https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77728
Tim Turner <timturnerc at yahoo dot com> changed:
What |Removed |Added
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CC| |timturnerc at yahoo dot com
--- Comment #64 from Tim Turner <timturnerc at yahoo dot com> ---
This patch fixes a segfault seen when attaching to a process on Solaris.
The steps leading to the segfault are:
http://www.compilatori.com/
- procfs_target::attach calls do_attach, at this point the inferior's
process slot in the target stack is empty.
- do_attach adds a thread with `add http://www.acpirateradio.co.uk/
_thread (&the_procfs_target, ptid)`
- in add_thread_silent, the passed target (&the_procfs_target) is
passed to find_inferior_ptid http://www.logoarts.co.uk/
- find_inferior_ptid returns nullptr, as there is no inferior with this
ptid that has &the_procfs_target as its process target
http://www.slipstone.co.uk/
- the nullptr `inf` is passed to find_thread_ptid, which dereferences
it, causing a segfault
- back in procfs_target::attach, after do_attach, we push the
http://embermanchester.uk/
the_procfs_target on the inferior's target stack, although we never
reach this because the segfault happens before. http://connstr.net/
To fix this, I think we need to do the same as is done in
inf_ptrace_target::attach: push the target early and unpush it in case
the attach fails (and keep it if the attach succeeds). http://joerg.li/
Implement it by moving target_unpush_up to target.h, so it can be
re-used here. Make procfs_target::attach use it. Note that just like
is mentioned http://www.jopspeech.com/ in inf_ptrace_target::attach, we
should push the target
before calling target_pid_to_str, so that calling target_pid_to_str ends
up in procfs_target::pid_to_str. http://www.wearelondonmade.com/
Tested by trying to attach on a process on gcc211 on the gcc compile
farm.
https://waytowhatsnext.com/
gdb/ChangeLog:
This patch fixes a segfault seen when attaching to a process on Solaris.
The steps leading to the segfault are: http://www.iu-bloomington.com/
- procfs_target::attach calls do_attach, at this point the inferior's
process slot in the target stack is empty. https://komiya-dental.com/
- do_attach adds a thread with `add_thread (&the_procfs_target, ptid)`
- in add_thread_silent, the passed target (&the_procfs_target) is
passed to find_inferior_ptid http://www-look-4.com/
- find_inferior_ptid returns nullptr, as there is no inferior with this
ptid that has &the_procfs_target as its process target
- the nullptr `inf` is passed to find_thread_ptid, which dereferences
it, causing a segfault https://www.webb-dev.co.uk/
- back in procfs_target::attach, after do_attach, we push the
the_procfs_target on the inferior's target stack, although we never
reach this because the segfault happens before.
To fix this, I think we need to do the same as is done in
inf_ptrace_target::attach: push the target early and unpush it in case
the attach fails (and keep it if the attach succeeds).
