Hi,
On Thu, Aug 10, 2017 at 03:43:23AM +0000, Sean Bruno wrote:
S> Author: sbruno
S> Date: Thu Aug 10 03:43:23 2017
S> New Revision: 322338
S> URL: https://svnweb.freebsd.org/changeset/base/322338
S>
S> Log:
S> Don't leak mbufs if clusers exceeds the number of segments. This would
S> leak mbufs over time causing crashes.
S>
S> PR: 221202
S> Submitted by: Matt Macy <m...@mattmacy.io>
S> Reported by: gergely.czu...@harmless.hu
S> Sponsored by: Limelight Networks
S>
S> Modified:
S> head/sys/net/iflib.c
S>
S> Modified: head/sys/net/iflib.c
S>
==============================================================================
S> --- head/sys/net/iflib.c Thu Aug 10 03:11:05 2017 (r322337)
S> +++ head/sys/net/iflib.c Thu Aug 10 03:43:23 2017 (r322338)
S> @@ -267,6 +267,8 @@ iflib_get_sctx(if_ctx_t ctx)
S> #define RX_SW_DESC_INUSE (1 << 3)
S> #define TX_SW_DESC_MAPPED (1 << 4)
S>
S> +#define M_TOOBIG M_UNUSED_8
If you DO use something, then please don't pretent it is unused. This creates
mess, when someone else will look into sys/mbuf.h and find M_UNUSED_8 there
clearly marked as available and will start using it.
However, my reading of the change is that only packets in a TX ring are
marked with this flag. And later they are checked in the same place, and
they don't travel out of iflib. So, it is a local flag, and in this case
you don't need to grab a global mbuf flag, and take any of the M_PROTO flags.
S> typedef struct iflib_sw_rx_desc_array {
S> bus_dmamap_t *ifsd_map; /* bus_dma maps for packet */
S> struct mbuf **ifsd_m; /* pkthdr mbufs */
S> @@ -2930,8 +2932,11 @@ iflib_busdma_load_mbuf_sg(iflib_txq_t txq, bus_dma_tag
S> m = m->m_next;
S> count++;
S> } while (m != NULL);
S> - if (count > *nsegs)
S> + if (count > *nsegs) {
S> + ifsd_m[pidx] = *m0;
S> + ifsd_m[pidx]->m_flags |= M_TOOBIG;
S> return (0);
S> + }
S> m = *m0;
S> count = 0;
S> do {
S> @@ -3241,8 +3246,15 @@ iflib_tx_desc_free(iflib_txq_t txq, int n)
S> if ((m = ifsd_m[cidx]) != NULL) {
S> /* XXX we don't support any drivers that batch
packets yet */
S> MPASS(m->m_nextpkt == NULL);
S> -
S> - m_free(m);
S> + /* if the number of clusters exceeds the number
of segments
S> + * there won't be space on the ring to save a
pointer to each
S> + * cluster so we simply free the list here
S> + */
S> + if (m->m_flags & M_TOOBIG) {
S> + m_freem(m);
S> + } else {
S> + m_free(m);
S> + }
S> ifsd_m[cidx] = NULL;
S> #if MEMORY_LOGGING
S> txq->ift_dequeued++;
Can you please explain the goal of the change? AFAIK, the problem
could be fixed with one liner:
- m_free(m);
+ m_freem(m);
n the iflib_tx_desc_free().
--
Totus tuus, Glebius.
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