From: Linus Torvalds <torvalds@linux-foundation.org>
To: "Maciej W. Rozycki" <macro@imgtec.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Andy Lutomirski <luto@kernel.org>,
Al Viro <viro@zeniv.linux.org.uk>,
Oleg Nesterov <oleg@redhat.com>,
Andrei Vagin <avagin@virtuozzo.com>,
Thomas Gleixner <tglx@linutronix.de>, Greg KH <greg@kroah.com>,
Andrey Vagin <avagin@openvz.org>, Serge Hallyn <serge@hallyn.com>,
Pavel Emelyanov <xemul@virtuozzo.com>,
Cyrill Gorcunov <gorcunov@openvz.org>,
Peter Zijlstra <peterz@infradead.org>, Willy Tarreau <w@1wt.eu>,
"linux-arch@vger.kernel.org" <linux-arch@vger.kernel.org>,
Linux API <linux-api@vger.kernel.org>,
Linux Containers <containers@lists.linux-foundation.org>,
Michael Kerrisk <mtk.manpages@gmail.com>,
Ralf Baechle <ralf@linux-mips.org>
Subject: Re: [PATCH 4/7] signal/mips: Document a conflict with SI_USER with SIGFPE
Date: Mon, 7 Aug 2017 10:41:39 -0700 [thread overview]
Message-ID: <CA+55aFx3ss90b4x2bo4si80kQUjMVL1zUX3Oxvu04OE14nUtFw@mail.gmail.com> (raw)
In-Reply-To: <alpine.DEB.2.00.1708071706290.17596@tp.orcam.me.uk>
On Mon, Aug 7, 2017 at 9:18 AM, Maciej W. Rozycki <macro@imgtec.com> wrote:
>
> So what would be the right value of `si_code' to use here for such an
> unexpected exception condition? I think `BUG()' would be too big a
> hammer here. Or wouldn't it?
Hell no. NEVER EVER BUG().
The only case to use BUG() is if there is some core data structure
(say, kernel stack) that is so corrupted that you know you cannot
continue. That's the *only* valid use.
If this is a "this condition cannot happen" issue, then just remove
the damn conditional. It's pointless. Adding a BUG() to show "this
cannot happen" is not acceptable.
Linus
next prev parent reply other threads:[~2017-08-07 17:41 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <87lgot2loq.fsf@xmission.com>
[not found] ` <87zid90vye.fsf_-_@xmission.com>
[not found] ` <20170615225426.GP31671@ZenIV.linux.org.uk>
[not found] ` <87poe4zrs1.fsf@xmission.com>
[not found] ` <CA+55aFxpv+gchzs7AYgSC8feAOV=B6mjFgBVm4Kx+83J2CNE-w@mail.gmail.com>
[not found] ` <87poe3vsa9.fsf@xmission.com>
[not found] ` <CALCETrX=SquyR8JZqHDNx=_FQKQo-0u9AxfdUwJs_hujVO2A-g@mail.gmail.com>
[not found] ` <87h8zfua59.fsf@xmission.com>
[not found] ` <CALCETrWPBn31Dye=81r2ZMainNOnDy5c_QxbU2uRjnJs0ie=Zg@mail.gmail.com>
[not found] ` <87r2yjsuwl.fsf@xmission.com>
[not found] ` <20170616191602.GA10675@1wt.eu>
2017-06-30 12:36 ` [PATCH 0/8] signal: Fix sending signals with siginfo Eric W. Biederman
2017-07-18 14:04 ` [PATCH v2 0/7] " Eric W. Biederman
2017-07-18 14:06 ` [PATCH 1/7] signal/alpha: Document a conflict with SI_USER for SIGTRAP Eric W. Biederman
2017-07-18 14:06 ` Eric W. Biederman
[not found] ` <20170718140651.15973-1-ebiederm-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org>
2017-07-18 18:22 ` Richard Henderson
2017-07-18 18:22 ` Richard Henderson
[not found] ` <87o9shg7t7.fsf_-_-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org>
2017-07-18 14:06 ` [PATCH 2/7] signal/ia64: Document a conflict with SI_USER with SIGFPE Eric W. Biederman
2017-07-18 14:06 ` Eric W. Biederman
2017-07-18 14:06 ` [PATCH 3/7] signal/sparc: " Eric W. Biederman
2017-07-18 14:06 ` Eric W. Biederman
2017-07-18 14:06 ` [PATCH 5/7] signal/testing: Don't look for __SI_FAULT in userspace Eric W. Biederman
2017-07-18 14:06 ` Eric W. Biederman
2017-07-18 14:06 ` [PATCH 6/7] fcntl: Don't use ambiguous SIG_POLL si_codes Eric W. Biederman
2017-07-18 14:06 ` Eric W. Biederman
[not found] ` <20170718140651.15973-6-ebiederm-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org>
2017-07-20 16:16 ` Oleg Nesterov
2017-07-20 16:16 ` Oleg Nesterov
2017-07-21 2:33 ` Eric W. Biederman
2017-07-18 14:06 ` [PATCH 7/7] signal: Remove kernel interal si_code magic Eric W. Biederman
2017-07-18 14:06 ` Eric W. Biederman
[not found] ` <20170718140651.15973-7-ebiederm-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org>
2017-07-18 16:57 ` Linus Torvalds
2017-07-18 16:57 ` Linus Torvalds
[not found] ` <CA+55aFyKsmf+BpYjcH30MGpHTDJ=zgYPx6kwyEB9CXXFxj_xsw-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2017-07-18 17:27 ` Eric W. Biederman
2017-07-18 17:27 ` Eric W. Biederman
[not found] ` <878tjlbqpt.fsf-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org>
2017-07-22 20:25 ` Simplfying copy_siginfo_to_user Eric W. Biederman
2017-07-22 20:25 ` Eric W. Biederman
[not found] ` <8760ek5ics.fsf_-_-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org>
2017-07-24 17:43 ` Linus Torvalds
2017-07-24 17:43 ` Linus Torvalds
[not found] ` <CA+55aFyH5W2doo9vxXta_-pXfNXqQ19d7z48k1hmfAot+aJvMw-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2017-07-24 19:01 ` Eric W. Biederman
2017-07-24 19:01 ` Eric W. Biederman
2017-07-25 1:37 ` Al Viro
2017-07-31 16:37 ` Eric W. Biederman
2017-07-18 14:06 ` [PATCH 4/7] signal/mips: Document a conflict with SI_USER with SIGFPE Eric W. Biederman
2017-08-07 16:18 ` Maciej W. Rozycki
2017-08-07 17:41 ` Linus Torvalds [this message]
2017-08-07 17:41 ` Linus Torvalds
2017-08-07 19:55 ` Ralf Baechle
2017-08-08 15:29 ` Eric W. Biederman
2017-08-08 15:29 ` Eric W. Biederman
2017-08-08 23:19 ` Maciej W. Rozycki
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