freebsd-skq

History

jhb 0472a49b7f Discard the correct thread event reported for a ptrace stop. When multiple threads wish to report a tracing event to a debugger, both threads call ptracestop() and one thread will win the race to be the reporting thread (p->p_xthread). The debugger uses PT_LWPINFO with the process ID to determine which thread / LWP is reporting an event and the details of that event. This event is cleared as a side effect of the subsequent ptrace event that resumed the process (PT_CONTINUE, PT_STEP, etc.). However, ptrace() was clearing the event identified by the LWP ID passed to the resume request even if that wasn't the 'p_xthread'. This could result in clearing an event that had not yet been observed by the debugger and leaving the existing event for 'p_thread' pending so that it was reported a second time. Specifically, if the debugger stopped due to a software breakpoint in one thread, but then switched to another thread that was used to resume (e.g. if the user switched to a different thread and issued a step), the resume request (PT_STEP) cleared a pending event (if any) for the thread being stepped. However, the process immediately stopped and the first thread reported it's breakpoint event a second time. The debugger decremented the PC for "both" breakpoint events which resulted in the PC now pointing into the middle of an instruction (on x86) and a SIGILL fault when the process was resumed a second time. To fix, always clear the pending event for 'p_xthread' when resuming a process. ptrace() still honors the requested LWP ID when enabling single-stepping (PT_STEP) or setting a different PC (PT_CONTINUE). Reported by: GDB testsuite (gdb.threads/continue-pending-status.exp) Reviewed by: kib MFC after: 1 week Differential Revision: https://reviews.freebsd.org/D12794		2017-10-27 03:16:19 +00:00
..
etc	Add supporting changes for `Add limited sandbox capability to "make check"`	2017-08-14 19:21:37 +00:00
freebsd_test_suite	Add ATF_REQUIRE_FEATURE and PLAIN_REQUIRE_FEATURE macros for	2015-12-16 05:44:53 +00:00
sys	Discard the correct thread event reported for a ptrace stop.	2017-10-27 03:16:19 +00:00
Kyuafile
Makefile	Use MK_CHECK_USE_SANDBOX in tests/..., to deal with the fact that	2017-08-02 22:24:08 +00:00
Makefile.depend	DIRDEPS_BUILD: Connect MK_TESTS.	2016-03-09 22:46:01 +00:00
Makefile.inc0	Use bsd.opts.mk, not src.opts.mk	2017-08-03 00:35:35 +00:00
README	Copy README into /usr/tests	2015-11-20 03:24:04 +00:00

README

src/tests: The FreeBSD test suite
=================================

To run the FreeBSD test suite:
(1)  Make sure that kyua is installed:
       pkg install kyua
(2)  To run the tests:
       kyua test -k /usr/tests/Kyuafile
(3)  To see the test results:
       kyua report  

For further information on using the test suite, read tests(7):
       man tests

Description of FreeBSD test suite
=================================
The build of the test suite is organized in the following manner:

* The build of all test artifacts is protected by the MK_TESTS knob.
  The user can disable these with the WITHOUT_TESTS setting in
  src.conf(5).

* The goal for /usr/tests/ (the installed test programs) is to follow
  the same hierarchy as /usr/src/ wherever possible, which in turn drives
  several of the design decisions described below.  This simplifies the
  discoverability of tests.  We want a mapping such as:

    /usr/src/bin/cp/      -> /usr/tests/bin/cp/
    /usr/src/lib/libc/    -> /usr/tests/lib/libc/
    /usr/src/usr.bin/cut/ -> /usr/tests/usr.bin/cut/
    ... and many more ...

* Test programs for specific utilities and libraries are located next
  to the source code of such programs.  For example, the tests for the
  src/lib/libcrypt/ library live in src/lib/libcrypt/tests/.  The tests/
  subdirectory is optional and should, in general, be avoided.

* The src/tests/ hierarchy (this directory) provides generic test
  infrastructure and glue code to join all test programs together into
  a single test suite definition.

* The src/tests/ hierarchy also includes cross-functional test programs:
  i.e. test programs that cover more than a single utility or library
  and thus don't fit anywhere else in the tree.  Consider this to follow
  the same rationale as src/share/man/: this directory contains generic
  manual pages while the manual pages that are specific to individual
  tools or libraries live next to the source code.

In order to keep the src/tests/ hierarchy decoupled from the actual test
programs being installed --which is a worthy goal because it simplifies
the addition of new test programs and simplifies the maintenance of the
tree-- the top-level Kyuafile does not know which subdirectories may
exist upfront.  Instead, such Kyuafile automatically detects, at
run-time, which */Kyuafile files exist and uses those directly.

Similarly, every directory in src/ that wants to install a Kyuafile to
just recurse into other subdirectories reuses this Kyuafile with
auto-discovery features.  As an example, take a look at src/lib/tests/
whose sole purpose is to install a Kyuafile into /usr/tests/lib/.
The goal in this specific case is for /usr/tests/lib/ to be generated
entirely from src/lib/.

-- 
$FreeBSD$