Bug 1789089

Summary:	JIT in pcre2 doesn't support CET
Product:	[Fedora] Fedora	Reporter:	H.J. Lu <hongjiu.lu>
Component:	pcre2	Assignee:	Petr Pisar <ppisar>
Status:	CLOSED RAWHIDE	QA Contact:	Fedora Extras Quality Assurance <extras-qa>
Severity:	unspecified	Docs Contact:
Priority:	unspecified
Version:	31	CC:	ppisar
Target Milestone:	---	Keywords:	FutureFeature
Target Release:	---
Hardware:	x86_64
OS:	Unspecified
URL:	https://bugs.exim.org/show_bug.cgi?id=2509
Whiteboard:
Fixed In Version:	pcre2-10.35-0.1.RC1.fc33	Doc Type:	If docs needed, set a value
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2020-01-09 07:41:54 UTC	Type:	Bug
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:	1802674

Description H.J. Lu 2020-01-08 17:34:56 UTC

On TGL,

$ git grep file_end
...
[ 9631.412090] traps: git[1226522] control protection ip:7f0cd6e12e80 sp:7f0cc4b62b58 error:3(endbranch)
(gdb) bt
#0  0x00007f6e13778580 in ?? ()
#1  0x00007f6e136e3be8 in jit_machine_stack_exec () from /lib64/libpcre2-8.so.0
#2  0x00007f6e13710299 in pcre2_jit_match_8 () from /lib64/libpcre2-8.so.0
#3  0x000055ecc89e7dc5 in patmatch ()
#4  0x000055ecc89e8fb4 in grep_source_1 ()
#5  0x000055ecc890b33a in run ()
#6  0x00007f6e136944e2 in start_thread () from /lib64/libpthread.so.0
#7  0x00007f6e135c34b3 in clone () from /lib64/libc.so.6
(gdb) disass 140110749730176,+16
Dump of assembler code from 0x7f6e13778580 to 0x7f6e13778590:
   0x00007f6e13778580:    push   %rbx  <<< Missing ENDBR64
   0x00007f6e13778581:    push   %r15
   0x00007f6e13778583:    push   %r14
   0x00007f6e13778585:    push   %r13
   0x00007f6e13778587:    push   %rbp
   0x00007f6e13778588:    mov    %rdi,%rbx
   0x00007f6e1377858b:    sub    $0x50,%rsp
   0x00007f6e1377858f:    mov    0x10(%rbx),%rax
End of assembler dump.
(gdb)

Comment 1 Petr Pisar 2020-01-09 07:41:54 UTC

Thank you for your concerns about PCRE2 code. Because this issue is not specific to Fedora, I forwarded your request to PCRE2 authors. <https://bugs.exim.org/show_bug.cgi?id=2509>  Please follow up there. Fedora will inherit CET support from upstream when it become available there. I will close this Fedora bug report is it must be dealt in upstream.

Comment 2 Petr Pisar 2020-01-09 13:34:20 UTC

PCRE2 author needs more detailed guiding what to do. What kind of jumps should be instrumented and what instructions should be used. H.J. Lu, please give him advice.

Comment 3 Petr Pisar 2020-02-13 17:25:25 UTC

The CET enablement landed to PCRE2 upstream with:

commit d0968b38f5e570f4eb061297c1b9f90e7c2a1396
Author: zherczeg <zherczeg@6239d852-aaf2-0410-a92c-79f79f948069>
Date:   Tue Jan 28 14:13:06 2020 +0000

    JIT compiler update.
    
    git-svn-id: svn://vcs.exim.org/pcre2/code/trunk@1215 6239d852-aaf2-0410-a92c-79f79f948069

When PCRE2 10.35 is released, this feature will emerge in Fedora.