--- /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
+@@ -209,6 +209,9 @@ 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;
+@@ -357,6 +360,9 @@ 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;