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Bug 1790058 - [RHEL 6 DTS 9] strace doesn't print stack trace for early syscalls
Summary: [RHEL 6 DTS 9] strace doesn't print stack trace for early syscalls
Keywords:
Status: CLOSED CURRENTRELEASE
Alias: None
Product: Red Hat Developer Toolset
Classification: Red Hat
Component: strace
Version: DTS 9.1 RHEL 6
Hardware: Unspecified
OS: Unspecified
unspecified
unspecified
Target Milestone: alpha
: 9.0
Assignee: Eugene Syromiatnikov
QA Contact: Edjunior Barbosa Machado
URL:
Whiteboard:
Depends On: 1783584 1788636
Blocks: 1790052 1790053 1790054 1790057
TreeView+ depends on / blocked
 
Reported: 2020-01-11 15:05 UTC by Eugene Syromiatnikov
Modified: 2020-06-03 14:42 UTC (History)
9 users (show)

Fixed In Version: devtoolset-9-strace-5.1-7.el6
Doc Type: If docs needed, set a value
Doc Text:
Clone Of: 1788636
Environment:
Last Closed: 2020-06-03 14:42:03 UTC
Target Upstream Version:
Embargoed:

Attachments (Terms of Use)

Description Eugene Syromiatnikov 2020-01-11 15:05:08 UTC 
+++ This bug was initially created as a clone of Bug #1788636 +++

Description of problem:
strace -k doesn't produce stack trace due to no dwarf found if it is being attached to running process.

Version-Release number of selected component (if applicable):
strace-5.3-1.fc31.x86_64

# rpm -qa '*-debuginfo'
dhcp-debuginfo-4.4.1-19.fc31.x86_64
dhcp-server-debuginfo-4.4.1-19.fc31.x86_64
glibc-debuginfo-2.30-8.fc31.x86_64

How reproducible:
100%

Steps to Reproduce:
1. dhcpd -f 
2. strace -k -p `pidof dhcpd`


Actual results:
select(9, [5<RAW:[0.0.0.0:1]> 6<socket:[41801]> 8<UDP:[0.0.0.0:67]>], [], NULL, NULL) = ? ERESTARTNOHAND (To be restarted if no handler)
 > No DWARF information found


Expected results:
select(9, [5<RAW:[0.0.0.0:1]> 6<socket:[43189]> 8<UDP:[0.0.0.0:67]>], [], NULL, NULL) = ? ERESTARTNOHAND (To be restarted if no handler)
 > /usr/lib64/libc-2.30.so(__select+0x1a) [0xf8f1a]
 > /usr/sbin/dhcpd(isc__socketmgr_waitevents+0x76) [0x257e06]
 > /usr/sbin/dhcpd(evloop+0x12f) [0x24725f]
 > /usr/sbin/dhcpd(isc__app_ctxrun+0x138) [0x247778]
 > /usr/sbin/dhcpd(dispatch+0x1b) [0x6cf7b]
 > /usr/sbin/dhcpd(main+0xf66) [0x18d16]
 > /usr/lib64/libc-2.30.so(__libc_start_main+0xf2) [0x271a2]
 > /usr/sbin/dhcpd(_start+0x2d) [0x1949d]


Additional info:

If the application is started under strace the option works fine (as per Expected result)

--- Additional comment from Dmitry V. Levin on 2020-01-07 19:40:11 UTC ---

This happens due to a cache initialization bug that results to a failure of printing stack trace for early syscalls.
Early syscalls in this case are those that precede the first syscall from memory mapping or execve families.
When a process is started by strace itself, the first syscall is usually execve.

Fixed by upstream commit v5.4-18-g69b2c33a77fa687feb41fafdbe187013aa812384, available at
https://github.com/strace/strace/commit/69b2c33a77fa687feb41fafdbe187013aa812384
https://gitlab.com/strace/strace/commit/69b2c33a77fa687feb41fafdbe187013aa812384

Thanks for reporting!

--- Additional comment from Dmitry V. Levin on 2020-01-07 19:44:40 UTC ---

FWIW, I have no idea when the fix will reach Fedora because updates of strace package are blocked by https://bugzilla.redhat.com/show_bug.cgi?id=1783584

--- Additional comment from Dmitry V. Levin on 2020-01-07 20:12:11 UTC ---

Meanwhile, you can install a fixed strace package from the scratch build for f31 at
https://koji.fedoraproject.org/koji/taskinfo?taskID=40246259
Comment 1 Eugene Syromiatnikov 2020-01-22 23:53:36 UTC 
Upstream commits:
69b2c33a77fa687feb41fafdbe187013aa812384 "unwind-libdw: fix initialization of libdwfl cache"
35e080ae319d25c1df82855cda3a1bb014e90ba6 "syscall: do not capture stack trace while the tracee executes strace code"
8e515c744935fe67e6a1b941f4c5414472c163b7 "tests: add strace-k-p test"
Comment 3 Eugene Syromiatnikov 2020-01-29 23:51:35 UTC 
Can be verified by checking the result of the included strace-k-p.test[1] against the new and the old strace version.

[1] http://pkgs.devel.redhat.com/cgit/rpms/strace/diff/0041-tests-add-strace-k-p-test.patch?h=devtoolset-9.1-rhel-6&id=5e712c09c6088fe07d232ecc0d7278e1d038f6a8
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