From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 652C73EAC75; Mon, 31 Aug 2026 11:21:49 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788175310; cv=none; b=CVnRMUsMbk5+WJdfb/DpCUJj7hZ5EQ1sHDM4ga9vh9+xI+6QKT8le1vswqu9Ht+92hMWN2razO+F2XVPjhCuMlqe482LwAgr7OXE1cH0M2byLK2Rir2CdJx6G+iNSqyrGkqfafPNmVEh0fqOy0lSVNXaCAnU/Z5XbhBafH8BBp4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788175310; c=relaxed/simple; bh=yA/Xz27iNSl0I/FYFPwMCx9PJl0ttUYbsV6seW06gok=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=jxByMPgFSB5mnPzNjygRjb+5NpbV+UfHj09Sftp5qRVY/2ZbFPJTBaYPQjbz5S8+sSpK7o5rtOa1E+ohFQvrsuxyINRgvNU92QtZa3VArSMgpiPPB1DeFIVLoc6wc9DBqEuV8MEyfI1xMhRknaE3e/ogf1T2OoK8ByIcW3aCViU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=oI+SfSZq; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="oI+SfSZq" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B7B2D1F000E9; Mon, 31 Aug 2026 11:21:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1788175309; bh=kB/2xO2CtThMIOvpgDlR1yhv6emlsZPwXXBBmEolq/U=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=oI+SfSZqMHQZ3+XfjEAMf1x3Vdswu1UFns9ZT7xz+Vi+RTFp6KSdrQO23Q4jow4Oq fwX/W2m0Jf82Jla/VF9p0A1ABXkK3BuX2zbpksRLhDOgVqDwm3+AWzxKgA/4UsuArW gBoqCa0mRayCkfNOrM7Q8lIKzU5DWjYid0uRVaYYBQShlGl2bU7N7IaEHZUxcGppDj X913fEvgGEZuw3ewgX1gIEMzvHEwHJCpLtMuRS6lSjlAY3IgHr4lwOurgsA+EvFzs3 yng7tt8Z522of86L63wCyen+nJ77ZA/DCBM1qdleUqlwxrPdkMkEJwCd2yLlxoygT0 K8coXOeX3gaYA== From: Christian Brauner Date: Mon, 31 Aug 2026 13:21:18 +0200 Subject: [PATCH 06/10] af_unix: record the pid of the connecting thread Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20260831-work-unix-passpidfd-v1-6-70cbfda0c7ba@kernel.org> References: <20260831-work-unix-passpidfd-v1-0-70cbfda0c7ba@kernel.org> In-Reply-To: <20260831-work-unix-passpidfd-v1-0-70cbfda0c7ba@kernel.org> To: Jakub Kicinski , Kuniyuki Iwashima , Oleg Nesterov Cc: "David S. Miller" , Eric Dumazet , Paolo Abeni , Simon Horman , Willem de Bruijn , netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Alexander Viro , Jan Kara , linux-fsdevel@vger.kernel.org, Alexander Mikhalitsyn , "Christian Brauner (Amutable)" X-Mailer: b4 0.17-dev-db0b7 X-Developer-Signature: v=1; a=openpgp-sha256; l=2771; i=brauner@kernel.org; h=from:subject:message-id; bh=yA/Xz27iNSl0I/FYFPwMCx9PJl0ttUYbsV6seW06gok=; b=owGbwMvMwCU28Zj0gdSKO4sYT6slMWRNTd4otmjuhXNHep2aGMvapxSzt5vKbej9vuHQvur+r 4smmpsqdpSyMIhxMciKKbI4tJuEyy3nqdhslKkBM4eVCWQIAxenAEzEeCvD/9LrDm4Xt9w8JDrN zimJyetEwMvTJ5OnXD7NmnGtOWXpLg6Gv4KN7+s9U2f1xGtYHTob6BVQ8t5voXSp2eQdTxY5clb sZgYA X-Developer-Key: i=brauner@kernel.org; a=openpgp; fpr=4880B8C9BD0E5106FC070F4F7B3C391EFEA93624 Currently only the struct pid of the thread-group leader is recorded. The identity of the actual thread that connected to a given socket cannot be retrieved. Add the plumbing to make it possible to retrieve a pidfd for the connecting thread. Nothing uses the thread-specific struct pid yet. No functional changes. Signed-off-by: Christian Brauner (Amutable) --- net/unix/af_unix.c | 30 +++++++++++++----------------- 1 file changed, 13 insertions(+), 17 deletions(-) diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c index 335abd23c9bf..d01ee76c8026 100644 --- a/net/unix/af_unix.c +++ b/net/unix/af_unix.c @@ -743,51 +743,47 @@ struct unix_peercred { static inline int prepare_peercred(struct unix_peercred *peercred) { - struct pid *pid; int err; - pid = task_tgid(current); - err = pidfs_register_pid(pid); - if (likely(!err)) { - peercred->peer_pid[PIDTYPE_TGID] = get_pid(pid); - peercred->peer_cred = get_current_cred(); + get_task_pids(peercred->peer_pid, current); + err = pidfs_register_pids(peercred->peer_pid); + if (unlikely(err)) { + put_pids(peercred->peer_pid); + return err; } - return err; + + peercred->peer_cred = get_current_cred(); + return 0; } static void drop_peercred(struct unix_peercred *peercred) { const struct cred *cred = NULL; - struct pid *pid = NULL; might_sleep(); - swap(peercred->peer_pid[PIDTYPE_TGID], pid); + put_pids(peercred->peer_pid); swap(peercred->peer_cred, cred); - - put_pid(pid); put_cred(cred); } static inline void init_peercred(struct sock *sk, const struct unix_peercred *peercred) { - sk->sk_peer_pid[PIDTYPE_TGID] = peercred->peer_pid[PIDTYPE_TGID]; + memcpy(sk->sk_peer_pid, peercred->peer_pid, sizeof(sk->sk_peer_pid)); sk->sk_peer_cred = peercred->peer_cred; } static void update_peercred(struct sock *sk, struct unix_peercred *peercred) { const struct cred *old_cred; - struct pid *old_pid; spin_lock(&sk->sk_peer_lock); - old_pid = sk->sk_peer_pid[PIDTYPE_TGID]; + swap_pids(sk->sk_peer_pid, peercred->peer_pid); old_cred = sk->sk_peer_cred; - init_peercred(sk, peercred); + sk->sk_peer_cred = peercred->peer_cred; spin_unlock(&sk->sk_peer_lock); - peercred->peer_pid[PIDTYPE_TGID] = old_pid; peercred->peer_cred = old_cred; } @@ -796,7 +792,7 @@ static void copy_peercred(struct sock *sk, struct sock *peersk) lockdep_assert_held(&unix_sk(peersk)->lock); spin_lock(&sk->sk_peer_lock); - sk->sk_peer_pid[PIDTYPE_TGID] = get_pid(peersk->sk_peer_pid[PIDTYPE_TGID]); + get_pids(sk->sk_peer_pid, peersk->sk_peer_pid); sk->sk_peer_cred = get_cred(peersk->sk_peer_cred); spin_unlock(&sk->sk_peer_lock); } -- 2.53.0