From: Linus Torvalds <torvalds@linux-foundation.org>
To: Tom Rix <trix@redhat.com>
Cc: Zheng Zengkai <zhengzengkai@huawei.com>,
Randy Dunlap <rdunlap@infradead.org>,
David Howells <dhowells@redhat.com>,
Hulk Robot <hulkci@huawei.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: Wed, 16 Jun 2021 09:29:00 -0700 [thread overview]
Message-ID: <CAHk-=wgW6yfsLUtepANX2PVkADR_7WDzk05YVhtw1ZBmDEGT2Q@mail.gmail.com> (raw)
In-Reply-To: <9d7873b6-e35c-ae38-9952-a1df443b2aea@redhat.com>
On Wed, Jun 16, 2021 at 9:22 AM Tom Rix <trix@redhat.com> wrote:
>
> to fix, add an unreachable() to the generic BUG()
>
> diff --git a/include/asm-generic/bug.h b/include/asm-generic/bug.h
> index f152b9bb916f..b250e06d7de2 100644
> --- a/include/asm-generic/bug.h
> +++ b/include/asm-generic/bug.h
> @@ -177,7 +177,10 @@ void __warn(const char *file, int line, void
> *caller, unsigned taint,
>
> #else /* !CONFIG_BUG */
> #ifndef HAVE_ARCH_BUG
> -#define BUG() do {} while (1)
> +#define BUG() do { \
> + do {} while (1); \
> + unreachable(); \
> + } while (0)
> #endif
I'm a bit surprised that the compiler doesn't make that code after an
infinite loop automatically be marked "unreachable". But at the same I
can imagine the compiler doing some checks without doing real flow
analysis, and doing "oh, that conditional branch is unconditional".
So this patch at least makes sense to me and I have no objections to
it, even if it makes me go "silly compiler, we shouldn't have to tell
you this".
So Ack from me on this.
Linus
next prev parent reply other threads:[~2021-06-16 16:29 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
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 [this message]
2021-06-18 15:23 ` Arnd Bergmann
2021-06-16 13:41 ` David Howells
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