On Thu, Nov 17, 2022 at 2:22 PM coverity-bot <keescook@xxxxxxxxxxxx> wrote: > > Hello! > > This is an experimental semi-automated report about issues detected by > Coverity from a scan of next-20221117 as part of the linux-next scan project: > https://scan.coverity.com/projects/linux-next-weekly-scan > > You're getting this email because you were associated with the identified > lines of code (noted below) that were touched by commits: > > Wed Nov 16 12:42:01 2022 +0000 > 4ebf802cf1c6 ("net: __sock_gen_cookie() cleanup") > > Coverity reported the following: > > *** CID 1527347: Error handling issues (CHECKED_RETURN) > net/core/sock_diag.c:33 in __sock_gen_cookie() > 27 { > 28 u64 res = atomic64_read(&sk->sk_cookie); > 29 > 30 if (!res) { > 31 u64 new = gen_cookie_next(&sock_cookie); > 32 > vvv CID 1527347: Error handling issues (CHECKED_RETURN) > vvv Calling "atomic64_try_cmpxchg" without checking return value (as is done elsewhere 8 out of 9 times). > 33 atomic64_try_cmpxchg(&sk->sk_cookie, &res, new); Hmmm. for some reason I thought @res was always updated... A fix would be to read sk->sk_cookie, but I guess your tool will still complain we do not care of atomic64_try_cmpxchg() return value ? diff --git a/net/core/sock_diag.c b/net/core/sock_diag.c index b11593cae5a09b15a10d6ba35bccc22263cb8fc8..58efb9c1c8dd4f8e5a3009a0176e1b96487daaff 100644 --- a/net/core/sock_diag.c +++ b/net/core/sock_diag.c @@ -31,6 +31,10 @@ u64 __sock_gen_cookie(struct sock *sk) u64 new = gen_cookie_next(&sock_cookie); atomic64_try_cmpxchg(&sk->sk_cookie, &res, new); + /* Another cpu/thread might have won the race, + * reload the final value. + */ + res = atomic64_read(&sk->sk_cookie); } return res; }
