kernel/linux.git/include/net/dst.h, branch v6.12.80

net: dst: introduce dst->dev_rcu

2025-12-18T12:55:22+00:00

[ Upstream commit caedcc5b6df1b2e2b5f39079e3369c1d4d5c5f50 ] Followup of commit 88fe14253e1818 ("net: dst: add four helpers to annotate data-races around dst->dev"). We want to gradually add explicit RCU protection to dst->dev, including lockdep support. Add an union to alias dst->dev_rcu and dst->dev. Add dst_dev_net_rcu() helper. Fixes: 4a6ce2b6f2ec ("net: introduce a new function dst_dev_put()") Cc: stable@vger.kernel.org Signed-off-by: Eric Dumazet Reviewed-by: David Ahern Link: https://patch.msgid.link/20250828195823.3958522-2-edumazet@google.com Signed-off-by: Jakub Kicinski Stable-dep-of: 50c127a69cd62 ("Replace three dst_dev() with a lockdep enabled helper.") Signed-off-by: Gyokhan Kochmarla Signed-off-by: Greg Kroah-Hartman

net: Add locking to protect skb->dev access in ip_output

2025-10-23T14:20:45+00:00

[ Upstream commit 1dbf1d590d10a6d1978e8184f8dfe20af22d680a ] In ip_output() skb->dev is updated from the skb_dst(skb)->dev this can become invalid when the interface is unregistered and freed, Introduced new skb_dst_dev_rcu() function to be used instead of skb_dst_dev() within rcu_locks in ip_output.This will ensure that all the skb's associated with the dev being deregistered will be transnmitted out first, before freeing the dev. Given that ip_output() is called within an rcu_read_lock() critical section or from a bottom-half context, it is safe to introduce an RCU read-side critical section within it. Multiple panic call stacks were observed when UL traffic was run in concurrency with device deregistration from different functions, pasting one sample for reference. [496733.627565][T13385] Call trace: [496733.627570][T13385] bpf_prog_ce7c9180c3b128ea_cgroupskb_egres+0x24c/0x7f0 [496733.627581][T13385] __cgroup_bpf_run_filter_skb+0x128/0x498 [496733.627595][T13385] ip_finish_output+0xa4/0xf4 [496733.627605][T13385] ip_output+0x100/0x1a0 [496733.627613][T13385] ip_send_skb+0x68/0x100 [496733.627618][T13385] udp_send_skb+0x1c4/0x384 [496733.627625][T13385] udp_sendmsg+0x7b0/0x898 [496733.627631][T13385] inet_sendmsg+0x5c/0x7c [496733.627639][T13385] __sys_sendto+0x174/0x1e4 [496733.627647][T13385] __arm64_sys_sendto+0x28/0x3c [496733.627653][T13385] invoke_syscall+0x58/0x11c [496733.627662][T13385] el0_svc_common+0x88/0xf4 [496733.627669][T13385] do_el0_svc+0x2c/0xb0 [496733.627676][T13385] el0_svc+0x2c/0xa4 [496733.627683][T13385] el0t_64_sync_handler+0x68/0xb4 [496733.627689][T13385] el0t_64_sync+0x1a4/0x1a8 Changes in v3: - Replaced WARN_ON() with WARN_ON_ONCE(), as suggested by Willem de Bruijn. - Dropped legacy lines mistakenly pulled in from an outdated branch. Changes in v2: - Addressed review comments from Eric Dumazet - Used READ_ONCE() to prevent potential load/store tearing - Added skb_dst_dev_rcu() and used along with rcu_read_lock() in ip_output Signed-off-by: Sharath Chandra Vurukala Reviewed-by: Eric Dumazet Link: https://patch.msgid.link/20250730105118.GA26100@hu-sharathv-hyd.qualcomm.com Signed-off-by: Jakub Kicinski Stable-dep-of: 833d4313bc1e ("mptcp: reset blackhole on success with non-loopback ifaces") Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

net: dst: add four helpers to annotate data-races around dst->dev

2025-10-23T14:20:45+00:00

[ Upstream commit 88fe14253e181878c2ddb51a298ae8c468a63010 ] dst->dev is read locklessly in many contexts, and written in dst_dev_put(). Fixing all the races is going to need many changes. We probably will have to add full RCU protection. Add three helpers to ease this painful process. static inline struct net_device *dst_dev(const struct dst_entry *dst) { return READ_ONCE(dst->dev); } static inline struct net_device *skb_dst_dev(const struct sk_buff *skb) { return dst_dev(skb_dst(skb)); } static inline struct net *skb_dst_dev_net(const struct sk_buff *skb) { return dev_net(skb_dst_dev(skb)); } static inline struct net *skb_dst_dev_net_rcu(const struct sk_buff *skb) { return dev_net_rcu(skb_dst_dev(skb)); } Fixes: 4a6ce2b6f2ec ("net: introduce a new function dst_dev_put()") Signed-off-by: Eric Dumazet Reviewed-by: Kuniyuki Iwashima Link: https://patch.msgid.link/20250630121934.3399505-7-edumazet@google.com Signed-off-by: Jakub Kicinski Stable-dep-of: 833d4313bc1e ("mptcp: reset blackhole on success with non-loopback ifaces") Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

