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Stephen Hemminger authored
The netlink interface to dump the connection tracking table has a race when entries are deleted at the same time. A customer reported a crash and the backtrace showed thatctnetlink_dump_table was running while a conntrack entry was being destroyed. (see https://bugzilla.vyatta.com/show_bug.cgi?id=6402). According to RCU documentation, when using hlist_nulls the reader must handle the case of seeing a deleted entry and not proceed further down the linked list. The old code would continue which caused the scan to walk into the free list. This patch uses locking (rather than RCU) for this operation which is guaranteed safe, and no longer requires getting reference while doing dump operation. Signed-off-by:
Stephen Hemminger <shemminger@vyatta.com> Signed-off-by:
Pablo Neira Ayuso <pablo@netfilter.org>
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