[Devel] [PATCH RHEL7 COMMIT] fs/fuse kio: fix mapping dereference in a dead map

[Konstantin Khorenko]

The commit is pushed to "branch-rh7-3.10.0-957.1.3.vz7.83.x-ovz" and will appear at https://src.openvz.org/scm/ovz/vzkernel.git
after rh7-3.10.0-957.1.3.vz7.83.4
------>
commit 6cbcbf6f3bb33517adf1b670c3003f462d1437f0
Author: Pavel Butsykin <pbutsykin at virtuozzo.com>
Date:   Thu Jan 10 12:28:16 2019 +0300

    fs/fuse kio: fix mapping dereference in a dead map
    
    MAP_ARGS() contains reference to struct pcs_map_entry::mapping,
    which can be NULL if map is dead.
    
    https://pmc.acronis.com/browse/VSTOR-19267
    
    Signed-off-by: Pavel Butsykin <pbutsykin at virtuozzo.com>
    Reviewed-by: Kirill Tkhai <ktkhai at virtuozzo.com>
---
 fs/fuse/kio/pcs/pcs_map.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/fs/fuse/kio/pcs/pcs_map.c b/fs/fuse/kio/pcs/pcs_map.c
index 817c7d6a9379..ad31d1222da3 100644
--- a/fs/fuse/kio/pcs/pcs_map.c
+++ b/fs/fuse/kio/pcs/pcs_map.c
@@ -1175,7 +1175,8 @@ void pcs_map_complete(struct pcs_map_entry *m, struct pcs_ioc_getmap *omap)
 	return;
 
 error:
-	TRACE(" map error: %d for " MAP_FMT "\n", error.value, MAP_ARGS(m));
+	TRACE("map error: %d, m:%p, index:%lu, state:%x\n", error.value, m,
+		m->index, m->state);
 	BUG_ON(!pcs_if_error(&error));
 
 	m->state &= ~PCS_MAP_RESOLVING;