Message-ID: <1433742241.2742.4.camel@perches.com>
Subject: [PATCH] checkpatch: Warn on BUG and BUG_ON uses
From: Joe Perches <joe@perches.com>
To: Linus Torvalds <torvalds@linux-foundation.org>,
        Andrew Morton <akpm@linux-foundation.org>
Cc: Tejun Heo <htejun@gmail.com>, Louis Langholtz <lou_langholtz@me.com>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        trivial@kernel.org, Rusty Russell <rusty@rustcorp.com.au>
Date: Sun, 07 Jun 2015 22:44:01 -0700
In-Reply-To: <CA+55aFwmOGaP1DN3frkfP+Df=jCwURqO22A6-5GqpMnZXkvMXA@mail.gmail.com>
References: <1433721270-9182-1-git-send-email-lou_langholtz@me.com>
	 <20150608000007.GA3543@mtj.duckdns.org>
	 <CA+55aFwmOGaP1DN3frkfP+Df=jCwURqO22A6-5GqpMnZXkvMXA@mail.gmail.com>
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Spake Linus:

> Hell no.
> 
> Stop with the random BUG_ON() additions.
> 
> I have said this before, and apparently I need to sat this again, and
> probably I will have to say it in the future.
> 
> We don't add BUG_ON's for random reasons.
> 
> The *ONLY* acceptable reason for a BUG_ON() is if the machine is dead
> anyway because of some major internal corruption.
> 
> We have too many BUG_ON's. We've had people add BUG_ON's because "this
> cannot happen", and then it turns out they were wrong, and they just
> killed the machine.
> 
> Dammit, there's no reason to add a BUG_ON() here in the first place,
> and the reason of "but but it's an unused error return": is f*cking
> retarded.
> 
> Stop this idiocy. We don't write crap code just to satisfy some random
> coding standard or shut up a compiler error.
> 
> At most, it could be a "WARN_ON_ONCE()". Maybe even just silently
> ignore the error. But BUG_ON()? Hell no.
>
> NO NO NO.
> 
> Quite frankly, if you want to add error handling, then dammit, add it
> right. And no, BUG_ON() is _never_ proper error handling.
> 
> BUG_ON() is for things like "uhhuh, somebody is trying to free a page
> that is already free". That is some serious internal corruption.
> 
> BUG_ON() is _not_ for "I'm not doing any error handling, so I'll
> sprinkle random lines of BUG_ON() like fairy dust to make the compiler
> happen".
> 
> Really.  I'm getting very tired indeed of people adding BUG_ON's like
> that. Stop it.

Signed-off-by: Joe Perches <joe@perches.com>
---
 scripts/checkpatch.pl | 11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index 69c4716..f3daa4e 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -3423,12 +3423,11 @@ sub process {
 			}
 		}
 
-# # no BUG() or BUG_ON()
-# 		if ($line =~ /\b(BUG|BUG_ON)\b/) {
-# 			print "Try to use WARN_ON & Recovery code rather than BUG() or BUG_ON()\n";
-# 			print "$herecurr";
-# 			$clean = 0;
-# 		}
+# avoid BUG() or BUG_ON()
+		if ($line =~ /\b(BUG|BUG_ON)\b/) {
+			WARN("BUG",
+			     "Avoid using $1 unless there is a serious corruption - try to use WARN_ON & recovery code instead\n" .  $herecurr);
+		}
 
 		if ($line =~ /\bLINUX_VERSION_CODE\b/) {
 			WARN("LINUX_VERSION_CODE",


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