[src/trunk]: src/sys/net PR/49386: Ryota Ozaki: Add a mutex for bpf creation/...

[christos <christos%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/57d190072737
branches:  trunk
changeset: 811165:57d190072737
user:      christos <christos%NetBSD.org@localhost>
date:      Wed Oct 14 19:40:09 2015 +0000

description:
PR/49386: Ryota Ozaki: Add a mutex for bpf creation/removal to avoid races.
Add M_CANFAIL to malloc.

diffstat:

 sys/net/bpf.c |  26 ++++++++++++++++++++------
 1 files changed, 20 insertions(+), 6 deletions(-)

diffs (145 lines):

diff -r 9f72fa0c9f9c -r 57d190072737 sys/net/bpf.c
--- a/sys/net/bpf.c     Wed Oct 14 18:31:52 2015 +0000
+++ b/sys/net/bpf.c     Wed Oct 14 19:40:09 2015 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: bpf.c,v 1.191 2015/05/30 19:14:46 joerg Exp $  */
+/*     $NetBSD: bpf.c,v 1.192 2015/10/14 19:40:09 christos Exp $       */
 
 /*
  * Copyright (c) 1990, 1991, 1993
@@ -39,7 +39,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: bpf.c,v 1.191 2015/05/30 19:14:46 joerg Exp $");
+__KERNEL_RCSID(0, "$NetBSD: bpf.c,v 1.192 2015/10/14 19:40:09 christos Exp $");
 
 #if defined(_KERNEL_OPT)
 #include "opt_bpf.h"
@@ -340,6 +340,7 @@
 static void
 bpf_attachd(struct bpf_d *d, struct bpf_if *bp)
 {
+       KASSERT(mutex_owned(&bpf_mtx));
        /*
         * Point d at bp, and add d to the interface's list of listeners.
         * Finally, point the driver's bpf cookie at the interface so
@@ -361,6 +362,8 @@
        struct bpf_d **p;
        struct bpf_if *bp;
 
+       KASSERT(mutex_owned(&bpf_mtx));
+
        bp = d->bd_bif;
        /*
         * Check if this descriptor had requested promiscuous mode.
@@ -476,6 +479,7 @@
        int s;
 
        KERNEL_LOCK(1, NULL);
+       mutex_enter(&bpf_mtx);
 
        /*
         * Refresh the PID associated with this bpf file.
@@ -490,15 +494,14 @@
                bpf_detachd(d);
        splx(s);
        bpf_freed(d);
-       mutex_enter(&bpf_mtx);
        LIST_REMOVE(d, bd_list);
-       mutex_exit(&bpf_mtx);
        callout_destroy(&d->bd_callout);
        seldestroy(&d->bd_sel);
        softint_disestablish(d->bd_sih);
        free(d, M_DEVBUF);
        fp->f_bpf = NULL;
 
+       mutex_exit(&bpf_mtx);
        KERNEL_UNLOCK_ONE(NULL);
 
        return (0);
@@ -900,10 +903,12 @@
         * Set device parameters.
         */
        case BIOCSDLT:
+               mutex_enter(&bpf_mtx);
                if (d->bd_bif == NULL)
                        error = EINVAL;
                else
                        error = bpf_setdlt(d, *(u_int *)addr);
+               mutex_exit(&bpf_mtx);
                break;
 
        /*
@@ -926,7 +931,9 @@
        case OBIOCSETIF:
 #endif
        case BIOCSETIF:
+               mutex_enter(&bpf_mtx);
                error = bpf_setif(d, addr);
+               mutex_exit(&bpf_mtx);
                break;
 
        /*
@@ -1152,6 +1159,7 @@
        char *cp;
        int unit_seen, i, s, error;
 
+       KASSERT(mutex_owned(&bpf_mtx));
        /*
         * Make sure the provided name has a unit number, and default
         * it to '0' if not specified.
@@ -1717,10 +1725,10 @@
 bpf_allocbufs(struct bpf_d *d)
 {
 
-       d->bd_fbuf = malloc(d->bd_bufsize, M_DEVBUF, M_WAITOK | M_CANFAIL);
+       d->bd_fbuf = malloc(d->bd_bufsize, M_DEVBUF, M_NOWAIT);
        if (!d->bd_fbuf)
                return (ENOBUFS);
-       d->bd_sbuf = malloc(d->bd_bufsize, M_DEVBUF, M_WAITOK | M_CANFAIL);
+       d->bd_sbuf = malloc(d->bd_bufsize, M_DEVBUF, M_NOWAIT);
        if (!d->bd_sbuf) {
                free(d->bd_fbuf, M_DEVBUF);
                return (ENOBUFS);
@@ -1770,6 +1778,7 @@
        if (bp == NULL)
                panic("bpfattach");
 
+       mutex_enter(&bpf_mtx);
        bp->bif_dlist = NULL;
        bp->bif_driverp = driverp;
        bp->bif_ifp = ifp;
@@ -1781,6 +1790,7 @@
        *bp->bif_driverp = NULL;
 
        bp->bif_hdrlen = hdrlen;
+       mutex_exit(&bpf_mtx);
 #if 0
        printf("bpf: %s attached\n", ifp->if_xname);
 #endif
@@ -1796,6 +1806,7 @@
        struct bpf_d *d;
        int s;
 
+       mutex_enter(&bpf_mtx);
        /* Nuke the vnodes for any open instances */
        LIST_FOREACH(d, &bpf_list, bd_list) {
                if (d->bd_bif != NULL && d->bd_bif->bif_ifp == ifp) {
@@ -1819,6 +1830,7 @@
                        goto again;
                }
        }
+       mutex_exit(&bpf_mtx);
 }
 
 /*
@@ -1879,6 +1891,8 @@
        struct ifnet *ifp;
        struct bpf_if *bp;
 
+       KASSERT(mutex_owned(&bpf_mtx));
+
        if (d->bd_bif->bif_dlt == dlt)
                return 0;
        ifp = d->bd_bif->bif_ifp;