Re: svn commit: r256519 - in head/sys: net netatalk netinet netinet6 netipx

From: Zhenlei Huang <zlei_at_FreeBSD.org>
Date: Tue, 30 Sep 2025 02:38:10 UTC

> On Sep 29, 2025, at 10:29 PM, Mateusz Guzik <mjguzik@gmail.com> wrote:
> 
> On Tue, Oct 15, 2013 at 12:31 PM Gleb Smirnoff <glebius@freebsd.org> wrote:
>> 
>> Author: glebius
>> Date: Tue Oct 15 10:31:42 2013
>> New Revision: 256519
>> URL: http://svnweb.freebsd.org/changeset/base/256519
>> 
>> Log:
>>    Remove ifa_init() and provide ifa_alloc() that will allocate and setup
>>  struct ifaddr internally.
>> 
>>  Sponsored by: Netflix
>>  Sponsored by: Nginx, Inc.
>> 
>> Modified:
>>  head/sys/net/if.c
>>  head/sys/net/if_var.h
>>  head/sys/netatalk/at_control.c
>>  head/sys/netinet/in.c
>>  head/sys/netinet6/in6.c
>>  head/sys/netipx/ipx.c
>> 
>> Modified: head/sys/net/if.c
>> ==============================================================================
>> --- head/sys/net/if.c   Tue Oct 15 10:19:24 2013        (r256518)
>> +++ head/sys/net/if.c   Tue Oct 15 10:31:42 2013        (r256519)
>> @@ -633,8 +633,7 @@ if_attach_internal(struct ifnet *ifp, in
>>                        socksize = sizeof(*sdl);
>>                socksize = roundup2(socksize, sizeof(long));
>>                ifasize = sizeof(*ifa) + 2 * socksize;
>> -               ifa = malloc(ifasize, M_IFADDR, M_WAITOK | M_ZERO);
>> -               ifa_init(ifa);
>> +               ifa = ifa_alloc(ifasize, M_WAITOK);
>>                sdl = (struct sockaddr_dl *)(ifa + 1);
>>                sdl->sdl_len = socksize;
>>                sdl->sdl_family = AF_LINK;
>> @@ -1417,13 +1416,23 @@ if_maddr_runlock(struct ifnet *ifp)
>> /*
>>  * Initialization, destruction and refcounting functions for ifaddrs.
>>  */
>> -void
>> -ifa_init(struct ifaddr *ifa)
>> +struct ifaddr *
>> +ifa_alloc(size_t size, int flags)
>> {
>> +       struct ifaddr *ifa;
>> +
>> +       KASSERT(size >= sizeof(struct ifaddr),
>> +           ("%s: invalid size %zu", __func__, size));
>> +
> 
> We have crashes stemming from this:
> 
> panic: ifa_alloc: invalid size 16
> 
> panic() at panic+0x43/frame 0xfffffe009e777760
> ifa_alloc() at ifa_alloc+0xd6/frame 0xfffffe009e777780
> in6_ifadd() at in6_ifadd+0xd8/frame 0xfffffe009e7778a0
> nd6_ra_input() at nd6_ra_input+0x1023/frame 0xfffffe009e777a80
> icmp6_input() at icmp6_input+0x5b6/frame 0xfffffe009e777c00
> ip6_input() at ip6_input+0xc94/frame 0xfffffe009e777ce0
> sppp_input() at sppp_input+0x502/frame 0xfffffe009e777d70
> pppoe_data_input() at pppoe_data_input+0x1e7/frame 0xfffffe009e777de0
> swi_net() at swi_net+0x19b/frame 0xfffffe009e777e60
> ithread_loop() at ithread_loop+0x266/frame 0xfffffe009e777ef0
> fork_exit() at fork_exit+0x82/frame 0xfffffe009e777f30
> fork_trampoline() at fork_trampoline+0xe/frame 0xfffffe009e777f30
> 
> in6_ifadd has:
>                        struct in6_addr taddr;
>                        ifa = ifa_alloc(sizeof(taddr), M_WAITOK);
> 
> should the assert be simply removed?

Hi Mateusz,

I believe you just found a bug.

Try the following patch please,

--- a/sys/netinet6/nd6_rtr.c
+++ b/sys/netinet6/nd6_rtr.c
@@ -1243,8 +1243,7 @@ in6_ifadd(struct nd_prefixctl *pr, int mcast)
 
                /* No suitable LL address, get the ifid directly */
                if (ifid_addr == NULL) {
-                       struct in6_addr taddr;
-                       ifa = ifa_alloc(sizeof(taddr), M_WAITOK);
+                       ifa = ifa_alloc(sizeof(struct in6_ifaddr), M_WAITOK);
                        if (ifa) {
                                ib = (struct in6_ifaddr *)ifa;
                                ifid_addr = &ib->ia_addr.sin6_addr;

