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| author | Jesper Dangaard Brouer <hawk@kernel.org> | 2025-07-16 18:26:53 +0200 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2025-07-18 16:59:05 -0700 |
| commit | a6f190630d070173897a7e98a30188b7638ba0a1 (patch) | |
| tree | 72e6fadd557f4929f49bca1fff592c1d34be0e3f /net/ipv6 | |
| parent | 8b7ab8eb52b51a7058edf0035e47b281f9fc9a19 (diff) | |
| download | linux-a6f190630d070173897a7e98a30188b7638ba0a1.tar.gz linux-a6f190630d070173897a7e98a30188b7638ba0a1.tar.bz2 linux-a6f190630d070173897a7e98a30188b7638ba0a1.zip | |
net: track pfmemalloc drops via SKB_DROP_REASON_PFMEMALLOC
Add a new SKB drop reason (SKB_DROP_REASON_PFMEMALLOC) to track packets
dropped due to memory pressure. In production environments, we've observed
memory exhaustion reported by memory layer stack traces, but these drops
were not properly tracked in the SKB drop reason infrastructure.
While most network code paths now properly report pfmemalloc drops, some
protocol-specific socket implementations still use sk_filter() without
drop reason tracking:
- Bluetooth L2CAP sockets
- CAIF sockets
- IUCV sockets
- Netlink sockets
- SCTP sockets
- Unix domain sockets
These remaining cases represent less common paths and could be converted
in a follow-up patch if needed. The current implementation provides
significantly improved observability into memory pressure events in the
network stack, especially for key protocols like TCP and UDP, helping to
diagnose problems in production environments.
Reported-by: Matt Fleming <mfleming@cloudflare.com>
Signed-off-by: Jesper Dangaard Brouer <hawk@kernel.org>
Link: https://patch.msgid.link/175268316579.2407873.11634752355644843509.stgit@firesoul
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'net/ipv6')
| -rw-r--r-- | net/ipv6/tcp_ipv6.c | 9 | ||||
| -rw-r--r-- | net/ipv6/udp.c | 4 |
2 files changed, 4 insertions, 9 deletions
diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c index 8f2c3cba1f1f..7577e7eb2c97 100644 --- a/net/ipv6/tcp_ipv6.c +++ b/net/ipv6/tcp_ipv6.c @@ -1834,14 +1834,12 @@ lookup: } refcounted = true; nsk = NULL; - if (!tcp_filter(sk, skb)) { + if (!tcp_filter(sk, skb, &drop_reason)) { th = (const struct tcphdr *)skb->data; hdr = ipv6_hdr(skb); tcp_v6_fill_cb(skb, hdr, th); nsk = tcp_check_req(sk, skb, req, false, &req_stolen, &drop_reason); - } else { - drop_reason = SKB_DROP_REASON_SOCKET_FILTER; } if (!nsk) { reqsk_put(req); @@ -1897,10 +1895,9 @@ process: nf_reset_ct(skb); - if (tcp_filter(sk, skb)) { - drop_reason = SKB_DROP_REASON_SOCKET_FILTER; + if (tcp_filter(sk, skb, &drop_reason)) goto discard_and_relse; - } + th = (const struct tcphdr *)skb->data; hdr = ipv6_hdr(skb); tcp_v6_fill_cb(skb, hdr, th); diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c index 6bbdadbd5fec..6a68f77da44b 100644 --- a/net/ipv6/udp.c +++ b/net/ipv6/udp.c @@ -894,10 +894,8 @@ static int udpv6_queue_rcv_one_skb(struct sock *sk, struct sk_buff *skb) udp_lib_checksum_complete(skb)) goto csum_error; - if (sk_filter_trim_cap(sk, skb, sizeof(struct udphdr))) { - drop_reason = SKB_DROP_REASON_SOCKET_FILTER; + if (sk_filter_trim_cap(sk, skb, sizeof(struct udphdr), &drop_reason)) goto drop; - } udp_csum_pull_header(skb); |