Messages in this thread |  | | | Date | Thu, 15 Dec 2011 14:44:11 -0800 | | From | Andrew Morton <> | | Subject | Re: [PATCH] Fix for binary_sysctl() memory leak |
| |
On Thu, 15 Dec 2011 14:38:58 -0800 Michel Lespinasse <walken@google.com> wrote:
> On Thu, Dec 15, 2011 at 2:19 PM, Andrew Morton > <akpm@linux-foundation.org> wrote: > > I think the patch is correct but the description is misleading? > > > > I see no memory leak here. __Calling __putname() directly simply > > bypasses some audit-related stuff. > > Hmmm, maybe I wasn't explicit enough about it. We are definitely > seeing a memory leak without the patch. > > When auditing is enabled, putname() calls audit_putname *instead* (not > in addition) to __putname(). Then, if a syscall is in progress, > audit_putname does not release the name - instead, it expects the name > to get released when the syscall completes, but that will happen only > if audit_getname() was called previously, i.e. if the name was > allocated with getname() rather than the naked __getname(). So, > __getname() followed by putname() ends up leaking memory. >
OK. Please resend with a new changelog?
The bug surprises me - it seems that it makes it trivial for userspace to cause leaking of mad amounts of kernel memory, which would cause the bug to be found and fixed quickly.
Is it a recent regression, or does the bug trigger only in weird circumstances, or what?
|  |