Re: [PATCH] pinctrl:sunplus: Add check for kmalloc

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



Le 23/05/2023 à 21:37, andy.shevchenko@xxxxxxxxx a écrit :
Tue, May 23, 2023 at 05:39:51PM +0000, Wells Lu 呂芳騰 kirjoitti:
Fix Smatch static checker warning:
potential null dereference 'configs'. (kmalloc returns null)

...

  			configs = kmalloc(sizeof(*configs), GFP_KERNEL);
+			if (!configs)

+				return -ENOMEM;

"Fixing" by adding a memory leak is not probably a good approach.

Do you mean I need to free all memory which are allocated in this subroutine before
return -ENOMEM?

This is my understanding of the code. But as I said... (see below)

...

  			configs = kmalloc(sizeof(*configs), GFP_KERNEL);
+			if (!configs)
+				return -ENOMEM;

Ditto.

...

It might be that I'm mistaken. In this case please add an explanation why in the commit
message.

^^^


Hmmm, not so sure.

Should be looked at more carefully, but
  dt_to_map_one_config		(in /drivers/pinctrl/devicetree.c)
    .dt_node_to_map
      --> sppctl_dt_node_to_map

Should dt_to_map_one_config() fail, pinctrl_dt_free_maps() is called
(see https://elixir.bootlin.com/linux/v6.4-rc1/source/drivers/pinctrl/devicetree.c#L281)

pinctrl_dt_free_maps() calls dt_free_map(), which calls .dt_free_map, so pinctrl_utils_free_map() (see https://elixir.bootlin.com/linux/v6.4-rc1/source/drivers/pinctrl/sunplus/sppctl.c#L978)

Finally the needed kfree seem to be called from here.
(see https://elixir.bootlin.com/linux/v6.4-rc1/source/drivers/pinctrl/pinctrl-utils.c#L119)


*This should obviously be double checked*, but looks safe to me.


BUT, in the same function, the of_get_parent() should be undone in case of error, as done at the end of the function, in the normal path.
This one seems to be missing, should a memory allocation error occur.


Just my 2c,

CJ




[Index of Archives]     [Linux SPI]     [Linux Kernel]     [Linux ARM (vger)]     [Linux ARM MSM]     [Linux Omap]     [Linux Arm]     [Linux Tegra]     [Fedora ARM]     [Linux for Samsung SOC]     [eCos]     [Linux Fastboot]     [Gcc Help]     [Git]     [DCCP]     [IETF Announce]     [Security]     [Linux MIPS]     [Yosemite Campsites]

  Powered by Linux