Restartable Sequences system call merged into Linux

[Stefan Liebler]

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?

Bye
Stefan