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authorOleg Nesterov <oleg@tv-sign.ru>2008-07-25 01:47:37 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2008-07-25 10:53:39 -0700
commit7b34e4283c685f5cc6ba6d30e939906eee0d4bcf (patch)
tree6822edd5c63db79e97b8c5379a18a058bc5405ff
parent3d749b9e676b26584a47e75c235aa6f69d0697ae (diff)
introduce PF_KTHREAD flag
Introduce the new PF_KTHREAD flag to mark the kernel threads. It is set by INIT_TASK() and copied to the forked childs (we could set it in kthreadd() along with PF_NOFREEZE instead). daemonize() was changed as well. In that case testing of PF_KTHREAD is racy, but daemonize() is hopeless anyway. This flag is cleared in do_execve(), before search_binary_handler(). Probably not the best place, we can do this in exec_mmap() or in start_thread(), or clear it along with PF_FORKNOEXEC. But I think this doesn't matter in practice, and if do_execve() fails kthread should die soon. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: Roland McGrath <roland@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--fs/exec.c1
-rw-r--r--include/linux/init_task.h2
-rw-r--r--include/linux/sched.h1
-rw-r--r--kernel/exit.c2
4 files changed, 4 insertions, 2 deletions
diff --git a/fs/exec.c b/fs/exec.c
index af249af4cca..cd2e8c9b124 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -1326,6 +1326,7 @@ int do_execve(char * filename,
if (retval < 0)
goto out;
+ current->flags &= ~PF_KTHREAD;
retval = search_binary_handler(bprm,regs);
if (retval >= 0) {
/* execve success */
diff --git a/include/linux/init_task.h b/include/linux/init_task.h
index 93c45acf249..021d8e720c7 100644
--- a/include/linux/init_task.h
+++ b/include/linux/init_task.h
@@ -122,7 +122,7 @@ extern struct group_info init_groups;
.state = 0, \
.stack = &init_thread_info, \
.usage = ATOMIC_INIT(2), \
- .flags = 0, \
+ .flags = PF_KTHREAD, \
.lock_depth = -1, \
.prio = MAX_PRIO-20, \
.static_prio = MAX_PRIO-20, \
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 79e749dbf81..eec64a4adb9 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1483,6 +1483,7 @@ static inline void put_task_struct(struct task_struct *t)
#define PF_EXITING 0x00000004 /* getting shut down */
#define PF_EXITPIDONE 0x00000008 /* pi exit done on shut down */
#define PF_VCPU 0x00000010 /* I'm a virtual CPU */
+#define PF_KTHREAD 0x00000020 /* I am a kernel thread */
#define PF_FORKNOEXEC 0x00000040 /* forked but didn't exec */
#define PF_SUPERPRIV 0x00000100 /* used super-user privileges */
#define PF_DUMPCORE 0x00000200 /* dumped core */
diff --git a/kernel/exit.c b/kernel/exit.c
index a7799d8a640..28a44a2612d 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -430,7 +430,7 @@ void daemonize(const char *name, ...)
* We don't want to have TIF_FREEZE set if the system-wide hibernation
* or suspend transition begins right now.
*/
- current->flags |= PF_NOFREEZE;
+ current->flags |= (PF_NOFREEZE | PF_KTHREAD);
if (current->nsproxy != &init_nsproxy) {
get_nsproxy(&init_nsproxy);