[lkml]   [2018]   [Mar]   [16]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: [PATCH v2] rslib: Remove VLAs by setting upper bound on nroots
On Thu, 15 Mar 2018 15:59:19 -0700 Kees Cook <> wrote:

> Avoid stack VLAs[1] by always allocating the upper bound of stack space
> needed. The existing users of rslib appear to max out at 24 roots[2],
> so use that as the upper bound until we have a reason to change it.
> Alternative considered: make init_rs() a true caller-instance and
> pre-allocate the workspaces. This would possibly need locking and
> a refactoring of the returned structure.
> Using kmalloc in this path doesn't look great, especially since at
> least one caller (pstore) is sensitive to allocations during rslib
> usage (it expects to run it during an Oops, for example).
> [1]
> [2]

Yeah, email [2] is rather important. This patch is a bit of a pig to

The restriction to 24 roots might be a significant one, dunno. Perhaps
we should just kmalloc these things?

Otherwise, RS_MAX_ROOTS becomes part of the rs interface and should be
documented and published in rslib.h?

 \ /
  Last update: 2018-03-16 23:38    [W:0.112 / U:2.652 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site