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Groups > linux.kernel > #1719564

Re: [PATCH v2] x86/microcode: Silence a static checker warning

From Dan Carpenter <dan.carpenter@oracle.com>
Newsgroups linux.kernel
Subject Re: [PATCH v2] x86/microcode: Silence a static checker warning
Date 2017-08-24 23:00 +0200
Message-ID <ui7ol-2YO-7@gated-at.bofh.it> (permalink)
References <ui6LF-2Jv-31@gated-at.bofh.it> <ui6LF-2Jv-29@gated-at.bofh.it> <ui7eG-2Ut-21@gated-at.bofh.it>
Organization linux.* mail to news gateway

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On Thu, Aug 24, 2017 at 10:47:14PM +0200, Borislav Petkov wrote:
> diff --git a/arch/x86/kernel/cpu/microcode/intel.c b/arch/x86/kernel/cpu/microcode/intel.c
> index 59edbe9d4ccb..0179f0fd8a79 100644
> --- a/arch/x86/kernel/cpu/microcode/intel.c
> +++ b/arch/x86/kernel/cpu/microcode/intel.c
> @@ -146,7 +146,7 @@ static bool microcode_matches(struct microcode_header_intel *mc_header,
>  	return false;
>  }
>  
> -static struct ucode_patch *__alloc_microcode_buf(void *data, unsigned int size)
> +static struct ucode_patch *memdup_patch(void *data, unsigned int size)
>  {
>  	struct ucode_patch *p;
>  
> @@ -183,11 +183,13 @@ static void save_microcode_patch(void *data, unsigned int size)
>  			if (mc_hdr->rev <= mc_saved_hdr->rev)
>  				continue;
>  
> -			p = __alloc_microcode_buf(data, size);
> -			if (IS_ERR(p))
> +			p = memdup_patch(data, size);
> +			if (IS_ERR(p)) {
>  				pr_err("Error allocating buffer %p\n", data);
> -			else
> -				list_replace(&iter->plist, &p->plist);
> +				continue;
> +			}
> +
> +			list_replace(&iter->plist, &p->plist);
>  		}
>  	}
>  

This is just cleanups and doesn't change the behavior.

> @@ -196,11 +198,12 @@ static void save_microcode_patch(void *data, unsigned int size)
>  	 * newly found.
>  	 */
>  	if (!prev_found) {
> -		p = __alloc_microcode_buf(data, size);
> -		if (IS_ERR(p))
> +		p = memdup_patch(data, size);
> +		if (IS_ERR(p)) {
>  			pr_err("Error allocating buffer for %p\n", data);
> -		else
> -			list_add_tail(&p->plist, &microcode_cache);
> +			return;
> +		}
> +		list_add_tail(&p->plist, &microcode_cache);
>  	}

The static checker is still going to complain about the error pointer
from the loop.  Perhaps we should only set prev_found if the memdup_patch()
inside the loop succeeds?

regards,
dan carpenter

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Thread

[PATCH v2] x86/microcode: Silence a static checker warning Dan Carpenter <dan.carpenter@oracle.com> - 2017-08-24 22:20 +0200
  Re: [PATCH v2] x86/microcode: Silence a static checker warning Borislav Petkov <bp@alien8.de> - 2017-08-24 22:50 +0200
    Re: [PATCH v2] x86/microcode: Silence a static checker warning Borislav Petkov <bp@alien8.de> - 2017-08-24 23:00 +0200
      Re: [PATCH v2] x86/microcode: Silence a static checker warning Dan Carpenter <dan.carpenter@oracle.com> - 2017-08-24 23:10 +0200
        Re: [PATCH v2] x86/microcode: Silence a static checker warning Borislav Petkov <bp@alien8.de> - 2017-08-24 23:20 +0200
          Re: [PATCH v2] x86/microcode: Silence a static checker warning Borislav Petkov <bp@alien8.de> - 2017-08-25 11:10 +0200
            Re: [PATCH v2] x86/microcode: Silence a static checker warning Borislav Petkov <bp@alien8.de> - 2017-08-25 11:20 +0200
              [PATCH] x86/microcode/intel: Improve microcode patches saving flow Borislav Petkov <bp@alien8.de> - 2017-08-25 12:10 +0200
                Re: [PATCH] x86/microcode/intel: Improve microcode patches saving  flow walter harms <wharms@bfs.de> - 2017-08-25 12:50 +0200
                Re: [PATCH] x86/microcode/intel: Improve microcode patches saving  flow Borislav Petkov <bp@alien8.de> - 2017-08-25 13:50 +0200
                [tip:x86/microcode] x86/microcode/intel: Improve microcode patches  saving flow tip-bot for Borislav Petkov <tipbot@zytor.com> - 2017-08-29 11:10 +0200
            Re: [PATCH v2] x86/microcode: Silence a static checker warning Dan Carpenter <dan.carpenter@oracle.com> - 2017-08-25 11:20 +0200
    Re: [PATCH v2] x86/microcode: Silence a static checker warning Dan Carpenter <dan.carpenter@oracle.com> - 2017-08-24 23:00 +0200
    Re: [PATCH v2] x86/microcode: Silence a static checker warning Joe Perches <joe@perches.com> - 2017-08-24 23:10 +0200

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