[PATCH] media: venus: Fix OPP table error handling

[Sasha Levin <sashal@kernel.org>]

The venus driver fails to check if dev_pm_opp_find_freq_{ceil,floor}()
returns an error pointer before calling dev_pm_opp_put(). This causes
a crash when OPP tables are not present in device tree.

Unable to handle kernel access to user memory outside uaccess routines
at virtual address 000000000000002e
...
pc : dev_pm_opp_put+0x1c/0x4c
lr : core_clks_enable+0x4c/0x16c [venus_core]

Add IS_ERR() checks before calling dev_pm_opp_put() to avoid
dereferencing error pointers.

Fixes: b179234b5e59 ("media: venus: pm_helpers: use opp-table for the frequency")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---

This addresses a new boot failure introduced in this PR and reported by
LKFT. Looks like the offending commit completely skipped linux-next :( 

https://qa-reports.linaro.org/lkft/linux-mainline-master/build/v6.16-11579-g35a813e010b9/testrun/29378041/suite/log-parser-boot/test/internal-error-oops-oops-smp/log

 drivers/media/platform/qcom/venus/pm_helpers.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/drivers/media/platform/qcom/venus/pm_helpers.c b/drivers/media/platform/qcom/venus/pm_helpers.c
index 8dd5a9b0d060..e32f8862a9f9 100644
--- a/drivers/media/platform/qcom/venus/pm_helpers.c
+++ b/drivers/media/platform/qcom/venus/pm_helpers.c
@@ -48,7 +48,8 @@ static int core_clks_enable(struct venus_core *core)
 	int ret;
 
 	opp = dev_pm_opp_find_freq_ceil(dev, &freq);
-	dev_pm_opp_put(opp);
+	if (!IS_ERR(opp))
+		dev_pm_opp_put(opp);
 
 	for (i = 0; i < res->clks_num; i++) {
 		if (IS_V6(core)) {
@@ -660,7 +661,8 @@ static int decide_core(struct venus_inst *inst)
 	/*TODO : divide this inst->load by work_route */
 
 	opp = dev_pm_opp_find_freq_floor(dev, &max_freq);
-	dev_pm_opp_put(opp);
+	if (!IS_ERR(opp))
+		dev_pm_opp_put(opp);
 
 	min_loaded_core(inst, &min_coreid, &min_load, false);
 	min_loaded_core(inst, &min_lp_coreid, &min_lp_load, true);
@@ -1121,7 +1123,8 @@ static int load_scale_v4(struct venus_inst *inst)
 	freq = max(freq_core1, freq_core2);
 
 	opp = dev_pm_opp_find_freq_floor(dev, &max_freq);
-	dev_pm_opp_put(opp);
+	if (!IS_ERR(opp))
+		dev_pm_opp_put(opp);
 
 	if (freq > max_freq) {
 		dev_dbg(dev, VDBGL "requested clock rate: %lu scaling clock rate : %lu\n",
@@ -1131,7 +1134,8 @@ static int load_scale_v4(struct venus_inst *inst)
 	}
 
 	opp = dev_pm_opp_find_freq_ceil(dev, &freq);
-	dev_pm_opp_put(opp);
+	if (!IS_ERR(opp))
+		dev_pm_opp_put(opp);
 
 set_freq:
 
-- 
2.39.5