Re: Restartable Sequences system call merged into Linux

[Adhemerval Zanella <adhemerval dot zanella at linaro dot org>]

On 11/07/2018 13:03, Stefan Liebler wrote:
> On 06/11/2018 09:49 PM, Mathieu Desnoyers wrote:
>> Hi!
>>
>> Good news! The restartable sequences (rseq) system call is now merged into the master
>> branch of the Linux kernel within the 4.18 merge window:
>>
>> https://github.com/torvalds/linux/commit/d82991a8688ad128b46db1b42d5d84396487a508
>>
>> It would be important to discuss how we should proceed to integrate the library part
>> of rseq (see tools/testing/selftests/rseq/rseq*.{ch}) into glibc, or if it should
>> live in a standalone project.
>>
>> It should be noted that there can be only one rseq TLS area registered per thread,
>> which can then be used by many libraries and by the executable, so this is a
>> process-wide (per-thread) resource that we need to manage carefully.
>>
>> Thoughts ?
>>
>> Thanks!
>>
>> Mathieu
>>
>>
> The structs rseq_cs and rseq are aligned to 32 bytes.
> Please have a look at the bug:
> "Bug 23403 - Wrong alignment of TLS variables"
> (https://sourceware.org/bugzilla/show_bug.cgi?id=23403).
> 
> @Carlos or somebody else:
> Should this be fixed in the upcoming glibc release?

I would consider this a block in fact.