Commit 7b34e428 authored by Oleg Nesterov's avatar Oleg Nesterov Committed by Linus Torvalds

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: default avatarOleg Nesterov <oleg@tv-sign.ru>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 3d749b9e
...@@ -1326,6 +1326,7 @@ int do_execve(char * filename, ...@@ -1326,6 +1326,7 @@ int do_execve(char * filename,
if (retval < 0) if (retval < 0)
goto out; goto out;
current->flags &= ~PF_KTHREAD;
retval = search_binary_handler(bprm,regs); retval = search_binary_handler(bprm,regs);
if (retval >= 0) { if (retval >= 0) {
/* execve success */ /* execve success */
......
...@@ -122,7 +122,7 @@ extern struct group_info init_groups; ...@@ -122,7 +122,7 @@ extern struct group_info init_groups;
.state = 0, \ .state = 0, \
.stack = &init_thread_info, \ .stack = &init_thread_info, \
.usage = ATOMIC_INIT(2), \ .usage = ATOMIC_INIT(2), \
.flags = 0, \ .flags = PF_KTHREAD, \
.lock_depth = -1, \ .lock_depth = -1, \
.prio = MAX_PRIO-20, \ .prio = MAX_PRIO-20, \
.static_prio = MAX_PRIO-20, \ .static_prio = MAX_PRIO-20, \
......
...@@ -1483,6 +1483,7 @@ static inline void put_task_struct(struct task_struct *t) ...@@ -1483,6 +1483,7 @@ static inline void put_task_struct(struct task_struct *t)
#define PF_EXITING 0x00000004 /* getting shut down */ #define PF_EXITING 0x00000004 /* getting shut down */
#define PF_EXITPIDONE 0x00000008 /* pi exit done on shut down */ #define PF_EXITPIDONE 0x00000008 /* pi exit done on shut down */
#define PF_VCPU 0x00000010 /* I'm a virtual CPU */ #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_FORKNOEXEC 0x00000040 /* forked but didn't exec */
#define PF_SUPERPRIV 0x00000100 /* used super-user privileges */ #define PF_SUPERPRIV 0x00000100 /* used super-user privileges */
#define PF_DUMPCORE 0x00000200 /* dumped core */ #define PF_DUMPCORE 0x00000200 /* dumped core */
......
...@@ -430,7 +430,7 @@ void daemonize(const char *name, ...) ...@@ -430,7 +430,7 @@ void daemonize(const char *name, ...)
* We don't want to have TIF_FREEZE set if the system-wide hibernation * We don't want to have TIF_FREEZE set if the system-wide hibernation
* or suspend transition begins right now. * or suspend transition begins right now.
*/ */
current->flags |= PF_NOFREEZE; current->flags |= (PF_NOFREEZE | PF_KTHREAD);
if (current->nsproxy != &init_nsproxy) { if (current->nsproxy != &init_nsproxy) {
get_nsproxy(&init_nsproxy); get_nsproxy(&init_nsproxy);
......
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