Re: [libvirt] [PATCH] Avoid async signal safety problem in glibc's setxid

On 15.11.2013 17:20, Daniel P. Berrange wrote: >The glibc setxid is supposed to be async signal safe, but >libc developers confirm that it is not. This causes a problem >when libvirt_lxc starts the FUSE thread and then runs clone() >to start the container. If the clone() was done before the >FUSE thread has completely started up, then the container >will hang in setxid after clone(). > >The fix is to avoid creating any threads until after the >container has been clone()'d. By avoiding any threads in >the parent, the child is no longer required to run in an >async signal safe context, and we thus avoid the glibc >bug. > >Signed-off-by: Daniel P. Berrange <berrange(a)redhat.com&gt; [...] >diff --git a/src/lxc/lxc_fuse.c b/src/lxc/lxc_fuse.c >index 9d12832..88e122e 100644 >--- a/src/lxc/lxc_fuse.c >+++ b/src/lxc/lxc_fuse.c [...] >@@ -364,6 +369,10 @@ int lxcSetupFuse(virLXCFusePtr *f ATTRIBUTE_UNUSED, > return 0; > } > >+int lxcStartFuse(virLXCFusePtr f ATTRIBUTE_UNUSED) >+{ >+} >+ > void lxcFreeFuse(virLXCFusePtr *f ATTRIBUTE_UNUSED) > { > } Hi Daniel, This hunk breaks the build on RHEL-6.4. lxc/lxc_fuse.c:374: error: control reaches end of non-void function [-Wreturn-type]