2024-02-06 19:42:38

by Rand Deeb

[permalink] [raw]
Subject: [PATCH] i2c: Remove redundant comparison in npcm_i2c_reg_slave

In the npcm_i2c_reg_slave() function, there was a redundant
comparison that checked if 'bus->slave' was null immediately after
assigning it the 'client' value. There were concerns about a
potential null dereference because of `client->adapter`, but
according to Wolfram Sang, "we trusted ourselves here" Therefore,
this comparison is unnecessary.

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

Signed-off-by: Rand Deeb <[email protected]>
---
drivers/i2c/busses/i2c-npcm7xx.c | 3 ---
1 file changed, 3 deletions(-)

diff --git a/drivers/i2c/busses/i2c-npcm7xx.c b/drivers/i2c/busses/i2c-npcm7xx.c
index c1b679737240..bdf35b86e559 100644
--- a/drivers/i2c/busses/i2c-npcm7xx.c
+++ b/drivers/i2c/busses/i2c-npcm7xx.c
@@ -1247,9 +1247,6 @@ static int npcm_i2c_reg_slave(struct i2c_client *client)

bus->slave = client;

- if (!bus->slave)
- return -EINVAL;
-
if (client->flags & I2C_CLIENT_TEN)
return -EAFNOSUPPORT;

--
2.34.1



2024-02-06 19:52:20

by Wolfram Sang

[permalink] [raw]
Subject: Re: [PATCH] i2c: Remove redundant comparison in npcm_i2c_reg_slave

On Tue, Feb 06, 2024 at 10:42:01PM +0300, Rand Deeb wrote:
> In the npcm_i2c_reg_slave() function, there was a redundant
> comparison that checked if 'bus->slave' was null immediately after
> assigning it the 'client' value. There were concerns about a
> potential null dereference because of `client->adapter`, but
> according to Wolfram Sang, "we trusted ourselves here" Therefore,
> this comparison is unnecessary.
>
> Found by Linux Verification Center (linuxtesting.org) with SVACE.
>
> Signed-off-by: Rand Deeb <[email protected]>

Reviewed-by: Wolfram Sang <[email protected]>


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2024-02-14 22:43:08

by Andi Shyti

[permalink] [raw]
Subject: Re: [PATCH] i2c: Remove redundant comparison in npcm_i2c_reg_slave

Hi

On Tue, 06 Feb 2024 22:42:01 +0300, Rand Deeb wrote:
> In the npcm_i2c_reg_slave() function, there was a redundant
> comparison that checked if 'bus->slave' was null immediately after
> assigning it the 'client' value. There were concerns about a
> potential null dereference because of `client->adapter`, but
> according to Wolfram Sang, "we trusted ourselves here" Therefore,
> this comparison is unnecessary.
>
> [...]

Applied to i2c/i2c-host on

git://git.kernel.org/pub/scm/linux/kernel/git/andi.shyti/linux.git

Thank you,
Andi

Patches applied
===============
[1/1] i2c: Remove redundant comparison in npcm_i2c_reg_slave
commit: 48acf8292280f257fb0047478153a81471ee7f4d