From: "wcohen at redhat dot com" <sourceware-bugzilla@sourceware.org>
To: systemtap@sourceware.org
Subject: [Bug runtime/30716] On x86_64 get objtool warnings: call to __get_user_nocheck_1() with UACCESS enabled
Date: Thu, 03 Aug 2023 19:45:02 +0000 [thread overview]
Message-ID: <bug-30716-6586-BpRLsfOymU@http.sourceware.org/bugzilla/> (raw)
In-Reply-To: <bug-30716-6586@http.sourceware.org/bugzilla/>
https://sourceware.org/bugzilla/show_bug.cgi?id=30716
William Cohen <wcohen at redhat dot com> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|NEW |ASSIGNED
--- Comment #1 from William Cohen <wcohen at redhat dot com> ---
objtool is reporting a call to a function with STAC (user-space access
set) and the target of the call is not on the whitelist. Below is a
link to the current linux 6.4.7 white list:
https://elixir.bootlin.com/linux/v6.4.7/source/tools/objtool/check.c#L1120
The __get_user_nocheck_* function used by the x86_64 are not on that
list. However, the implementations of the functions in
arch/x86/lib/getuser.S do have surrounding ASM_STAC/ASM_CLAC instructions:
https://elixir.bootlin.com/linux/v6.4.7/source/arch/x86/lib/getuser.S#L100
If these funcions were inlined, objtools would claim "recursive UACESS
enabled" and "redundant UACCESS disable":
https://elixir.bootlin.com/linux/v6.4.7/source/tools/objtool/check.c#L3737
The course of action is to have the systemtap code do the calls to
these architecture specific functions without the additional STAC/CLAC
from user_access_begin/user_access_end. One concern is how the user
space accesses are implemented on other architectures and making sure
that the fix works across all architectures.
--
You are receiving this mail because:
You are the assignee for the bug.
next prev parent reply other threads:[~2023-08-03 19:45 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-08-02 15:28 [Bug runtime/30716] New: " wcohen at redhat dot com
2023-08-03 19:45 ` wcohen at redhat dot com [this message]
2023-08-23 13:09 ` [Bug runtime/30716] " fche at redhat dot com
2023-10-25 23:09 ` wcohen at redhat dot com
2024-03-05 0:33 ` wcohen at redhat dot com
2024-03-07 18:55 ` wcohen at redhat dot com
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=bug-30716-6586-BpRLsfOymU@http.sourceware.org/bugzilla/ \
--to=sourceware-bugzilla@sourceware.org \
--cc=systemtap@sourceware.org \
/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 read-only IMAP folder(s) and NNTP newsgroup(s).