On Sat, Oct 07, 2017 at 03:02:17AM +0100, Al Viro wrote: > > I do wonder if we shouldn't just use something like > > > > "skip leading zeroes, copy to size-limited stack location instead" > > > > because the input length really *is* limited once you skip leading > > zeroes (and whatever base marker we have). We might have at most a > > 64-bit value in octal, so 22 bytes max. > > > > But I guess just changing the two GFP_KERNEL's to GFP_ATOMIC is much simpler. > > There's match_strdup() as well... > > FWIW, ext2 side also looks fishy; it might be cleaner if we > collected new state into some object and applied it only after the last > possible failure exit. The entire "restore the original state" logics > would go away... I'm not saying that the bug had been introduced by conversion to spinlock, BTW - it was racy back when ext2_remount() relied upon BKL. I hadn't considered the atomicity issues back then - mea culpa...
