[PATCH] net/tls: fix kernel panic when alloc_page failed

[Pengtao He <hept.hept.hept@gmail.com>]

We cannot set frag_list to NULL pointer when alloc_page failed.
It will be used in tls_strp_check_queue_ok when the next time
tls_strp_read_sock is called.

Unable to handle kernel NULL pointer dereference
at virtual address 0000000000000028
 Call trace:
 tls_strp_check_rcv+0x128/0x27c
 tls_strp_data_ready+0x34/0x44
 tls_data_ready+0x3c/0x1f0
 tcp_data_ready+0x9c/0xe4
 tcp_data_queue+0xf6c/0x12d0
 tcp_rcv_established+0x52c/0x798

Signed-off-by: Pengtao He <hept.hept.hept@gmail.com>
---
 net/tls/tls_strp.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/net/tls/tls_strp.c b/net/tls/tls_strp.c
index 77e33e1e340e..65b0da6fdf6a 100644
--- a/net/tls/tls_strp.c
+++ b/net/tls/tls_strp.c
@@ -396,7 +396,6 @@ static int tls_strp_read_copy(struct tls_strparser *strp, bool qshort)
 		return 0;
 
 	shinfo = skb_shinfo(strp->anchor);
-	shinfo->frag_list = NULL;
 
 	/* If we don't know the length go max plus page for cipher overhead */
 	need_spc = strp->stm.full_len ?: TLS_MAX_PAYLOAD_SIZE + PAGE_SIZE;
@@ -412,6 +411,8 @@ static int tls_strp_read_copy(struct tls_strparser *strp, bool qshort)
 				   page, 0, 0);
 	}
 
+	shinfo->frag_list = NULL;
+
 	strp->copy_mode = 1;
 	strp->stm.offset = 0;
 
-- 
2.37.1