coredump: avoid pointless cred reference count bump

The creds are allocated via prepare_creds() which has already taken a
reference.

Link: https://lore.kernel.org/r/20241125-work-cred-v2-12-68b9d38bb5b2@kernel.org
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Christian Brauner <brauner@kernel.org>

Author: brauner

fs/coredump.c

@@ -576,7 +576,7 @@ void do_coredump(const kernel_siginfo_t *siginfo)
 	if (retval < 0)
 		goto fail_creds;
 
-	old_cred = override_creds(get_new_cred(cred));
+	old_cred = override_creds(cred);
 
 	ispipe = format_corename(&cn, &cprm, &argv, &argc);
 
@@ -781,7 +781,7 @@ void do_coredump(const kernel_siginfo_t *siginfo)
 	kfree(argv);
 	kfree(cn.corename);
 	coredump_finish(core_dumped);
-	put_cred(revert_creds(old_cred));
+	revert_creds(old_cred);
 fail_creds:
 	put_cred(cred);
 fail: