Bug 1788636

Summary: strace doesn't print stack trace for early syscalls
Product: [Fedora] Fedora Reporter: Pavel Zhukov <pzhukov>
Component: straceAssignee: Dmitry V. Levin <ldv>
Status: CLOSED UPSTREAM QA Contact: Fedora Extras Quality Assurance <extras-qa>
Severity: unspecified Docs Contact:
Priority: unspecified    
Version: 31CC: esyr, hannsj_uhl, ldv, roland
Target Milestone: ---   
Target Release: ---   
Hardware: Unspecified   
OS: Unspecified   
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Story Points: ---
Clone Of:
: 1790052 1790053 1790054 1790057 1790058 (view as bug list) Environment:
Last Closed: 2020-01-07 19:40:11 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: 1783584    
Bug Blocks: 1790052, 1790053, 1790054, 1790057, 1790058    

Description Pavel Zhukov 2020-01-07 16:42:33 UTC 
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)
Comment 1 Dmitry V. Levin 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!
Comment 2 Dmitry V. Levin 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
Comment 3 Dmitry V. Levin 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