[PATCH net-next v2 0/2] ipv6: mcast: annotate data races in /proc/net/igmp6

[Yuyang Huang]

/proc/net/igmp6 walks IPv6 multicast memberships under RCU without
holding idev->mc_lock, taking a lockless snapshot of two fields that
writers update under the lock: mca_flags and mca_work.timer.expires.

Patch 1 adds WRITE_ONCE() to all mca_flags update sites and READ_ONCE()
to the procfs reader.  Patch 2 does the same for the timer.expires read
in the procfs path.

Changes in v2:
- patch 2: read mca_flags before timer.expires to match write-side
  ordering and avoid printing a garbage timer value.

Yuyang Huang (2):
  ipv6: mcast: annotate data-races around mca_flags
  ipv6: mcast: annotate igmp6 timer expiry race

 net/ipv6/mcast.c | 55 ++++++++++++++++++++++++++++++------------------
 1 file changed, 34 insertions(+), 21 deletions(-)

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2.43.0