From: Jakub Kicinski jakub.kicinski@netronome.com
[ Upstream commit 4a9c2e3746e6151fd5d077259d79ce9ca86d47d7 ]
This reverts the first part of commit 4e485d06bb8c ("strparser: Call skb_unclone conditionally"). To build a message with multiple fragments we need our own root of frag_list. We can't simply use the frag_list of orig_skb, because it will lead to linking all orig_skbs together creating very long frag chains, and causing stack overflow on kfree_skb() (which is called recursively on the frag_lists).
BUG: stack guard page was hit at 00000000d40fad41 (stack is 0000000029dde9f4..000000008cce03d5) kernel stack overflow (double-fault): 0000 [#1] PREEMPT SMP RIP: 0010:free_one_page+0x2b/0x490
Call Trace: __free_pages_ok+0x143/0x2c0 skb_release_data+0x8e/0x140 ? skb_release_data+0xad/0x140 kfree_skb+0x32/0xb0
[...]
skb_release_data+0xad/0x140 ? skb_release_data+0xad/0x140 kfree_skb+0x32/0xb0 skb_release_data+0xad/0x140 ? skb_release_data+0xad/0x140 kfree_skb+0x32/0xb0 skb_release_data+0xad/0x140 ? skb_release_data+0xad/0x140 kfree_skb+0x32/0xb0 skb_release_data+0xad/0x140 ? skb_release_data+0xad/0x140 kfree_skb+0x32/0xb0 skb_release_data+0xad/0x140 __kfree_skb+0xe/0x20 tcp_disconnect+0xd6/0x4d0 tcp_close+0xf4/0x430 ? tcp_check_oom+0xf0/0xf0 tls_sk_proto_close+0xe4/0x1e0 [tls] inet_release+0x36/0x60 __sock_release+0x37/0xa0 sock_close+0x11/0x20 __fput+0xa2/0x1d0 task_work_run+0x89/0xb0 exit_to_usermode_loop+0x9a/0xa0 do_syscall_64+0xc0/0xf0 entry_SYSCALL_64_after_hwframe+0x44/0xa9
Let's leave the second unclone conditional, as I'm not entirely sure what is its purpose :)
Fixes: 4e485d06bb8c ("strparser: Call skb_unclone conditionally") Signed-off-by: Jakub Kicinski jakub.kicinski@netronome.com Reviewed-by: Dirk van der Merwe dirk.vandermerwe@netronome.com Reviewed-by: Eric Dumazet edumazet@google.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Sasha Levin alexander.levin@microsoft.com --- net/strparser/strparser.c | 12 +++++------- 1 file changed, 5 insertions(+), 7 deletions(-)
diff --git a/net/strparser/strparser.c b/net/strparser/strparser.c index da1a676860ca..0f4e42792878 100644 --- a/net/strparser/strparser.c +++ b/net/strparser/strparser.c @@ -140,13 +140,11 @@ static int __strp_recv(read_descriptor_t *desc, struct sk_buff *orig_skb, /* We are going to append to the frags_list of head. * Need to unshare the frag_list. */ - if (skb_has_frag_list(head)) { - err = skb_unclone(head, GFP_ATOMIC); - if (err) { - STRP_STATS_INCR(strp->stats.mem_fail); - desc->error = err; - return 0; - } + err = skb_unclone(head, GFP_ATOMIC); + if (err) { + STRP_STATS_INCR(strp->stats.mem_fail); + desc->error = err; + return 0; }
if (unlikely(skb_shinfo(head)->frag_list)) {