1194841 - Add SECCOMP_FILTER_FLAG_TSYNC support to flame-kk kernel

Status: RESOLVED FIXED

(Firefox OS Graveyard :: General, defect)

Description

[Jed Davis [:jld] ⟨⏰|UTC-8⟩ ⟦he/him⟧]

SECCOMP_FILTER_FLAG_TSYNC allows enabling seccomp-bpf on all threads of a multithreaded process at once, without needing our current workaround of reading procfs and using async signal handlers; Gecko support landed in bug 1004011.  I have a cherry-pick of the Nexus 5 Lollipop kernel branch's backport, which I'll file a pull request for once I have a bug number.

As a side-effect, this should make bug 1185118 stop happening.  It's not entirely clear why things are hanging there, because there's no reliable STR and our crash dumps don't give me visibility into what's going on in the kernel, but this will let us not use the code that's triggering the bug.

Comment 1

[Jed Davis [:jld] ⟨⏰|UTC-8⟩ ⟦he/him⟧]

Attachment: GitHub PR link

If this needs more/other reviewers, please feel free to edit the flags.

Comment 2

[Michael Wu [:mwu]]

Comment on attachment 8648216 [details] [review]
GitHub PR link

Don't know how this works, but I like the idea of it. Guess that makes it a f+?

Is SECCOMP_FILTER_FLAG_TSYNC required on lollipop based builds? If not, it probably should be.

Comment 3

[Guillaume Destuynder [:kang] [this account is no longer active]]

Comment on attachment 8648216 [details] [review]
GitHub PR link

the patches look sane - im not sure either what causes the issue without tsync, however, since its upstream now its also nicer than the /proc solution.

Comment 4

[Jed Davis [:jld] ⟨⏰|UTC-8⟩ ⟦he/him⟧]

Thanks for the review/feedback; sorry for losing track of this bug.

https://github.com/mozilla-b2g/codeaurora_kernel_msm/commit/b3531e28c2273ecdc37613ffd13dd8beb99123a8

Comment 5

[Jed Davis [:jld] ⟨⏰|UTC-8⟩ ⟦he/him⟧]

(In reply to Michael Wu [:mwu] from comment #2)
> Is SECCOMP_FILTER_FLAG_TSYNC required on lollipop based builds? If not, it
> probably should be.

Not yet.  Filed as bug 1206803.