[ was: Re: [backtrace] Avoid segfault  ]
On 27-01-19 22:53, Ian Lance Taylor wrote:
> On Sun, Jan 27, 2019 at 1:16 PM Tom de Vries <tdevries@suse.de> wrote:
>>
>> On 25-01-19 18:15, Nathan Sidwell wrote:
>>> On 1/25/19 5:28 AM, Tom de Vries wrote:
>>>>
>>>> This patch fixes it by passing "" instead of NULL, in the call to
>>>> elf_add at line 3083 (for .gnu_debugaltlink), not the call to elf_add at
>>>> line 3044 (for .gnu_debuglink) mentioned above.
>>>>
>>>> Nathan, does this fix the problem for you? If not, can you provide a
>>>> reproducer, or give a hint on how one could be constructed?
>>>
>>> I still hit the problem, and am installing this as sufficiently obvious.
>>>  I'm on a fedora system debugging pr88995.  The debuglink_name is
>>> "../../.dwz/isl-0.16.1-7.fc29.x86_64"
>>>
>>
>> I've managed to reproduce this segfault instance by adding a test-case
>> that uses both build-id and dwz.
>>
>> OK for trunk?
> 
>> +elf_for_test.c: elf.c
>> + PWD=$$(pwd -P); \
>> + BUILD_ID_DIR="usr/lib/debug/.build-id/"; \
>> + SEARCH='#define SYSTEM_BUILD_ID_DIR'; \
>> + REPLACE="#define SYSTEM_BUILD_ID_DIR \"$$PWD/$$BUILD_ID_DIR\""; \
>> + $(SED) "s%^$$SEARCH.*\$$%$$REPLACE%" \
>> + $< \
>> + > $@
> 
> You need to use a temporary file, such as $@.tmp, for the final sed
> command, followed by a mv to $@.  Otherwise a failure in the sed will
> leave what appears to be an up to date file.

I noticed the same problem in the xcoff_%.c pattern rule.

OK for trunk?

Thanks,
- Tom