Package: ltrace
Version: 0.7.3+git20240814-0.3
Severity: normal
Tags: upstream
X-Debbugs-Cc: [email protected]
Dear Maintainer,
*** Reporter, please consider answering these questions, where appropriate ***
* What led up to the situation?
emacs was hung with 100% CPU utilisation. I wanted to know why.
* What exactly did you do (or not do) that was effective (or
ineffective)?
I attempted to diagnose the problem using "ltrace -p".
* What was the outcome of this action?
ltrace crashed because one of the libraries that emacs linked against wasn't
present in the filesystem, probably because it had been upgraded.
* What outcome did you expect instead?
ltrace shows me what emacs is doing (or nothing if emacs is just spinning inside
its own code).
I wrote this shell script to reproduce the issue
"""
#!/bin/sh -e
cd `mktemp -d`
echo "===> Building in $PWD ..."
cat <<__END__ > lib.h
void DoNothing();
__END__
cat <<__END__ > lib.c
#include "lib.h"
void DoNothing() {}
__END__
gcc -shared -O -o liblib.so -Wall -Werror -fPIC lib.c
cat <<__END__ > main.c
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include "lib.h"
int main() {
if (unlink("liblib.so") == -1) {
perror("unlink liblib.so");
exit(1);
}
while (1) {
sleep(1);
DoNothing();
}
return 0;
}
__END__
gcc -L$PWD -Wl,-rpath=$PWD -Wall -Werror -O -o bin main.c -llib
./bin &
echo "===> Running ltrace -p $! ..."
ltrace -p $!
"""
/proc/sys/kernel/yama/ptrace_scope must contain the value 0 for this to work.
Sample output:
"""
===> Building in /tmp/tmp.oldWtch6po ...
===> Running ltrace -p 4025257 ...
Can't open /tmp/tmp.oldWtch6po/liblib.so: No such file or directory
Couldn't determine base address of /tmp/tmp.oldWtch6po/liblib.so
ltrace: ltrace-elf.c:426: ltelf_destroy: Assertion
`(<e->plt_relocs)->elt_size == sizeof(GElf_Rela)' failed.
"""
Backtrace from gdb:
"""
#0 __pthread_kill_implementation (threadid=<optimized out>,
signo=signo@entry=6, no_tid=no_tid@entry=0)
at ./nptl/pthread_kill.c:44
#1 0x00007f63dfed3ebf in __pthread_kill_internal (threadid=<optimized out>,
signo=6)
at ./nptl/pthread_kill.c:78
#2 0x00007f63dfe7fd82 in __GI_raise (sig=sig@entry=6) at
../sysdeps/posix/raise.c:26
#3 0x00007f63dfe684f0 in __GI_abort () at ./stdlib/abort.c:79
#4 0x00007f63dfe68418 in __assert_fail_base (
fmt=0x7f63dffecca0 "%s%s%s:%u: %s%sAssertion `%s' failed.\n%n",
assertion=assertion@entry=0x557841e313e0 "(<e->plt_relocs)->elt_size ==
sizeof(GElf_Rela)",
file=file@entry=0x557841e331ec "ltrace-elf.c", line=line@entry=426,
function=function@entry=0x557841e367d0 <__PRETTY_FUNCTION__.5>
"ltelf_destroy") at ./assert/assert.c:96
#5 0x00007f63dfe78692 in __assert_fail (
assertion=assertion@entry=0x557841e313e0 "(<e->plt_relocs)->elt_size ==
sizeof(GElf_Rela)",
file=file@entry=0x557841e331ec "ltrace-elf.c", line=line@entry=426,
function=function@entry=0x557841e367d0 <__PRETTY_FUNCTION__.5>
"ltelf_destroy") at ./assert/assert.c:105
#6 0x0000557841e0e07a in ltelf_destroy (lte=0x7ffd79d48fb0) at
./ltrace-elf.c:426
#7 ltelf_destroy (lte=0x7ffd79d48fb0) at ./ltrace-elf.c:421
#8 0x0000557841e0fa83 in read_module (lib=lib@entry=0x55785b1a97f0,
proc=proc@entry=0x55785b1e5620,
filename=filename@entry=0x7ffd79d49180 "/tmp/tmp.oldWtch6po/liblib.so",
bias=<optimized out>,
main=main@entry=0) at ./ltrace-elf.c:1180
#9 0x0000557841e0fbec in ltelf_read_library (lib=lib@entry=0x55785b1a97f0,
proc=proc@entry=0x55785b1e5620,
filename=filename@entry=0x7ffd79d49180 "/tmp/tmp.oldWtch6po/liblib.so",
bias=<optimized out>)
at ./ltrace-elf.c:1290
#10 0x0000557841e07caa in crawl_linkmap (proc=proc@entry=0x55785b1e5620,
dbg=dbg@entry=0x7ffd79d4b1e0)
at ./sysdeps/linux-gnu/proc.c:547
#11 0x0000557841e08678 in linkmap_init (proc=proc@entry=0x55785b1e5620,
dyn_addr=<optimized out>)
at ./sysdeps/linux-gnu/proc.c:627
#12 0x0000557841dfed35 in process_hit_start (proc=<optimized out>) at
./proc.c:537
#13 0x0000557841dfef12 in open_pid (pid=4025257) at ./proc.c:597
#14 0x0000557841dfccd7 in ltrace_init (argc=<optimized out>, argv=<optimized
out>) at ./libltrace.c:141
#15 0x0000557841dfc96d in main (argc=<optimized out>, argv=<optimized out>) at
./main.c:47
"""
*** End of the template - remove these template lines ***
-- System Information:
Debian Release: rodete
Architecture: amd64 (x86_64)
Foreign Architectures: i386
Kernel: Linux 6.10.11-1rodete2-amd64 (SMP w/64 CPU threads; PREEMPT)
Kernel taint flags: TAINT_PROPRIETARY_MODULE, TAINT_OOT_MODULE,
TAINT_UNSIGNED_MODULE
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8),
LANGUAGE=en_GB:en_US
Shell: /bin/sh linked to /usr/bin/bash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled
Versions of packages ltrace depends on:
ii libc6 2.40-6+gl0
ii libelf1t64 0.192-4
ii libselinux1 3.7-3
ltrace recommends no packages.
ltrace suggests no packages.
-- no debconf information
