From: Jeff Garzik <jeff@garzik.org>
To: Satyam Sharma <satyam@infradead.org>
Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
James Bottomley <james.bottomley@steeleye.com>,
Oliver Neukum <oliver@neukum.name>,
linux-scsi@vger.kernel.org,
Andrew Morton <akpm@linux-foundation.org>,
Ingo Molnar <mingo@elte.hu>
Subject: Re: [PATCH -mm] DC395x SCSI driver: Shut up uninitialized variable build warning
Date: Sun, 02 Sep 2007 16:23:59 -0400 [thread overview]
Message-ID: <46DB1BDF.4090100@garzik.org> (raw)
In-Reply-To: <alpine.LFD.0.999.0709030152260.29617@enigma.security.iitk.ac.in>
Satyam Sharma wrote:
> drivers/scsi/dc395x.c: In function ‘dc395x_init_one’:
> drivers/scsi/dc395x.c:4272: warning: ‘ptr’ may be used uninitialized in this function
>
> has been verified to be a bogus warning. Let's shut it up.
>
> Signed-off-by: Satyam Sharma <satyam@infradead.org>
>
> ---
>
> drivers/scsi/dc395x.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> --- linux-2.6.23-rc4-mm1/drivers/scsi/dc395x.c~fix 2007-09-02 20:57:51.000000000 +0530
> +++ linux-2.6.23-rc4-mm1/drivers/scsi/dc395x.c 2007-09-02 21:10:49.000000000 +0530
> @@ -4269,7 +4269,7 @@ static int __devinit adapter_sg_tables_a
> const unsigned srbs_per_page = PAGE_SIZE/SEGMENTX_LEN;
> int srb_idx = 0;
> unsigned i = 0;
> - struct SGentry *ptr;
> + struct SGentry * uninitialized_var(ptr);
For things like this, we need to see (perhaps a separate email in the
same thread) your build details: config, arch, compiler version, etc.
This warning does not appear on x86 or x86-64 here, with the current
version of gcc. And I'm not so sure we want to be adding these markers
for older versions of the compiler, or for what is ultimately a
temporary [situation | configuration] in the grand scheme of things.
I paid careful attention to my recent set of uninitialized_var() markers
(now upstream), making sure that they persisted across several compiler
versions, ensuring the warning was not a temporary optimizer bug quickly
remedied.
I hope to encourage similar diligence in others :) These markers have
the very-real potential downside of hiding bugs, so they should be used
sparingly.
Jeff
next prev parent reply other threads:[~2007-09-02 20:24 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <alpine.LFD.0.999.0709022344550.27844@enigma.security.iitk.ac.i n>
2007-09-02 20:02 ` [-mm patchset] War on warnings Satyam Sharma
2007-09-02 20:04 ` Jesper Juhl
2007-09-02 20:39 ` Satyam Sharma
2007-09-02 20:30 ` Jesper Juhl
2007-09-02 20:07 ` [PATCH -mm] sisusbvga: Fix bug and build warnings Satyam Sharma
2007-09-02 20:11 ` Jesper Juhl
2007-09-02 20:32 ` Satyam Sharma
2007-09-02 20:23 ` Jesper Juhl
2007-09-02 21:18 ` Alistair John Strachan
2007-09-02 21:38 ` Satyam Sharma
2007-09-02 22:27 ` Satyam Sharma
2007-09-09 21:32 ` patch usb-sisusbvga-fix-bug-and-build-warnings.patch added to gregkh-2.6 tree gregkh
2007-09-02 20:09 ` [PATCH -mm] sunrpc svc: Shut up bogus uninitialized variable warning Satyam Sharma
2007-09-02 20:11 ` [PATCH -mm] net/wireless/sysfs.c: Shut up build warning Satyam Sharma
2007-09-02 20:24 ` Johannes Berg
2007-09-02 20:12 ` [PATCH -mm] drivers/usb/serial/bus.c: Fix incompatible pointer type warning Satyam Sharma
2007-09-02 20:13 ` [PATCH -mm] IPS SCSI driver: Check return of scsi_add_host() Satyam Sharma
2007-09-02 20:03 ` Jesper Juhl
2007-09-02 20:32 ` Jeff Garzik
2007-09-02 22:39 ` Satyam Sharma
2007-09-02 20:15 ` [PATCH -mm] sb16: Shut up uninitialized var build warning Satyam Sharma
2007-09-02 22:06 ` Rene Herman
2007-09-02 22:34 ` Satyam Sharma
2007-09-20 17:52 ` Denys Vlasenko
2007-09-22 4:20 ` Rene Herman
2007-09-02 20:16 ` [PATCH -mm] drivers/mmc/core/bus.c: Fix unused var warning Satyam Sharma
2007-09-03 9:04 ` Pierre Ossman
2007-09-02 20:18 ` [PATCH -mm] I2O: Fix "defined but not used" build warnings Satyam Sharma
2007-09-02 20:20 ` [PATCH -mm] mpt fusion: Shut up uninitialized variable warnings Satyam Sharma
2007-09-02 20:21 ` [PATCH -mm] es18xx: Shut up uninitialized var build warning Satyam Sharma
2007-09-02 22:14 ` Rene Herman
2007-09-02 20:22 ` [PATCH -mm] drivers/md/: Shut up uninitialized variable warnings Satyam Sharma
2007-09-02 20:34 ` Jeff Garzik
2007-09-02 20:57 ` Satyam Sharma
2007-09-02 20:23 ` [PATCH -mm] DC395x SCSI driver: Shut up uninitialized variable build warning Satyam Sharma
2007-09-02 20:23 ` Jeff Garzik [this message]
2007-09-02 20:49 ` Satyam Sharma
2007-09-02 20:43 ` Jeff Garzik
2007-09-02 20:24 ` [PATCH -mm] i386 cpuid_count: Fix argument signedness warnings Satyam Sharma
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