4.9-stable patches

added patches:
	zswap-don-t-param_set_charp-while-holding-spinlock.patch

diff --git a/queue-4.9/series b/queue-4.9/series
index e111a51dd5419b4f363dc3501902d5726dd59c81..f9d4e8a59062ecca518410d49a879d2fb8262028 100644 (file)
--- a/queue-4.9/series
+++ b/queue-4.9/series
@@ -22,3 +22,4 @@ alsa-aloop-release-cable-upon-open-error-path.patch
 alsa-aloop-fix-inconsistent-format-due-to-incomplete-rule.patch
 alsa-aloop-fix-racy-hw-constraints-adjustment.patch
 x86-acpi-reduce-code-duplication-in-mp_override_legacy_irq.patch
+zswap-don-t-param_set_charp-while-holding-spinlock.patch

diff --git a/queue-4.9/zswap-don-t-param_set_charp-while-holding-spinlock.patch b/queue-4.9/zswap-don-t-param_set_charp-while-holding-spinlock.patch
new file mode 100644 (file)
index 0000000..0dc8e26
--- /dev/null
+++ b/queue-4.9/zswap-don-t-param_set_charp-while-holding-spinlock.patch
@@ -0,0 +1,63 @@
+From fd5bb66cd934987e49557455b6497fc006521940 Mon Sep 17 00:00:00 2001
+From: Dan Streetman <ddstreet@ieee.org>
+Date: Mon, 27 Feb 2017 14:26:53 -0800
+Subject: zswap: don't param_set_charp while holding spinlock
+
+From: Dan Streetman <ddstreet@ieee.org>
+
+commit fd5bb66cd934987e49557455b6497fc006521940 upstream.
+
+Change the zpool/compressor param callback function to release the
+zswap_pools_lock spinlock before calling param_set_charp, since that
+function may sleep when it calls kmalloc with GFP_KERNEL.
+
+While this problem has existed for a while, I wasn't able to trigger it
+using a tight loop changing either/both the zpool and compressor params; I
+think it's very unlikely to be an issue on the stable kernels, especially
+since most zswap users will change the compressor and/or zpool from sysfs
+only one time each boot - or zero times, if they add the params to the
+kernel boot.
+
+Fixes: c99b42c3529e ("zswap: use charp for zswap param strings")
+Link: http://lkml.kernel.org/r/20170126155821.4545-1-ddstreet@ieee.org
+Signed-off-by: Dan Streetman <dan.streetman@canonical.com>
+Reported-by: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
+Cc: Michal Hocko <mhocko@kernel.org>
+Cc: Minchan Kim <minchan@kernel.org>
+Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
+Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
+Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ mm/zswap.c |   12 ++++++++----
+ 1 file changed, 8 insertions(+), 4 deletions(-)
+
+--- a/mm/zswap.c
++++ b/mm/zswap.c
+@@ -752,18 +752,22 @@ static int __zswap_param_set(const char
+       pool = zswap_pool_find_get(type, compressor);
+       if (pool) {
+               zswap_pool_debug("using existing", pool);
++              WARN_ON(pool == zswap_pool_current());
+               list_del_rcu(&pool->list);
+-      } else {
+-              spin_unlock(&zswap_pools_lock);
+-              pool = zswap_pool_create(type, compressor);
+-              spin_lock(&zswap_pools_lock);
+       }
+ 
++      spin_unlock(&zswap_pools_lock);
++
++      if (!pool)
++              pool = zswap_pool_create(type, compressor);
++
+       if (pool)
+               ret = param_set_charp(s, kp);
+       else
+               ret = -EINVAL;
+ 
++      spin_lock(&zswap_pools_lock);
++
+       if (!ret) {
+               put_pool = zswap_pool_current();
+               list_add_rcu(&pool->list, &zswap_pools);