From 656d9125376006cf696b0836f1c6723a892629ca Mon Sep 17 00:00:00 2001
From: Martin Schwidefsky <schwidefsky@de.ibm.com>
Date: Fri, 17 Feb 2012 10:29:22 +0100
Subject: [S390] 3215 deadlock with tty_wakeup

The 3215 driver calls tty_wakeup from irq context while holding the
device spinlock. If printk is called by any function on the callchain
starting from tty_wakeup the system deadlocks on the device spinlock.
Using a tasklet to call tty_wakup solves the problem.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
---
 drivers/s390/char/con3215.c | 22 +++++++++++++++-------
 1 file changed, 15 insertions(+), 7 deletions(-)

(limited to 'drivers/s390')

diff --git a/drivers/s390/char/con3215.c b/drivers/s390/char/con3215.c
index 934458ad55e5..e71a50d4b221 100644
--- a/drivers/s390/char/con3215.c
+++ b/drivers/s390/char/con3215.c
@@ -87,6 +87,7 @@ struct raw3215_info {
 	struct tty_struct *tty;	      /* pointer to tty structure if present */
 	struct raw3215_req *queued_read; /* pointer to queued read requests */
 	struct raw3215_req *queued_write;/* pointer to queued write requests */
+	struct tasklet_struct tlet;   /* tasklet to invoke tty_wakeup */
 	wait_queue_head_t empty_wait; /* wait queue for flushing */
 	struct timer_list timer;      /* timer for delayed output */
 	int line_pos;		      /* position on the line (for tabs) */
@@ -333,20 +334,24 @@ static inline void raw3215_try_io(struct raw3215_info *raw)
 	}
 }
 
+/*
+ * Call tty_wakeup from tasklet context
+ */
+static void raw3215_wakeup(unsigned long data)
+{
+	struct raw3215_info *raw = (struct raw3215_info *) data;
+	tty_wakeup(raw->tty);
+}
+
 /*
  * Try to start the next IO and wake up processes waiting on the tty.
  */
 static void raw3215_next_io(struct raw3215_info *raw)
 {
-	struct tty_struct *tty;
-
 	raw3215_mk_write_req(raw);
 	raw3215_try_io(raw);
-	tty = raw->tty;
-	if (tty != NULL &&
-	    RAW3215_BUFFER_SIZE - raw->count >= RAW3215_MIN_SPACE) {
-	    	tty_wakeup(tty);
-	}
+	if (raw->tty && RAW3215_BUFFER_SIZE - raw->count >= RAW3215_MIN_SPACE)
+		tasklet_schedule(&raw->tlet);
 }
 
 /*
@@ -682,6 +687,7 @@ static int raw3215_probe (struct ccw_device *cdev)
 		return -ENOMEM;
 	}
 	init_waitqueue_head(&raw->empty_wait);
+	tasklet_init(&raw->tlet, raw3215_wakeup, (unsigned long) raw);
 
 	dev_set_drvdata(&cdev->dev, raw);
 	cdev->handler = raw3215_irq;
@@ -901,6 +907,7 @@ static int __init con3215_init(void)
 
 	raw->flags |= RAW3215_FIXED;
 	init_waitqueue_head(&raw->empty_wait);
+	tasklet_init(&raw->tlet, raw3215_wakeup, (unsigned long) raw);
 
 	/* Request the console irq */
 	if (raw3215_startup(raw) != 0) {
@@ -966,6 +973,7 @@ static void tty3215_close(struct tty_struct *tty, struct file * filp)
 	tty->closing = 1;
 	/* Shutdown the terminal */
 	raw3215_shutdown(raw);
+	tasklet_kill(&raw->tlet);
 	tty->closing = 0;
 	raw->tty = NULL;
 }
-- 
cgit v1.2.3


From 048cd4e51d24ebf7f3552226d03c769d6ad91658 Mon Sep 17 00:00:00 2001
From: Heiko Carstens <heiko.carstens@de.ibm.com>
Date: Mon, 27 Feb 2012 10:01:52 +0100
Subject: compat: fix compile breakage on s390

The new is_compat_task() define for the !COMPAT case in
include/linux/compat.h conflicts with a similar define in
arch/s390/include/asm/compat.h.

