From: Tony Luck <tony.luck@intel.com>
To: Borislav Petkov <bp@alien8.de>
Cc: "Tony Luck" <tony.luck@intel.com>,
x86@kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org,
"Andy Lutomirski" <luto@kernel.org>,
"Aili Yao" <yaoaili@kingsoft.com>,
"HORIGUCHI NAOYA( 堀口 直也)" <naoya.horiguchi@nec.com>
Subject: [PATCH 1/4] x86/mce: Fix copyin code to return -EFAULT on machine check.
Date: Thu, 25 Mar 2021 17:02:32 -0700 [thread overview]
Message-ID: <20210326000235.370514-2-tony.luck@intel.com> (raw)
In-Reply-To: <20210326000235.370514-1-tony.luck@intel.com>
When copy from user fails due to a machine check on poison reading
user data it should return an error code.
---
Separate patch just now, but likely needs to be combined with patches
to iteration code for bisection safety.
---
arch/x86/lib/copy_user_64.S | 18 +++++++++++-------
1 file changed, 11 insertions(+), 7 deletions(-)
diff --git a/arch/x86/lib/copy_user_64.S b/arch/x86/lib/copy_user_64.S
index 77b9b2a3b5c8..2987118c541a 100644
--- a/arch/x86/lib/copy_user_64.S
+++ b/arch/x86/lib/copy_user_64.S
@@ -14,6 +14,7 @@
#include <asm/alternative-asm.h>
#include <asm/asm.h>
#include <asm/smap.h>
+#include <asm/errno.h>
#include <asm/export.h>
#include <asm/trapnr.h>
@@ -237,18 +238,21 @@ SYM_CODE_START_LOCAL(.Lcopy_user_handle_tail)
cmp $X86_TRAP_MC,%eax /* check if X86_TRAP_MC */
je 3f
1: rep movsb
-2: mov %ecx,%eax
+ mov %ecx,%eax
+ ASM_CLAC
+ ret
+
+2:
+ cmp $X86_TRAP_MC,%eax
+ je 3f
+ mov %ecx,%eax
ASM_CLAC
ret
/*
- * Return zero to pretend that this copy succeeded. This
- * is counter-intuitive, but needed to prevent the code
- * in lib/iov_iter.c from retrying and running back into
- * the poison cache line again. The machine check handler
- * will ensure that a SIGBUS is sent to the task.
+ * Return -EFAULT for the machine check cases
*/
-3: xorl %eax,%eax
+3: movl $-EFAULT,%eax
ASM_CLAC
ret
--
2.29.2
next prev parent reply other threads:[~2021-03-26 0:02 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-26 0:02 [RFC 0/4] Fix machine check recovery for copy_from_user Tony Luck
2021-03-26 0:02 ` Tony Luck [this message]
2021-04-06 19:24 ` [PATCH 1/4] x86/mce: Fix copyin code to return -EFAULT on machine check Borislav Petkov
2021-03-26 0:02 ` [PATCH 2/4] mce/iter: Check for copyin failure & return error up stack Tony Luck
2021-03-26 0:02 ` [PATCH 3/4] mce/copyin: fix to not SIGBUS when copying from user hits poison Tony Luck
2021-04-07 21:18 ` Borislav Petkov
2021-04-07 21:43 ` Luck, Tony
2021-04-08 8:49 ` Borislav Petkov
2021-04-08 17:08 ` Luck, Tony
2021-04-13 10:07 ` Borislav Petkov
2021-04-13 16:13 ` Luck, Tony
2021-04-14 13:05 ` Borislav Petkov
2021-03-26 0:02 ` [PATCH 4/4] x86/mce: Avoid infinite loop for copy from user recovery Tony Luck
2021-04-08 13:36 ` Borislav Petkov
2021-04-08 16:06 ` Luck, Tony
2021-04-08 2:13 ` [RFC 0/4] Fix machine check recovery for copy_from_user Aili Yao
2021-04-08 14:39 ` Luck, Tony
2021-04-09 6:49 ` Aili Yao
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20210326000235.370514-2-tony.luck@intel.com \
--to=tony.luck@intel.com \
--cc=bp@alien8.de \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=luto@kernel.org \
--cc=naoya.horiguchi@nec.com \
--cc=x86@kernel.org \
--cc=yaoaili@kingsoft.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).