Commit 76fe334f authored Jul 21, 2016 by Andrey Smirnov Committed by Boris Brezillon Sep 23, 2016

mtd: nand: Error out if cmd_ctrl() is missing



If no user specified chip->select_chip() function is provided, code in
nand_base.c will automatically set this hook to nand_select_chip(),
which in turn depends on chip->cmd_ctrl() hook being valid. Not
providing both of those functions in NAND controller driver (for example
by mistake) will result in a bit cryptic segfault. Same is true for
chip->cmdfunc().

To avoid the above scenario add a check in nand_scan_dent and error out
if cmd_ctrl() is not provided.

Suggested-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Suggested-by: Brian Norris <computersforpeace@gmail.com>
Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>

parent 75c19e58

drivers/mtd/nand/nand_base.c

+9 −0

Original line number	Diff line number	Diff line
		@@ -4140,6 +4140,15 @@ int nand_scan_ident(struct mtd_info *mtd, int maxchips,
		if (!mtd->name && mtd->dev.parent)
		mtd->name = dev_name(mtd->dev.parent);

		if ((!chip->cmdfunc \|\| !chip->select_chip) && !chip->cmd_ctrl) {
		/*
		* Default functions assigned for chip_select() and
		* cmdfunc() both expect cmd_ctrl() to be populated,
		* so we need to check that that's the case
		*/
		pr_err("chip.cmd_ctrl() callback is not provided");
		return -EINVAL;
		}
		/* Set the default functions */
		nand_set_defaults(chip, chip->options & NAND_BUSWIDTH_16);