From: Youquan Song <youquan.song@linux.intel.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Youquan Song <youquan.song@linux.intel.com>,
Tony Luck <tony.luck@intel.com>, Borislav Petkov <bp@alien8.de>,
Josh Poimboeuf <jpoimboe@redhat.com>,
x86@kernel.org, linux-kernel@vger.kernel.org,
Zhiquan Li <zhiquan1.li@intel.com>,
Youquan Song <youquan.song@intel.com>
Subject: Re: [PATCH] x86/uaccess: restore get_user exception type to EX_TYPE_UACCESS
Date: Fri, 1 Apr 2022 20:45:19 +0800 [thread overview]
Message-ID: <20220401124519.GA6935@linux-youquan.bj.intel.com> (raw)
In-Reply-To: <20220331175113.GV8939@worktop.programming.kicks-ass.net>
On Thu, Mar 31, 2022 at 07:51:13PM +0200, Peter Zijlstra wrote:
> On Thu, Mar 31, 2022 at 07:31:25PM +0800, Youquan Song wrote:
> > > Did you do your testing on RHEL or something daft like that?
> > Tested on RHEL8.x
>
> Right; the home of obsolete software.. :-)
>
> > > Something like the below can also work, I suppose. But please, add
> > > coherent comments to the extable code with useful references to the MCE
> > > code that does this abuse.
> > Here is the full fix patch depending on your suggestion. Thanks a lot!
>
> Did you verify this was indeed the only UACCESS I lost?
The full fix patch has included a change in error_context to identify
this case to be MCE_IN_KERNEL_COPYIN. I verfied it fix the issue.
In addition, LTP was run and no issues were reported.
@@ -286,6 +286,7 @@ static noinstr int error_context(struct mce *m, struct pt_regs *regs)
switch (fixup_type) {
case EX_TYPE_UACCESS:
case EX_TYPE_COPY:
+ case EX_TYPE_UA_IMM_REG:
if (!copy_user)
return IN_KERNEL;
m->kflags |= MCE_IN_KERNEL_COPYIN;
-Youquan
next prev parent reply other threads:[~2022-04-01 13:53 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-03-28 20:17 [PATCH] x86/uaccess: restore get_user exception type to EX_TYPE_UACCESS Tony Luck
2022-03-30 12:32 ` Peter Zijlstra
2022-03-31 11:31 ` Youquan Song
2022-03-31 17:51 ` Peter Zijlstra
2022-04-01 12:45 ` Youquan Song [this message]
2022-04-01 17:01 ` Peter Zijlstra
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