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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 /drivers/net/tun.c | |
| parent | 8b7ab8eb52b51a7058edf0035e47b281f9fc9a19 (diff) | |
| download | linux-next-a6f190630d070173897a7e98a30188b7638ba0a1.tar.gz linux-next-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 'drivers/net/tun.c')
| -rw-r--r-- | drivers/net/tun.c | 6 |
1 files changed, 2 insertions, 4 deletions
diff --git a/drivers/net/tun.c b/drivers/net/tun.c index 49bcd12a4ac8..e65228ba3fae 100644 --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -1002,8 +1002,8 @@ static unsigned int run_ebpf_filter(struct tun_struct *tun, /* Net device start xmit */ static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev) { + enum skb_drop_reason drop_reason = SKB_DROP_REASON_NOT_SPECIFIED; struct tun_struct *tun = netdev_priv(dev); - enum skb_drop_reason drop_reason; int txq = skb->queue_mapping; struct netdev_queue *queue; struct tun_file *tfile; @@ -1032,10 +1032,8 @@ static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev) } if (tfile->socket.sk->sk_filter && - sk_filter(tfile->socket.sk, skb)) { - drop_reason = SKB_DROP_REASON_SOCKET_FILTER; + sk_filter_reason(tfile->socket.sk, skb, &drop_reason)) goto drop; - } len = run_ebpf_filter(tun, skb, len); if (len == 0) { |