From: Ingo Molnar <mingo@elte.hu>
Date: Fri, 7 Mar 2008 09:47:43 +0000 (+0100)
Subject: drivers/char/esp.c: fix bootup lockup
X-Git-Tag: v2.6.25-rc5~15
X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=80d38f9a7871d9bafc3f244dabe48b41a58de705;p=linux-2.6

drivers/char/esp.c: fix bootup lockup

randconfig testing found a bootup lockup in drivers/char/esp.c because
of a spinlock that wasn't correctly initialized.

I'm not sure why it became more prominent in 2.6.25-rc4, the bug seems
rather old and i've been doing allyesconfig bootups for ages with
CONFIG_ESP enabled.

This fixes this bootup lockup:

 PM: Adding info for No Bus:ttyP63
 ttyP32 at 0x0240 (irq = 0) is an ESP primary port
 BUG: spinlock lockup on CPU#0, swapper/1, f56dd004
 Pid: 1, comm: swapper Not tainted 2.6.25-rc4-sched-devel.git-x86-latest.git #402 [<c03ac6f4>] _raw_spin_lock+0x134/0x140
  [<c08649be>] _spin_lock_irqsave+0x5e/0x80
  [<c0b9fbfe>] ? espserial_init+0x2be/0x6e0
  [<c0b9fbfe>] espserial_init+0x2be/0x6e0
  [<c0b877a3>] kernel_init+0x83/0x260
  [<c0b9f940>] ? espserial_init+0x0/0x6e0
  [<c010416a>] ? restore_nocheck_notrace+0x0/0xe
  [<c0b87720>] ? kernel_init+0x0/0x260
  [<c0b87720>] ? kernel_init+0x0/0x260
  [<c0104507>] kernel_thread_helper+0x7/0x10
  =======================

kzalloc() is not the way to initialize spinlocks anymore.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---

diff --git a/drivers/char/esp.c b/drivers/char/esp.c
index c01e26d9ee..f3fe620673 100644
--- a/drivers/char/esp.c
+++ b/drivers/char/esp.c
@@ -2484,6 +2484,7 @@ static int __init espserial_init(void)
 			return 0;
 		}
 
+		spin_lock_init(&info->lock);
 		/* rx_trigger, tx_trigger are needed by autoconfig */
 		info->config.rx_trigger = rx_trigger;
 		info->config.tx_trigger = tx_trigger;