add spinlock patch

6 files changed, 118 insertions, 5 deletions

diff --git a/00-kmsg-spinlock_irq.patch b/00-kmsg-spinlock_irq.patch
new file mode 100644
index 0000000..7271015
--- /dev/null
+++ b/00-kmsg-spinlock_irq.patch
@@ -0,0 +1,112 @@
+From: liu chuansheng <chuansheng.liu@intel.com>
+Subject: [PATCH] printk: replacing the raw_spin_lock/unlock with raw_spin_lock/unlock_irq
+
+In function devkmsg_read/writev/llseek/poll/open()..., the function
+raw_spin_lock/unlock is used, there is potential deadlock case happening.
+CPU1: thread1 doing the cat /dev/kmsg:
+        raw_spin_lock(&logbuf_lock);
+        while (user->seq == log_next_seq) {
+when thread1 run here, at this time one interrupt is coming on CPU1 and running
+based on this thread,if the interrupt handle called the printk which need the
+logbuf_lock spin also, it will cause deadlock.
+
+So we should use raw_spin_lock/unlock_irq here.
+
+Signed-off-by: liu chuansheng <chuansheng.liu@intel.com>
+---
+ kernel/printk.c |   24 ++++++++++++------------
+ 1 file changed, 12 insertions(+), 12 deletions(-)
+
+--- a/kernel/printk.c
++++ b/kernel/printk.c
+@@ -430,20 +430,20 @@ static ssize_t devkmsg_read(struct file
+ 	ret = mutex_lock_interruptible(&user->lock);
+ 	if (ret)
+ 		return ret;
+-	raw_spin_lock(&logbuf_lock);
++	raw_spin_lock_irq(&logbuf_lock);
+ 	while (user->seq == log_next_seq) {
+ 		if (file->f_flags & O_NONBLOCK) {
+ 			ret = -EAGAIN;
+-			raw_spin_unlock(&logbuf_lock);
++			raw_spin_unlock_irq(&logbuf_lock);
+ 			goto out;
+ 		}
+ 
+-		raw_spin_unlock(&logbuf_lock);
++		raw_spin_unlock_irq(&logbuf_lock);
+ 		ret = wait_event_interruptible(log_wait,
+ 					       user->seq != log_next_seq);
+ 		if (ret)
+ 			goto out;
+-		raw_spin_lock(&logbuf_lock);
++		raw_spin_lock_irq(&logbuf_lock);
+ 	}
+ 
+ 	if (user->seq < log_first_seq) {
+@@ -451,7 +451,7 @@ static ssize_t devkmsg_read(struct file
+ 		user->idx = log_first_idx;
+ 		user->seq = log_first_seq;
+ 		ret = -EPIPE;
+-		raw_spin_unlock(&logbuf_lock);
++		raw_spin_unlock_irq(&logbuf_lock);
+ 		goto out;
+ 	}
+ 
+@@ -501,7 +501,7 @@ static ssize_t devkmsg_read(struct file
+ 
+ 	user->idx = log_next(user->idx);
+ 	user->seq++;
+-	raw_spin_unlock(&logbuf_lock);
++	raw_spin_unlock_irq(&logbuf_lock);
+ 
+ 	if (len > count) {
+ 		ret = -EINVAL;
+@@ -528,7 +528,7 @@ static loff_t devkmsg_llseek(struct file
+ 	if (offset)
+ 		return -ESPIPE;
+ 
+-	raw_spin_lock(&logbuf_lock);
++	raw_spin_lock_irq(&logbuf_lock);
+ 	switch (whence) {
+ 	case SEEK_SET:
+ 		/* the first record */
+@@ -552,7 +552,7 @@ static loff_t devkmsg_llseek(struct file
+ 	default:
+ 		ret = -EINVAL;
+ 	}
+-	raw_spin_unlock(&logbuf_lock);
++	raw_spin_unlock_irq(&logbuf_lock);
+ 	return ret;
+ }
+ 
+@@ -566,14 +566,14 @@ static unsigned int devkmsg_poll(struct
+ 
+ 	poll_wait(file, &log_wait, wait);
+ 
+-	raw_spin_lock(&logbuf_lock);
++	raw_spin_lock_irq(&logbuf_lock);
+ 	if (user->seq < log_next_seq) {
+ 		/* return error when data has vanished underneath us */
+ 		if (user->seq < log_first_seq)
+ 			ret = POLLIN|POLLRDNORM|POLLERR|POLLPRI;
+ 		ret = POLLIN|POLLRDNORM;
+ 	}
+-	raw_spin_unlock(&logbuf_lock);
++	raw_spin_unlock_irq(&logbuf_lock);
+ 
+ 	return ret;
+ }
+@@ -597,10 +597,10 @@ static int devkmsg_open(struct inode *in
+ 
+ 	mutex_init(&user->lock);
+ 
+-	raw_spin_lock(&logbuf_lock);
++	raw_spin_lock_irq(&logbuf_lock);
+ 	user->idx = log_first_idx;
+ 	user->seq = log_first_seq;
+-	raw_spin_unlock(&logbuf_lock);
++	raw_spin_unlock_irq(&logbuf_lock);
+ 
+ 	file->private_data = user;
+ 	return 0;
diff --git a/kmsg-escape.patch b/01-kmsg-escape.patch
index 7a01496..7a01496 100644
--- a/kmsg-escape.patch
+++ b/01-kmsg-escape.patch
diff --git a/kmsg-facility-len.patch b/02-kmsg-facility-len.patch
index 70fd915..70fd915 100644
--- a/kmsg-facility-len.patch
+++ b/02-kmsg-facility-len.patch
diff --git a/kmsg-nonblock-race.patch b/03-kmsg-nonblock-race.patch
index 6e766f2..6e766f2 100644
--- a/kmsg-nonblock-race.patch
+++ b/03-kmsg-nonblock-race.patch
diff --git a/kmsg-cons-fix.patch b/04-kmsg-cons-fix.patch
index 1109747..1109747 100644
--- a/kmsg-cons-fix.patch
+++ b/04-kmsg-cons-fix.patch
diff --git a/series b/series
index f23d26f..fb9a0a1 100644
--- a/series
+++ b/series
@@ -1,5 +1,6 @@
-kmsg-escape.patch
-kmsg-facility-len.patch
-kmsg-nonblock-race.patch
-test-modules.patch
-kmsg-cons-fix.patch
+#test-modules.patch
+00-kmsg-spinlock_irq.patch
+01-kmsg-escape.patch
+02-kmsg-facility-len.patch
+03-kmsg-nonblock-race.patch
+04-kmsg-cons-fix.patch