gpu: nvgpu: fix mutex wrong acquire

Wrong acquire/release sequence.

 DEBUG_LOCKS_WARN_ON(rt_mutex_owner(lock) != current)
 ....
 CPU: 4 PID: 5404 Comm: cyclictest.sh Not tainted 4.9.201-rt134-tegra #1
 Hardware name: Jetson-AGX (DT)
 ....
 Call trace:
 [<ffffff800810e4f8>] debug_rt_mutex_unlock+0x58/0x68
 [<ffffff8008f34d0c>] rt_mutex_unlock+0x4c/0xb0
 [<ffffff8008f36ea8>] _mutex_unlock+0x20/0x2c
 [<ffffff8000f69d80>] nvgpu_cg_elcg_set_elcg_enabled+0x78/0xf0 [nvgpu]
 [<ffffff8000f7bd44>] nvgpu_intr_nonstall_cb+0x21bc/0x22f0 [nvgpu]
 [<ffffff800875b304>] dev_attr_store+0x44/0x60
 [<ffffff80082dca44>] sysfs_kf_write+0x5c/0x78
 [<ffffff80082dbd28>] kernfs_fop_write+0xc0/0x1d8
 [<ffffff8008245b60>] __vfs_write+0x48/0x128
 [<ffffff8008246b3c>] vfs_write+0xac/0x1b8
 [<ffffff800824808c>] SyS_write+0x5c/0xc8

Bug 3227296

Suggested-by: Bibek Basu <bbasu@nvidia.com>
Signed-off-by: Sumit Gupta <sumitg@nvidia.com>
Change-Id: I932a23700539422c07de045dde516c52dd8348cf
Reviewed-on: https://git-master.nvidia.com/r/c/linux-nvgpu/+/2472903
Reviewed-by: svc-mobile-coverity <svc-mobile-coverity@nvidia.com>
Reviewed-by: Sagar Kamble <skamble@nvidia.com>
Reviewed-by: Bibek Basu <bbasu@nvidia.com>
Reviewed-by: mobile promotions <svcmobile_promotions@nvidia.com>
Tested-by: Bibek Basu <bbasu@nvidia.com>
Tested-by: mobile promotions <svcmobile_promotions@nvidia.com>
GVS: Gerrit_Virtual_Submit

1 files changed, 1 insertions, 1 deletions

diff --git a/drivers/gpu/nvgpu/common/power_features/cg/cg.c b/drivers/gpu/nvgpu/common/power_features/cg/cg.c
index 7b66a81d..2c61fb29 100644
--- a/drivers/gpu/nvgpu/common/power_features/cg/cg.c
+++ b/drivers/gpu/nvgpu/common/power_features/cg/cg.c
@@ -473,7 +473,7 @@ void nvgpu_cg_elcg_set_elcg_enabled(struct gk20a *g, bool enable)
 
         gk20a_gr_wait_initialized(g);
 
-        nvgpu_mutex_release(&g->cg_pg_lock);
+        nvgpu_mutex_acquire(&g->cg_pg_lock);
         if (enable) {
                 if (!g->elcg_enabled) {
                         g->elcg_enabled = true;