| Message ID | 160522369822.135009.15718253545046438408.stgit@john-XPS-13-9370 (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | BPF |
| Headers | show |
| Series | sockmap fixes | expand |
| Context | Check | Description |
|---|---|---|
| netdev/cover_letter | success | Link |
| netdev/fixes_present | success | Link |
| netdev/patch_count | success | Link |
| netdev/tree_selection | success | Clearly marked for bpf |
| netdev/subject_prefix | success | Link |
| netdev/source_inline | success | Was 0 now: 0 |
| netdev/verify_signedoff | success | Link |
| netdev/module_param | success | Was 0 now: 0 |
| netdev/build_32bit | success | Errors and warnings before: 1 this patch: 1 |
| netdev/kdoc | success | Errors and warnings before: 0 this patch: 0 |
| netdev/verify_fixes | success | Link |
| netdev/checkpatch | success | total: 0 errors, 0 warnings, 0 checks, 18 lines checked |
| netdev/build_allmodconfig_warn | success | Errors and warnings before: 1 this patch: 1 |
| netdev/header_inline | success | Link |
| netdev/stable | success | Stable not CCed |
diff --git a/net/core/skmsg.c b/net/core/skmsg.c index f747ee341fe8..7ec1fdc083e4 100644 --- a/net/core/skmsg.c +++ b/net/core/skmsg.c @@ -425,9 +425,16 @@ static int sk_psock_skb_ingress_enqueue(struct sk_buff *skb, struct sock *sk, struct sk_msg *msg) { - int num_sge = skb_to_sgvec(skb, msg->sg.data, 0, skb->len); - int copied; + int num_sge, copied; + /* skb linearize may fail with ENOMEM, but lets simply try again + * later if this happens. Under memory pressure we don't want to + * drop the skb. We need to linearize the skb so that the mapping + * in skb_to_sgvec can not error. + */ + if (skb_linearize(skb)) + return -EAGAIN; + num_sge = skb_to_sgvec(skb, msg->sg.data, 0, skb->len); if (unlikely(num_sge < 0)) { kfree(msg); return num_sge;
When skb has a frag_list its possible for skb_to_sgvec() to fail. This happens when the scatterlist has fewer elements to store pages than would be needed for the initial skb plus any of its frags. This case appears rare, but is possible when running an RX parser/verdict programs exposed to the internet. Currently, when this happens we throw an error, break the pipe, and kfree the msg. This effectively breaks the application or forces it to do a retry. Lets catch this case and handle it by doing an skb_linearize() on any skb we receive with frags. At this point skb_to_sgvec should not fail because the failing conditions would require frags to be in place. Fixes: 604326b41a6fb ("bpf, sockmap: convert to generic sk_msg interface") Signed-off-by: John Fastabend <john.fastabend@gmail.com> --- net/core/skmsg.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-)