Best regards,
Zhenlei

> 
>> +       ifa = malloc(size, M_IFADDR, M_ZERO | flags);
>> +       if (ifa == NULL)
>> +               return (NULL);
>> 
>>        mtx_init(&ifa->ifa_mtx, "ifaddr", NULL, MTX_DEF);
>>        refcount_init(&ifa->ifa_refcnt, 1);
>>        ifa->if_data.ifi_datalen = sizeof(ifa->if_data);
>> +
>> +       return (ifa);
>> }
>> 
>> void
>> 
>> Modified: head/sys/net/if_var.h
>> ==============================================================================
>> --- head/sys/net/if_var.h       Tue Oct 15 10:19:24 2013        (r256518)
>> +++ head/sys/net/if_var.h       Tue Oct 15 10:31:42 2013        (r256519)
>> @@ -819,8 +819,8 @@ struct ifaddr {
>> #define        IFA_LOCK(ifa)           mtx_lock(&(ifa)->ifa_mtx)
>> #define        IFA_UNLOCK(ifa)         mtx_unlock(&(ifa)->ifa_mtx)
>> 
>> +struct ifaddr *        ifa_alloc(size_t size, int flags);
>> void   ifa_free(struct ifaddr *ifa);
>> -void   ifa_init(struct ifaddr *ifa);
>> void   ifa_ref(struct ifaddr *ifa);
>> #endif
>> 
>> 
>> Modified: head/sys/netatalk/at_control.c
>> ==============================================================================
>> --- head/sys/netatalk/at_control.c      Tue Oct 15 10:19:24 2013        (r256518)
>> +++ head/sys/netatalk/at_control.c      Tue Oct 15 10:31:42 2013        (r256519)
>> @@ -199,16 +199,10 @@ at_control(struct socket *so, u_long cmd
>>                 * allocate a fresh one.
>>                 */
>>                if (aa == NULL) {
>> -                       aa = malloc(sizeof(struct at_ifaddr), M_IFADDR,
>> -                           M_NOWAIT | M_ZERO);
>> -                       if (aa == NULL) {
>> -                               error = ENOBUFS;
>> -                               goto out;
>> -                       }
>> -                       callout_init(&aa->aa_callout, CALLOUT_MPSAFE);
>> +                       ifa = ifa_alloc(sizeof(struct at_ifaddr), M_WAITOK);
>> +                       aa = (struct at_ifaddr *)ifa;
>> 
>> -                       ifa = (struct ifaddr *)aa;
>> -                       ifa_init(ifa);
>> +                       callout_init(&aa->aa_callout, CALLOUT_MPSAFE);
>> 
>>                        /*
>>                         * As the at_ifaddr contains the actual sockaddrs,
>> 
>> Modified: head/sys/netinet/in.c
>> ==============================================================================
>> --- head/sys/netinet/in.c       Tue Oct 15 10:19:24 2013        (r256518)
>> +++ head/sys/netinet/in.c       Tue Oct 15 10:31:42 2013        (r256519)
>> @@ -404,16 +404,8 @@ in_control(struct socket *so, u_long cmd
>>                        goto out;
>>                }
>>                if (ia == NULL) {
>> -                       ia = (struct in_ifaddr *)
>> -                               malloc(sizeof *ia, M_IFADDR, M_NOWAIT |
>> -                                   M_ZERO);
>> -                       if (ia == NULL) {
>> -                               error = ENOBUFS;
>> -                               goto out;
>> -                       }
>> -
>> -                       ifa = &ia->ia_ifa;
>> -                       ifa_init(ifa);
>> +                       ifa = ifa_alloc(sizeof(struct in_ifaddr), M_WAITOK);
>> +                       ia = (struct in_ifaddr *)ifa;
>>                        ifa->ifa_addr = (struct sockaddr *)&ia->ia_addr;
>>                        ifa->ifa_dstaddr = (struct sockaddr *)&ia->ia_dstaddr;
>>                        ifa->ifa_netmask = (struct sockaddr *)&ia->ia_sockmask;
>> 
>> Modified: head/sys/netinet6/in6.c
>> ==============================================================================
>> --- head/sys/netinet6/in6.c     Tue Oct 15 10:19:24 2013        (r256518)
>> +++ head/sys/netinet6/in6.c     Tue Oct 15 10:31:42 2013        (r256519)
>> @@ -1141,12 +1141,9 @@ in6_update_ifa(struct ifnet *ifp, struct
>>                 * RA, it is called under an interrupt context.  So, we should
>>                 * call malloc with M_NOWAIT.
>>                 */
>> -               ia = (struct in6_ifaddr *) malloc(sizeof(*ia), M_IFADDR,
>> -                   M_NOWAIT);
>> +               ia = (struct in6_ifaddr *)ifa_alloc(sizeof(*ia), M_NOWAIT);
>>                if (ia == NULL)
>>                        return (ENOBUFS);
>> -               bzero((caddr_t)ia, sizeof(*ia));
>> -               ifa_init(&ia->ia_ifa);
>>                LIST_INIT(&ia->ia6_memberships);
>>                /* Initialize the address and masks, and put time stamp */
>>                ia->ia_ifa.ifa_addr = (struct sockaddr *)&ia->ia_addr;
>> 
>> Modified: head/sys/netipx/ipx.c
>> ==============================================================================
>> --- head/sys/netipx/ipx.c       Tue Oct 15 10:19:24 2013        (r256518)
>> +++ head/sys/netipx/ipx.c       Tue Oct 15 10:31:42 2013        (r256519)
>> @@ -190,13 +190,8 @@ ipx_control(struct socket *so, u_long cm
>>                if (td && (error = priv_check(td, PRIV_NET_SETLLADDR)) != 0)
>>                        goto out;
>>                if (ia == NULL) {
>> -                       ia = malloc(sizeof(*ia), M_IFADDR, M_NOWAIT | M_ZERO);
>> -                       if (ia == NULL) {
>> -                               error = ENOBUFS;
>> -                               goto out;
>> -                       }
>> -                       ifa = (struct ifaddr *)ia;
>> -                       ifa_init(ifa);
>> +                       ifa = ifa_alloc(sizeof(struct ipx_ifaddr), M_WAITOK);
>> +                       ia = (struct ipx_ifaddr *)ifa;
>>                        ia->ia_ifp = ifp;
>>                        ifa->ifa_addr = (struct sockaddr *)&ia->ia_addr;
>>                        ifa->ifa_netmask = (struct sockaddr *)&ipx_netmask;