Messages in this thread | | | Date | Tue, 17 Oct 2017 12:32:38 +0200 | From | Daniel Borkmann <> | Subject | Re: [PATCH] bpf: devmap: Check attr->max_entries more carefully |
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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 <sp3485@columbia.edu> >>> Reported-by: syzkaller <syzkaller@googlegroups.com> >>> Signed-off-by: Richard Weinberger <richard@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
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