Re: [PATCH][next] ACPI: APEI: EINJ: Fix check and iounmap of uninitialized pointer p

[Colin King (gmail)]

On 25/06/2025 22:40, Ira Weiny wrote:
> Colin Ian King wrote:
> > In the case where a request_mem_region call fails and pointer r is null
> > the error exit path via label 'out' will check for a non-null pointer
> > p and try to iounmap it. However, pointer p has not been assigned a
> > value at this point, so it may potentially contain any garbage value.
> > Fix this by ensuring pointer p is initialized to NULL.
> >
> > Fixes: 1a35c88302a3 ("ACPI: APEI: EINJ: Fix kernel test sparse warnings")
> > Signed-off-by: Colin Ian King <colin.i.king@xxxxxxxxx>
> > ---
> >   drivers/acpi/apei/einj-core.c | 2 +-
> >   1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/acpi/apei/einj-core.c b/drivers/acpi/apei/einj-core.c
> > index 7930acd1d3f3..fc801587df8e 100644
> > --- a/drivers/acpi/apei/einj-core.c
> > +++ b/drivers/acpi/apei/einj-core.c
> > @@ -401,7 +401,7 @@ static int __einj_error_trigger(u64 trigger_paddr, u32 type,
> >   	u32 table_size;
> >   	int rc = -EIO;
> >   	struct acpi_generic_address *trigger_param_region = NULL;
> > -	struct acpi_einj_trigger __iomem *p;
> > +	struct acpi_einj_trigger __iomem *p = NULL;
>
> Apparently my review of these was pretty weak...  :-/
>
> That said; Why not skip a goto as well?

Because the goto uses a shared return path and hence reduces the amount 
of return epilogue used in the generated code.

Colin

> Ira
>
> diff --git a/drivers/acpi/apei/einj-core.c b/drivers/acpi/apei/einj-core.c
> index d6d7e36e3647..fae01795e7f6 100644
> --- a/drivers/acpi/apei/einj-core.c
> +++ b/drivers/acpi/apei/einj-core.c
> @@ -410,7 +410,7 @@ static int __einj_error_trigger(u64 trigger_paddr, u32 type,
>                         (unsigned long long)trigger_paddr,
>                         (unsigned long long)trigger_paddr +
>                              sizeof(trigger_tab) - 1);
> -               goto out;
> +               return -EIO;
>          }
>          p = ioremap_cache(trigger_paddr, sizeof(*p));
>          if (!p) {
> @@ -502,7 +502,6 @@ static int __einj_error_trigger(u64 trigger_paddr, u32 type,
>                             table_size - sizeof(trigger_tab));
>   out_rel_header:
>          release_mem_region(trigger_paddr, sizeof(trigger_tab));
> -out:
>          if (p)
>                  iounmap(p);
>

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