| Message ID | 20221001171027.2101923-3-fabien.parent@linaro.org |
|---|---|
| State | New |
| Headers | show |
| Series | [1/3] cpufreq: qcom: fix memory leak in error path | expand |
On 01-10-22, 19:10, Fabien Parent wrote: > This commit fixes a kernel oops because of a write in some read-only memory: > > [ 9.068287] Unable to handle kernel write to read-only memory at virtual address ffff800009240ad8 > ..snip.. > [ 9.138790] Internal error: Oops: 9600004f [#1] PREEMPT SMP > ..snip.. > [ 9.269161] Call trace: > [ 9.276271] __memcpy+0x5c/0x230 > [ 9.278531] snprintf+0x58/0x80 > [ 9.282002] qcom_cpufreq_msm8939_name_version+0xb4/0x190 > [ 9.284869] qcom_cpufreq_probe+0xc8/0x39c > ..snip.. > > The following line defines a pointer that point to a char buffer stored > in read-only memory: > > char *pvs_name = PVS_NAME; > > This pointer is meant to hold a template "speedXX-pvsXX-vXX" where the > XX values get overridden by the qcom_cpufreq_krait_name_version function. Since > the template is actually stored in read-only memory, when the function > executes the following call we get an oops: > > snprintf(*pvs_name, sizeof(PVS_NAME), "speed%d-pvs%d-v%d", > speed, pvs, pvs_ver); > > To fix this issue, we instead store the template name onto the stack by > using the following syntax: > > char pvs_name_buffer[] = PVS_NAME; > > Because the `pvs_name` needs to be able to be assigned to NULL, the > template buffer is stored in the pvs_name_template and not under the > pvs_name variable. > > Signed-off-by: Fabien Parent <fabien.parent@linaro.org> No Fixes or Cc:Stable for this ? This looks like a bug fix and this should be sent before patch 2/3 so it can be back ported properly. > --- > drivers/cpufreq/qcom-cpufreq-nvmem.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/drivers/cpufreq/qcom-cpufreq-nvmem.c b/drivers/cpufreq/qcom-cpufreq-nvmem.c > index 64ce077a4848..3e097262f612 100644 > --- a/drivers/cpufreq/qcom-cpufreq-nvmem.c > +++ b/drivers/cpufreq/qcom-cpufreq-nvmem.c > @@ -269,7 +269,8 @@ static int qcom_cpufreq_probe(struct platform_device *pdev) > struct nvmem_cell *speedbin_nvmem; > struct device_node *np; > struct device *cpu_dev; > - char *pvs_name = PVS_NAME_TEMPLATE; > + char pvs_name_buffer[] = PVS_NAME_TEMPLATE; > + char *pvs_name = pvs_name_buffer; > unsigned cpu; > const struct of_device_id *match; > int ret; > -- > 2.37.2
diff --git a/drivers/cpufreq/qcom-cpufreq-nvmem.c b/drivers/cpufreq/qcom-cpufreq-nvmem.c index 64ce077a4848..3e097262f612 100644 --- a/drivers/cpufreq/qcom-cpufreq-nvmem.c +++ b/drivers/cpufreq/qcom-cpufreq-nvmem.c @@ -269,7 +269,8 @@ static int qcom_cpufreq_probe(struct platform_device *pdev) struct nvmem_cell *speedbin_nvmem; struct device_node *np; struct device *cpu_dev; - char *pvs_name = PVS_NAME_TEMPLATE; + char pvs_name_buffer[] = PVS_NAME_TEMPLATE; + char *pvs_name = pvs_name_buffer; unsigned cpu; const struct of_device_id *match; int ret;
This commit fixes a kernel oops because of a write in some read-only memory: [ 9.068287] Unable to handle kernel write to read-only memory at virtual address ffff800009240ad8 ..snip.. [ 9.138790] Internal error: Oops: 9600004f [#1] PREEMPT SMP ..snip.. [ 9.269161] Call trace: [ 9.276271] __memcpy+0x5c/0x230 [ 9.278531] snprintf+0x58/0x80 [ 9.282002] qcom_cpufreq_msm8939_name_version+0xb4/0x190 [ 9.284869] qcom_cpufreq_probe+0xc8/0x39c ..snip.. The following line defines a pointer that point to a char buffer stored in read-only memory: char *pvs_name = PVS_NAME; This pointer is meant to hold a template "speedXX-pvsXX-vXX" where the XX values get overridden by the qcom_cpufreq_krait_name_version function. Since the template is actually stored in read-only memory, when the function executes the following call we get an oops: snprintf(*pvs_name, sizeof(PVS_NAME), "speed%d-pvs%d-v%d", speed, pvs, pvs_ver); To fix this issue, we instead store the template name onto the stack by using the following syntax: char pvs_name_buffer[] = PVS_NAME; Because the `pvs_name` needs to be able to be assigned to NULL, the template buffer is stored in the pvs_name_template and not under the pvs_name variable. Signed-off-by: Fabien Parent <fabien.parent@linaro.org> --- drivers/cpufreq/qcom-cpufreq-nvmem.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)