Messages in this thread | | | Subject | Re: [patch 3/3] mm: variable length argument support | From | Peter Zijlstra <> | Date | Tue, 07 Aug 2007 21:26:36 +0200 |
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On Tue, 2007-08-07 at 12:20 -0700, Andrew Morton wrote: > On Tue, 7 Aug 2007 21:03:57 +0200 > Olaf Hering <olaf@aepfle.de> wrote: > > > On Wed, Jun 13, Peter Zijlstra wrote: > > > > > From: Ollie Wild <aaw@google.com> > > > > > > Remove the arg+env limit of MAX_ARG_PAGES by copying the strings directly > > > from the old mm into the new mm. > > > > > +++ linux-2.6-2/include/linux/binfmts.h 2007-06-13 11:52:46.000000000 +0200 > > > @@ -6,11 +6,13 @@ > > > struct pt_regs; > > > > > > /* > > > - * MAX_ARG_PAGES defines the number of pages allocated for arguments > > > - * and envelope for the new program. 32 should suffice, this gives > > > - * a maximum env+arg of 128kB w/4KB pages! > > > + * These are the maximum length and maximum number of strings passed to the > > > + * execve() system call. MAX_ARG_STRLEN is essentially random but serves to > > > + * prevent the kernel from being unduly impacted by misaddressed pointers. > > > + * MAX_ARG_STRINGS is chosen to fit in a signed 32-bit integer. > > > */ > > > -#define MAX_ARG_PAGES 32 > > > +#define MAX_ARG_STRLEN (PAGE_SIZE * 32) > > > +#define MAX_ARG_STRINGS 0x7FFFFFFF > > > > This adds a new usage of PAGE_SIZE to an exported header. > > How can this be fixed for 2.6.23? > > Put #ifdef __KERNEL__ around it?
Sounds like a good idea, since its new there should not yet be anybody using it.
If anything, someone used to use MAX_ARG_PAGES in userspace, which we just now broke. Olaf said he'd grep a distro source base to find out :-)
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