From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Date: Tue, 3 Mar 2020 16:34:32 +0000 (+0100)
Subject: 4.4-stable patches
X-Git-Tag: v4.19.108~17
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=ff9b166a2cf494680ab2c24da8f3a8c17ded88e1;p=thirdparty%2Fkernel%2Fstable-queue.git

4.4-stable patches

added patches:
	padata-always-acquire-cpu_hotplug_lock-before-pinst-lock.patch
---

diff --git a/queue-4.4/padata-always-acquire-cpu_hotplug_lock-before-pinst-lock.patch b/queue-4.4/padata-always-acquire-cpu_hotplug_lock-before-pinst-lock.patch
new file mode 100644
index 00000000000..c66528fd091
--- /dev/null
+++ b/queue-4.4/padata-always-acquire-cpu_hotplug_lock-before-pinst-lock.patch
@@ -0,0 +1,67 @@
+From 38228e8848cd7dd86ccb90406af32de0cad24be3 Mon Sep 17 00:00:00 2001
+From: Daniel Jordan <daniel.m.jordan@oracle.com>
+Date: Tue, 3 Dec 2019 14:31:11 -0500
+Subject: padata: always acquire cpu_hotplug_lock before pinst->lock
+
+From: Daniel Jordan <daniel.m.jordan@oracle.com>
+
+commit 38228e8848cd7dd86ccb90406af32de0cad24be3 upstream.
+
+lockdep complains when padata's paths to update cpumasks via CPU hotplug
+and sysfs are both taken:
+
+  # echo 0 > /sys/devices/system/cpu/cpu1/online
+  # echo ff > /sys/kernel/pcrypt/pencrypt/parallel_cpumask
+
+  ======================================================
+  WARNING: possible circular locking dependency detected
+  5.4.0-rc8-padata-cpuhp-v3+ #1 Not tainted
+  ------------------------------------------------------
+  bash/205 is trying to acquire lock:
+  ffffffff8286bcd0 (cpu_hotplug_lock.rw_sem){++++}, at: padata_set_cpumask+0x2b/0x120
+
+  but task is already holding lock:
+  ffff8880001abfa0 (&pinst->lock){+.+.}, at: padata_set_cpumask+0x26/0x120
+
+  which lock already depends on the new lock.
+
+padata doesn't take cpu_hotplug_lock and pinst->lock in a consistent
+order.  Which should be first?  CPU hotplug calls into padata with
+cpu_hotplug_lock already held, so it should have priority.
+
+Fixes: 6751fb3c0e0c ("padata: Use get_online_cpus/put_online_cpus")
+Signed-off-by: Daniel Jordan <daniel.m.jordan@oracle.com>
+Cc: Eric Biggers <ebiggers@kernel.org>
+Cc: Herbert Xu <herbert@gondor.apana.org.au>
+Cc: Steffen Klassert <steffen.klassert@secunet.com>
+Cc: linux-crypto@vger.kernel.org
+Cc: linux-kernel@vger.kernel.org
+Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+
+---
+ kernel/padata.c |    4 ++--
+ 1 file changed, 2 insertions(+), 2 deletions(-)
+
+--- a/kernel/padata.c
++++ b/kernel/padata.c
+@@ -640,8 +640,8 @@ int padata_set_cpumask(struct padata_ins
+ 	struct cpumask *serial_mask, *parallel_mask;
+ 	int err = -EINVAL;
+ 
+-	mutex_lock(&pinst->lock);
+ 	get_online_cpus();
++	mutex_lock(&pinst->lock);
+ 
+ 	switch (cpumask_type) {
+ 	case PADATA_CPU_PARALLEL:
+@@ -659,8 +659,8 @@ int padata_set_cpumask(struct padata_ins
+ 	err =  __padata_set_cpumasks(pinst, parallel_mask, serial_mask);
+ 
+ out:
+-	put_online_cpus();
+ 	mutex_unlock(&pinst->lock);
++	put_online_cpus();
+ 
+ 	return err;
+ }
diff --git a/queue-4.4/series b/queue-4.4/series
index bf0c18fb2eb..99d230b1cb1 100644
--- a/queue-4.4/series
+++ b/queue-4.4/series
@@ -37,3 +37,4 @@ mm-gup-ensure-real-head-page-is-ref-counted-when-using-hugepages.patch
 mm-prevent-get_user_pages-from-overflowing-page-refcount.patch
 pipe-add-pipe_buf_get-helper.patch
 fs-prevent-page-refcount-overflow-in-pipe_buf_get.patch
+padata-always-acquire-cpu_hotplug_lock-before-pinst-lock.patch