On 10/17/2017 12:29 PM, Mark Rutland wrote:
On Mon, Oct 16, 2017 at 08:52:13PM +0200, Daniel Borkmann wrote:
[ +Tejun, Mark, John ]
On 10/16/2017 12:00 AM, Richard Weinberger wrote:
max_entries is user controlled and used as input for __alloc_percpu().
This function expects that the allocation size is a power of two and
less than PCPU_MIN_UNIT_SIZE.
Otherwise a WARN() is triggered.
Fixes: 11393cc9b9be ("xdp: Add batching support to redirect map")
Reported-by: Shankara Pailoor <sp3...@columbia.edu>
Reported-by: syzkaller <syzkal...@googlegroups.com>
Signed-off-by: Richard Weinberger <rich...@nod.at>
Thanks for the patch, Richard. There was a prior discussion here [1] on
the same issue, I thought this would have been resolved by now, but looks
like it's still open and there was never a follow-up, at least I don't see
it in the percpu tree if I didn't miss anything.
Sorry, this was on my todo list, but I've been bogged down with some
other work.
Ok, no problem.
I would suggest, we do the following below and pass __GFP_NOWARN from BPF
side to the per-cpu allocs. This is kind of a generic 'issue' and we shouldn't
add more code which bails out anyway just to work around the WARN(). Lets
handle it properly instead.
Agreed. The below patch looks good to me, (with the suggested change to
the BPF side).
If Tejun is fine with the one below, I could cook and official patch and
cleanup the remaining call-sites from BPF which have similar pattern.
That would be great; thanks for taking this on.
I'll prepare a set including BPF side for today.
Thanks,
Daniel
