Re: [PATCH 1/5] glibc: Perform rseq(2) registration at C startup and thread creation (v10)
From: Mathieu Desnoyers
Date: Fri Jun 14 2019 - 09:52:02 EST
----- On Jun 14, 2019, at 3:42 PM, Florian Weimer fweimer@xxxxxxxxxx wrote:
> * Mathieu Desnoyers:
>> + /* Publicize rseq registration ownership. This must be performed
>> + after rtld re-relocation, before invoking constructors of
>> + preloaded libraries. */
>> + rseq_init ();
> Please add a comment that IFUNC resolvers do not see the initialized
> value. I think this is okay because we currently do not support access
> to extern variables in IFUNC resolvers.
Do IFUNC resolvers happen to observe the __rseq_handled address that
was internal to ld.so ?
If so, we could simply initialize __rseq_handled twice: early before calling
IFUNC resolvers, and after ld.so re-relocation.