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Date: Fri, 13 Mar 2020 09:58:07 +0800 From: peng.fan@....com To: broonie@...nel.org, gregkh@...uxfoundation.org, rafael@...nel.org Cc: linux-imx@....com, linux-kernel@...r.kernel.org, Peng Fan <peng.fan@....com> Subject: [PATCH V2] regmap: debugfs: check count when read regmap file From: Peng Fan <peng.fan@....com> 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@....com> --- drivers/base/regmap/regmap-debugfs.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/drivers/base/regmap/regmap-debugfs.c b/drivers/base/regmap/regmap-debugfs.c index e72843fe41df..089e5dc7144a 100644 --- a/drivers/base/regmap/regmap-debugfs.c +++ b/drivers/base/regmap/regmap-debugfs.c @@ -227,6 +227,9 @@ static ssize_t regmap_read_debugfs(struct regmap *map, unsigned int from, 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; @@ -371,6 +374,9 @@ static ssize_t regmap_reg_ranges_read_file(struct file *file, 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; -- 2.16.4
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