linux-kernel - Re: ext4_lazyinit_thread: 'ret' may be used uninitialized in this function

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Message-ID: <20101102182911.GE25614@thunk.org>
Date:	Tue, 2 Nov 2010 14:29:11 -0400
From:	Ted Ts'o <tytso@....edu>
To:	Lukas Czerner <lczerner@...hat.com>
Cc:	Stefan Richter <stefanr@...6.in-berlin.de>,
	linux-ext4@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: ext4_lazyinit_thread: 'ret' may be used uninitialized in this
 function

On Mon, Nov 01, 2010 at 04:27:26PM +0100, Lukas Czerner wrote:
> 
> thank you for noticing this, because I actually do not see the warning
> (I wonder why...), but it is definitely a bug, so the trivial patch below
> should fix that.

This is a slightly less trivial fix that eliminates the need for the
"ret" variable entirely.

						- Ted

commit e048924538f0c62d18306e2fea0e22dac0140f6e
Author: Theodore Ts'o <tytso@....edu>
Date:   Tue Nov 2 14:19:30 2010 -0400

    ext4: "ret" may be used uninitialized in ext4_lazyinit_thread()
    
    Newer GCC's reported the following build warning:
    
       fs/ext4/super.c: In function 'ext4_lazyinit_thread':
       fs/ext4/super.c:2702: warning: 'ret' may be used uninitialized in this function
    
    Fix it by removing the need for the ret variable in the first place.
    
    Signed-off-by: "Lukas Czerner" <lczerner@...hat.com>
    Reported-by: "Stefan Richter" <stefanr@...6.in-berlin.de>
    Signed-off-by: "Theodore Ts'o" <tytso@....edu>

diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 8d1d942..4d7ef31 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -2699,7 +2699,6 @@ static int ext4_lazyinit_thread(void *arg)
 	struct ext4_li_request *elr;
 	unsigned long next_wakeup;
 	DEFINE_WAIT(wait);
-	int ret;
 
 	BUG_ON(NULL == eli);
 
@@ -2723,13 +2722,12 @@ cont_thread:
 			elr = list_entry(pos, struct ext4_li_request,
 					 lr_request);
 
-			if (time_after_eq(jiffies, elr->lr_next_sched))
-				ret = ext4_run_li_request(elr);
-
-			if (ret) {
-				ret = 0;
-				ext4_remove_li_request(elr);
-				continue;
+			if (time_after_eq(jiffies, elr->lr_next_sched)) {
+				if (ext4_run_li_request(elr) != 0) {
+					/* error, remove the lazy_init job */
+					ext4_remove_li_request(elr);
+					continue;
+				}
 			}
 
 			if (time_before(elr->lr_next_sched, next_wakeup))
--
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