Re: die('zend_mm_heap corrupted'); // TODO: Better error message

On Tue, 9 Oct 2018 at 07:16, Dmitry Stogov <dmitry@zend.com> wrote: > Hi Rowan, > > > This error message is triggered when Zend MM used in improper way, e.g. > invalid pointer free, etc. > > MM can't provide useful information about the context and reason. > I get that it can't provide the *reason*, but that doesn't mean there can't be any *context*: - Will it always occur during shutdown? If so, the message could include "during shutdown". If not, could the message indicate whether it is or not? - The ZEND_MM_CHECK macro takes a message, but all 15 uses of it pass the same message, "zend_mm_heap corrupted"; are they really identical? Could making each message distinct help improve bug reports? - The printf format in zend_mm_panic could add something other than a newline, e.g. "PHP Engine Error: %s", to make this line clearer in the logs to people who have never heard of "Zend MM". - Ideally, it would also include a timestamp; without this, it can be very hard to line up which requests are failing, or even how often it is happening. So, rather than the current message: zend_mm_heap corrupted It would be great to see: [09-Oct-2018 09:33:03 Europe/London] PHP Fatal Error: zend_mm_heap corrupted (invalid page offset) during process shutdown. Even better would be for this to drop into the PHP error log, rather than echoing to stderr, but I realise that might be more complicated during a "panic" scenario like this. > The best way to find the reason of the problem is running php under > valgrind. > > > $ USE_ZEND_ALLOC=0 valgrind php ... > > > In most cases valgrind will show incorrect MM operations and their history. > I'm not proficient enough with C to get far with that, so my main concerns are 1) ensuring these errors are clearly visible in the logs; and 2) helping provide useful context in a bug report against core or an extension. Regards, -- Rowan Collins [IMSoP]