| Message ID | 1441978907-19520-1-git-send-email-van.freenix@gmail.com |
|---|---|
| State | Accepted |
| Commit | 2ce401d56b36a7492b26646b94d1fe9194880a1a |
| Headers | show |
On Fri, Sep 11, 2015 at 09:41:47PM +0800, Peng Fan wrote: > In drivers/mtd/mtd_blkdevs.c: > 406 set_capacity(gd, (new->size * tr->blksize) >> 9); > The type of new->size is unsigned long and the type of tr->blksize is int, > the result of 'new->size * tr->blksize' may exceed ULONG_MAX on 32bit > machines. > > I use nand chip MT29F32G08CBADBWP which is 4GB and the parameters passed > to kernel is 'mtdparts=gpmi-nand:-(user)', the whole nand chip will be > treated as a 4GB mtd partition. new->size is 0x800000 and tr->blksize is > 0x200, 'new->size * tr->blksize' however is 0. This is what we do not want > to see. > > Using type cast u64 to fix the multiplication overflow issue. > > Signed-off-by: Peng Fan <van.freenix@gmail.com> > Cc: David Woodhouse <dwmw2@infradead.org> > Cc: Brian Norris <computersforpeace@gmail.com> > --- > > Changes V2: > use type cast to avoid build break for platforms which does not support 64 bit multilplication. Thanks, pushed to l2-mtd.git
diff --git a/drivers/mtd/mtd_blkdevs.c b/drivers/mtd/mtd_blkdevs.c index 44dc965..cb47d79 100644 --- a/drivers/mtd/mtd_blkdevs.c +++ b/drivers/mtd/mtd_blkdevs.c @@ -399,7 +399,7 @@ int add_mtd_blktrans_dev(struct mtd_blktrans_dev *new) snprintf(gd->disk_name, sizeof(gd->disk_name), "%s%d", tr->name, new->devnum); - set_capacity(gd, (new->size * tr->blksize) >> 9); + set_capacity(gd, ((u64)new->size * tr->blksize) >> 9); /* Create the request queue */ spin_lock_init(&new->queue_lock);
In drivers/mtd/mtd_blkdevs.c: 406 set_capacity(gd, (new->size * tr->blksize) >> 9); The type of new->size is unsigned long and the type of tr->blksize is int, the result of 'new->size * tr->blksize' may exceed ULONG_MAX on 32bit machines. I use nand chip MT29F32G08CBADBWP which is 4GB and the parameters passed to kernel is 'mtdparts=gpmi-nand:-(user)', the whole nand chip will be treated as a 4GB mtd partition. new->size is 0x800000 and tr->blksize is 0x200, 'new->size * tr->blksize' however is 0. This is what we do not want to see. Using type cast u64 to fix the multiplication overflow issue. Signed-off-by: Peng Fan <van.freenix@gmail.com> Cc: David Woodhouse <dwmw2@infradead.org> Cc: Brian Norris <computersforpeace@gmail.com> --- Changes V2: use type cast to avoid build break for platforms which does not support 64 bit multilplication. drivers/mtd/mtd_blkdevs.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)