git: a6c4fe2d1a38 - main - if_vxlan: Update *m0 after a pullup

From: Mark Johnston <markj_at_FreeBSD.org>
Date: Tue, 12 May 2026 20:06:09 UTC
The branch main has been updated by markj:

URL: https://cgit.FreeBSD.org/src/commit/?id=a6c4fe2d1a38885914b1c3e85508b965ccdb7874

commit a6c4fe2d1a38885914b1c3e85508b965ccdb7874
Author:     Mark Johnston <markj@FreeBSD.org>
AuthorDate: 2026-05-12 17:50:15 +0000
Commit:     Mark Johnston <markj@FreeBSD.org>
CommitDate: 2026-05-12 20:05:19 +0000

    if_vxlan: Update *m0 after a pullup
    
    vxlan_input()'s caller is supposed to free *m0 if it is non-NULL after
    the function returns.  vxlan_input() failed to update *m0 after the
    pullup however, so if it hits an error case after the pullup, we'll free
    the mbuf twice.  Currently this can happen only if the interface is
    brought down or due to a packet loop.
    
    Reported by:    Yuxiang Yang, Yizhou Zhao, Xuewei Feng, Qi Li, and Ke Xu from Tsinghua University using GLM5.1 from Z.ai
    Reviewed by:    pouria, zlei
    MFC after:      1 week
    Differential Revision:  https://reviews.freebsd.org/D56944
---
 sys/net/if_vxlan.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/sys/net/if_vxlan.c b/sys/net/if_vxlan.c
index 3d51c3c421ff..da219217480f 100644
--- a/sys/net/if_vxlan.c
+++ b/sys/net/if_vxlan.c
@@ -2876,8 +2876,7 @@ vxlan_input(struct vxlan_socket *vso, uint32_t vni, struct mbuf **m0,
 
 	ifp = sc->vxl_ifp;
 	if (m->m_len < ETHER_HDR_LEN &&
-	    (m = m_pullup(m, ETHER_HDR_LEN)) == NULL) {
-		*m0 = NULL;
+	    (m = *m0 = m_pullup(m, ETHER_HDR_LEN)) == NULL) {
 		error = ENOBUFS;
 		goto out;
 	}