Re: [libvirt] [PATCH] Fix potential deadlock across fork() in QEMU driver

From: "Daniel P. Berrange" <berrange(a)redhat.com&gt; The hook scripts used by virCommand must be careful wrt accessing any mutexes that may have been held by other threads in the parent process. With the recent refactorigng

there are 2 potential flaws lurking, which will become real deadlock bugs once the global QEMU driver lock is removed. Remove use of the QEMU driver lock from the hook function by passing in the 'virQEMUDriverConfigPtr' instance directly. Add functions to the virSecurityManager to be invoked before and after fork, to ensure the mutex is held by the current thread. This allows it to be safely used in the hook script in the child procss.

Signed-off-by: Daniel P. Berrange <berrange(a)redhat.com&gt; --- src/libvirt_private.syms | 2 ++ src/qemu/qemu_process.c | 16 ++++++++++++---- src/security/security_manager.c | 20 ++++++++++++++++++++ src/security/security_manager.h | 3 +++ 4 files changed, 37 insertions(+), 4 deletions(-)