2022-12-01 18:03:02

by Valentina Goncharenko

[permalink] [raw]

Subject: [PATCH 2/2] net: encx24j600: Fix invalid logic in reading of MISTAT register

---

A loop for reading MISTAT register continues while regmap_read() fails
and (mistat & BUSY), but if regmap_read() fails a value of mistat is
undefined.

The patch proposes to check for BUSY flag only when regmap_read()
succeed. Compile test only.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Fixes: d70e53262f5c ("net: Microchip encx24j600 driver")
Signed-off-by: Valentina Goncharenko <[email protected]>
---
drivers/net/ethernet/microchip/encx24j600-regmap.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/microchip/encx24j600-regmap.c b/drivers/net/ethernet/microchip/encx24j600-regmap.c
index 2e337c7a5773..5693784eec5b 100644
--- a/drivers/net/ethernet/microchip/encx24j600-regmap.c
+++ b/drivers/net/ethernet/microchip/encx24j600-regmap.c
@@ -359,7 +359,7 @@ static int regmap_encx24j600_phy_reg_read(void *context, unsigned int reg,
goto err_out;

usleep_range(26, 100);
- while (((ret = regmap_read(ctx->regmap, MISTAT, &mistat)) != 0) &&
+ while (((ret = regmap_read(ctx->regmap, MISTAT, &mistat)) == 0) &&
(mistat & BUSY))
cpu_relax();

@@ -397,7 +397,7 @@ static int regmap_encx24j600_phy_reg_write(void *context, unsigned int reg,
goto err_out;

usleep_range(26, 100);
- while (((ret = regmap_read(ctx->regmap, MISTAT, &mistat)) != 0) &&
+ while (((ret = regmap_read(ctx->regmap, MISTAT, &mistat)) == 0) &&
(mistat & BUSY))
cpu_relax();

--
2.25.1

2022-12-02 08:45:16

by Pavan Chebbi

[permalink] [raw]

Subject: Re: [PATCH 2/2] net: encx24j600: Fix invalid logic in reading of MISTAT register

---

On Thu, Dec 1, 2022 at 11:04 PM Valentina Goncharenko
<[email protected]> wrote:
>
> A loop for reading MISTAT register continues while regmap_read() fails
> and (mistat & BUSY), but if regmap_read() fails a value of mistat is
> undefined.
>
> The patch proposes to check for BUSY flag only when regmap_read()
> succeed. Compile test only.
>
> Found by Linux Verification Center (linuxtesting.org) with SVACE.
>
> Fixes: d70e53262f5c ("net: Microchip encx24j600 driver")
> Signed-off-by: Valentina Goncharenko <[email protected]>
> ---
> drivers/net/ethernet/microchip/encx24j600-regmap.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/net/ethernet/microchip/encx24j600-regmap.c b/drivers/net/ethernet/microchip/encx24j600-regmap.c
> index 2e337c7a5773..5693784eec5b 100644
> --- a/drivers/net/ethernet/microchip/encx24j600-regmap.c
> +++ b/drivers/net/ethernet/microchip/encx24j600-regmap.c
> @@ -359,7 +359,7 @@ static int regmap_encx24j600_phy_reg_read(void *context, unsigned int reg,
> goto err_out;
>
> usleep_range(26, 100);
> - while (((ret = regmap_read(ctx->regmap, MISTAT, &mistat)) != 0) &&
> + while (((ret = regmap_read(ctx->regmap, MISTAT, &mistat)) == 0) &&
> (mistat & BUSY))
> cpu_relax();
>
> @@ -397,7 +397,7 @@ static int regmap_encx24j600_phy_reg_write(void *context, unsigned int reg,
> goto err_out;
>
> usleep_range(26, 100);
> - while (((ret = regmap_read(ctx->regmap, MISTAT, &mistat)) != 0) &&
> + while (((ret = regmap_read(ctx->regmap, MISTAT, &mistat)) == 0) &&
> (mistat & BUSY))
> cpu_relax();
>
> --
> 2.25.1
>
Looks OK to me.
Reviewed-by: Pavan Chebbi <[email protected]>

---

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