This is the minimal patch which fixes the build issues.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
 arch/s390/include/asm/compat.h  | 7 -------
 arch/s390/kernel/process.c      | 1 -
 arch/s390/kernel/ptrace.c       | 2 +-
 arch/s390/kernel/setup.c        | 2 +-
 arch/s390/kernel/signal.c       | 1 -
 arch/s390/mm/fault.c            | 1 -
 arch/s390/mm/mmap.c             | 2 +-
 drivers/s390/block/dasd_eckd.c  | 2 +-
 drivers/s390/block/dasd_ioctl.c | 1 +
 drivers/s390/char/fs3270.c      | 1 +
 drivers/s390/char/vmcp.c        | 1 +
 drivers/s390/cio/chsc_sch.c     | 1 +
 drivers/s390/scsi/zfcp_cfdc.c   | 1 +
 13 files changed, 9 insertions(+), 14 deletions(-)

(limited to 'drivers/s390')

diff --git a/arch/s390/include/asm/compat.h b/arch/s390/include/asm/compat.h
index 2e49748b27da..234f1d859cea 100644
--- a/arch/s390/include/asm/compat.h
+++ b/arch/s390/include/asm/compat.h
@@ -172,13 +172,6 @@ static inline int is_compat_task(void)
 	return is_32bit_task();
 }
 
-#else
-
-static inline int is_compat_task(void)
-{
-	return 0;
-}
-
 #endif
 
 static inline void __user *arch_compat_alloc_user_space(long len)
diff --git a/arch/s390/kernel/process.c b/arch/s390/kernel/process.c
index 4261aa799774..e795933eb2cb 100644
--- a/arch/s390/kernel/process.c
+++ b/arch/s390/kernel/process.c
@@ -29,7 +29,6 @@
 #include <asm/irq.h>
 #include <asm/timer.h>
 #include <asm/nmi.h>
-#include <asm/compat.h>
 #include <asm/smp.h>
 #include "entry.h"
 
diff --git a/arch/s390/kernel/ptrace.c b/arch/s390/kernel/ptrace.c
index 9d82ed4bcb27..61f95489d70c 100644
--- a/arch/s390/kernel/ptrace.c
+++ b/arch/s390/kernel/ptrace.c
@@ -20,8 +20,8 @@
 #include <linux/regset.h>
 #include <linux/tracehook.h>
 #include <linux/seccomp.h>
+#include <linux/compat.h>
 #include <trace/syscall.h>
-#include <asm/compat.h>
 #include <asm/segment.h>
 #include <asm/page.h>
 #include <asm/pgtable.h>
diff --git a/arch/s390/kernel/setup.c b/arch/s390/kernel/setup.c
index 354de0763eff..3b2efc81f34e 100644
--- a/arch/s390/kernel/setup.c
+++ b/arch/s390/kernel/setup.c
@@ -46,6 +46,7 @@
 #include <linux/kexec.h>
 #include <linux/crash_dump.h>
 #include <linux/memory.h>
+#include <linux/compat.h>
 
 #include <asm/ipl.h>
 #include <asm/uaccess.h>
@@ -59,7 +60,6 @@
 #include <asm/ptrace.h>
 #include <asm/sections.h>
 #include <asm/ebcdic.h>
-#include <asm/compat.h>
 #include <asm/kvm_virtio.h>
 #include <asm/diag.h>
 
diff --git a/arch/s390/kernel/signal.c b/arch/s390/kernel/signal.c
index a8ba840294ff..2d421d90fada 100644
--- a/arch/s390/kernel/signal.c
+++ b/arch/s390/kernel/signal.c
@@ -30,7 +30,6 @@
 #include <asm/ucontext.h>
 #include <asm/uaccess.h>
 #include <asm/lowcore.h>
-#include <asm/compat.h>
 #include "entry.h"
 
 #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
diff --git a/arch/s390/mm/fault.c b/arch/s390/mm/fault.c
index 354dd39073ef..e8fcd928dc78 100644
--- a/arch/s390/mm/fault.c
+++ b/arch/s390/mm/fault.c
@@ -36,7 +36,6 @@
 #include <asm/pgtable.h>
 #include <asm/irq.h>
 #include <asm/mmu_context.h>
-#include <asm/compat.h>
 #include "../kernel/entry.h"
 
