Bug 208105 - Looping for "Reservation" (ll/sc) code.
Summary: Looping for "Reservation" (ll/sc) code.
Alias: None
Product: Fedora
Classification: Fedora
Component: frysk   
(Show other bugs)
Version: rawhide
Hardware: powerpc
OS: Linux
Target Milestone: ---
Assignee: Andrew Cagney
QA Contact: Len DiMaggio
Whiteboard: bzcl34nup
Depends On: 207287
TreeView+ depends on / blocked
Reported: 2006-09-26 14:20 UTC by Andrew Cagney
Modified: 2008-05-07 00:53 UTC (History)
8 users (show)

Fixed In Version:
Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of:
Last Closed: 2008-05-07 00:53:23 UTC
Type: ---
Regression: ---
Mount Type: ---
Documentation: ---
Verified Versions:
Category: ---
oVirt Team: ---
RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: ---

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Description Andrew Cagney 2006-09-26 14:20:30 UTC
+++ This bug was initially created as a clone of Bug #207287 +++

gdb currently does not support single-stepping through "Reserved"-utilizing code
as each single-step resets the Reservation and so the loop deadlocks.

-- Additional comment from jkratoch@redhat.com on 2006-09-20 10:34 EST --
Yes, the bug is due to looping due to the Reservation, looping inside:
0x0fc45d58 <pthread_create@@GLIBC_2.1+268>:     lwarx   r3,0,r28
0x0fc45d5c <pthread_create@@GLIBC_2.1+272>:     cmpw    r3,r29
0x0fc45d60 <pthread_create@@GLIBC_2.1+276>:     bne-    0xfc45d6c
0x0fc45d64 <pthread_create@@GLIBC_2.1+280>:     stwcx.  r0,0,r28
0x0fc45d68 <pthread_create@@GLIBC_2.1+284>:     bne-    0xfc45d58

Cloning as a different Bug, only for Component "gdb".

Comment 1 Mark Wielaard 2006-10-31 12:58:16 UTC
While instruction stepping the stwcx will always fail since the address
reservation of the lwarx instruction will be lost. This should most likely be
"fixed" on a higher level by using breakpoints in fstep. When a lwarx/stwcx pair
for an address plus bne- backjump to the lwarx instruction is found while
instruction stepping we can set a breakpoint at the instruction after the
backjump and continue the process till the breakpoint is hit. Then reset this
breakpoint and continue instruction stepping.

Comment 3 Bug Zapper 2008-04-03 18:20:06 UTC
Based on the date this bug was created, it appears to have been reported
against rawhide during the development of a Fedora release that is no
longer maintained. In order to refocus our efforts as a project we are
flagging all of the open bugs for releases which are no longer
maintained. If this bug remains in NEEDINFO thirty (30) days from now,
we will automatically close it.

If you can reproduce this bug in a maintained Fedora version (7, 8, or
rawhide), please change this bug to the respective version and change
the status to ASSIGNED. (If you're unable to change the bug's version
or status, add a comment to the bug and someone will change it for you.)

Thanks for your help, and we apologize again that we haven't handled
these issues to this point.

The process we're following is outlined here:

We will be following the process here:
http://fedoraproject.org/wiki/BugZappers/HouseKeeping to ensure this
doesn't happen again.

Comment 4 Bug Zapper 2008-05-07 00:53:21 UTC
This bug has been in NEEDINFO for more than 30 days since feedback was
first requested. As a result we are closing it.

If you can reproduce this bug in the future against a maintained Fedora
version please feel free to reopen it against that version.

The process we're following is outlined here:

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