amt: no longer rely on RTNL in amt_fill_info()

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Update amt_fill_info() to run under RCU read lock instead of RTNL.

The AMT device configuration fields (mode, relay_port, gw_port, local_ip,
discovery_ip, max_tunnels) and stream_dev pointer are initialized during
device creation (amt_newlink) and are immutable. Accessing them locklessly
is safe. The stream_dev net_device structure is protected from being freed
by RCU.

The only field that can change concurrently is amt->remote_ip, which is
updated in the packet receive path (amt_advertisement_handler) and
workqueue (amt_req_work). Add READ_ONCE()/WRITE_ONCE() annotations
around amt->remote_ip to prevent data races.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>
Link: https://patch.msgid.link/20260701125016.3650708-1-edumazet@google.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

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Eric Dumazet 2026-07-01 12:50:16 +00:00 • committed by Paolo Abeni

parent d7261cdb95

commit 586c4dcf28

1 changed files with 27 additions and 16 deletions

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drivers/net/amt.c

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