--- /dev/null
+From 5e34af4142ffe68f01c8a9acae83300f8911e20c Mon Sep 17 00:00:00 2001
+From: Tadeusz Struk <tadeusz.struk@linaro.org>
+Date: Thu, 10 Mar 2022 15:25:38 -0800
+Subject: net: ipv6: fix skb_over_panic in __ip6_append_data
+
+From: Tadeusz Struk <tadeusz.struk@linaro.org>
+
+commit 5e34af4142ffe68f01c8a9acae83300f8911e20c upstream.
+
+Syzbot found a kernel bug in the ipv6 stack:
+LINK: https://syzkaller.appspot.com/bug?id=205d6f11d72329ab8d62a610c44c5e7e25415580
+The reproducer triggers it by sending a crafted message via sendmmsg()
+call, which triggers skb_over_panic, and crashes the kernel:
+
+skbuff: skb_over_panic: text:ffffffff84647fb4 len:65575 put:65575
+head:ffff888109ff0000 data:ffff888109ff0088 tail:0x100af end:0xfec0
+dev:<NULL>
+
+Update the check that prevents an invalid packet with MTU equal
+to the fregment header size to eat up all the space for payload.
+
+The reproducer can be found here:
+LINK: https://syzkaller.appspot.com/text?tag=ReproC&x=1648c83fb00000
+
+Reported-by: syzbot+e223cf47ec8ae183f2a0@syzkaller.appspotmail.com
+Signed-off-by: Tadeusz Struk <tadeusz.struk@linaro.org>
+Acked-by: Willem de Bruijn <willemb@google.com>
+Link: https://lore.kernel.org/r/20220310232538.1044947-1-tadeusz.struk@linaro.org
+Signed-off-by: Jakub Kicinski <kuba@kernel.org>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ net/ipv6/ip6_output.c | 4 ++--
+ 1 file changed, 2 insertions(+), 2 deletions(-)
+
+--- a/net/ipv6/ip6_output.c
++++ b/net/ipv6/ip6_output.c
+@@ -1429,8 +1429,8 @@ static int __ip6_append_data(struct sock
+ sizeof(struct frag_hdr) : 0) +
+ rt->rt6i_nfheader_len;
+
+- if (mtu < fragheaderlen ||
+- ((mtu - fragheaderlen) & ~7) + fragheaderlen < sizeof(struct frag_hdr))
++ if (mtu <= fragheaderlen ||
++ ((mtu - fragheaderlen) & ~7) + fragheaderlen <= sizeof(struct frag_hdr))
+ goto emsgsize;
+
+ maxfraglen = ((mtu - fragheaderlen) & ~7) + fragheaderlen -