On Mon, Oct 28, 2013 at 10:33 PM, Rashika Kheria <[email protected]> wrote: > > > > On Mon, Oct 28, 2013 at 7:15 PM, Weijie Yang <[email protected]> > wrote: >> >> On Mon, Oct 28, 2013 at 8:21 PM, Rashika Kheria >> <[email protected]> wrote: >> > This patch fixes the bug in reset_store caused by accessing NULL >> > pointer. >> > Hence, It introduces a check for bdev. It also removes unnecessary check >> > of bdev for fsync_bdev(). >> > >> > Signed-off-by: Rashika Kheria <[email protected]> >> > --- >> > >> > This revision fixes the following issues of the previous revision- >> > Seperating patches into Bug fix and Smatch fix >> > >> > drivers/staging/zram/zram_drv.c | 6 ++++-- >> > 1 file changed, 4 insertions(+), 2 deletions(-) >> > >> > diff --git a/drivers/staging/zram/zram_drv.c >> > b/drivers/staging/zram/zram_drv.c >> > index 2c4ed52..d640a8f 100644 >> > --- a/drivers/staging/zram/zram_drv.c >> > +++ b/drivers/staging/zram/zram_drv.c >> > @@ -648,6 +648,9 @@ static ssize_t reset_store(struct device *dev, >> > zram = dev_to_zram(dev); >> > bdev = bdget_disk(zram->disk, 0); >> > >> > + if (!bdev) >> > + return -EBUSY; >> > + >> >> I am not sure how does it happen. Would you please make it clear to me? >> > > Hi Weijie, > > The bdev gets its value from bdget_disk() which could fail when memory is > less available and hence bdev can be NULL. > > If this check is not introduced then we might reference NULL pointer in the > later part of the code.
I see. Thanks! > I hope I am clear. > > Thanks, > > -- > Rashika Kheria > B.Tech CSE > IIIT Hyderabad -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
