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From: Miquel Raynal <miquel.raynal@bootlin.com>
To: Arnd Bergmann <arnd@arndb.de>,
	Miquel Raynal <miquel.raynal@bootlin.com>,
	Richard Weinberger <richard@nod.at>,
	Vignesh Raghavendra <vigneshr@ti.com>,
	Vincenzo Aliberti <vincenzo.aliberti@gmail.com>,
	Brian Norris <computersforpeace@gmail.com>
Cc: Richard Fontana <rfontana@redhat.com>,
	linux-mtd@lists.infradead.org, linux-kernel@vger.kernel.org,
	clang-built-linux@googlegroups.com
Subject: Re: [PATCH] mtd: lpddr: fix excessive stack usage with clang
Date: Mon,  7 Sep 2020 09:34:12 +0200	[thread overview]
Message-ID: <20200907073412.27402-1-miquel.raynal@bootlin.com> (raw)
In-Reply-To: <20200505140136.263461-1-arnd@arndb.de>

On Tue, 2020-05-05 at 14:01:16 UTC, Arnd Bergmann wrote:
> Building lpddr2_nvm with clang can result in a giant stack usage
> in one function:
> 
> drivers/mtd/lpddr/lpddr2_nvm.c:399:12: error: stack frame size of 1144 bytes in function 'lpddr2_nvm_probe' [-Werror,-Wframe-larger-than=]
> 
> The problem is that clang decides to build a copy of the mtd_info
> structure on the stack and then do a memcpy() into the actual version. It
> shouldn't really do it that way, but it's not strictly a bug either.
> 
> As a workaround, use a static const version of the structure to assign
> most of the members upfront and then only set the few members that
> require runtime knowledge at probe time.
> 
> Fixes: 96ba9dd65788 ("mtd: lpddr: add driver for LPDDR2-NVM PCM memories")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
> Acked-by: Miquel Raynal <miquel.raynal@bootlin.com>

Applied to https://git.kernel.org/pub/scm/linux/kernel/git/mtd/linux.git mtd/next, thanks.

Miquel

WARNING: multiple messages have this Message-ID (diff)
From: Miquel Raynal <miquel.raynal@bootlin.com>
To: Arnd Bergmann <arnd@arndb.de>,
	Miquel Raynal <miquel.raynal@bootlin.com>,
	Richard Weinberger <richard@nod.at>,
	Vignesh Raghavendra <vigneshr@ti.com>,
	Vincenzo Aliberti <vincenzo.aliberti@gmail.com>,
	Brian Norris <computersforpeace@gmail.com>
Cc: Richard Fontana <rfontana@redhat.com>,
	linux-mtd@lists.infradead.org, linux-kernel@vger.kernel.org,
	clang-built-linux@googlegroups.com
Subject: Re: [PATCH] mtd: lpddr: fix excessive stack usage with clang
Date: Mon,  7 Sep 2020 09:34:12 +0200	[thread overview]
Message-ID: <20200907073412.27402-1-miquel.raynal@bootlin.com> (raw)
In-Reply-To: <20200505140136.263461-1-arnd@arndb.de>

On Tue, 2020-05-05 at 14:01:16 UTC, Arnd Bergmann wrote:
> Building lpddr2_nvm with clang can result in a giant stack usage
> in one function:
> 
> drivers/mtd/lpddr/lpddr2_nvm.c:399:12: error: stack frame size of 1144 bytes in function 'lpddr2_nvm_probe' [-Werror,-Wframe-larger-than=]
> 
> The problem is that clang decides to build a copy of the mtd_info
> structure on the stack and then do a memcpy() into the actual version. It
> shouldn't really do it that way, but it's not strictly a bug either.
> 
> As a workaround, use a static const version of the structure to assign
> most of the members upfront and then only set the few members that
> require runtime knowledge at probe time.
> 
> Fixes: 96ba9dd65788 ("mtd: lpddr: add driver for LPDDR2-NVM PCM memories")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
> Acked-by: Miquel Raynal <miquel.raynal@bootlin.com>

Applied to https://git.kernel.org/pub/scm/linux/kernel/git/mtd/linux.git mtd/next, thanks.

Miquel

______________________________________________________
Linux MTD discussion mailing list
http://lists.infradead.org/mailman/listinfo/linux-mtd/

  parent reply	other threads:[~2020-09-07  7:34 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-05-05 14:01 [PATCH] mtd: lpddr: fix excessive stack usage with clang Arnd Bergmann
2020-05-05 14:01 ` Arnd Bergmann
2020-05-06  2:38 ` Nathan Chancellor
2020-05-06  2:38   ` Nathan Chancellor
2020-05-07 10:21   ` Miquel Raynal
2020-05-07 10:21     ` Miquel Raynal
2020-09-07  7:34 ` Miquel Raynal [this message]
2020-09-07  7:34   ` Miquel Raynal

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