.part.0+0x1cc/0x2e0 [drm]
    drm_close_helper.isra.0+0x74/0x84 [drm]
    drm_release+0x78/0x120 [drm]
    __fput+0x78/0x23c
    ____fput+0x1c/0x30
    task_work_run+0xcc/0x22c
    do_exit+0x304/0x9f4
    do_group_exit+0x44/0xb0
    __wake_up_parent+0x0/0x3c
    invoke_syscall+0x50/0x120
    el0_svc_common.constprop.0+0x4c/0xf4
    do_el0_svc+0x30/0x9c
    el0_svc+0x20/0x60
    el0t_64_sync_handler+0xe8/0xf0
    el0t_64_sync+0x1a0/0x1a4
   Code: aa0003f5 a90153f3 f8408eb3 aa1303e0 (f85e8674)
   ---[ end trace 39b2fa37509a2be2 ]---
   Fixing recursive fault but reboot is needed!

Fixes: 86c2a0f000c1 drm/msm: ("Small submitqueue creation cleanup")
Reported-by: Steev Klimaszewski <steev at kali.org>
Signed-off-by: Rob Clark <robdclark at chromium.org>
---
 drivers/gpu/drm/msm/msm_drv.c         | 3 +++
 drivers/gpu/drm/msm/msm_submitqueue.c | 4 ----
 2 files changed, 3 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/msm/msm_drv.c b/drivers/gpu/drm/msm/msm_drv.c
index f350de754f84..938765ad7109 100644
--- a/drivers/gpu/drm/msm/msm_drv.c
+++ b/drivers/gpu/drm/msm/msm_drv.c
@@ -689,6 +689,9 @@ static int context_init(struct drm_device *dev, struct drm_file *file)
 	if (!ctx)
 		return -ENOMEM;
 
+	INIT_LIST_HEAD(&ctx->submitqueues);
+	rwlock_init(&ctx->queuelock);
+
 	kref_init(&ctx->ref);
 	msm_submitqueue_init(dev, ctx);
 
diff --git a/drivers/gpu/drm/msm/msm_submitqueue.c b/drivers/gpu/drm/msm/msm_submitqueue.c
index 32a55d81b58b..7ce0771b5582 100644
--- a/drivers/gpu/drm/msm/msm_submitqueue.c
+++ b/drivers/gpu/drm/msm/msm_submitqueue.c
@@ -140,10 +140,6 @@ int msm_submitqueue_init(struct drm_device *drm, struct msm_file_private *ctx)
 	 */
 	default_prio = DIV_ROUND_UP(max_priority, 2);
 
-	INIT_LIST_HEAD(&ctx->submitqueues);
-
-	rwlock_init(&ctx->queuelock);
-
 	return msm_submitqueue_create(drm, ctx, default_prio, 0, NULL);
 }
 
-- 
2.31.1