--- /dev/null
+From 74edd08a4fbf51d65fd8f4c7d8289cd0f392bd91 Mon Sep 17 00:00:00 2001
+From: Peng Fan <peng.fan@nxp.com>
+Date: Fri, 13 Mar 2020 09:58:07 +0800
+Subject: regmap: debugfs: check count when read regmap file
+
+From: Peng Fan <peng.fan@nxp.com>
+
+commit 74edd08a4fbf51d65fd8f4c7d8289cd0f392bd91 upstream.
+
+When executing the following command, we met kernel dump.
+dmesg -c > /dev/null; cd /sys;
+for i in `ls /sys/kernel/debug/regmap/* -d`; do
+ echo "Checking regmap in $i";
+ cat $i/registers;
+done && grep -ri "0x02d0" *;
+
+It is because the count value is too big, and kmalloc fails. So add an
+upper bound check to allow max size `PAGE_SIZE << (MAX_ORDER - 1)`.
+
+Signed-off-by: Peng Fan <peng.fan@nxp.com>
+Link: https://lore.kernel.org/r/1584064687-12964-1-git-send-email-peng.fan@nxp.com
+Signed-off-by: Mark Brown <broonie@kernel.org>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+
+---
+ drivers/base/regmap/regmap-debugfs.c | 6 ++++++
+ 1 file changed, 6 insertions(+)
+
+--- a/drivers/base/regmap/regmap-debugfs.c
++++ b/drivers/base/regmap/regmap-debugfs.c
+@@ -204,6 +204,9 @@ static ssize_t regmap_read_debugfs(struc
+ if (*ppos < 0 || !count)
+ return -EINVAL;
+
++ if (count > (PAGE_SIZE << (MAX_ORDER - 1)))
++ count = PAGE_SIZE << (MAX_ORDER - 1);
++
+ buf = kmalloc(count, GFP_KERNEL);
+ if (!buf)
+ return -ENOMEM;
+@@ -352,6 +355,9 @@ static ssize_t regmap_reg_ranges_read_fi
+ if (*ppos < 0 || !count)
+ return -EINVAL;
+
++ if (count > (PAGE_SIZE << (MAX_ORDER - 1)))
++ count = PAGE_SIZE << (MAX_ORDER - 1);
++
+ buf = kmalloc(count, GFP_KERNEL);
+ if (!buf)
+ return -ENOMEM;
--- /dev/null
+From 2c4306f719b083d17df2963bc761777576b8ad1b Mon Sep 17 00:00:00 2001
+From: Eric Sandeen <sandeen@redhat.com>
+Date: Mon, 16 Apr 2018 23:07:27 -0700
+Subject: xfs: set format back to extents if xfs_bmap_extents_to_btree
+
+From: Eric Sandeen <sandeen@redhat.com>
+
+commit 2c4306f719b083d17df2963bc761777576b8ad1b upstream.
+
+If xfs_bmap_extents_to_btree fails in a mode where we call
+xfs_iroot_realloc(-1) to de-allocate the root, set the
+format back to extents.
+
+Otherwise we can assume we can dereference ifp->if_broot
+based on the XFS_DINODE_FMT_BTREE format, and crash.
+
+Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=199423
+Signed-off-by: Eric Sandeen <sandeen@redhat.com>
+Reviewed-by: Christoph Hellwig <hch@lst.de>
+Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
+Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
+Signed-off-by: Nobuhiro Iwamatsu (CIP) <nobuhiro1.iwamatsu@toshiba.co.jp>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ fs/xfs/libxfs/xfs_bmap.c | 4 ++++
+ 1 file changed, 4 insertions(+)
+
+--- a/fs/xfs/libxfs/xfs_bmap.c
++++ b/fs/xfs/libxfs/xfs_bmap.c
+@@ -781,6 +781,8 @@ try_another_ag:
+ *logflagsp = 0;
+ if ((error = xfs_alloc_vextent(&args))) {
+ xfs_iroot_realloc(ip, -1, whichfork);
++ ASSERT(ifp->if_broot == NULL);
++ XFS_IFORK_FMT_SET(ip, whichfork, XFS_DINODE_FMT_EXTENTS);
+ xfs_btree_del_cursor(cur, XFS_BTREE_ERROR);
+ return error;
+ }
+@@ -801,6 +803,8 @@ try_another_ag:
+ }
+ if (WARN_ON_ONCE(args.fsbno == NULLFSBLOCK)) {
+ xfs_iroot_realloc(ip, -1, whichfork);
++ ASSERT(ifp->if_broot == NULL);
++ XFS_IFORK_FMT_SET(ip, whichfork, XFS_DINODE_FMT_EXTENTS);
+ xfs_btree_del_cursor(cur, XFS_BTREE_ERROR);
+ return -ENOSPC;
+ }