Re: [PHP-DEV] How to debug a segmentation fault?

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January 29, 2020 10:59 nikita.ppv@gmail.com (Nikita Popov)
On Tue, Jan 28, 2020 at 5:29 PM Benjamin Morel morel@gmail.com>
wrote:

> Hi internals, > > I'm encountering a SIGSEGV in PHP-FPM on PHP 7.4.2 in a Symfony app. The > bug seems to happen during the rendering of a Twig template; this makes it > hard for me to pinpoint the code that triggers the segfault. > > Could you please tell me what the procedure to collect information is, so > that I can file a useful bug report? >
As the first step, I would always suggest to reproduce this issue with the CLI binary (this includes the builtin server under -S localhost:8000 -t public). That way you don't have to deal with multi-process FPM. Once that is done, the easiest way to get some useful debugging information is to run PHP under valgrind, this is done using "USE_ZEND_ALLOC=0 valgrind php ...". Nikita