From: Artem Blagodarenko <artem.blagodarenko@hpe.com>
Date: Fri, 21 Aug 2020 17:43:38 +0000 (-0400)
Subject: LU-13942 obd: check if sbi->ll_md_exp is initialized
X-Git-Tag: 2.14.52~35
X-Git-Url: https://git.whamcloud.com/?a=commitdiff_plain;h=1de8c3739d6bac76b63a0e59a8aadf4ce491f88a;p=fs%2Flustre-release.git

LU-13942 obd: check if sbi->ll_md_exp is initialized

Null reference at the start of obd_statfs() function is possible
because of ll_fill_super vs lctl race.

ll_md_exp is initialized in ll_fill_super()->
client_common_fill_super(), but if mount process stucks
in lustre_process_log() it doesn't reach client_common_fill_super().

Change-Id: Ife72a62ba42573e2a9c6d244e36cde738b70c15a
hpe-bug-id: LUS-9150
Signed-off-by: Artem Blagodarenko <artem.blagodarenko@hpe.com>
Reviewed-on: https://es-gerrit.dev.cray.com/157732
Reviewed-by: Alexander Zarochentsev <c17826@cray.com>
Tested-by: Alexander Lezhoev <c17454@cray.com>
Reviewed-by: Andriy Skulysh <c17819@cray.com>
Reviewed-on: https://review.whamcloud.com/39812
Reviewed-by: James Simmons <jsimmons@infradead.org>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
---

diff --git a/lustre/include/obd_class.h b/lustre/include/obd_class.h
index 1dc5f12..6be7628 100644
--- a/lustre/include/obd_class.h
+++ b/lustre/include/obd_class.h
@@ -1046,13 +1046,14 @@ static inline int obd_statfs(const struct lu_env *env, struct obd_export *exp,
 			     struct obd_statfs *osfs, time64_t max_age,
 			     __u32 flags)
 {
-	struct obd_device *obd = exp->exp_obd;
+	struct obd_device *obd;
 	int rc = 0;
 
 	ENTRY;
-	if (unlikely(obd == NULL))
+	if (unlikely(exp == NULL || exp->exp_obd == NULL))
 		RETURN(-EINVAL);
 
+	obd = exp->exp_obd;
 	OBD_CHECK_DEV_ACTIVE(obd);
 
 	if (unlikely(!obd->obd_type || !obd->obd_type->typ_dt_ops->o_statfs)) {