Date: Mon, 29 Nov 2010 11:50:19 -0800 From: Jack Vogel <jfvogel@gmail.com> To: Eugene Grosbein <eugen@eg.sd.rdtc.ru> Cc: freebsd-net <freebsd-net@freebsd.org> Subject: Re: em(4) updated to version 7.1.8 Message-ID: <AANLkTikYPfyqvuuwZa_AdwyhCY4o73ymP3TMr1GvPM8M@mail.gmail.com> In-Reply-To: <20101129192312.GA33547@rdtc.ru> References: <201011270946271408828@yahoo.com.cn> <AANLkTikG8RJQw%2Bh1SHZPs1cHGrM%2B3LfniZrdLqVoPVtr@mail.gmail.com> <AANLkTi=YjG40%2BDj7471wyv3aeXGJgoL1GC33iNaypsrW@mail.gmail.com> <AANLkTi=LgejYxRXnxLtkvB-Qfp2u%2BtySdriWHfGWPQjL@mail.gmail.com> <20101128081617.GA90332@zibbi.meraka.csir.co.za> <AANLkTinF1fovumkeXxWgaKi_bNiUCnqgWAtdaCaXELzO@mail.gmail.com> <20101129175128.GA32977@rdtc.ru> <AANLkTin4=kN27dMeWXzGUpTpx9HiZ3T-aymbyjMrsBn8@mail.gmail.com> <20101129182652.GA33150@rdtc.ru> <AANLkTimL1VHbjjv7a6RTdyj4VGcJxfNfTjc4fCcaSHXY@mail.gmail.com> <20101129192312.GA33547@rdtc.ru>
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True, there is no check, I do not see a way in which the mbuf
pointer should be NULL, however, perhaps I should change things
to follow what the igb driver does, always checking for NULL and
freeing the existing mbuf to allow em_refresh_mbufs() to repop.
If you say you have had panics then there must be a path to have
it NULL.
Jack
On Mon, Nov 29, 2010 at 11:23 AM, Eugene Grosbein <eugen@eg.sd.rdtc.ru>wrote:
> On Mon, Nov 29, 2010 at 11:10:22AM -0800, Jack Vogel wrote:
>
> > Not sure what code you created this from, but its not the new driver,
>
> Yes, that's for previous version and that's what keeps my production
> servers from panicing.
>
> > things have been reorganized and I do not believe this issue exists.
> > Please test with the latest.
>
> I'd rather not risk. Here is the same check for today's RELENG_8 driver.
> Please, please take a look. After several days of nearly gigabit load
> it has already happened m_head was NULL here, in previous version.
> Can it be possible in current version?
> There is still no check before dereferencing.
>
> --- if_em.c.orig 2010-11-30 01:16:17.000000000 +0600
> +++ if_em.c 2010-11-30 01:19:09.000000000 +0600
> @@ -4321,10 +4321,12 @@
>
> /* Reset state, keep loaded DMA map and reuse */
> m = rbuf->m_head;
> + if(m) {
> m->m_len = m->m_pkthdr.len = adapter->rx_mbuf_sz;
> m->m_flags |= M_PKTHDR;
> m->m_data = m->m_ext.ext_buf;
> m->m_next = NULL;
> + }
>
> return;
> }
>
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