From mboxrd@z Thu Jan 1 00:00:00 1970 From: Steven Rostedt Subject: [PATCH RT 02/13] random: avoid preempt_disable()ed section Date: Wed, 17 Jan 2018 10:14:06 -0500 Message-ID: <20180117151430.804706484@goodmis.org> References: <20180117151404.093229667@goodmis.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Cc: Thomas Gleixner , Carsten Emde , Sebastian Andrzej Siewior , John Kacur , Paul Gortmaker , Julia Cartwright , Daniel Wagner , tom.zanussi@linux.intel.com, Alex Shi To: linux-kernel@vger.kernel.org, linux-rt-users Return-path: Content-Disposition: inline; filename=0002-random-avoid-preempt_disable-ed-section.patch Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-rt-users.vger.kernel.org 3.18.91-rt98-rc1 stable review patch. If anyone has any objections, please let me know. ------------------ From: Sebastian Andrzej Siewior 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@vger.kernel.org # where it applies to Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Steven Rostedt (VMware) --- 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 acb8e7c218d1..06c4b06fcea0 100644 --- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -260,6 +260,7 @@ #include #include #include +#include #include #include @@ -1712,6 +1713,7 @@ 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 @@ -1727,12 +1729,12 @@ 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; } @@ -1749,12 +1751,12 @@ 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