Bug 481682
| Summary: | linux-2.6-misc-utrace-update.patch contains incorrect optimization | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Product: | Red Hat Enterprise Linux 5 | Reporter: | Dmitry V. Levin <ldv> | ||||||||||
| Component: | kernel | Assignee: | Vitaly Mayatskikh <vmayatsk> | ||||||||||
| Status: | CLOSED ERRATA | QA Contact: | Red Hat Kernel QE team <kernel-qe> | ||||||||||
| Severity: | medium | Docs Contact: | |||||||||||
| Priority: | low | ||||||||||||
| Version: | 5.5 | CC: | anton, jmarchan, kolyshkin, roland, vmayatsk | ||||||||||
| Target Milestone: | rc | ||||||||||||
| Target Release: | --- | ||||||||||||
| Hardware: | x86_64 | ||||||||||||
| OS: | Linux | ||||||||||||
| URL: | http://bugzilla.openvz.org/show_bug.cgi?id=1150 | ||||||||||||
| Whiteboard: | |||||||||||||
| Fixed In Version: | Doc Type: | Bug Fix | |||||||||||
| Doc Text: | Story Points: | --- | |||||||||||
| Clone Of: | |||||||||||||
| : | 484871 (view as bug list) | Environment: | |||||||||||
| Last Closed: | 2009-09-02 09:02:56 UTC | Type: | --- | ||||||||||
| Regression: | --- | Mount Type: | --- | ||||||||||
| Documentation: | --- | CRM: | |||||||||||
| Verified Versions: | Category: | --- | |||||||||||
| oVirt Team: | --- | RHEL 7.3 requirements from Atomic Host: | |||||||||||
| Cloudforms Team: | --- | Target Upstream Version: | |||||||||||
| Embargoed: | |||||||||||||
| Bug Depends On: | |||||||||||||
| Bug Blocks: | 484871 | ||||||||||||
| Attachments: |
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The issue was found while running Fedora 10 containers on an RHEL5+OpenVZ kernel. Relative OpenVZ bug: http://bugzilla.openvz.org/show_bug.cgi?id=1150 Created attachment 331182 [details]
test case source
Simple test case, compile with -m32 and run on x86-64 kernel.
The RHEL5 code is the same (broken) as upstream. I'll fix it upstream and then RHEL5 should backport the change so it continues to match upstream.
Created attachment 331183 [details]
test case source
Test case fixed to exit 0 for correct and nonzero for bug.
Also, I forgot to note that to reproduce you have to have auditd disabled:
/sbin/chkconfig auditd off; reboot
Created attachment 331187 [details]
fix posted upstream
Wait to see if upstream takes this as is, but almost certain they will.
With s,/x86/,/x86_64/,g this same patch applies to RHEL5 fine.
> The RHEL5 code is the same (broken) as upstream.
RHEL5 is not broken, I wasn't able to reproduce it. As I understood, this is due to this check:
testl $(_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT|_TIF_SECCOMP),threadinfo_flags(%r10)
jnz ia32_tracesys
And we have TIF_SYSCALL_AUDIT set.
Also, it's possible to make the patch shorter:
--- a/arch/x86/ia32/ia32entry.S
+++ b/arch/x86/ia32/ia32entry.S
@@ -417,6 +417,7 @@ ENTRY(ia32_syscall)
GET_THREAD_INFO(%r10)
orl $TS_COMPAT,TI_status(%r10)
testl $_TIF_WORK_SYSCALL_ENTRY,TI_flags(%r10)
+ movq $-ENOSYS,RAX-ARGOFFSET(%rsp)
jnz ia32_tracesys
ia32_do_syscall:
cmpl $(IA32_NR_syscalls-1),%eax
I've tested it yesterday, but didn't post upstream yet.
It is broken. See comment#3 on how to reproduce it. Shorter patch does not mean shorter code path, which is what matters. Anyway, I've already posted upstream. Upstream fix was merged: http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=c09249f8d1b84344eca882547afdbffee8c09d14 (In reply to comment #6) > It is broken. See comment#3 on how to reproduce it. Yeah, I forgot to reboot machine after disabling audit. This request was evaluated by Red Hat Product Management for inclusion in a Red Hat Enterprise Linux maintenance release. Product Management has requested further review of this request by Red Hat Engineering, for potential inclusion in a Red Hat Enterprise Linux Update release for currently deployed products. This request is not yet committed for inclusion in an Update release. Updating PM score. in kernel-2.6.18-133.el5 You can download this test kernel from http://people.redhat.com/dzickus/el5 Please do NOT transition this bugzilla state to VERIFIED until our QE team has sent specific instructions indicating when to do so. However feel free to provide a comment indicating that this fix has been verified. An advisory has been issued which should help the problem described in this bug report. This report is therefore being closed with a resolution of ERRATA. For more information on therefore solution and/or where to find the updated files, please follow the link below. You may reopen this bug report if the solution does not work for you. http://rhn.redhat.com/errata/RHSA-2009-1243.html |
Created attachment 330051 [details] proposed fix in kernel-2.6.18-128.el5 and prior versions, arch/x86_64/ia32/ia32entry.S hunk of the linux-2.6-misc-utrace-update.patch contains incorrect optimization. As result, out-of-table 32-bit syscalls on the x86_64 kernel do not return ENOSYS (unless the caller is being ptraced). For example, glibc-2.9+ popen() goes mad when pipe2 syscall returns its number 331 instead of fail with ENOSYS. As result, FC10+ 32-bit processes on RHEL5 x86_64 kernel break once popen(3) is called.