2005-01-10 21:36:38 +01:00
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/* Low level child interface to ptrace.
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2004-09-12 15:04:41 +02:00
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2018-01-01 05:43:02 +01:00
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Copyright (C) 2004-2018 Free Software Foundation, Inc.
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2004-09-12 15:04:41 +02:00
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This file is part of GDB.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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2007-08-23 20:08:50 +02:00
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the Free Software Foundation; either version 3 of the License, or
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2004-09-12 15:04:41 +02:00
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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2007-08-23 20:08:50 +02:00
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along with this program. If not, see <http://www.gnu.org/licenses/>. */
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2004-09-12 15:04:41 +02:00
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#ifndef INF_PTRACE_H
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#define INF_PTRACE_H
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/* Create a prototype ptrace target. The client can override it with
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local methods. */
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extern struct target_ops *inf_ptrace_target (void);
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2005-01-10 21:36:38 +01:00
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/* Create a "traditional" ptrace target. REGISTER_U_OFFSET should be
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a function returning the offset within the user area where a
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particular register is stored. */
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extern struct target_ops *
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2007-05-10 23:36:00 +02:00
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inf_ptrace_trad_target (CORE_ADDR (*register_u_offset)
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(struct gdbarch *, int, int));
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2005-01-10 21:36:38 +01:00
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2016-01-15 21:21:07 +01:00
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/* Return which PID to pass to ptrace in order to observe/control the
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tracee identified by PTID. */
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extern pid_t get_ptrace_pid (ptid_t);
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Fix failure to detach if process exits while detaching on Linux
This commit fixes detaching on Linux when some thread exits the whole
thread group (process) just while we're detaching.
On Linux, a ptracer must detach from each LWP individually, with
PTRACE_DETACH. Since PTRACE_DETACH sets the thread running free, if
one of the already-detached threads causes the whole thread group to
exit (e.g., simply calls exit), the kernel force-kills the other
threads in the group, making them zombie, just as we're still
detaching them. Since PTRACE_DETACH against a zombie thread fails
with ESRCH, and gdb/gdbserver are not expecting this, the detach fails
with an error like: "Can't detach process: No such process.".
This patch detects this detach failure as normal, and instead of
erroring out, reaps the now-dead thread.
New test included, that exercises several different scenarios that
cause GDB/GDBserver to error out when it should not.
Tested on x86-64 GNU/Linux with {unix, native-gdbserver,
native-extended-gdbserver}
Note: without the previous fix, the "single-process + continue"
variant of the new test would fail with:
(gdb) PASS: gdb.threads/process-dies-while-detaching.exp: single-process: continue: watchpoint: switch to parent
continue
Continuing.
Warning:
Could not insert hardware watchpoint 3.
Could not insert hardware breakpoints:
You may have requested too many hardware breakpoints/watchpoints.
Command aborted.
(gdb) FAIL: gdb.threads/process-dies-while-detaching.exp: single-process: continue: watchpoint: continue
gdb/gdbserver/ChangeLog:
2016-07-01 Pedro Alves <palves@redhat.com>
Antoine Tremblay <antoine.tremblay@ericsson.com>
* linux-low.c: Change interface to take the target lwp_info
pointer directly and return void. Handle detaching from a zombie
thread.
(linux_detach_lwp_callback): New function.
(linux_detach): Detach from the leader thread after detaching from
the clone threads.
gdb/ChangeLog:
2016-07-01 Pedro Alves <palves@redhat.com>
Antoine Tremblay <antoine.tremblay@ericsson.com>
* inf-ptrace.c (inf_ptrace_detach_success): New function, factored
out from ...
(inf_ptrace_detach): ... here.
* inf-ptrace.h (inf_ptrace_detach_success): New declaration.
* linux-nat.c (get_pending_status): Rename to ...
(get_detach_signal): ... this, and return a host signal instead of
filling in a wait status.
(detach_one_lwp): New function, factored out from detach_callback
and adjusted to handle detaching from a zombie thread.
(detach_callback): Skip the leader thread.
(linux_nat_detach): No longer defer to inf_ptrace_detach to detach
the leader thread, nor build a signal string to pass down.
Instead, use target_announce_detach, detach_one_lwp and
inf_ptrace_detach_success.
gdb/testsuite/ChangeLog:
2016-07-01 Pedro Alves <palves@redhat.com>
Antoine Tremblay <antoine.tremblay@ericsson.com>
* gdb.threads/process-dies-while-detaching.c: New file.
* gdb.threads/process-dies-while-detaching.exp: New file.
