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From: Joshua Clayton <stillcompiling@gmail.com>
To: Oleg Drokin <oleg.drokin@intel.com>,
	Andreas Dilger <andreas.dilger@intel.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: lustre-devel@lists.lustre.org, devel@driverdev.osuosl.org,
	linux-kernel@vger.kernel.org,
	Joshua Clayton <stillcompiling@gmail.com>
Subject: [PATCH] staging: lustre: fix lock imbalance
Date: Sat, 26 Dec 2015 20:41:09 -0800	[thread overview]
Message-ID: <1451191269-27624-1-git-send-email-stillcompiling@gmail.com> (raw)

nrs_resource_put_safe() might hold a lock one one struct
while operating on the other.
There are 2 levels of structures.
Use nrs_policy_put(), which has locking baked in.

sparse gives the following warning:
drivers/staging/lustre//lustre/ptlrpc/nrs.c:498:39:
warning: context imbalance in 'nrs_resource_put_safe' -
  different lock contexts for basic block
---
 drivers/staging/lustre/lustre/ptlrpc/nrs.c | 13 ++-----------
 1 file changed, 2 insertions(+), 11 deletions(-)

diff --git a/drivers/staging/lustre/lustre/ptlrpc/nrs.c b/drivers/staging/lustre/lustre/ptlrpc/nrs.c
index 7044e1f..9028b12 100644
--- a/drivers/staging/lustre/lustre/ptlrpc/nrs.c
+++ b/drivers/staging/lustre/lustre/ptlrpc/nrs.c
@@ -496,18 +496,9 @@ static void nrs_resource_put_safe(struct ptlrpc_nrs_resource **resp)
 	}
 
 	for (i = 0; i < NRS_RES_MAX; i++) {
-		if (pols[i] == NULL)
-			continue;
-
-		if (nrs == NULL) {
-			nrs = pols[i]->pol_nrs;
-			spin_lock(&nrs->nrs_lock);
-		}
-		nrs_policy_put_locked(pols[i]);
+		if (pols[i])
+			nrs_policy_put(pols[i]);
 	}
-
-	if (nrs != NULL)
-		spin_unlock(&nrs->nrs_lock);
 }
 
 /**
-- 
2.6.4


             reply	other threads:[~2015-12-27  5:08 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-12-27  4:41 Joshua Clayton [this message]
2015-12-27  5:32 ` [PATCH] staging: lustre: fix lock imbalance kbuild test robot
2015-12-27  6:47   ` [PATCH v2] " Joshua Clayton

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