Use write_trylock_irqsave in ptrace_attach

This patch makes ptrace_attach use write_trylock_irqsave().

[akpm@linux-foundation.org: remove unneeded initialisation]
Signed-off-by: Sripathi Kodi <sripathik@in.ibm.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 3 insertions, 4 deletions

diff --git a/kernel/ptrace.c b/kernel/ptrace.c
index ad7949a589dd..b1d11f1c7cf7 100644
--- a/kernel/ptrace.c
+++ b/kernel/ptrace.c
@@ -161,6 +161,7 @@ int ptrace_may_attach(struct task_struct *task)
 int ptrace_attach(struct task_struct *task)
 {
         int retval;
+        unsigned long flags;
 
         audit_ptrace(task);
 
@@ -181,9 +182,7 @@ repeat:
          * cpu's that may have task_lock).
          */
         task_lock(task);
-        local_irq_disable();
-        if (!write_trylock(&tasklist_lock)) {
-                local_irq_enable();
+        if (!write_trylock_irqsave(&tasklist_lock, flags)) {
                 task_unlock(task);
                 do {
                         cpu_relax();
@@ -211,7 +210,7 @@ repeat:
         force_sig_specific(SIGSTOP, task);
 
 bad:
-        write_unlock_irq(&tasklist_lock);
+        write_unlock_irqrestore(&tasklist_lock, flags);
         task_unlock(task);
 out:
         return retval;