Add a follow-up fix for thermal_core

2 files changed, 93 insertions, 0 deletions

diff --git a/queue-3.16/series b/queue-3.16/series
index af3ada7e..e7a9d0f9 100644
--- a/queue-3.16/series
+++ b/queue-3.16/series
@@ -41,6 +41,7 @@ s390-topology-avoid-firing-events-before-kobjs-are-created.patch
 s390-cio-avoid-calling-strlen-on-null-pointer.patch
 s390-cio-exclude-subchannels-with-no-parent-from-pseudo-check.patch
 thermal-fix-use-after-free-when-unregistering-thermal-zone-device.patch
+thermal-fix-deadlock-in-thermal-thermal_zone_device_check.patch
 cifs-fix-max-ea-value-size.patch
 fuse-fix-missing-unlock_page-in-fuse_writepage.patch
 cifs-fix-oplock-handling-for-smb-2.1-protocols.patch
diff --git a/queue-3.16/thermal-fix-deadlock-in-thermal-thermal_zone_device_check.patch b/queue-3.16/thermal-fix-deadlock-in-thermal-thermal_zone_device_check.patch
new file mode 100644
index 00000000..08ae436a
--- /dev/null
+++ b/queue-3.16/thermal-fix-deadlock-in-thermal-thermal_zone_device_check.patch
@@ -0,0 +1,92 @@
+From: Wei Wang <wvw@google.com>
+Date: Tue, 12 Nov 2019 12:42:23 -0800
+Subject: thermal: Fix deadlock in thermal thermal_zone_device_check
+
+commit 163b00cde7cf2206e248789d2780121ad5e6a70b upstream.
+
+1851799e1d29 ("thermal: Fix use-after-free when unregistering thermal zone
+device") changed cancel_delayed_work to cancel_delayed_work_sync to avoid
+a use-after-free issue. However, cancel_delayed_work_sync could be called
+insides the WQ causing deadlock.
+
+[54109.642398] c0   1162 kworker/u17:1   D    0 11030      2 0x00000000
+[54109.642437] c0   1162 Workqueue: thermal_passive_wq thermal_zone_device_check
+[54109.642447] c0   1162 Call trace:
+[54109.642456] c0   1162  __switch_to+0x138/0x158
+[54109.642467] c0   1162  __schedule+0xba4/0x1434
+[54109.642480] c0   1162  schedule_timeout+0xa0/0xb28
+[54109.642492] c0   1162  wait_for_common+0x138/0x2e8
+[54109.642511] c0   1162  flush_work+0x348/0x40c
+[54109.642522] c0   1162  __cancel_work_timer+0x180/0x218
+[54109.642544] c0   1162  handle_thermal_trip+0x2c4/0x5a4
+[54109.642553] c0   1162  thermal_zone_device_update+0x1b4/0x25c
+[54109.642563] c0   1162  thermal_zone_device_check+0x18/0x24
+[54109.642574] c0   1162  process_one_work+0x3cc/0x69c
+[54109.642583] c0   1162  worker_thread+0x49c/0x7c0
+[54109.642593] c0   1162  kthread+0x17c/0x1b0
+[54109.642602] c0   1162  ret_from_fork+0x10/0x18
+[54109.643051] c0   1162 kworker/u17:2   D    0 16245      2 0x00000000
+[54109.643067] c0   1162 Workqueue: thermal_passive_wq thermal_zone_device_check
+[54109.643077] c0   1162 Call trace:
+[54109.643085] c0   1162  __switch_to+0x138/0x158
+[54109.643095] c0   1162  __schedule+0xba4/0x1434
+[54109.643104] c0   1162  schedule_timeout+0xa0/0xb28
+[54109.643114] c0   1162  wait_for_common+0x138/0x2e8
+[54109.643122] c0   1162  flush_work+0x348/0x40c
+[54109.643131] c0   1162  __cancel_work_timer+0x180/0x218
+[54109.643141] c0   1162  handle_thermal_trip+0x2c4/0x5a4
+[54109.643150] c0   1162  thermal_zone_device_update+0x1b4/0x25c
+[54109.643159] c0   1162  thermal_zone_device_check+0x18/0x24
+[54109.643167] c0   1162  process_one_work+0x3cc/0x69c
+[54109.643177] c0   1162  worker_thread+0x49c/0x7c0
+[54109.643186] c0   1162  kthread+0x17c/0x1b0
+[54109.643195] c0   1162  ret_from_fork+0x10/0x18
+[54109.644500] c0   1162 cat             D    0  7766      1 0x00000001
+[54109.644515] c0   1162 Call trace:
+[54109.644524] c0   1162  __switch_to+0x138/0x158
+[54109.644536] c0   1162  __schedule+0xba4/0x1434
+[54109.644546] c0   1162  schedule_preempt_disabled+0x80/0xb0
+[54109.644555] c0   1162  __mutex_lock+0x3a8/0x7f0
+[54109.644563] c0   1162  __mutex_lock_slowpath+0x14/0x20
+[54109.644575] c0   1162  thermal_zone_get_temp+0x84/0x360
+[54109.644586] c0   1162  temp_show+0x30/0x78
+[54109.644609] c0   1162  dev_attr_show+0x5c/0xf0
+[54109.644628] c0   1162  sysfs_kf_seq_show+0xcc/0x1a4
+[54109.644636] c0   1162  kernfs_seq_show+0x48/0x88
+[54109.644656] c0   1162  seq_read+0x1f4/0x73c
+[54109.644664] c0   1162  kernfs_fop_read+0x84/0x318
+[54109.644683] c0   1162  __vfs_read+0x50/0x1bc
+[54109.644692] c0   1162  vfs_read+0xa4/0x140
+[54109.644701] c0   1162  SyS_read+0xbc/0x144
+[54109.644708] c0   1162  el0_svc_naked+0x34/0x38
+[54109.845800] c0   1162 D 720.000s 1->7766->7766 cat [panic]
+
+Fixes: 1851799e1d29 ("thermal: Fix use-after-free when unregistering thermal zone device")
+Signed-off-by: Wei Wang <wvw@google.com>
+Signed-off-by: Zhang Rui <rui.zhang@intel.com>
+Cc: Ido Schimmel <idosch@mellanox.com>
+Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
+---
+ drivers/thermal/thermal_core.c | 4 ++--
+ 1 file changed, 2 insertions(+), 2 deletions(-)
+
+--- a/drivers/thermal/thermal_core.c
++++ b/drivers/thermal/thermal_core.c
+@@ -333,7 +333,7 @@ static void thermal_zone_device_set_poll
+ 		mod_delayed_work(system_freezable_wq, &tz->poll_queue,
+ 				 msecs_to_jiffies(delay));
+ 	else
+-		cancel_delayed_work_sync(&tz->poll_queue);
++		cancel_delayed_work(&tz->poll_queue);
+ }
+ 
+ static void monitor_thermal_zone(struct thermal_zone_device *tz)
+@@ -1625,7 +1625,7 @@ void thermal_zone_device_unregister(stru
+ 
+ 	mutex_unlock(&thermal_list_lock);
+ 
+-	thermal_zone_device_set_polling(tz, 0);
++	cancel_delayed_work_sync(&tz->poll_queue);
+ 
+ 	if (tz->type[0])
+ 		device_remove_file(&tz->device, &dev_attr_type);