linux-kernel - Re: [Patch 3/9] fs/compat.c: fix resource leaks and wrong goto's

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Message-ID: <20080512034609.GB2572@hacking>
Date:	Mon, 12 May 2008 11:46:09 +0800
From:	WANG Cong <xiyou.wangcong@...il.com>
To:	Al Viro <viro@...IV.linux.org.uk>
Cc:	WANG Cong <xiyou.wangcong@...il.com>,
	LKML <linux-kernel@...r.kernel.org>,
	Andrew Morton <akpm@...l.org>, WANG Cong <wangcong@...ux.org>
Subject: Re: [Patch 3/9] fs/compat.c: fix resource leaks and wrong goto's

On Sat, May 10, 2008 at 09:35:43PM +0100, Al Viro wrote:
>On Sat, May 10, 2008 at 08:21:11PM +0100, Al Viro wrote:
>> On Thu, May 08, 2008 at 09:52:28PM +0800, WANG Cong wrote:
>> > Use free_arg_pages() to free the pages allocated by copy_strings_kernel()
>> > on failure. And fix some related wrong goto pathes.
>> 
>> Kinda; free_arg_pages() is needed here, but there's no need to mess with
>> goto - just put it under out:
>> 
>> Note that it's essentially just a part of freeing bprm; it's _not_ a "clean
>> collected strings, so that we could add new ones".
>
>FWIW, I'd suggest this:


Hmm, looks fine. But, see below.

>
>diff --git a/fs/compat.c b/fs/compat.c
>index 332a869..ed43e17 100644
>--- a/fs/compat.c
>+++ b/fs/compat.c
>@@ -1405,7 +1405,7 @@ int compat_do_execve(char * filename,
> 		/* execve success */
> 		security_bprm_free(bprm);
> 		acct_update_integrals(current);
>-		kfree(bprm);
>+		free_bprm(bprm);
> 		return retval;
> 	}
> 
>@@ -1424,7 +1424,7 @@ out_file:
> 	}
> 
> out_kfree:
>-	kfree(bprm);
>+	free_bprm(bprm);
> 
> out_ret:
> 	return retval;
>diff --git a/fs/exec.c b/fs/exec.c
>index aeaa979..ad545b0 100644
>--- a/fs/exec.c
>+++ b/fs/exec.c
>@@ -1251,6 +1251,12 @@ int search_binary_handler(struct linux_binprm *bprm,struct pt_regs *regs)
> 
> EXPORT_SYMBOL(search_binary_handler);
> 
>+void free_bprm(struct linux_binprm *bprm)
>+{
>+	free_arg_pages(bprm);
>+	kfree(bprm);
>+}
>+
> /*
>  * sys_execve() executes a new program.
>  */
>@@ -1320,17 +1326,15 @@ int do_execve(char * filename,
> 	retval = search_binary_handler(bprm,regs);
> 	if (retval >= 0) {
> 		/* execve success */
>-		free_arg_pages(bprm);
> 		security_bprm_free(bprm);
> 		acct_update_integrals(current);
>-		kfree(bprm);
>+		free_bprm(bprm);
> 		if (displaced)
> 			put_files_struct(displaced);
> 		return retval;
> 	}
> 
> out:
>-	free_arg_pages(bprm);


Why just drop this? No need to call free_bprm()?


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