Re: [PATCH v2 net-next] ipv4: fib: fix route re-dump in inet_dump_fib() on multi-batch dump

[Ido Schimmel]

On Tue, Jun 30, 2026 at 04:42:20PM +0800, Pengfei Zhang wrote:
> inet_dump_fib() saves its progress in cb->args[1] as a positional
> index within the current hash chain.  Between batches, a concurrent
> fib_new_table() can insert a new table at the chain head, shifting
> all existing entries.  On resume the saved index lands on a different
> table, causing already-dumped tables to be re-dumped and the
> originally suspended table to restart from the beginning.
> 
> Fix by storing tb->tb_id in cb->args[1] instead of a positional
> index, mirroring the fix applied to inet6_dump_fib() in commit
> 9facb861dc6b ("ipv6: fib6: fix NULL deref in fib6_walk_continue()
> on multi-batch dump").
> 
> Signed-off-by: Pengfei Zhang <zhangfeionline@xxxxxxxxx>

Reviewed-by: Ido Schimmel <idosch@xxxxxxxxxx>