From: Linus Torvalds <torvalds@linux-foundation.org>
To: Randy Dunlap <rdunlap@infradead.org>
Cc: David Howells <dhowells@redhat.com>,
Hulk Robot <hulkci@huawei.com>,
Zheng Zengkai <zhengzengkai@huawei.com>,
Tom Rix <trix@redhat.com>,
linux-afs@lists.infradead.org,
Marc Dionne <marc.dionne@auristor.com>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] afs: fix no return statement in function returning non-void
Date: Tue, 15 Jun 2021 17:32:45 -0700 [thread overview]
Message-ID: <CAHk-=whPPWYXKQv6YjaPQgQCf+78S+0HmAtyzO1cFMdcqQp5-A@mail.gmail.com> (raw)
In-Reply-To: <f2764b10-dd0d-cabf-0264-131ea5829fed@infradead.org>
On Tue, Jun 15, 2021 at 4:58 PM Randy Dunlap <rdunlap@infradead.org> wrote:
>
> Some implementations of BUG() are macros, not functions,
Not "some", I think. Most.
> so "unreachable" is not applicable AFAIK.
Sure it is. One common pattern is the x86 one:
#define BUG() \
do { \
instrumentation_begin(); \
_BUG_FLAGS(ASM_UD2, 0); \
unreachable(); \
} while (0)
and that "unreachable()" is exactly what I'm talking about.
So I repeat: what completely broken compiler / config / architecture
is it that needs that "return 0" after a BUG() statement?
Because that environment is broken, and the warning is bogus and wrong.
It might not be the compiler. It might be some architecture that does
this wrong. It might be some very particular configuration that does
something bad and makes the "unreachable()" not work (or not exist).
But *that* is the bug that should be fixed. Not adding a pointless and
incorrect line that makes no sense, just to hide the real bug.
Linus
Linus
next prev parent reply other threads:[~2021-06-16 0:33 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-15 11:55 [PATCH] afs: fix no return statement in function returning non-void David Howells
2021-06-15 12:03 ` David Howells
2021-06-15 14:49 ` Linus Torvalds
2021-06-15 23:58 ` Randy Dunlap
2021-06-16 0:32 ` Linus Torvalds [this message]
2021-06-16 1:38 ` Randy Dunlap
2021-06-16 2:19 ` Randy Dunlap
2021-06-16 3:15 ` Zheng Zengkai
2021-06-16 12:56 ` Tom Rix
2021-06-16 14:34 ` Linus Torvalds
2021-06-16 16:22 ` Tom Rix
2021-06-16 16:29 ` Linus Torvalds
2021-06-18 15:23 ` Arnd Bergmann
2021-06-16 13:41 ` David Howells
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