2016-07-01 12:16:33 +02:00
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/* Cleanup the inferior after a successful ptrace detach. */
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Make linux_nat_detach/thread_db_detach use the inferior parameter
This patch makes these two functions actually use the inferior parameter
added by the previous patch, instead of reading inferior_ptid. I chose
these two, because they are the one actually used when I detach on my
GNU/Linux system, so they were easy to test.
I took the opportunity to pass the inferior being detached to
inf_ptrace_detach_success, so it could use it too. From there, it made
sense to add an overload of detach_inferior that takes the inferior
directly rather than the pid, to avoid having to pass inf->pid only for
the callee to look up the inferior structure by pid.
gdb/ChangeLog:
* inf-ptrace.c (inf_ptrace_detach): Adjust call to
inf_ptrace_detach_success.
(inf_ptrace_detach_success): Add inferior parameter, use it
instead of inferior_ptid, pass it to detach_inferior.
* inf-ptrace.h (inf_ptrace_detach_success): Add inferior
parameter.
* inferior.c (detach_inferior): Add overload that takes an
inferior object.
* inferior.h (detach_inferior): Likewise.
* linux-nat.c (linux_nat_detach): Use the inf parameter, don't
use inferior_ptid, adjust call to inf_ptrace_detach_success.
* linux-thread-db.c (thread_db_detach): Use inf parameter.
2018-01-19 17:48:11 +01:00
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extern void inf_ptrace_detach_success (struct target_ops *ops, inferior *inf);
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Fix failure to detach if process exits while detaching on Linux
This commit fixes detaching on Linux when some thread exits the whole
thread group (process) just while we're detaching.
On Linux, a ptracer must detach from each LWP individually, with
PTRACE_DETACH. Since PTRACE_DETACH sets the thread running free, if
one of the already-detached threads causes the whole thread group to
exit (e.g., simply calls exit), the kernel force-kills the other
threads in the group, making them zombie, just as we're still
detaching them. Since PTRACE_DETACH against a zombie thread fails
with ESRCH, and gdb/gdbserver are not expecting this, the detach fails
with an error like: "Can't detach process: No such process.".
This patch detects this detach failure as normal, and instead of
erroring out, reaps the now-dead thread.
New test included, that exercises several different scenarios that
cause GDB/GDBserver to error out when it should not.
Tested on x86-64 GNU/Linux with {unix, native-gdbserver,
native-extended-gdbserver}
Note: without the previous fix, the "single-process + continue"
variant of the new test would fail with:
(gdb) PASS: gdb.threads/process-dies-while-detaching.exp: single-process: continue: watchpoint: switch to parent
continue
Continuing.
Warning:
Could not insert hardware watchpoint 3.
Could not insert hardware breakpoints:
You may have requested too many hardware breakpoints/watchpoints.
Command aborted.
(gdb) FAIL: gdb.threads/process-dies-while-detaching.exp: single-process: continue: watchpoint: continue
gdb/gdbserver/ChangeLog:
2016-07-01 Pedro Alves <palves@redhat.com>
Antoine Tremblay <antoine.tremblay@ericsson.com>
* linux-low.c: Change interface to take the target lwp_info
pointer directly and return void. Handle detaching from a zombie
thread.
(linux_detach_lwp_callback): New function.
(linux_detach): Detach from the leader thread after detaching from
the clone threads.
gdb/ChangeLog:
2016-07-01 Pedro Alves <palves@redhat.com>
Antoine Tremblay <antoine.tremblay@ericsson.com>
* inf-ptrace.c (inf_ptrace_detach_success): New function, factored
out from ...
(inf_ptrace_detach): ... here.
* inf-ptrace.h (inf_ptrace_detach_success): New declaration.
* linux-nat.c (get_pending_status): Rename to ...
(get_detach_signal): ... this, and return a host signal instead of
filling in a wait status.
(detach_one_lwp): New function, factored out from detach_callback
and adjusted to handle detaching from a zombie thread.
(detach_callback): Skip the leader thread.
(linux_nat_detach): No longer defer to inf_ptrace_detach to detach
the leader thread, nor build a signal string to pass down.
Instead, use target_announce_detach, detach_one_lwp and
inf_ptrace_detach_success.
gdb/testsuite/ChangeLog:
2016-07-01 Pedro Alves <palves@redhat.com>
Antoine Tremblay <antoine.tremblay@ericsson.com>
* gdb.threads/process-dies-while-detaching.c: New file.
* gdb.threads/process-dies-while-detaching.exp: New file.
2016-07-01 12:16:33 +02:00
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2004-09-12 15:04:41 +02:00
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#endif
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