From: Willy Tarreau <w@1wt.eu>
To: Russell King - ARM Linux <linux@arm.linux.org.uk>
Cc: linux-arch@vger.kernel.org, josh@joshtriplett.org,
linux-kernel@vger.kernel.org, Arnd Bergmann <arnd@arndb.de>,
linux-arm-kernel@lists.infradead.org
Subject: Re: [RFC] asm-generic: default BUG_ON(x) to "if(x) BUG()"
Date: Mon, 23 Nov 2015 17:52:19 +0100 [thread overview]
Message-ID: <20151123165219.GD768@1wt.eu> (raw)
In-Reply-To: <20151123163750.GT8644@n2100.arm.linux.org.uk>
On Mon, Nov 23, 2015 at 04:37:50PM +0000, Russell King - ARM Linux wrote:
> On Mon, Nov 23, 2015 at 05:33:59PM +0100, Willy Tarreau wrote:
> > I think you could do better by simply calling panic("BUG!") instead as
> > BUG() does. It will avoid the printk() call and pushing the file/line
> > number onto the stack. It will also probably not inflate the rodata this
> > way.
>
> Does that not depend on the architectures BUG() implementation? If an
> architecture implements it as a signalling illegal instruction and a
> lookup table, changing it to be a panic() would probably be more code.
That's a very good point, I didn't think about it and yes I think you're
right then (eg: when CONFIG_DEBUG_BUGVERBOSE is not set, x86 and arm will
only emit a single instruction).
Best regards,
Willy
WARNING: multiple messages have this Message-ID (diff)
From: w@1wt.eu (Willy Tarreau)
To: linux-arm-kernel@lists.infradead.org
Subject: [RFC] asm-generic: default BUG_ON(x) to "if(x) BUG()"
Date: Mon, 23 Nov 2015 17:52:19 +0100 [thread overview]
Message-ID: <20151123165219.GD768@1wt.eu> (raw)
In-Reply-To: <20151123163750.GT8644@n2100.arm.linux.org.uk>
On Mon, Nov 23, 2015 at 04:37:50PM +0000, Russell King - ARM Linux wrote:
> On Mon, Nov 23, 2015 at 05:33:59PM +0100, Willy Tarreau wrote:
> > I think you could do better by simply calling panic("BUG!") instead as
> > BUG() does. It will avoid the printk() call and pushing the file/line
> > number onto the stack. It will also probably not inflate the rodata this
> > way.
>
> Does that not depend on the architectures BUG() implementation? If an
> architecture implements it as a signalling illegal instruction and a
> lookup table, changing it to be a panic() would probably be more code.
That's a very good point, I didn't think about it and yes I think you're
right then (eg: when CONFIG_DEBUG_BUGVERBOSE is not set, x86 and arm will
only emit a single instruction).
Best regards,
Willy
next prev parent reply other threads:[~2015-11-23 16:52 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-11-23 16:25 [RFC] asm-generic: default BUG_ON(x) to "if(x) BUG()" Arnd Bergmann
2015-11-23 16:25 ` Arnd Bergmann
2015-11-23 16:33 ` Willy Tarreau
2015-11-23 16:33 ` Willy Tarreau
2015-11-23 16:37 ` Russell King - ARM Linux
2015-11-23 16:37 ` Russell King - ARM Linux
2015-11-23 16:52 ` Willy Tarreau [this message]
2015-11-23 16:52 ` Willy Tarreau
2015-11-23 16:52 ` Arnd Bergmann
2015-11-23 16:52 ` Arnd Bergmann
2015-11-23 17:04 ` Willy Tarreau
2015-11-23 17:04 ` Willy Tarreau
2015-11-23 17:22 ` Russell King - ARM Linux
2015-11-23 17:22 ` Russell King - ARM Linux
2015-11-23 19:29 ` Arnd Bergmann
2015-11-23 19:29 ` Arnd Bergmann
2015-11-23 16:34 ` Russell King - ARM Linux
2015-11-23 16:34 ` Russell King - ARM Linux
2015-11-23 20:16 ` Josh Triplett
2015-11-23 20:16 ` Josh Triplett
2015-11-23 20:16 ` Josh Triplett
2015-11-23 20:58 ` Arnd Bergmann
2015-11-23 20:58 ` Arnd Bergmann
2015-11-23 21:17 ` Josh Triplett
2015-11-23 21:17 ` Josh Triplett
2015-11-23 21:30 ` Arnd Bergmann
2015-11-23 21:30 ` Arnd Bergmann
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