From 5c660b610b258c62739e58ceb18d238d19932b36 Mon Sep 17 00:00:00 2001
From: Stanislav Kozina <skozina@redhat.com>
Date: Thu, 9 Aug 2012 14:48:58 +0100
Subject: [PATCH] --- yaml --- r: 325631 b: refs/heads/master c:
 00aaae033e323af33740e7012a8ba4b0fa6dce20 h: refs/heads/master i:   325629:
 76c99ffe8e0700863614013e9187df7eb90e34d7   325627:
 05845ce99826805fa4b07549f121735379e2a0c5   325623:
 af4a4dee27a6b8ce1be4bb2b3ea73a388b80921d   325615:
 417b77f0485c3c197fce70afdb22e43fd5a8fd65   325599:
 ed92331c3fb46d5be1d00ab5a52c1daa31957146   325567:
 cf75ad9345ea3ed5cff4f9d03b56320974d79fb3   325503:
 7aa9e09e540bb44c18932f5b65c046977a3ec79b   325375:
 eaca102308de1c3c6db6a2d9f4e40bb8b7542555   325119:
 4aef51d4ae2409b6d3dac340003bbf48582c0b5b   324607:
 3e275cd4f18a97bb227afd80f3923e91e3e4b40f   323583:
 375e9e592b0105b5df2a309561edfe803bd6ef7b v: v3

---
 [refs]                    | 2 +-
 trunk/drivers/tty/n_tty.c | 6 +++++-
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/[refs] b/[refs]
index 0ce1fa8d1d11..52495e71f97a 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 857196e2758f01ec40f93429013963ca5f22cbae
+refs/heads/master: 00aaae033e323af33740e7012a8ba4b0fa6dce20
diff --git a/trunk/drivers/tty/n_tty.c b/trunk/drivers/tty/n_tty.c
index 101790cea4ae..20de673a7730 100644
--- a/trunk/drivers/tty/n_tty.c
+++ b/trunk/drivers/tty/n_tty.c
@@ -1838,13 +1838,13 @@ static ssize_t n_tty_read(struct tty_struct *tty, struct file *file,
 
 		if (tty->icanon && !L_EXTPROC(tty)) {
 			/* N.B. avoid overrun if nr == 0 */
+			spin_lock_irqsave(&tty->read_lock, flags);
 			while (nr && tty->read_cnt) {
 				int eol;
 
 				eol = test_and_clear_bit(tty->read_tail,
 						tty->read_flags);
 				c = tty->read_buf[tty->read_tail];
-				spin_lock_irqsave(&tty->read_lock, flags);
 				tty->read_tail = ((tty->read_tail+1) &
 						  (N_TTY_BUF_SIZE-1));
 				tty->read_cnt--;
@@ -1862,15 +1862,19 @@ static ssize_t n_tty_read(struct tty_struct *tty, struct file *file,
 					if (tty_put_user(tty, c, b++)) {
 						retval = -EFAULT;
 						b--;
+						spin_lock_irqsave(&tty->read_lock, flags);
 						break;
 					}
 					nr--;
 				}
 				if (eol) {
 					tty_audit_push(tty);
+					spin_lock_irqsave(&tty->read_lock, flags);
 					break;
 				}
+				spin_lock_irqsave(&tty->read_lock, flags);
 			}
+			spin_unlock_irqrestore(&tty->read_lock, flags);
 			if (retval)
 				break;
 		} else {