11.04debugdebuggingsudo
I just recently upgraded from 10.04 to 11.04 and gdb won't allow me to attach to processes anymore I get the error
Attaching to process 10144 Could not
attach to process. If your uid
matches the uid of the target process,
check the setting of
/proc/sys/kernel/yama/ptrace_scope, or
try again as the root user. For more
details, see
/etc/sysctl.d/10-ptrace.conf ptrace:
Operation not permitted.
How do I fix this so that I can debug again without sudo?
Under certain situations, the -dbg packages don't work correctly. Instead, try the -dbgsym packages, available from the separate "debug symbols" repository:
https://wiki.ubuntu.com/DebuggingProgramCrash
However, when trying this locally with Ubuntu 9.10, I have no problem loading symbols using the existing php5-dbg package. Perhaps make sure you have the latest updates installed first, and then try it?
As an example:
$ cat /tmp/test.php
<?php sleep(10); ?>
$ gdb php
...
(gdb) run /tmp/test.php
...
^C
Program received signal SIGINT, Interrupt.
0xf7fe0430 in __kernel_vsyscall ()
(gdb) bt
#0 0xf7fe0430 in __kernel_vsyscall ()
#1 0xf7a13b50 in nanosleep () from /lib/tls/i686/cmov/libc.so.6
#2 0xf7a13991 in sleep () from /lib/tls/i686/cmov/libc.so.6
#3 0x081fbfc1 in zif_sleep (ht=1, return_value=0x866d204,
return_value_ptr=0x0, this_ptr=0x0, return_value_used=0)
at /build/buildd/php5-5.2.10.dfsg.1/ext/standard/basic_functions.c:4787
#4 0x082f9616 in zend_do_fcall_common_helper_SPEC (execute_data=0xffffafbc)
at /build/buildd/php5-5.2.10.dfsg.1/Zend/zend_vm_execute.h:200
#5 0x082f511b in execute (op_array=0x866d7f0)
at /build/buildd/php5-5.2.10.dfsg.1/Zend/zend_vm_execute.h:92
#6 0x082cf414 in zend_execute_scripts (type=8, retval=0x0, file_count=3)
at /build/buildd/php5-5.2.10.dfsg.1/Zend/zend.c:1215
#7 0x08284166 in php_execute_script (primary_file=0xffffd454)
at /build/buildd/php5-5.2.10.dfsg.1/main/main.c:2046
#8 0x08352c38 in main (argc=2, argv=0xffffd554)
at /build/buildd/php5-5.2.10.dfsg.1/sapi/cli/php_cli.c:1170
Best Answer
In Maverick Meerkat (10.10) Ubuntu introduced a patch to disallow ptracing of non-child processes by non-root users - ie. only a process which is a parent of another process can ptrace it for normal users - whilst root can still ptrace every process. Hence why you can use gdb to attach via sudo still.
You can temporarily disable this restriction (and revert to the old behaviour allowing your user to ptrace (gdb) any of their other processes) by doing:
To permanently allow it edit
/etc/sysctl.d/10-ptrace.confand change the line:To read:
For some background on why this change was made, see the Ubuntu wiki.