Messages in this thread | | | Subject | Re: [PATCH 10/10] powerpc: remove address space overrides using set_fs() | From | Christophe Leroy <> | Date | Wed, 2 Sep 2020 15:24:39 +0200 |
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Le 02/09/2020 à 15:13, David Laight a écrit : > From: Christoph Hellwig >> Sent: 02 September 2020 13:37 >> >> On Wed, Sep 02, 2020 at 08:15:12AM +0200, Christophe Leroy wrote: >>>> - return 0; >>>> - return (size == 0 || size - 1 <= seg.seg - addr); >>>> + if (addr >= TASK_SIZE_MAX) >>>> + return false; >>>> + if (size == 0) >>>> + return false; >>> >>> __access_ok() was returning true when size == 0 up to now. Any reason to >>> return false now ? >> >> No, this is accidental and broken. Can you re-run your benchmark with >> this fixed? > > Is TASK_SIZE_MASK defined such that you can do: > > return (addr | size) < TASK_SIZE_MAX) || !size;
TASK_SIZE_MAX will usually be 0xc0000000
With: addr = 0x80000000; size = 0x80000000;
I expect it to fail ....
With the formula you propose it will succeed, won't it ?
Christophe
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