kernel/linux.git/include/net/dst.h, branch v6.1.168

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

2026-01-17T15:39:28+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 - Dropped legacy lines mistakenly pulled in from an outdated branch.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 [ Keerthana: Backported the patch to v5.15-v6.1 ] Signed-off-by: Keerthana K Signed-off-by: Greg Kroah-Hartman

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

2025-03-07T15:56:46+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: c64a0727f9b1 ("net: ipv6: fix dst ref loop on input in seg6 lwt") Signed-off-by: Sasha Levin

net: add atomic_long_t to net_device_stats fields

2022-12-31T12:33:02+00:00

[ Upstream commit 6c1c5097781f563b70a81683ea6fdac21637573b ] Long standing KCSAN issues are caused by data-race around some dev->stats changes. Most performance critical paths already use per-cpu variables, or per-queue ones. It is reasonable (and more correct) to use atomic operations for the slow paths. This patch adds an union for each field of net_device_stats, so that we can convert paths that are not yet protected by a spinlock or a mutex. netdev_stats_to_stats64() no longer has an #if BITS_PER_LONG==64 Note that the memcpy() we were using on 64bit arches had no provision to avoid load-tearing, while atomic_long_read() is providing the needed protection at no cost. Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller Signed-off-by: Sasha Levin

net: Remove unused inline function dst_hold_and_use()

2022-09-26T18:48:14+00:00

All uses of dst_hold_and_use() have been removed since commit 1202cdd66531 ("Remove DECnet support from kernel"), so remove it. Signed-off-by: Gaosheng Cui Signed-off-by: Jakub Kicinski

net: dst: add net device refcount tracking to dst_entry

2021-12-07T00:05:10+00:00

We want to track all dev_hold()/dev_put() to ease leak hunting. Signed-off-by: Eric Dumazet Signed-off-by: Jakub Kicinski

sk_buff: track dst status in slow_gro

2021-07-29T11:18:11+00:00

Similar to the previous patch, but covering the dst field: the slow_gro flag is additionally set when a dst is attached to the skb RFC -> v1: - use the existing flag instead of adding a new one Signed-off-by: Paolo Abeni Signed-off-by: David S. Miller

net: Consolidate common blackhole dst ops

2021-03-10T20:24:18+00:00

Move generic blackhole dst ops to the core and use them from both ipv4_dst_blackhole_ops and ip6_dst_blackhole_ops where possible. No functional change otherwise. We need these also in other locations and having to define them over and over again is not great. Signed-off-by: Daniel Borkmann Signed-off-by: David S. Miller

net: indirect call helpers for ipv4/ipv6 dst_check functions

2021-02-03T22:51:40+00:00

This patch avoids the indirect call for the common case: ip6_dst_check and ipv4_dst_check Signed-off-by: Brian Vazquez Signed-off-by: Jakub Kicinski

net: use indirect call helpers for dst_mtu

2021-02-03T22:51:39+00:00

This patch avoids the indirect call for the common case: ip6_mtu and ipv4_mtu Signed-off-by: Brian Vazquez Signed-off-by: Jakub Kicinski

net: use indirect call helpers for dst_output

2021-02-03T22:51:39+00:00

This patch avoids the indirect call for the common case: ip6_output and ip_output Signed-off-by: Brian Vazquez Signed-off-by: Jakub Kicinski