Re: [PATCH 4.4.y-cip 17/23] PM / OPP: Fix NULL pointer dereference crash when disabling OPPs

Pavel Machek


On Wed 2020-07-08 23:45:48, Chen-Yu Tsai (Moxa) wrote:
From: Jon Hunter <jonathanh@...>

commit 78ecc56247f0ec2bc0cf6f2f2af69e98d99767bc upstream.

Commit 7d34d56ef334 (PM / OPP: Disable OPPs that aren't supported by
the regulator) causes a crash to happen on Tegra124 Jetson TK1 when
using the DFLL clock source for the CPU. The DFLL manages the voltage
itself and so there is no regulator specified for the OPPs and so we
get a crash when we try to dereference the regulator pointer. Fix
this by checking to see if the regulator IS_ERR_OR_NULL before
dereferencing it.

Fixes: 7d34d56ef334 (PM / OPP: Disable OPPs that aren't supported by
So this one should be close to the patch it fixes, or maybe squashed

Best regards,

diff --git a/drivers/base/power/opp/core.c b/drivers/base/power/opp/core.c
index 91b4cc261d84a..067379f931662 100644
--- a/drivers/base/power/opp/core.c
+++ b/drivers/base/power/opp/core.c
@@ -975,7 +975,7 @@ static bool _opp_supported_by_regulators(struct dev_pm_opp *opp,
struct regulator *reg = dev_opp->regulator;

- if (!IS_ERR(reg) &&
+ if (!IS_ERR_OR_NULL(reg) &&
!regulator_is_supported_voltage(reg, opp->u_volt_min,
opp->u_volt_max)) {
pr_warn("%s: OPP minuV: %lu maxuV: %lu, not supported by regulator\n",
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