Messages in this thread | | | Subject | Re: [PATCH] lib: Reduce user_access_begin() boundaries in strncpy_from_user() and strnlen_user() | From | Christophe Leroy <> | Date | Fri, 24 Jan 2020 07:25:51 +0100 |
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Le 23/01/2020 à 19:47, Linus Torvalds a écrit : > On Thu, Jan 23, 2020 at 12:34 AM Christophe Leroy > <christophe.leroy@c-s.fr> wrote: >> >> The range passed to user_access_begin() by strncpy_from_user() and >> strnlen_user() starts at 'src' and goes up to the limit of userspace >> allthough reads will be limited by the 'count' param. >> >> On 32 bits powerpc (book3s/32) access has to be granted for each 256Mbytes >> segment and the cost increases with the number of segments to unlock. >> >> Limit the range with 'count' param. > > Ack. I'm tempted to take this for 5.5 too, just so that the > unquestionably trivial fixes are in that baseline, and the > infrastructure is ready for any architecture that has issues like > this.
It would be nice, then the user_access_begin stuff for powerpc could go for 5.6 without worring about.
Thanks Christophe
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