[PATCH] Threads shouldn't inherit PF_NOFREEZE

The PF_NOFREEZE process flag should not be inherited when a thread is
forked.  This patch (as585) removes the flag from the child.

This problem is starting to show up more and more as drivers turn to the
kthread API instead of using kernel_thread().  As a result, their kernel
threads are now children of the kthread worker instead of modprobe, and
they inherit the PF_NOFREEZE flag.  This can cause problems during system
suspend; the kernel threads are not getting frozen as they ought to be.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

diff --git a/kernel/fork.c b/kernel/fork.c
index 533ce27f4b2c0938f91c948aa682bc992579ba96..280bd44ac4411634c0eb845c01be8ca3a5f22b7c 100644 (file)
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -848,7 +848,7 @@ static inline void copy_flags(unsigned long clone_flags, struct task_struct *p)
 {
        unsigned long new_flags = p->flags;
 
-       new_flags &= ~PF_SUPERPRIV;
+       new_flags &= ~(PF_SUPERPRIV | PF_NOFREEZE);
        new_flags |= PF_FORKNOEXEC;
        if (!(clone_flags & CLONE_PTRACE))
                p->ptrace = 0;