Re: [PATCH v7 3/8] Move malloc hooks into a compat DSO

[Siddhesh Poyarekar via Libc-alpha <libc-alpha@sourceware.org>]

On 7/9/21 1:38 PM, Florian Weimer wrote:
> * Siddhesh Poyarekar:
> 
>> Remove all malloc hook uses from core malloc functions and move it
>> into a new library libc_malloc_debug.so.  With this, the hooks now no
>> longer have any effect on the core library.
>>
>> libc_malloc_debug.so is a malloc interposer that needs to be preloaded
>> to get hooks functionality back so that the debugging features that
>> depend on the hooks, i.e. malloc-check, mcheck and mtrace work again.
>> Without the preloaded DSO these debugging features will be nops.
>> These features will be ported away from hooks in subsequent patches.
>>
>> Similarly, legacy applications that need hooks functionality need to
>> preload libc_malloc_debug.so.
>>
>> The symbols exported by libc_malloc_debug.so are maintained at exactly
>> the same version as libc.so.
>>
>> Finally, static binaries will no longer be able to use malloc
>> debugging features since they cannot preload the debugging DSO.
> 
> Commit subject could be adjusted because the DSO contains more than just
> the hooks.

OK, I'll update it to "Introduce malloc debug DSO"

> This patch needs to update the shlib-versions file on architectures
> which do not use DEFAULT.  For example, on ia64-linux-gnu, there is a
> malloc/check-abi-libc_malloc_debug failure that looks like this:

Thanks, fixed locally.

Siddhesh