Description of problem: After one sets+clears an unhit watchpoint later processes being debugged on the same CPU will skip two instructions with a single PTRACE_SINGLESTEP. Version-Release number of selected component (if applicable): kernel-2.6.23.1-42.fc8.x86_64 kernel-2.6.24.3-50.fc8.x86_64 kernel-2.6.25-0.172.rc7.git4.fc9.x86_64 (Rawhide) kernel-vanilla-2.6.25-0.101.rc4.git3.fc8.x86_64 (AFAIK NON-utrace!) How reproducible: Always. Steps to Reproduce: 1. wget -O step-to-breakpoint.c 'http://sources.redhat.com/cgi-bin/cvsweb.cgi/~checkout~/tests/ptrace-tests/tests/step-to-breakpoint.c?cvsroot=systemtap'; gcc -o step-to-breakpoint step-to-breakpoint.c -Wall -ggdb2 -D_GNU_SOURCE; ./step-to-breakpoint; echo $? Actual results: 1 Expected results: 0 Additional info: It also breaks various GDB testcase: gdb.base/call-sc.exp Tested on: Intel(R) Xeon(TM) CPU 3.20GHz model : 3 stepping : 4 Dual CPU dual core (cpus=4)
Problem is unreproducible on F-8: kernel-2.6.23.1-42.fc8.x86_64 kernel-2.6.24.3-50.fc8.x86_64 on: Dual Core AMD Opteron(tm) Processor 275 cpu family : 15 model : 33 stepping : 2 Therefore also due to the problem specifics expecting it is an Intel CPU errata but I did not find it listed at: http://www.intel.com/design/mobile/specupdt/309222.htm February 2008 Revision 016
The test case passes for me on my machines: cpu family : 6 model : 15 model name : Intel(R) Xeon(R) CPU 5120 @ 1.86GHz stepping : 6 I tried 2.6.24.3-34.fc8 and upstreamish bleeding edge hacking kernel.
Verified as reproducibile on dell-pe2850-01.rhts.boston.redhat.com (still the same host but the problem is really common in the RHTS farm) after loading microcode-20080220.dat as found in microcode_ctl-1.17-1.44.fc9 being loaded on F-8 kernel-2.6.23.1-42.fc8.x86_64 using F-8 microcode_ctl-1.17-1.38.fc8.x86_64.
I will try to get Intel to evaluate this.
The problem is most probably listed as N37 in the Intel Errata suggested by Geoff G.: http://www.intel.com/design/intarch/specupdt/249199.htm so it affects Intel processors having in /proc/cpuinfo: cpu family : 15 Unfortunately from the N37 description I do not see a simple kernel workaround for it, fortunately the problem is no longer present on the recent Intel CPUs. Still this is not a response from Intel, just my preliminary expectation.
I just had various people on #devel run it, and here was one box that returned 1 from the test: RHEL4.? running 2.6.9-68.26.EL.nmiwatchdog cpu family : 15 model : 104 model name : AMD Turion(tm) 64 X2 Mobile Technology TL-58 stepping : 2 It's a laptop, aris is testing on it and says it's benl's. So that would seem to argue against CPU erratum...
The erratum N37 description mentions several specific cases with many details, and those cases are definitely not coming up in this test case.
(In reply to comment #8) > It's a laptop, aris is testing on it and says it's benl's. So that would seem > to argue against CPU erratum... Tried it there (on AMD) repeatedly and the problem is really reproducible there.
This message is a reminder that Fedora 8 is nearing its end of life. Approximately 30 (thirty) days from now Fedora will stop maintaining and issuing updates for Fedora 8. It is Fedora's policy to close all bug reports from releases that are no longer maintained. At that time this bug will be closed as WONTFIX if it remains open with a Fedora 'version' of '8'. Package Maintainer: If you wish for this bug to remain open because you plan to fix it in a currently maintained version, simply change the 'version' to a later Fedora version prior to Fedora 8's end of life. Bug Reporter: Thank you for reporting this issue and we are sorry that we may not be able to fix it before Fedora 8 is end of life. If you would still like to see this bug fixed and are able to reproduce it against a later version of Fedora please change the 'version' of this bug to the applicable version. If you are unable to change the version, please add a comment here and someone will do it for you. Although we aim to fix as many bugs as possible during every release's lifetime, sometimes those efforts are overtaken by events. Often a more recent Fedora release includes newer upstream software that fixes bugs or makes them obsolete. The process we are following is described here: http://fedoraproject.org/wiki/BugZappers/HouseKeeping
Fedora 8 changed to end-of-life (EOL) status on 2009-01-07. Fedora 8 is no longer maintained, which means that it will not receive any further security or bug fix updates. As a result we are closing this bug. If you can reproduce this bug against a currently maintained version of Fedora please feel free to reopen this bug against that version. Thank you for reporting this bug and we are sorry it could not be fixed.
Verified on: kernel-2.6.29-0.207.rc7.ptrace.fc11.x86_64 "ptrace" - just removed: ApplyPatch linux-2.6-utrace.patch
This bug appears to have been reported against 'rawhide' during the Fedora 11 development cycle. Changing version to '11'. More information and reason for this action is here: http://fedoraproject.org/wiki/BugZappers/HouseKeeping
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Bug has been verified by CAI Qian as existing in RHEL-6 Beta 1.
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Fedora 13 changed to end-of-life (EOL) status on 2011-06-25. Fedora 13 is no longer maintained, which means that it will not receive any further security or bug fix updates. As a result we are closing this bug. If you can reproduce this bug against a currently maintained version of Fedora please feel free to reopen this bug against that version. Thank you for reporting this bug and we are sorry it could not be fixed.