From: Sasha Levin <levinsasha928@gmail.com>
To: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Dave Jones <davej@redhat.com>,
kexec@lists.infradead.org,
linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: BUG: unable to handle kernel paging request at ffffc7ff81000398 (sys_kexec_load)
Date: Sat, 28 Jan 2012 10:11:30 -0500 [thread overview]
Message-ID: <1327763490.16907.1.camel@lappy> (raw)
In-Reply-To: <m1lip0s5nt.fsf@fess.ebiederm.org>
On Sat, 2012-01-21 at 20:49 -0800, Eric W. Biederman wrote:
> Interesting.
>
> The fact that this happens in native_set_pte would suggest that we are
> trying to write to a page table that does not exist. So this might
> be a layer below kexec_load that has the problem.
>
> Do you have the kernel you were testing? A disassembly of the
> native_set_pte, machine_kexec_prepare and sys_kexec_load
> would be interesting, for attempting to trace this back to what went
> wrong.
I did some work into investigating it today, looks like it's simple to trigger it using the following code:
#include <fcntl.h>
int main(void)
{
char dummy[4096] = {0};
syscall(246, 0xffffffff81008000, 1, dummy, 2);
return 0;
}
I'll continue trying to figure out whats wrong, but hopefully this lead will help in reproducing it easily.
--
Sasha.
next prev parent reply other threads:[~2012-01-28 15:11 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-01-22 6:06 BUG: unable to handle kernel paging request at ffffc7ff81000398 (sys_kexec_load) Sasha Levin
2012-01-22 4:49 ` Eric W. Biederman
2012-01-22 7:18 ` Sasha Levin
2012-01-28 15:11 ` Sasha Levin [this message]
2012-01-28 20:54 ` Eric W. Biederman
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