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From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Trond Myklebust <trond.myklebust@hammerspace.com>,
	Sasha Levin <sashal@kernel.org>,
	linux-nfs@vger.kernel.org
Subject: [PATCH AUTOSEL 4.14 127/371] NFSv4/flexfiles: Fix invalid deref in FF_LAYOUT_DEVID_NODE()
Date: Thu, 16 Jan 2020 12:19:59 -0500
Message-ID: <20200116172403.18149-70-sashal@kernel.org> (raw)
In-Reply-To: <20200116172403.18149-1-sashal@kernel.org>

From: Trond Myklebust <trond.myklebust@hammerspace.com>

[ Upstream commit 108bb4afd351d65826648a47f11fa3104e250d9b ]

If the attempt to instantiate the mirror's layout DS pointer failed,
then that pointer may hold a value of type ERR_PTR(), so we need
to check that before we dereference it.

Fixes: 65990d1afbd2d ("pNFS/flexfiles: Fix a deadlock on LAYOUTGET")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/nfs/flexfilelayout/flexfilelayout.h | 32 +++++++++++++++-----------
 1 file changed, 19 insertions(+), 13 deletions(-)

diff --git a/fs/nfs/flexfilelayout/flexfilelayout.h b/fs/nfs/flexfilelayout/flexfilelayout.h
index d6515f1584f3..d78ec99b6c4c 100644
--- a/fs/nfs/flexfilelayout/flexfilelayout.h
+++ b/fs/nfs/flexfilelayout/flexfilelayout.h
@@ -131,16 +131,6 @@ FF_LAYOUT_LSEG(struct pnfs_layout_segment *lseg)
 			    generic_hdr);
 }
 
-static inline struct nfs4_deviceid_node *
-FF_LAYOUT_DEVID_NODE(struct pnfs_layout_segment *lseg, u32 idx)
-{
-	if (idx >= FF_LAYOUT_LSEG(lseg)->mirror_array_cnt ||
-	    FF_LAYOUT_LSEG(lseg)->mirror_array[idx] == NULL ||
-	    FF_LAYOUT_LSEG(lseg)->mirror_array[idx]->mirror_ds == NULL)
-		return NULL;
-	return &FF_LAYOUT_LSEG(lseg)->mirror_array[idx]->mirror_ds->id_node;
-}
-
 static inline struct nfs4_ff_layout_ds *
 FF_LAYOUT_MIRROR_DS(struct nfs4_deviceid_node *node)
 {
@@ -150,9 +140,25 @@ FF_LAYOUT_MIRROR_DS(struct nfs4_deviceid_node *node)
 static inline struct nfs4_ff_layout_mirror *
 FF_LAYOUT_COMP(struct pnfs_layout_segment *lseg, u32 idx)
 {
-	if (idx >= FF_LAYOUT_LSEG(lseg)->mirror_array_cnt)
-		return NULL;
-	return FF_LAYOUT_LSEG(lseg)->mirror_array[idx];
+	struct nfs4_ff_layout_segment *fls = FF_LAYOUT_LSEG(lseg);
+
+	if (idx < fls->mirror_array_cnt)
+		return fls->mirror_array[idx];
+	return NULL;
+}
+
+static inline struct nfs4_deviceid_node *
+FF_LAYOUT_DEVID_NODE(struct pnfs_layout_segment *lseg, u32 idx)
+{
+	struct nfs4_ff_layout_mirror *mirror = FF_LAYOUT_COMP(lseg, idx);
+
+	if (mirror != NULL) {
+		struct nfs4_ff_layout_ds *mirror_ds = mirror->mirror_ds;
+
+		if (!IS_ERR_OR_NULL(mirror_ds))
+			return &mirror_ds->id_node;
+	}
+	return NULL;
 }
 
 static inline u32
-- 
2.20.1


  parent reply index

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20200116172403.18149-1-sashal@kernel.org>
2020-01-16 17:19 ` [PATCH AUTOSEL 4.14 114/371] fs/nfs: Fix nfs_parse_devname to not modify it's argument Sasha Levin
2020-01-16 17:19 ` [PATCH AUTOSEL 4.14 117/371] NFS: Fix a soft lockup in the delegation recovery code Sasha Levin
2020-01-16 17:19 ` [PATCH AUTOSEL 4.14 121/371] NFS/pnfs: Bulk destroy of layouts needs to be safe w.r.t. umount Sasha Levin
2020-01-16 17:19 ` Sasha Levin [this message]
2020-01-16 17:20 ` [PATCH AUTOSEL 4.14 172/371] NFS: Don't interrupt file writeout due to fatal errors Sasha Levin

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