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authorVitaly Kuznetsov <vkuznets@redhat.com>2015-03-18 12:29:22 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2015-03-25 11:53:54 +0100
commitf3f6eb80872becdbce07f7d2670d3f8ae5119752 (patch)
treeed64c447de26e00eb51f54ddfa9052b69bcca3c3 /drivers/hv
parentfde25d25dbd997067058f7d4c2ff31600157e6f2 (diff)
Drivers: hv: hv_balloon: keep locks balanced on add_memory() failure
When add_memory() fails the following BUG is observed: [ 743.646107] hv_balloon: hot_add memory failed error is -17 [ 743.679973] [ 743.680930] ===================================== [ 743.680930] [ BUG: bad unlock balance detected! ] [ 743.680930] 3.19.0-rc5_bug1131426+ #552 Not tainted [ 743.680930] ------------------------------------- [ 743.680930] kworker/0:2/255 is trying to release lock (&dm_device.ha_region_mutex) at: [ 743.680930] [<ffffffff81aae5fe>] mutex_unlock+0xe/0x10 [ 743.680930] but there are no more locks to release! This happens as we don't acquire ha_region_mutex and hot_add_req() expects us to as it does unconditional mutex_unlock(). Acquire the lock on the error path. The current char-next branch is broken and this patch fixes the bug. Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Acked-by: Jason Wang <jasowang@redhat.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/hv')
-rw-r--r--drivers/hv/hv_balloon.c1
1 files changed, 1 insertions, 0 deletions
diff --git a/drivers/hv/hv_balloon.c b/drivers/hv/hv_balloon.c
index c5bb87244dd7..f1f17c5ad8d8 100644
--- a/drivers/hv/hv_balloon.c
+++ b/drivers/hv/hv_balloon.c
@@ -652,6 +652,7 @@ static void hv_mem_hot_add(unsigned long start, unsigned long size,
}
has->ha_end_pfn -= HA_CHUNK;
has->covered_end_pfn -= processed_pfn;
+ mutex_lock(&dm_device.ha_region_mutex);
break;
}