From e87d8ada291d77f065b36c27c0b8c20ab858650b Mon Sep 17 00:00:00 2001 From: Samuel Thibault Date: Wed, 17 Aug 2016 14:34:38 +0200 Subject: [PATCH] hurd: Document how EINTR should be handled in critical sections * hurd/hurd/signal.h (_hurd_critical_section_lock): Document how EINTR should be handled. --- ChangeLog | 5 +++++ hurd/hurd/signal.h | 8 +++++++- 2 files changed, 12 insertions(+), 1 deletion(-) diff --git a/ChangeLog b/ChangeLog index 3d2bdc8..ce14d88 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,8 @@ +2019-03-16 Samuel Thibault + + * hurd/hurd/signal.h (_hurd_critical_section_lock): Document how EINTR + should be handled. + 2019-03-15 Joseph Myers * sysdeps/unix/sysv/linux/syscall-names.list: Update kernel diff --git a/hurd/hurd/signal.h b/hurd/hurd/signal.h index c30f536..b0b5366 100644 --- a/hurd/hurd/signal.h +++ b/hurd/hurd/signal.h @@ -168,7 +168,13 @@ extern int _hurd_core_limit; A critical section is a section of code which cannot safely be interrupted to run a signal handler; for example, code that holds any lock cannot be interrupted lest the signal handler try to take the same lock and - deadlock result. */ + deadlock result. + + As a consequence, a critical section will see its RPCs return EINTR, even if + SA_RESTART is set! In that case, the critical section should be left, so + that the handler can run, and the whole critical section be tried again, to + avoid unexpectingly exposing EINTR to the application. + */ extern void *_hurd_critical_section_lock (void); -- 2.7.4