net: dst: annotate data-races around dst->output

2025-08-15T10:13:41+00:00

[ Upstream commit 2dce8c52a98995c4719def6f88629ab1581c0b82 ] dst_dev_put() can overwrite dst->output while other cpus might read this field (for instance from dst_output()) Add READ_ONCE()/WRITE_ONCE() annotations to suppress potential issues. We will likely need RCU protection in the future. Fixes: 4a6ce2b6f2ec ("net: introduce a new function dst_dev_put()") Signed-off-by: Eric Dumazet Reviewed-by: Kuniyuki Iwashima Link: https://patch.msgid.link/20250630121934.3399505-6-edumazet@google.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

net: dst: annotate data-races around dst->input

2025-08-15T10:13:41+00:00

[ Upstream commit f1c5fd34891a1c242885f48c2e4dc52df180f311 ] dst_dev_put() can overwrite dst->input while other cpus might read this field (for instance from dst_input()) Add READ_ONCE()/WRITE_ONCE() annotations to suppress potential issues. We will likely need full RCU protection later. Fixes: 4a6ce2b6f2ec ("net: introduce a new function dst_dev_put()") Signed-off-by: Eric Dumazet Reviewed-by: Kuniyuki Iwashima Link: https://patch.msgid.link/20250630121934.3399505-5-edumazet@google.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

include: net: add static inline dst_dev_overhead() to dst.h

2025-02-21T13:01:38+00:00

[ Upstream commit 0600cf40e9b36fe17f9c9f04d4f9cef249eaa5e7 ] Add static inline dst_dev_overhead() function to include/net/dst.h. This helper function is used by ioam6_iptunnel, rpl_iptunnel and seg6_iptunnel to get the dev's overhead based on a cache entry (dst_entry). If the cache is empty, the default and generic value skb->mac_len is returned. Otherwise, LL_RESERVED_SPACE() over dst's dev is returned. Signed-off-by: Justin Iurman Cc: Alexander Lobakin Cc: Vadim Fedorenko Signed-off-by: Paolo Abeni Stable-dep-of: 92191dd10730 ("net: ipv6: fix dst ref loops in rpl, seg6 and ioam6 lwtunnels") Signed-off-by: Sasha Levin

net: Correct spelling in headers

2024-08-26T16:37:23+00:00

Correct spelling in Networking headers. As reported by codespell. Signed-off-by: Simon Horman Link: https://patch.msgid.link/20240822-net-spell-v1-12-3a98971ce2d2@kernel.org Signed-off-by: Jakub Kicinski

net: dst: Make dst_destroy() static and return void.

2024-02-06T10:45:53+00:00

Since commit 52df157f17e56 ("xfrm: take refcnt of dst when creating struct xfrm_dst bundle") dst_destroy() returns only NULL and no caller cares about the return value. There are no in in-tree users of dst_destroy() outside of the file. Make dst_destroy() static and return void. Signed-off-by: Sebastian Andrzej Siewior Reviewed-by: Eric Dumazet Link: https://lore.kernel.org/r/20240202163746.2489150-1-bigeasy@linutronix.de Signed-off-by: Paolo Abeni

ipv6: drop feature RTAX_FEATURE_ALLFRAG

2023-10-26T01:04:29+00:00

RTAX_FEATURE_ALLFRAG was added before the first git commit: https://www.mail-archive.com/bk-commits-head@vger.kernel.org/msg03399.html The feature would send packets to the fragmentation path if a box receives a PMTU value with less than 1280 byte. However, since commit 9d289715eb5c ("ipv6: stop sending PTB packets for MTU < 1280"), such message would be simply discarded. The feature flag is neither supported in iproute2 utility. In theory one can still manipulate it with direct netlink message, but it is not ideal because it was based on obsoleted guidance of RFC-2460 (replaced by RFC-8200). The feature would always test false at the moment, so remove related code or mark them as unused. Signed-off-by: Yan Zhai Reviewed-by: Florian Westphal Reviewed-by: Eric Dumazet Link: https://lore.kernel.org/r/d78e44dcd9968a252143ffe78460446476a472a1.1698156966.git.yan@cloudflare.com Signed-off-by: Jakub Kicinski

net: dst: remove unnecessary input parameter in dst_alloc and dst_init

2023-09-12T09:42:25+00:00

Since commit 1202cdd66531("Remove DECnet support from kernel") has been merged, all callers pass in the initial_ref value of 1 when they call dst_alloc(). Therefore, remove initial_ref when the dst_alloc() is declared and replace initial_ref with 1 in dst_alloc(). Also when all callers call dst_init(), the value of initial_ref is 1. Therefore, remove the input parameter initial_ref of the dst_init() and replace initial_ref with the value 1 in dst_init. Signed-off-by: Zhengchao Shao Link: https://lore.kernel.org/r/20230911125045.346390-1-shaozhengchao@huawei.com Signed-off-by: Paolo Abeni