Re: [PATCH dwarves] dwarf_loader: fix termination on BTF encoding error

[Alan Maguire <alan.maguire@oracle.com>]

On 01/04/2025 14:43, Domenico Andreoli wrote:
> On Tue, Apr 01, 2025 at 01:57:25PM +0100, Alan Maguire wrote:
>> On 28/03/2025 17:40, Ihor Solodrai wrote:
>>> When BTF encoding thread aborts because of an error, dwarf loader
>>> worker threads get stuck in cus_queue__enqdeq_job() at:
>>>
>>>     pthread_cond_wait(&cus_processing_queue.job_added, &cus_processing_queue.mutex);
>>>
>>> To avoid this, introduce an abort flag into cus_processing_queue, and
>>> atomically check for it in the deq loop. The flag is only set in case
>>> of a worker thread exiting on error. Make sure to pthread_cond_signal
>>> to the waiting threads to let them exit too.
>>>
>>> In cus__process_file fix the check of an error returned from
>>> dwfl_getmodules: it may return a positive number when a
>>> callback (cus__process_dwflmod in our case) returns an error.
>>>
>>> Link: https://lore.kernel.org/dwarves/Z-JzFrXaopQCYd6h@localhost/
>>>
>>> Reported-by: Domenico Andreoli <domenico.andreoli@linux.com>
>>> Signed-off-by: Ihor Solodrai <ihor.solodrai@linux.dev>
>>
>> Thanks for the fix! I've tested this with the problematic module+vmlinux
>> BTF and the previously-hanging pahole goes on to fail as expected; also
>> run it through the work-in-progress CI, building and testing on x86_64
>> and aarch64, no issues found. If anyone else has a chance to ack or test
>> it, that would be great. Thanks!
> 
> Tested-by: Domenico Andreoli <domenico.andreoli@linux.com>
> 
> I rebuilt the Debian package with that patch applied and it then started
> to fail consistently because of the extra c++ symbols.
> 
> When I use the switch --lang_exclude=rust,c++11, it works without
> errors.
> 
> Thank you Alan and Ihor for the fast support!
> 

Fix applied to next branch at
https://git.kernel.org/pub/scm/devel/pahole/pahole.git , thanks!

Alan