* Re: [PATCH] m68k: fix find_next bitops [not found] <1301050810-11329-1-git-send-email-akinobu.mita@gmail.com> @ 2011-03-30 18:02 ` Geert Uytterhoeven 2011-03-30 20:09 ` Andreas Schwab 0 siblings, 1 reply; 4+ messages in thread From: Geert Uytterhoeven @ 2011-03-30 18:02 UTC (permalink / raw) To: Akinobu Mita, Andreas Schwab Cc: linux-kernel, akpm, Roman Zippel, linux-m68k, Michael Schmitz 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 ^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] m68k: fix find_next bitops 2011-03-30 18:02 ` [PATCH] m68k: fix find_next bitops Geert Uytterhoeven @ 2011-03-30 20:09 ` Andreas Schwab 2011-03-31 6:02 ` Akinobu Mita 0 siblings, 1 reply; 4+ messages in thread From: Andreas Schwab @ 2011-03-30 20:09 UTC (permalink / raw) To: Geert Uytterhoeven Cc: Akinobu Mita, linux-kernel, akpm, Roman Zippel, linux-m68k, Michael Schmitz Geert Uytterhoeven <geert@linux-m68k.org> writes: > Andreas, do you think it's worth keeping (and fixing) the m68k "optimized" > versions? Should be easy to add the required offset >= size checks. Andreas. -- Andreas Schwab, schwab@linux-m68k.org GPG Key fingerprint = 58CA 54C7 6D53 942B 1756 01D3 44D5 214B 8276 4ED5 "And now for something completely different." ^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] m68k: fix find_next bitops 2011-03-30 20:09 ` Andreas Schwab @ 2011-03-31 6:02 ` Akinobu Mita 2011-03-31 6:16 ` Geert Uytterhoeven 0 siblings, 1 reply; 4+ messages in thread From: Akinobu Mita @ 2011-03-31 6:02 UTC (permalink / raw) To: Andreas Schwab Cc: Geert Uytterhoeven, linux-kernel, akpm, Roman Zippel, linux-m68k, Michael Schmitz 2011/3/31 Andreas Schwab <schwab@linux-m68k.org>: > Geert Uytterhoeven <geert@linux-m68k.org> writes: > >> Andreas, do you think it's worth keeping (and fixing) the m68k "optimized" >> versions? > > Should be easy to add the required offset >= size checks. OK, I'll try to fix the optimized version. Or, could someone who can test on the real hardware fix this problem? ^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] m68k: fix find_next bitops 2011-03-31 6:02 ` Akinobu Mita @ 2011-03-31 6:16 ` Geert Uytterhoeven 0 siblings, 0 replies; 4+ messages in thread From: Geert Uytterhoeven @ 2011-03-31 6:16 UTC (permalink / raw) To: Akinobu Mita Cc: Andreas Schwab, linux-kernel, akpm, Roman Zippel, linux-m68k, Michael Schmitz On Thu, Mar 31, 2011 at 08:02, Akinobu Mita <akinobu.mita@gmail.com> wrote: > 2011/3/31 Andreas Schwab <schwab@linux-m68k.org>: >> Geert Uytterhoeven <geert@linux-m68k.org> writes: >> >>> Andreas, do you think it's worth keeping (and fixing) the m68k "optimized" >>> versions? >> >> Should be easy to add the required offset >= size checks. > > OK, I'll try to fix the optimized version. > Or, could someone who can test on the real hardware fix this problem? I'll have a look... 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 ^ permalink raw reply [flat|nested] 4+ messages in thread
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2011-03-30 18:02 ` [PATCH] m68k: fix find_next bitops Geert Uytterhoeven
2011-03-30 20:09 ` Andreas Schwab
2011-03-31 6:02 ` Akinobu Mita
2011-03-31 6:16 ` Geert Uytterhoeven
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