[PATCH net-next v3 0/2] ipv4: update rt_flush_dev() and two dst.dev readers

[xuanqiang.luo@linux.dev]

From: Xuanqiang Luo <xuanqiang.luo@linux.dev>

Patch 1 makes the rt_flush_dev() write to rt->dst.dev use
rcu_assign_pointer(), matching the existing dst_dev_rcu() readers.

Patch 2 makes ip_rt_send_redirect() and ip_rt_get_source() use one
dst.dev snapshot throughout each operation, so a concurrent rt_flush_dev()
update cannot make them use values from two devices.

v3:
- Split the rt_flush_dev() change into a separate patch.
- Update PATCH 2 subject and commit message to describe the actual scope
  more clearly.
- Drop the Fixes tag.
- Fix local variable ordering for netdev reverse xmas tree style.

Thanks to Ido Schimmel for the feedback.

v2: https://lore.kernel.org/lkml/20260701032434.17500-1-xuanqiang.luo@linux.dev/
- Use dst_dev_rcu() and dev_net_rcu() for the RCU readers.
- Use rcu_assign_pointer() when publishing the uncached route device
  replacement.
- Slightly adjust the commit message wording because this issue was found
  by inspection, not from an observed user-visible failure.

v1: https://lore.kernel.org/all/20260630094250.29386-1-xuanqiang.luo@linux.dev/

Xuanqiang Luo (2):
  ipv4: use rcu_assign_pointer() in rt_flush_dev()
  ipv4: snapshot dst.dev in ip_rt_send_redirect() and ip_rt_get_source()

 net/ipv4/route.c | 33 +++++++++++++++++++--------------
 1 file changed, 19 insertions(+), 14 deletions(-)

-- 
2.43.0