From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To: Dmitry Vyukov <dvyukov@google.com>
Cc: syzbot <syzbot+f2ca20d4aa1408b0385a@syzkaller.appspotmail.com>,
alexander.deucher@amd.com, Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@intel.com>,
"H. Peter Anvin" <hpa@zytor.com>,
LKML <linux-kernel@vger.kernel.org>,
Ingo Molnar <mingo@redhat.com>,
nicholas.kazlauskas@amd.com, Rik van Riel <riel@surriel.com>,
sunpeng.li@amd.com,
syzkaller-bugs <syzkaller-bugs@googlegroups.com>,
Thomas Gleixner <tglx@linutronix.de>,
the arch/x86 maintainers <x86@kernel.org>,
zhan.liu@amd.com
Subject: Re: WARNING in switch_fpu_return
Date: Wed, 8 Jan 2020 09:55:32 +0100 [thread overview]
Message-ID: <20200108085532.37ycr24gryqhkkto@linutronix.de> (raw)
In-Reply-To: <CACT4Y+ax6URhDKBREy6XLx=nKFLGSmt87Z-oU3E1D8SAJwBcrg@mail.gmail.com>
Hi Dmitry,
On 2020-01-08 05:28:31 [+0100], Dmitry Vyukov wrote:
> > > userspace arch: i386
> >
> > So I tried to reproduce this. syz-prog2c made .c out of the above link.
> > It starts with:
> > |int main(void)
> > | {
> > | syscall(__NR_mmap, 0x20000000ul, 0x1000000ul, 3ul, 0x32ul, -1, 0);
>
> Hi Sebastian,
>
> If you want to generate a C repro for 386 arch, you need to add
> -arch=386 flag to syz-prog2c (then it hopefully should use mmap2).
Ah okay. I've been looking at
https://github.com/google/syzkaller/blob/master/docs/syzbot.md#crash-does-not-reproduce
and it says
|Note: if the report contains userspace arch: i386, then the program
|needs to be built with -m32 flag.
and with the argument you mentioned it the compiled C code uses mmap2.
Thanks.
Now the 32bit testcase reboots, too :)
> But FWIW syzbot wasn't able to reproduce it with a C program,
> otherwise it would have been provided it. But that may be for various
> reasons.
Yeah, my memory was also that a C-testcase is provided. But there was this
https://syzkaller.appspot.com/x/repro.syz?x=10cc8971e00000
link so I assumed I should use it myself and I missed the update that
something changed.
So what should I do with the file above? Feed it to `syz-execprog' or is
it a rough idea what the test case should have done?
Sebastian
next prev parent reply other threads:[~2020-01-08 8:55 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-02 2:25 WARNING in switch_fpu_return syzbot
2020-01-07 20:53 ` Sebastian Andrzej Siewior
2020-01-08 4:28 ` Dmitry Vyukov
2020-01-08 8:55 ` Sebastian Andrzej Siewior [this message]
2020-01-08 9:03 ` Dmitry Vyukov
2020-03-22 22:41 ` syzbot
2020-03-23 15:01 ` Sean Christopherson
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