[PATCH RT 03/10] random: avoid preempt_disable()ed section

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



4.4.97-rt111-rc2 stable review patch.
If anyone has any objections, please let me know.

------------------

From: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>

extract_crng() will use sleeping locks while in a preempt_disable()
section due to get_cpu_var().
Work around it with local_locks.

Cc: stable-rt@xxxxxxxxxxxxxxx # where it applies to
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
Signed-off-by: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx>
---
 drivers/char/random.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/drivers/char/random.c b/drivers/char/random.c
index fecc40a69df8..b41745c5962c 100644
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -260,6 +260,7 @@
 #include <linux/irq.h>
 #include <linux/syscalls.h>
 #include <linux/completion.h>
+#include <linux/locallock.h>
 
 #include <asm/processor.h>
 #include <asm/uaccess.h>
@@ -1796,6 +1797,7 @@ int random_int_secret_init(void)
 
 static DEFINE_PER_CPU(__u32 [MD5_DIGEST_WORDS], get_random_int_hash)
 		__aligned(sizeof(unsigned long));
+static DEFINE_LOCAL_IRQ_LOCK(hash_entropy_int_lock);
 
 /*
  * Get a random word for internal kernel use only. Similar to urandom but
@@ -1811,12 +1813,12 @@ unsigned int get_random_int(void)
 	if (arch_get_random_int(&ret))
 		return ret;
 
-	hash = get_cpu_var(get_random_int_hash);
+	hash = &get_locked_var(hash_entropy_int_lock, get_random_int_hash);
 
 	hash[0] += current->pid + jiffies + random_get_entropy();
 	md5_transform(hash, random_int_secret);
 	ret = hash[0];
-	put_cpu_var(get_random_int_hash);
+	put_locked_var(hash_entropy_int_lock, get_random_int_hash);
 
 	return ret;
 }
@@ -1833,12 +1835,12 @@ unsigned long get_random_long(void)
 	if (arch_get_random_long(&ret))
 		return ret;
 
-	hash = get_cpu_var(get_random_int_hash);
+	hash = &get_locked_var(hash_entropy_int_lock, get_random_int_hash);
 
 	hash[0] += current->pid + jiffies + random_get_entropy();
 	md5_transform(hash, random_int_secret);
 	ret = *(unsigned long *)hash;
-	put_cpu_var(get_random_int_hash);
+	put_locked_var(hash_entropy_int_lock, get_random_int_hash);
 
 	return ret;
 }
-- 
2.13.2


--
To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html



[Index of Archives]     [RT Stable]     [Kernel Newbies]     [IDE]     [Security]     [Git]     [Netfilter]     [Bugtraq]     [Yosemite]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Linux ATA RAID]     [Samba]     [Video 4 Linux]     [Device Mapper]

  Powered by Linux