From: Linus Torvalds <torvalds@linux-foundation.org>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Andy Lutomirski <luto@amacapital.net>,
Jens Axboe <axboe@kernel.dk>, Kees Cook <keescook@chromium.org>,
Jann Horn <jannh@google.com>, Will Deacon <will@kernel.org>
Subject: Re: [PATCH] mm/tlb: Fix use_mm() vs TLB invalidate
Date: Fri, 21 Feb 2020 11:19:22 -0800 [thread overview]
Message-ID: <CAHk-=wi4uO+Djqr4Jc1TnCofwxUTuXHtgkgwnVX86q06UGV6DA@mail.gmail.com> (raw)
In-Reply-To: <20200221111138.GX14897@hirez.programming.kicks-ass.net>
On Fri, Feb 21, 2020 at 3:11 AM Peter Zijlstra <peterz@infradead.org> wrote:
>
> + BUG_ON(!(tsk->flags & PF_KTHREAD));
> + BUG_ON(tsk->mm != NULL);
Stop this craziness.
There is absolutely ZERO excuse for this kind of garbage.
Making this a BUG_ON() will just cause all the possible debugging info
to be thrown away and lost, and you often have a dead machine.
For absolutely no good reason.
Make it a WARN_ON_ONCE(). If it triggers, everything works the way it
always did, but we get notified.
Stop with the stupid crazy BUG_ON() crap already. It is actively _bad_
for debugging.
Linus
next prev parent reply other threads:[~2020-02-21 19:19 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-21 11:11 [PATCH] mm/tlb: Fix use_mm() vs TLB invalidate Peter Zijlstra
2020-02-21 19:19 ` Linus Torvalds [this message]
2020-02-21 19:22 ` Andy Lutomirski
2020-02-21 19:26 ` Linus Torvalds
2020-02-21 23:10 ` Kees Cook
2020-02-21 23:57 ` Linus Torvalds
2020-02-22 0:29 ` Kees Cook
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