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From: David Laight <david.laight.linux@gmail.com>
To: Alexandre Ghiti <alex@ghiti.fr>
Cc: Christoph Hellwig <hch@lst.de>, kernel test robot <lkp@intel.com>,
	oe-kbuild-all@lists.linux.dev, linux-kernel@vger.kernel.org,
	Carlos Maiolino <cem@kernel.org>,
	"Darrick J. Wong" <djwong@kernel.org>,
	linux-riscv@lists.infradead.org
Subject: Re: fs/xfs/xfs_buf.c:1534 xfs_buf_submit_bio() warn: unsigned '_x' is never less than zero.
Date: Mon, 17 Feb 2025 13:12:03 +0000	[thread overview]
Message-ID: <20250217131203.2657cc4b@pumpkin> (raw)
In-Reply-To: <a14347d2-6189-49bc-a1cc-e5959e76e6c2@ghiti.fr>

On Mon, 17 Feb 2025 13:06:49 +0100
Alexandre Ghiti <alex@ghiti.fr> wrote:

> Hi Christoph,
> 
> On 17/02/2025 10:24, Christoph Hellwig wrote:
> > On Mon, Feb 17, 2025 at 01:53:08PM +0800, kernel test robot wrote:  
> >> New smatch warnings:
> >> fs/xfs/xfs_buf.c:1534 xfs_buf_submit_bio() warn: unsigned '_x' is never less than zero.  
> > Looks like this is an issue in the riscv virt_to_page implementation
> > which also shows up in various other places.  Any chance this could get
> > fixed in the riscv code?  
> 
> 
> To me, the only test that could give rise to this warning is the last 
> part of:
> 
> #define is_linear_mapping(x) \
>          ((x) >= PAGE_OFFSET && (!IS_ENABLED(CONFIG_64BIT) || (x) < 
> PAGE_OFFSET + KERN_VIRT_SIZE))
> 
> But given that the config is a 32-bit config, it should not be evaluated 
> at all.
> 
> Could that be a false-positive and then an issue in smatch?

Why is smatch even looking.
The equivalent check in gcc has been moved to -W2 because of all false positives.

	David

_______________________________________________
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linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv

WARNING: multiple messages have this Message-ID (diff)
From: David Laight <david.laight.linux@gmail.com>
To: Alexandre Ghiti <alex@ghiti.fr>
Cc: Christoph Hellwig <hch@lst.de>, kernel test robot <lkp@intel.com>,
	oe-kbuild-all@lists.linux.dev, linux-kernel@vger.kernel.org,
	Carlos Maiolino <cem@kernel.org>,
	"Darrick J. Wong" <djwong@kernel.org>,
	linux-riscv@lists.infradead.org
Subject: Re: fs/xfs/xfs_buf.c:1534 xfs_buf_submit_bio() warn: unsigned '_x' is never less than zero.
Date: Mon, 17 Feb 2025 13:12:03 +0000	[thread overview]
Message-ID: <20250217131203.2657cc4b@pumpkin> (raw)
In-Reply-To: <a14347d2-6189-49bc-a1cc-e5959e76e6c2@ghiti.fr>

On Mon, 17 Feb 2025 13:06:49 +0100
Alexandre Ghiti <alex@ghiti.fr> wrote:

> Hi Christoph,
> 
> On 17/02/2025 10:24, Christoph Hellwig wrote:
> > On Mon, Feb 17, 2025 at 01:53:08PM +0800, kernel test robot wrote:  
> >> New smatch warnings:
> >> fs/xfs/xfs_buf.c:1534 xfs_buf_submit_bio() warn: unsigned '_x' is never less than zero.  
> > Looks like this is an issue in the riscv virt_to_page implementation
> > which also shows up in various other places.  Any chance this could get
> > fixed in the riscv code?  
> 
> 
> To me, the only test that could give rise to this warning is the last 
> part of:
> 
> #define is_linear_mapping(x) \
>          ((x) >= PAGE_OFFSET && (!IS_ENABLED(CONFIG_64BIT) || (x) < 
> PAGE_OFFSET + KERN_VIRT_SIZE))
> 
> But given that the config is a 32-bit config, it should not be evaluated 
> at all.
> 
> Could that be a false-positive and then an issue in smatch?

Why is smatch even looking.
The equivalent check in gcc has been moved to -W2 because of all false positives.

	David

  reply	other threads:[~2025-02-17 13:25 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-02-17  5:53 fs/xfs/xfs_buf.c:1534 xfs_buf_submit_bio() warn: unsigned '_x' is never less than zero kernel test robot
2025-02-17  9:24 ` Christoph Hellwig
2025-02-17  9:24   ` Christoph Hellwig
2025-02-17 12:06   ` Alexandre Ghiti
2025-02-17 12:06     ` Alexandre Ghiti
2025-02-17 13:12     ` David Laight [this message]
2025-02-17 13:12       ` David Laight
2025-02-18  0:39       ` Philip Li
2025-02-18  0:39         ` Philip Li
2025-02-18 14:21         ` Dan Carpenter
2025-02-18 14:21           ` Dan Carpenter
2025-02-18 14:46           ` Alexandre Ghiti
2025-02-18 14:46             ` Alexandre Ghiti
2025-02-18 19:53     ` David Laight
2025-02-18 19:53       ` David Laight

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