2023-12-16 01:17:05

by rjingar

[permalink] [raw]
Subject: [PATCH 1/2] platform/x86/intel/pmc: Fix hang in pmc_core_send_ltr_ignore()

From: Rajvi Jingar <[email protected]>

For input value 0, PMC stays unassigned which causes crash while trying
to access PMC for register read/write. Include LTR index 0 in pmc_index
and ltr_index calculation.

Fixes: 2bcef4529222 ("platform/x86:intel/pmc: Enable debugfs multiple PMC support")
Signed-off-by: Rajvi Jingar <[email protected]>
---
drivers/platform/x86/intel/pmc/core.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/platform/x86/intel/pmc/core.c b/drivers/platform/x86/intel/pmc/core.c
index 983e3a8f4910..55eb6a4683fb 100644
--- a/drivers/platform/x86/intel/pmc/core.c
+++ b/drivers/platform/x86/intel/pmc/core.c
@@ -474,7 +474,7 @@ int pmc_core_send_ltr_ignore(struct pmc_dev *pmcdev, u32 value)
* is based on the contiguous indexes from ltr_show output.
* pmc index and ltr index needs to be calculated from it.
*/
- for (pmc_index = 0; pmc_index < ARRAY_SIZE(pmcdev->pmcs) && ltr_index > 0; pmc_index++) {
+ for (pmc_index = 0; pmc_index < ARRAY_SIZE(pmcdev->pmcs) && ltr_index >= 0; pmc_index++) {
pmc = pmcdev->pmcs[pmc_index];

if (!pmc)
--
2.34.1



2023-12-18 12:30:17

by Ilpo Järvinen

[permalink] [raw]
Subject: Re: [PATCH 1/2] platform/x86/intel/pmc: Fix hang in pmc_core_send_ltr_ignore()

On Fri, 15 Dec 2023, rjingar wrote:

> From: Rajvi Jingar <[email protected]>
>
> For input value 0, PMC stays unassigned which causes crash while trying
> to access PMC for register read/write. Include LTR index 0 in pmc_index
> and ltr_index calculation.
>
> Fixes: 2bcef4529222 ("platform/x86:intel/pmc: Enable debugfs multiple PMC support")
> Signed-off-by: Rajvi Jingar <[email protected]>
> ---
> drivers/platform/x86/intel/pmc/core.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/platform/x86/intel/pmc/core.c b/drivers/platform/x86/intel/pmc/core.c
> index 983e3a8f4910..55eb6a4683fb 100644
> --- a/drivers/platform/x86/intel/pmc/core.c
> +++ b/drivers/platform/x86/intel/pmc/core.c
> @@ -474,7 +474,7 @@ int pmc_core_send_ltr_ignore(struct pmc_dev *pmcdev, u32 value)
> * is based on the contiguous indexes from ltr_show output.
> * pmc index and ltr index needs to be calculated from it.
> */
> - for (pmc_index = 0; pmc_index < ARRAY_SIZE(pmcdev->pmcs) && ltr_index > 0; pmc_index++) {
> + for (pmc_index = 0; pmc_index < ARRAY_SIZE(pmcdev->pmcs) && ltr_index >= 0; pmc_index++) {
> pmc = pmcdev->pmcs[pmc_index];
>
> if (!pmc)
>

Reviewed-by: Ilpo J?rvinen <[email protected]>

I'll have to say though I really don't like they way that function is
playing with fire by mixing the use of signed and unsigned variables.

As is, this can only be triggered through a debugfs write and we're
already in -rc6 so IMO next material.

--
i.

2023-12-18 13:20:56

by Ilpo Järvinen

[permalink] [raw]
Subject: Re: [PATCH 1/2] platform/x86/intel/pmc: Fix hang in pmc_core_send_ltr_ignore()

On Fri, 15 Dec 2023 17:16:50 -0800, rjingar wrote:

> For input value 0, PMC stays unassigned which causes crash while trying
> to access PMC for register read/write. Include LTR index 0 in pmc_index
> and ltr_index calculation.
>
>


Thank you for your contribution, it has been applied to my local
review-ilpo branch. Note it will show up in the public
platform-drivers-x86/review-ilpo branch only once I've pushed my
local branch there, which might take a while.

The list of commits applied:
[1/2] platform/x86/intel/pmc: Fix hang in pmc_core_send_ltr_ignore()
commit: fbcf67ce5a9e2831c14bdfb895be05213e611724

--
i.