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authorJakub Kicinski <jakub.kicinski@netronome.com>2019-04-10 21:04:32 +0300
committerDavid S. Miller <davem@davemloft.net>2019-04-10 23:07:02 +0300
commit4a9c2e3746e6151fd5d077259d79ce9ca86d47d7 (patch)
tree745bb98ce86c2b200e8d2c642ddcf65c4cb9a2ef /net
parent35b71a34ada62c9573847a324bf06a133fe11b11 (diff)
downloadlinux-4a9c2e3746e6151fd5d077259d79ce9ca86d47d7.tar.xz
net: strparser: partially revert "strparser: Call skb_unclone conditionally"
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>
Diffstat (limited to 'net')
-rw-r--r--net/strparser/strparser.c12
1 files changed, 5 insertions, 7 deletions
diff --git a/net/strparser/strparser.c b/net/strparser/strparser.c
index 860dcfb95ee4..fa6c977b4c41 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)) {