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authorAnton Vorontsov <anton.vorontsov@linaro.org>2012-05-31 16:26:26 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2012-05-31 17:49:30 -0700
commit2c922c51e6924298f8271d75732964f1ffdecaf2 (patch)
tree7ce86f8702cdf9ad93ad37064654fa21a43f411b /arch/um/kernel/reboot.c
parent137d1a26c842a384c98dd2a6a605014fddf5c777 (diff)
downloadlinux-stericsson-2c922c51e6924298f8271d75732964f1ffdecaf2.tar.gz
um: properly check all process' threads for a live mm
kill_off_processes() might miss a valid process, this is because checking for process->mm is not enough. Process' main thread may exit or detach its mm via use_mm(), but other threads may still have a valid mm. To catch this we use find_lock_task_mm(), which walks up all threads and returns an appropriate task (with task lock held). Suggested-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Anton Vorontsov <anton.vorontsov@linaro.org> Cc: Richard Weinberger <richard@nod.at> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch/um/kernel/reboot.c')
-rw-r--r--arch/um/kernel/reboot.c13
1 files changed, 7 insertions, 6 deletions
diff --git a/arch/um/kernel/reboot.c b/arch/um/kernel/reboot.c
index 1411f4e79f9a..3d15243ce692 100644
--- a/arch/um/kernel/reboot.c
+++ b/arch/um/kernel/reboot.c
@@ -6,6 +6,7 @@
#include "linux/sched.h"
#include "linux/spinlock.h"
#include "linux/slab.h"
+#include "linux/oom.h"
#include "kern_util.h"
#include "os.h"
#include "skas.h"
@@ -25,13 +26,13 @@ static void kill_off_processes(void)
read_lock(&tasklist_lock);
for_each_process(p) {
- task_lock(p);
- if (!p->mm) {
- task_unlock(p);
+ struct task_struct *t;
+
+ t = find_lock_task_mm(p);
+ if (!t)
continue;
- }
- pid = p->mm->context.id.u.pid;
- task_unlock(p);
+ pid = t->mm->context.id.u.pid;
+ task_unlock(t);
os_kill_ptraced_process(pid, 1);
}
read_unlock(&tasklist_lock);