From: Peng Fan <peng.fan@xxxxxxx> 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@xxxxxxx> Link: https://lore.kernel.org/r/1584064687-12964-1-git-send-email-peng.fan@xxxxxxx Signed-off-by: Mark Brown <broonie@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- 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;
