Messages in this thread | | | Date | Wed, 30 Mar 2011 20:02:50 +0200 | Subject | Re: [PATCH] m68k: fix find_next bitops | From | Geert Uytterhoeven <> |
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On Fri, Mar 25, 2011 at 12:00, Akinobu Mita <akinobu.mita@gmail.com> wrote: > find_next bitops on m68k (find_next_zero_bit, find_next_bit, and > find_next_bit_le) may cause out of bounds memory access > when the bitmap size in bits % 32 != 0 and offset (the bitnumber > to start searching at) is very close to the bitmap size. > > For example, > > unsigned long bitmap[2] = { 0, 0 }; > find_next_bit(bitmap, 63, 62); > > 1. find_next_bit() tries to find any set bits in bitmap[1], > but no bits set. > > 2. Then find_first_bit(bimap + 2, -1) > > 3. Unfortunately find_fist_bit() takes unsigned int as the size argument. > > 4. find_first_bit will access bitmap[2~] until it find any set bits. > > This switches find_next bitops to use generic implementation of > find bitops to fix the problem.
Andreas, do you think it's worth keeping (and fixing) the m68k "optimized" versions?
Gr{oetje,eeting}s,
Geert
-- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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