6.6-stable review patch. If anyone has any objections, please let me know.
------------------
From: Neil Armstrong <neil.armstrong@xxxxxxxxxx>
[ 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@xxxxxxxxxx>
Signed-off-by: Viresh Kumar <viresh.kumar@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
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 3c26130dc75e3..218cb2e7f3605 100644
--- a/drivers/opp/core.c
+++ b/drivers/opp/core.c
@@ -116,6 +116,15 @@ 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
@@ -850,7 +859,8 @@ 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;
}
@@ -881,7 +891,8 @@ 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;
}
--
2.39.5
