From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793210275; b=lC+s1wkThKxdeXpKUtRfXvqowLaO2s5FztcX+T1qp6sG2jVD/WLbFajT8E8hTmqUYvKX kq9hcdz9fcX4LLe/6l9+tWeNKZSRsPpe0edQJ8XhDTQn30Qpa4vMfV830UGI+HBNqcXIE yy0Qdj58iuGCuB4M+BiworKrL5G9HhXjzx/Qa/1TE8/Y1NjzRqKeWsDKEpvjFem2Nssx9 d+/higQOswexw2ptLpOGlu2gPGuG7rthm3LIhH/upTA78++9plcCTKtAgzl4kFdLFdk7x Z0TW2u/Ppa619lSopy0rOCQCO1XIO+f1sHDNRieUygGUrfIMGwaPvvHLfDIx3S0RRsQ== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793210275; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:User-Agent:X-stable:X-Patchwork-Hint: MIME-Version:Content-Transfer-Encoding; bh=9OmtLjPzcPuisTUM3NhMQuSXm0oE5unCQijxCCWZxjw=; b=p36yjOkCD4hoGOd8GqpiakVLRMfMZ8W0w5R2ZopM4KqvpjzyTytmI+NiDeOxvBPvERXV Tk7gGk1XpqwZ1LFwyxNU2e/cbhgMkn7TNhPbVe+LG65k824OKIRyNh0A23uZ94MEXRWf8 oGIV4mu+B2IoNQCRnegF3E/ydv1WdblG5KV8CJKkatlTxG6+wmEFC+S9+gEsxIVQPpG8l dw8nZOfG2/oKYKZjJAWQYFqi6rIwNawBezl0c/8J4y5sQLqTJ/83CJLwsLM0o6yWe/4AG Vjb1ssVZqmrNhj9IbplnV1el1ni31FB/rVYZBL1zyUZTPAe0qJAKiH29rNR9/QQdkzg== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=ZyRfWHYV; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 80650606A31D; Wed, 28 Oct 2026 17:57:55 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=ZyRfWHYV Received: by smtp.kernel.org (Postfix) with ESMTPSA id D18091F01825; Wed, 28 Oct 2026 17:57:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1793210275; bh=9OmtLjPzcPuisTUM3NhMQuSXm0oE5unCQijxCCWZxjw=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=ZyRfWHYVxlehzqbklwk2JA1kJzF1Mt9XrryVzGOrjSEzwlfv1kSVIf1poEPG0BeI4 DU1WWbuLn62xv/ZVIthVXKolUkjmfub9dxRZehswuBpXHgl+thYaAA3jEY9+66uijS R217li7Q16vPiPT9Qcrq0AV+5TzsXGo5LcTp8FbA= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Oleg Nesterov , Aviv Vaknin , Bradley Morgan , "Christian Brauner (Amutable)" , Sasha Levin Subject: [PATCH 6.6 101/168] pid_namespace: make zap_pid_ns_processes() freezable Date: Wed, 28 Oct 2026 18:00:37 +0100 Message-ID: <20261028165945.478191829@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261028165943.089486480@linuxfoundation.org> References: <20261028165943.089486480@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore X-Mailing-List: patches@lists.linux.dev List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Aviv Vaknin [ Upstream commit 81933038f5e273d17ed22792f906889393b204c5 ] When the init of a pid namespace exits, zap_pid_ns_processes() waits until all other pids in the namespace are freed. A tracer outside the namespace that does not reap its traced zombies keeps those pids allocated, so this wait has no upper bound, and while it lasts every suspend attempt fails: Freezing user space processes failed after 20.006 seconds (2 tasks refusing to freeze, wq_busy=0): Neither wait is freezable. The first loop sleeps in do_wait(), which returns -ERESTARTSYS on the freezer's fake signal; the loop then clears TIF_SIGPENDING and waits again without ever freezing. The final loop sleeps in TASK_INTERRUPTIBLE, and since nothing clears TIF_SIGPENDING there, schedule() returns immediately after the first freeze attempt and the task spins until the wait ends. Sleep in TASK_INTERRUPTIBLE | TASK_FREEZABLE in do_wait(), so that the freezer can freeze tasks waiting there directly, and in TASK_IDLE | TASK_FREEZABLE in the final loop, like coredump_task_exit() does. This was hit with Chromium-based browsers: crashpad ptrace-attaches the threads of a crashed renderer, which is a pid namespace init, and does not reap those killed during the dump. Fixes: 3eb07c8c8adb ("pid namespaces: destroy pid namespace on init's death") Fixes: b9a985db9896 ("pid_ns: Sleep in TASK_INTERRUPTIBLE in zap_pid_ns_processes") Cc: stable@vger.kernel.org # 6.1+ Suggested-by: Oleg Nesterov Signed-off-by: Aviv Vaknin Link: https://patch.msgid.link/20261002202820.3433318-1-vaknins33@gmail.com Acked-by: Oleg Nesterov Reviewed-by: Bradley Morgan Signed-off-by: Christian Brauner (Amutable) Signed-off-by: Sasha Levin --- kernel/exit.c | 2 +- kernel/pid_namespace.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/kernel/exit.c b/kernel/exit.c index 07a17f0916107..e2dae48578d96 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -1648,7 +1648,7 @@ static long do_wait(struct wait_opts *wo) add_wait_queue(¤t->signal->wait_chldexit, &wo->child_wait); do { - set_current_state(TASK_INTERRUPTIBLE); + set_current_state(TASK_INTERRUPTIBLE | TASK_FREEZABLE); retval = __do_wait(wo); if (retval != -ERESTARTSYS) break; diff --git a/kernel/pid_namespace.c b/kernel/pid_namespace.c index e9b2bb260ee6c..eea15232f6690 100644 --- a/kernel/pid_namespace.c +++ b/kernel/pid_namespace.c @@ -245,7 +245,7 @@ void zap_pid_ns_processes(struct pid_namespace *pid_ns) * free_pid() will awaken this task. */ for (;;) { - set_current_state(TASK_INTERRUPTIBLE); + set_current_state(TASK_IDLE | TASK_FREEZABLE); if (pid_ns->pid_allocated == init_pids) break; /* -- 2.53.0