From: "mjw at redhat dot com" <sourceware-bugzilla@sourceware.org>
To: systemtap@sourceware.org
Subject: [Bug runtime/16553] New: unwind stack code shouldn't need pragma:uprobes if it isn't used for user space probing
Date: Mon, 10 Feb 2014 19:01:00 -0000 [thread overview]
Message-ID: <bug-16553-6586@http.sourceware.org/bugzilla/> (raw)
https://sourceware.org/bugzilla/show_bug.cgi?id=16553
Bug ID: 16553
Summary: unwind stack code shouldn't need pragma:uprobes if it
isn't used for user space probing
Product: systemtap
Version: unspecified
Status: NEW
Severity: normal
Priority: P2
Component: runtime
Assignee: systemtap at sourceware dot org
Reporter: mjw at redhat dot com
The following commit introduced a dependency on uprobes for the stack/unwind
code:
commit 6a80494e753367b7096a928705312dfdfa437201
Author: Frank Ch. Eigler <fche@elastic.org>
Date: Fri May 7 12:57:50 2010 -0400
PR11573: infer need for uprobes from special embedded-c markup tag
* tapset/ucontext-unwind.stp: Mark up these babies with /* pragma:uprobes
*/
* elaborate.cxx (typeresolution_info::visit_embeddedcode): Look for that
and activate session.need_uprobes if found.
This was introduced to solve Bug 11573 - uprobe_get_pc, sayonara.
See specifically runtime/stack.c (_stp_stack_unwind_one_user) which does:
#ifdef STAPCONF_UPROBE_GET_PC
maybe_pc = 0;
if (ri) {
maybe_pc = uprobe_get_pc(ri, UNW_PC(info), UNW_SP(info));
if (!maybe_pc)
printk("SYSTEMTAP ERROR: uprobe_get_return returned
0\n");
else
UNW_PC(info) = maybe_pc;
}
#endif
Which is needed whenever there might be any uretprobes installed to fix up any
addresses which might point to trampoline code instead of the original pc.
To make sure that code can be executed all unwinding/ubacktrace tapset
functions now have a pragma:uprobes. But if uprobes wasn't actually used to set
u[ret]probes then this is too strict a requirement.
--
You are receiving this mail because:
You are the assignee for the bug.
reply other threads:[~2014-02-10 19:01 UTC|newest]
Thread overview: [no followups] expand[flat|nested] mbox.gz Atom feed
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-16553-6586@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).