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gdb.python/py-unwind: Disable stack protection

[I made some typo fixes but forgot to amend my commit before sending the patch,
 hence this v2.]

I see the following failure on Ubuntu 16.04's gcc 5.4.0:

Running /home/emaisin/src/binutils-gdb/gdb/testsuite/gdb.python/py-unwind.exp ...
FAIL: gdb.python/py-unwind.exp: continue to breakpoint: break backtrace-broken
FAIL: gdb.python/py-unwind.exp: Backtrace restored by unwinder (pattern 1)

The problem is that the test expects a very particular stack layout.
When stack protection is enabled, it adds a canary value which looks
like an additional local variable.  This makes the test complain about
a bad stack layout and fail.

The simple solution is to disable stack protection for that test using
-fno-stack-protector.  I checked older compilers (gcc 4.4, clang 3.5)
and they support that flag, so I don't think it's necessary to probe for
whether the compiler supports it.

Maybe a better solution would be to change the test to make it cope with
different stack layouts (perhaps it could save addresses of stuff in
some global variables which GDB/the unwinder would read).  I'll go with
the simple solution for now though.

gdb/testsuite/ChangeLog:

	* gdb.python/py-unwind.exp: Disable stack protection when
	building test file.
This commit is contained in:
Simon Marchi 2017-07-22 00:01:03 +02:00
parent 82c7806625
commit dcd27ddf87
2 changed files with 11 additions and 1 deletions
gdb/testsuite

View File

@ -1,3 +1,8 @@
2017-07-22 Simon Marchi <simon.marchi@ericsson.com>
* gdb.python/py-unwind.exp: Disable stack protection when
building test file.
2017-07-20 Pedro Alves <palves@redhat.com>
* gdb.base/default.exp (set language): Adjust expected output.

View File

@ -20,7 +20,12 @@ load_lib gdb-python.exp
standard_testfile
if { [prepare_for_testing "failed to prepare" ${testfile} ${srcfile}] } {
# Stack protection can make the stack look a bit different, breaking the
# assumptions this test has about its layout.
set flags "additional_flags=-fno-stack-protector"
if { [prepare_for_testing "failed to prepare" ${testfile} ${srcfile} "debug $flags"] } {
return -1
}