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authorOleg Nesterov <oleg@redhat.com>2015-11-06 16:32:25 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2015-11-06 17:50:42 -0800
commit9a13049e83f346cb1cbd60c64e520a73c396af16 (patch)
tree11a2ac2ac28dbfa477d5b4f1e14a2173b4867a8f
parentbe0e6f290f78b84a3b21b8c8c46819c4514fe632 (diff)
downloadlinux-9a13049e83f346cb1cbd60c64e520a73c396af16.tar.bz2
signal: introduce kernel_signal_stop() to fix jffs2_garbage_collect_thread()
jffs2_garbage_collect_thread() can race with SIGCONT and sleep in TASK_STOPPED state after it was already sent. Add the new helper, kernel_signal_stop(), which does this correctly. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Reviewed-by: Tejun Heo <tj@kernel.org> Cc: David Woodhouse <dwmw2@infradead.org> Cc: Felipe Balbi <balbi@ti.com> Cc: Markus Pargmann <mpa@pengutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--fs/jffs2/background.c3
-rw-r--r--include/linux/sched.h10
2 files changed, 11 insertions, 2 deletions
diff --git a/fs/jffs2/background.c b/fs/jffs2/background.c
index f3145fd86d86..53cc7350af33 100644
--- a/fs/jffs2/background.c
+++ b/fs/jffs2/background.c
@@ -132,8 +132,7 @@ static int jffs2_garbage_collect_thread(void *_c)
case SIGSTOP:
jffs2_dbg(1, "%s(): SIGSTOP received\n",
__func__);
- set_current_state(TASK_STOPPED);
- schedule();
+ kernel_signal_stop();
break;
case SIGKILL:
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 3d54924b4b86..4069febaa34a 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -2475,6 +2475,16 @@ static inline int kernel_dequeue_signal(siginfo_t *info)
return ret;
}
+static inline void kernel_signal_stop(void)
+{
+ spin_lock_irq(&current->sighand->siglock);
+ if (current->jobctl & JOBCTL_STOP_DEQUEUED)
+ __set_current_state(TASK_STOPPED);
+ spin_unlock_irq(&current->sighand->siglock);
+
+ schedule();
+}
+
extern void release_task(struct task_struct * p);
extern int send_sig_info(int, struct siginfo *, struct task_struct *);
extern int force_sigsegv(int, struct task_struct *);