From: Linus Torvalds <torvalds@linux-foundation.org>
To: Sean Christopherson <sean.j.christopherson@intel.com>
Cc: "Daniel Díaz" <daniel.diaz@linaro.org>,
"Naresh Kamboju" <naresh.kamboju@linaro.org>,
"Stephen Rothwell" <sfr@canb.auug.org.au>,
"Matthew Wilcox (Oracle)" <willy@infradead.org>,
zenglg.jy@cn.fujitsu.com,
"Peter Zijlstra (Intel)" <peterz@infradead.org>,
"Viresh Kumar" <viresh.kumar@linaro.org>,
"X86 ML" <x86@kernel.org>,
"open list" <linux-kernel@vger.kernel.org>,
lkft-triage@lists.linaro.org,
"Eric W. Biederman" <ebiederm@xmission.com>,
linux-mm <linux-mm@kvack.org>,
linux-m68k <linux-m68k@lists.linux-m68k.org>,
"Linux-Next Mailing List" <linux-next@vger.kernel.org>,
"Thomas Gleixner" <tglx@linutronix.de>,
kasan-dev <kasan-dev@googlegroups.com>,
"Dmitry Vyukov" <dvyukov@google.com>,
"Geert Uytterhoeven" <geert@linux-m68k.org>,
"Christian Brauner" <christian.brauner@ubuntu.com>,
"Ingo Molnar" <mingo@redhat.com>, "LTP List" <ltp@lists.linux.it>,
"Al Viro" <viro@zeniv.linux.org.uk>
Subject: Re: [LTP] mmstress[1309]: segfault at 7f3d71a36ee8 ip 00007f3d77132bdf sp 00007f3d71a36ee8 error 4 in libc-2.27.so[7f3d77058000+1aa000]
Date: Fri, 23 Oct 2020 08:52:50 -0700 [thread overview]
Message-ID: <CAHk-=wjBjUvjN_Mw2Oo5XMUJFSREi3d9AHTSFmgp-a42ZH_K_w@mail.gmail.com> (raw)
In-Reply-To: <20201023050214.GG23681@linux.intel.com>
On Thu, Oct 22, 2020 at 10:02 PM Sean Christopherson
<sean.j.christopherson@intel.com> wrote:
>
> I haven't reproduced the crash, but I did find a smoking gun that confirms the
> "register shenanigans are evil shenanigans" theory. I ran into a similar thing
> recently where a seemingly innocuous line of code after loading a value into a
> register variable wreaked havoc because it clobbered the input register.
Yup, that certainly looks like the smoking gun.
Thanks for finding an example of this, clearly I'll have to either go
back to the "conditionally use 'A' or 'a' depending on size" model, or
perhaps try Rasmus' patch.
Linus
next prev parent reply other threads:[~2020-10-23 15:53 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-21 16:58 Naresh Kamboju
2020-10-21 17:05 ` Linus Torvalds
2020-10-21 17:22 ` Naresh Kamboju
2020-10-22 20:55 ` Naresh Kamboju
2020-10-22 23:43 ` Linus Torvalds
2020-10-23 0:11 ` Linus Torvalds
2020-10-23 0:22 ` Linus Torvalds
2020-10-23 1:36 ` [LTP] " Daniel Díaz
2020-10-23 3:05 ` Linus Torvalds
2020-10-23 5:02 ` Sean Christopherson
2020-10-23 7:14 ` Rasmus Villemoes
2020-10-23 15:54 ` Linus Torvalds
2020-10-23 16:32 ` Linus Torvalds
2020-10-23 17:50 ` Naresh Kamboju
2020-10-23 15:52 ` Linus Torvalds [this message]
2020-10-23 17:00 ` Naresh Kamboju
2020-10-23 17:50 ` Linus Torvalds
2020-10-23 21:15 ` Song Liu
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