 #ifndef CONFIG_64BIT
diff --git a/arch/s390/mm/mmap.c b/arch/s390/mm/mmap.c
index f09c74881b7e..a0155c02e324 100644
--- a/arch/s390/mm/mmap.c
+++ b/arch/s390/mm/mmap.c
@@ -29,8 +29,8 @@
 #include <linux/mman.h>
 #include <linux/module.h>
 #include <linux/random.h>
+#include <linux/compat.h>
 #include <asm/pgalloc.h>
-#include <asm/compat.h>
 
 static unsigned long stack_maxrandom_size(void)
 {
diff --git a/drivers/s390/block/dasd_eckd.c b/drivers/s390/block/dasd_eckd.c
index 70880be26015..2617b1ed4709 100644
--- a/drivers/s390/block/dasd_eckd.c
+++ b/drivers/s390/block/dasd_eckd.c
@@ -18,12 +18,12 @@
 #include <linux/hdreg.h>	/* HDIO_GETGEO			    */
 #include <linux/bio.h>
 #include <linux/module.h>
+#include <linux/compat.h>
 #include <linux/init.h>
 
 #include <asm/debug.h>
 #include <asm/idals.h>
 #include <asm/ebcdic.h>
-#include <asm/compat.h>
 #include <asm/io.h>
 #include <asm/uaccess.h>
 #include <asm/cio.h>
diff --git a/drivers/s390/block/dasd_ioctl.c b/drivers/s390/block/dasd_ioctl.c
index f1a2016829fc..792c69e78fe2 100644
--- a/drivers/s390/block/dasd_ioctl.c
+++ b/drivers/s390/block/dasd_ioctl.c
@@ -13,6 +13,7 @@
 #define KMSG_COMPONENT "dasd"
 
 #include <linux/interrupt.h>
+#include <linux/compat.h>
 #include <linux/major.h>
 #include <linux/fs.h>
 #include <linux/blkpg.h>
diff --git a/drivers/s390/char/fs3270.c b/drivers/s390/char/fs3270.c
index e71298158f9e..911704571b9c 100644
--- a/drivers/s390/char/fs3270.c
+++ b/drivers/s390/char/fs3270.c
@@ -11,6 +11,7 @@
 #include <linux/console.h>
 #include <linux/init.h>
 #include <linux/interrupt.h>
+#include <linux/compat.h>
 #include <linux/module.h>
 #include <linux/list.h>
 #include <linux/slab.h>
diff --git a/drivers/s390/char/vmcp.c b/drivers/s390/char/vmcp.c
index 75bde6a8b7dc..89c03e6b1c0c 100644
--- a/drivers/s390/char/vmcp.c
+++ b/drivers/s390/char/vmcp.c
@@ -13,6 +13,7 @@
 
 #include <linux/fs.h>
 #include <linux/init.h>
+#include <linux/compat.h>
 #include <linux/kernel.h>
 #include <linux/miscdevice.h>
 #include <linux/slab.h>
diff --git a/drivers/s390/cio/chsc_sch.c b/drivers/s390/cio/chsc_sch.c
index 0c87b0fc7714..8f9a1a384496 100644
--- a/drivers/s390/cio/chsc_sch.c
+++ b/drivers/s390/cio/chsc_sch.c
@@ -8,6 +8,7 @@
  */
 
 #include <linux/slab.h>
+#include <linux/compat.h>
 #include <linux/device.h>
 #include <linux/module.h>
 #include <linux/uaccess.h>
diff --git a/drivers/s390/scsi/zfcp_cfdc.c b/drivers/s390/scsi/zfcp_cfdc.c
index 303dde09d294..fab2c2592a97 100644
--- a/drivers/s390/scsi/zfcp_cfdc.c
+++ b/drivers/s390/scsi/zfcp_cfdc.c
@@ -11,6 +11,7 @@
 #define KMSG_COMPONENT "zfcp"
 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
 
+#include <linux/compat.h>
 #include <linux/slab.h>
 #include <linux/types.h>
 #include <linux/miscdevice.h>
-- 
cgit v1.2.3