6.1-stable review patch. If anyone has any objections, please let me know.
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From: Neil Armstrong neil.armstrong@linaro.org
[ Upstream commit b44b9bc7cab2967c3d6a791b1cd542c89fc07f0e ]
If a driver calls dev_pm_opp_find_bw_ceil/floor() the retrieve bandwidth from the OPP table but the bandwidth table was not created because the interconnect properties were missing in the OPP consumer node, the kernel will crash with:
Unable to handle kernel NULL pointer dereference at virtual address 0000000000000004 ... pc : _read_bw+0x8/0x10 lr : _opp_table_find_key+0x9c/0x174 ... Call trace: _read_bw+0x8/0x10 (P) _opp_table_find_key+0x9c/0x174 (L) _find_key+0x98/0x168 dev_pm_opp_find_bw_ceil+0x50/0x88 ...
In order to fix the crash, create an assert function to check if the bandwidth table was created before trying to get a bandwidth with _read_bw().
Fixes: add1dc094a74 ("OPP: Use generic key finding helpers for bandwidth key") Signed-off-by: Neil Armstrong neil.armstrong@linaro.org Signed-off-by: Viresh Kumar viresh.kumar@linaro.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/opp/core.c | 15 +++++++++++++-- 1 file changed, 13 insertions(+), 2 deletions(-)
diff --git a/drivers/opp/core.c b/drivers/opp/core.c index 53286063df558..4211cfb27350f 100644 --- a/drivers/opp/core.c +++ b/drivers/opp/core.c @@ -119,6 +119,15 @@ static bool assert_clk_index(struct opp_table *opp_table, return opp_table->clk_count > index; }
+/* + * Returns true if bandwidth table is large enough to contain the bandwidth index. + */ +static bool assert_bandwidth_index(struct opp_table *opp_table, + unsigned int index) +{ + return opp_table->path_count > index; +} + /** * dev_pm_opp_get_voltage() - Gets the voltage corresponding to an opp * @opp: opp for which voltage has to be returned for @@ -847,7 +856,8 @@ struct dev_pm_opp *dev_pm_opp_find_bw_ceil(struct device *dev, unsigned int *bw, unsigned long temp = *bw; struct dev_pm_opp *opp;
- opp = _find_key_ceil(dev, &temp, index, true, _read_bw, NULL); + opp = _find_key_ceil(dev, &temp, index, true, _read_bw, + assert_bandwidth_index); *bw = temp; return opp; } @@ -878,7 +888,8 @@ struct dev_pm_opp *dev_pm_opp_find_bw_floor(struct device *dev, unsigned long temp = *bw; struct dev_pm_opp *opp;
- opp = _find_key_floor(dev, &temp, index, true, _read_bw, NULL); + opp = _find_key_floor(dev, &temp, index, true, _read_bw, + assert_bandwidth_index); *bw = temp; return opp; }