From 17a62de1ff4c7548748a8d264382131f523f071a Mon Sep 17 00:00:00 2001 From: Samuel Thibault Date: Thu, 28 Aug 2014 22:08:39 +0200 Subject: [PATCH] Fix hang on fork If e.g. a signal is being received while we are running fork(), the signal thread may be having our SS lock when we make the space copy, and thus in the child we can not take the SS lock any more. * sysdeps/mach/hurd/fork.c (__fork): Lock SS->lock around __proc_dostop call. Signed-off-by: Samuel Thibault --- ChangeLog | 5 +++++ sysdeps/mach/hurd/fork.c | 4 ++++ 2 files changed, 9 insertions(+) diff --git a/ChangeLog b/ChangeLog index 23c900dcf7..eb604b854b 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,8 @@ +2014-08-28 Samuel Thibault + + * sysdeps/mach/hurd/fork.c (__fork): Lock SS->lock around + __proc_dostop call. + 2014-08-27 Mark Wielaard [BZ #17319] diff --git a/sysdeps/mach/hurd/fork.c b/sysdeps/mach/hurd/fork.c index 60c34c7620..51bc2c0753 100644 --- a/sysdeps/mach/hurd/fork.c +++ b/sysdeps/mach/hurd/fork.c @@ -129,9 +129,13 @@ __fork (void) ports_locked = 1; + /* Keep our SS locked while stopping other threads, so they don't get a + chance to have it locked in the copied space. */ + __spin_lock (&ss->lock); /* Stop all other threads while copying the address space, so nothing changes. */ err = __proc_dostop (_hurd_ports[INIT_PORT_PROC].port, ss->thread); + __spin_unlock (&ss->lock); if (!err) { stopped = 1;