Ahmed Sayeed <ahmedsayeed1...@yahoo.com> added the comment:
This patch fixes a segfault seen when attaching to a process on Solaris.
The steps leading to the segfault are:
http://www.compilatori.com/tech/xiaomi/
- 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/tech/forest-fires/ _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/tech/drone-cameras/
- 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/tech/express-van/
- 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/technology/telegram/
the_procfs_target on the inferior's target stack, although we never
reach this because the segfault happens before.
http://connstr.net/tech/mars-surface/
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/tech/cars-comparison/
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/tech/xiaomi-headset/ 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/tech/driving-assistant/
Tested by trying to attach on a process on gcc211 on the gcc compile
farm.
https://waytowhatsnext.com/health/vaccination-rates/
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/health/amoled-display/
- procfs_target::attach calls do_attach, at this point the inferior's
process slot in the target stack is empty.
https://komiya-dental.com/health/telegram-account/
- 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/services/usb-type-a/
- 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/property/house-sales-in-2020/
- 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).
----------
components: +Regular Expressions -Library (Lib)
nosy: +ahmedsayeed1982, ezio.melotti, mrabarnett -Carl.Crowder, eric.araujo,
petri.lehtinen, python-dev, r.david.murray, vinay.sajip
versions: +Python 3.10 -Python 2.7, Python 3.1, Python 3.2, Python 3.3
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<https://bugs.python.org/issue12168>
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