From: Josh Poimboeuf <jpoimboe@redhat.com>
To: yang oliver <yang_oliver@hotmail.com>
Cc: "tglx@linutronix.de" <tglx@linutronix.de>,
"mingo@redhat.com" <mingo@redhat.com>,
"hpa@zytor.com" <hpa@zytor.com>,
"luto@kernel.org" <luto@kernel.org>,
"x86@kernel.org" <x86@kernel.org>,
"rostedt@goodmis.org" <rostedt@goodmis.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Yong Yang <yangoliver@gmail.com>
Subject: Re: [PATCH] x86/nmi/64: avoid passing user space rsp of pt_regs to nmi handler
Date: Tue, 22 Aug 2017 12:51:16 -0500 [thread overview]
Message-ID: <20170822175115.k3tdjlkltua7lkiu@treble> (raw)
In-Reply-To: <HKXPR03MB083752B4BC323446E30BFFA28A840@HKXPR03MB0837.apcprd03.prod.outlook.com>
On Tue, Aug 22, 2017 at 05:09:19PM +0000, yang oliver wrote:
> From: Yong Yang <yangoliver@gmail.com>
>
> While NMI interrupts the very beginning of SYSCALL, the rsp could
> be still user space address without loading kernel address. Then
> the pt_regs constructed by the NMI entry point could have a user
> space rsp. If a NMI handler tried to dump stack by using this rsp,
> it can cause the kernel panic.
To me this sounds like an unwinder bug. The unwinder is supposed to
have checks to prevent it from accessing user space. I know you had
previously reported this for an older (pre-4.9) kernel. Have you
verified the bug still exists on a recent kernel?
--
Josh
next prev parent reply other threads:[~2017-08-22 17:51 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <HKXPR03MB083752B4BC323446E30BFFA28A840@HKXPR03MB0837.apcprd03.prod.outlook.com>
2017-08-22 17:39 ` Fwd: " oliver yang
2017-08-22 17:51 ` Josh Poimboeuf [this message]
2017-08-23 14:19 ` oliver yang
2017-08-23 15:20 ` Josh Poimboeuf
2017-08-23 16:51 ` Andy Lutomirski
2017-08-23 17:34 ` oliver yang
2017-08-23 17:30 ` oliver yang
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