On Mon, Sep 29, 2003 at 05:47:41PM +0200, Pawel Jakub Dawidek wrote: > On Mon, Sep 29, 2003 at 05:22:47PM +0300, earthman wrote: > +> how to allocate some memory chunk > +> in user space memory from kernel code? > +> how to do it correctly? > > Here you got sample kernel module which do this: > > http://garage.freebsd.pl/usmalloc.tgz > http://garage.freebsd.pl/usmalloc.README
Errrr... but won't this interfere *badly* with userland programs which attempt to allocate memory after making the syscall in question? I mean, won't the application's memory manager attempt to allocate the next chunk of memory right over the region that you have stolen with this brk(2) invocation? Thus, when the application tries to write into its newly-allocated memory, it will overwrite the data that the kernel has placed there, and any attempt to access the kernel's data later will fail in wonderfully unpredictable ways :) G'luck, Peter -- Peter Pentchev [EMAIL PROTECTED] [EMAIL PROTECTED] [EMAIL PROTECTED] PGP key: http://people.FreeBSD.org/~roam/roam.key.asc Key fingerprint FDBA FD79 C26F 3C51 C95E DF9E ED18 B68D 1619 4553 No language can express every thought unambiguously, least of all this one.
pgp00000.pgp
Description: PGP signature
