The patch titled
Subject: um: should hold tasklist_lock while traversing processes
has been added to the -mm tree. Its filename is
um-should-hold-tasklist_lock-while-traversing-processes.patch
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From: Anton Vorontsov <anton.vorontsov@xxxxxxxxxx>
Subject: um: should hold tasklist_lock while traversing processes
Traversing the tasks requires holding tasklist_lock, otherwise it is
unsafe.
p.s. However, I'm not sure that calling os_kill_ptraced_process() in the
atomic context is correct. It seem to work, but please take a closer
look.
Signed-off-by: Anton Vorontsov <anton.vorontsov@xxxxxxxxxx>
Cc: Richard Weinberger <richard@xxxxxx>
Cc: Oleg Nesterov <oleg@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
arch/um/kernel/reboot.c | 3 +++
1 file changed, 3 insertions(+)
diff -puN arch/um/kernel/reboot.c~um-should-hold-tasklist_lock-while-traversing-processes arch/um/kernel/reboot.c
--- a/arch/um/kernel/reboot.c~um-should-hold-tasklist_lock-while-traversing-processes
+++ a/arch/um/kernel/reboot.c
@@ -4,6 +4,7 @@
*/
#include "linux/sched.h"
+#include "linux/spinlock.h"
#include "linux/slab.h"
#include "kern_util.h"
#include "os.h"
@@ -22,6 +23,7 @@ static void kill_off_processes(void)
struct task_struct *p;
int pid;
+ read_lock(&tasklist_lock);
for_each_process(p) {
if (p->mm == NULL)
continue;
@@ -29,6 +31,7 @@ static void kill_off_processes(void)
pid = p->mm->context.id.u.pid;
os_kill_ptraced_process(pid, 1);
}
+ read_unlock(&tasklist_lock);
}
}
_
Subject: Subject: um: should hold tasklist_lock while traversing processes
Patches currently in -mm which might be from anton.vorontsov@xxxxxxxxxx are
cpu-introduce-clear_tasks_mm_cpumask-helper.patch
arm-use-clear_tasks_mm_cpumask.patch
powerpc-use-clear_tasks_mm_cpumask.patch
sh-use-clear_tasks_mm_cpumask.patch
blackfin-a-couple-of-task-mm-handling-fixes.patch
blackfin-fix-possible-deadlock-in-decode_address.patch
um-should-hold-tasklist_lock-while-traversing-processes.patch
um-fix-possible-race-on-task-mm.patch
um-properly-check-all-process-threads-for-a-live-mm.patch
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