netfilter: nf_tables: don't use 'data_size' uninitialized

Commit 2c865a8a28a1 ("netfilter: nf_tables: add rule blob layout") never
initialized the new 'data_size' variable.

I'm not sure how it ever worked, but it might have worked almost by
accident - gcc seems to occasionally miss these kinds of 'variable used
uninitialized' situations, but I've seen it do so because it ended up
zero-initializing them due to some other simplification.

But clang is very unhappy about it all, and correctly reports

    net/netfilter/nf_tables_api.c:8278:4: error: variable 'data_size' is uninitialized when used here [-Werror,-Wuninitialized]
                            data_size += sizeof(*prule) + rule->dlen;
    net/netfilter/nf_tables_api.c:8263:30: note: initialize the variable 'data_size' to silence this warning
            unsigned int size, data_size;
                                         = 0
    1 error generated.

and this fix just initializes 'data_size' to zero before the loop.

Fixes: 2c865a8a28a1 ("netfilter: nf_tables: add rule blob layout")
Cc: Pablo Neira Ayuso <>
Cc: Jakub Kicinski <>
Cc: David Miller <>
Signed-off-by: Linus Torvalds <>
1 file changed