Revert "Improve ptrace-error detection on Linux targets"

This reverts commit 381beca6146ac68b57edf47d28cdb335fbd11635.

The patch hasn't been fully reviewed yet, and Pedro would like to see
more fixes.

2 files changed, 0 insertions, 148 deletions

diff --git a/gdb/doc/ChangeLog b/gdb/doc/ChangeLog
index 003c8c2ffea..0a10fa3fade 100644
--- a/gdb/doc/ChangeLog
+++ b/gdb/doc/ChangeLog
@@ -1,8 +1,3 @@
-2019-09-26  Sergio Durigan Junior  <sergiodj@redhat.com>
-
-	* gdb.texinfo (Linux kernel ptrace restrictions): New appendix
-	section.
-
 2019-09-20  Ulrich Weigand  <uweigand@de.ibm.com>
 
 	* doc/gdb.texinfo (Remote Configuration): Remove documentation for
diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
index e7b5b18f2b3..f2713c03960 100644
--- a/gdb/doc/gdb.texinfo
+++ b/gdb/doc/gdb.texinfo
@@ -182,9 +182,6 @@ software in general.  We will miss him.
                                 @value{GDBN}
 * Operating System Information:: Getting additional information from
                                  the operating system
-* Linux kernel ptrace restrictions::        Restrictions sometimes
-                                            imposed by the Linux
-                                            kernel on @code{ptrace}
 * Trace File Format::		GDB trace file format
 * Index Section Format::        .gdb_index section format
 * Man Pages::			Manual pages
@@ -44668,146 +44665,6 @@ should contain a comma-separated list of cores that this process
 is running on.  Target may provide additional columns,
 which @value{GDBN} currently ignores.
 
-@node Linux kernel ptrace restrictions
-@appendix Linux kernel @code{ptrace} restrictions
-@cindex linux kernel ptrace restrictions, attach
-
-The @code{ptrace} system call is used by @value{GDBN} and
-@code{gdbserver} on GNU/Linux to, among other things, attach to a new
-or existing inferior in order to start debugging it.  Due to security
-concerns, some distributions and vendors disable or severely restrict
-the ability to perform these operations, which can make @value{GDBN}
-or @code{gdbserver} malfunction.  In this section, we will expand on
-how this malfunction can manifest itself, and how to modify the
-system's settings in order to be able to use @value{GDBN} and
-@code{gdbserver} properly.
-
-@menu
-* The error message::                   The error message displayed when the
-                                        system prevents @value{GDBN}
-                                        or @code{gdbserver} from using
-                                        @code{ptrace}
-* SELinux's deny_ptrace::               SELinux and the @code{deny_ptrace} option
-* Yama's ptrace_scope::                 Yama and the @code{ptrace_scope} setting
-* Docker and seccomp::                  Docker and the @code{seccomp}
-                                        infrastructure
-@end menu
-
-@node The error message
-@appendixsection The error message
-
-When the system prevents @value{GDBN} or @code{gdbserver} from using
-the @code{ptrace} system call, you will likely see a descriptive error
-message explaining what is wrong and how to attempt to fix the
-problem.  For example, when SELinux's @code{deny_ptrace} option is
-enabled, you can see:
-
-@smallexample
-$ gdb program
-...
-(@value{GDBP}) run
-Starting program: program
-warning: Could not trace the inferior process.
-Error:
-warning: ptrace: Permission denied
-The SELinux 'deny_ptrace' option is enabled and preventing @value{GDBN}
-from using 'ptrace'.  You can disable it by executing (as root):
-
-  setsebool deny_ptrace off
-
-If you are debugging the inferior remotely, the instruction(s) above must
-be performed in the target system (e.g., where GDBserver is running).
-During startup program exited with code 127.
-(@value{GDBP})
-@end smallexample
-
-Sometimes, it may not be possible to acquire the necessary data to
-determine the root cause of the failure.  In this case, you will see a
-generic error message pointing you to this section:
-
-@smallexample
-$ gdb program
-...
-Starting program: program
-warning: Could not trace the inferior process.
-Error:
-warning: ptrace: Permission denied
-There might be restrictions preventing ptrace from working.  Please see
-the appendix "Linux kernel ptrace restrictions" in the GDB documentation
-for more details.
-During startup program exited with code 127.
-(@value{GDBP})
-@end smallexample
-
-@node SELinux's deny_ptrace
-@appendixsection SELinux's @code{deny_ptrace}
-@cindex SELinux
-@cindex deny_ptrace
-
-If you are using SELinux, you might want to check whether the
-@code{deny_ptrace} option is enabled by doing:
-
-@smallexample
-$ getsebool deny_ptrace
-deny_ptrace --> on
-@end smallexample
-
-If the option is enabled, you can disable it by doing, as root:
-
-@smallexample
-# setsebool deny_ptrace off
-@end smallexample
-
-The option will be disabled until the next reboot.  If you would like
-to disable it permanently, you can do (as root):
-
-@smallexample
-# setsebool -P deny_ptrace off
-@end smallexample
-
-@node Yama's ptrace_scope
-@appendixsection Yama's @code{ptrace_scope}
-@cindex yama, ptrace_scope
-
-If your system has Yama enabled, you might want to check whether the
-@code{ptrace_scope} setting is enabled by checking the value of
-@file{/proc/sys/kernel/yama/ptrace_scope}:
-
-@smallexample
-$ cat /proc/sys/kernel/yama/ptrace_scope
-0
-@end smallexample
-
-If you see anything other than @code{0}, @value{GDBN} or
-@code{gdbserver} can be affected by it.  You can temporarily disable
-the feature by doing, as root:
-
-@smallexample
-# sysctl kernel.yama.ptrace_scope=0
-kernel.yama.ptrace_scope = 0
-@end smallexample
-
-You can make this permanent by doing, as root:
-
-@smallexample
-# sysctl -w kernel.yama.ptrace_scope=0
-kernel.yama.ptrace_scope = 0
-@end smallexample
-
-@node Docker and seccomp
-@appendixsection Docker and @code{seccomp}
-@cindex docker, seccomp
-
-If you are using Docker (@uref{https://www.docker.com/}) containers,
-you will probably have to disable its @code{seccomp} protections in
-order to be able to use @value{GDBN} or @code{gdbserver}.  To do that,
-you can use the options @code{--cap-add=SYS_PTRACE --security-opt
-seccomp=unconfined} when invoking Docker:
-
-@smallexample
-$ docker run --cap-add=SYS_PTRACE --security-opt seccomp=unconfined
-@end smallexample
-
 @node Trace File Format
 @appendix Trace File Format
 @cindex trace file format