git: b84629b21aea - stable/15 - if_vxlan: Update *m0 after a pullup

The branch stable/15 has been updated by markj:

URL: https://cgit.FreeBSD.org/src/commit/?id=b84629b21aea01a70f389fe30d02f70cf71be896

commit b84629b21aea01a70f389fe30d02f70cf71be896
Author:     Mark Johnston <markj@FreeBSD.org>
AuthorDate: 2026-05-12 17:50:15 +0000
Commit:     Mark Johnston <markj@FreeBSD.org>
CommitDate: 2026-05-19 14:08:32 +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
    
    (cherry picked from commit a6c4fe2d1a38885914b1c3e85508b965ccdb7874)
---
 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 f3a8410a2258..fc3d3752e0ae 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;
 	}