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=1793207588; b=0Ed3xk+BzyuFJUpy4xnw7NIEaW0u76CAv0csUKnUAeKcpkSyFSZYvosfRYEdp29p8rFc unB4PEigqRMj0AGPjUr/F92d5Dtj444c3e1QbZzFvzCzzAyL87YkLwI4BhtnSOCLmRFA4 SGhfY5YFpjifr+P/7Z1JYOeoZ9jhQ/JPBKZXo8JLZPGynea3A7wW/M7V0+0BXf+90j78I /gLcehAHVZh4MOKdWxRdV+gfYQ8hIGXQp/6vDeXPZMToETSrWhXu2JRYF4R5jJNCleDW0 /vZYfDX76bbbX4SH8sZeK42LJcrl4qaegxS58rbagQrEcO0/coT+yzrBYavepMDSghg== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793207588; 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=sf6M4HLCC6edJmQURybIZrMHWxD9v3qqzQoGF4qIBM0=; b=cykMzrFM8qlrK7Dbw5IhrpZUBF+8HE8x+hP39PNwzL9ZftAcLJJ1GJFrCPhxj3h2+HFe mb5E1TXAvOBU9ETmRsU5x1Ow3PLn2wAfqUI1kjMXyWaGoQhsDULgFrd9VLbUHgl7Jpp7d 0gSjXJFfduG6N9ilYcgp/77/Z9RSDbVEoI6c/FP3V+a9HixO1UdckOsfy/pjJEsyRPtRw z+Ro2WYDXOTJy5P12pJbJHELTTXqPaJMwEg3uGmfNRC5rglC5xdMqHTHwG1BtZZbZ3q/o CqJPocT0thtZnyYAsj/iaQT4+53JM+9UCE/hJAAFr7wt/JSft35RH9Bq1AVeaBNSmsQ== 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=Mew6ZWRT; 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 67F34606A335; Wed, 28 Oct 2026 17:13:08 +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=Mew6ZWRT Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6A52B1F031E3; Wed, 28 Oct 2026 17:13:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1793207588; bh=sf6M4HLCC6edJmQURybIZrMHWxD9v3qqzQoGF4qIBM0=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=Mew6ZWRT6tp3fz0QG/QWl1ZRZ2K5VaHWgzH9AAyBJkcvNK7VmSH33bjK24CLsKxr/ FPY5uz82SqR5houT6maFJqaHtS1CWfKmnJFM4m0mswJLOyso4qMaWQ/2ckpHKwKlmo x3GK4LK52YTlEiAJTj79ND2w0p9TyCpSwkerHHUg= 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)" Subject: [PATCH 6.12 068/247] pid_namespace: make zap_pid_ns_processes() freezable Date: Wed, 28 Oct 2026 17:57:51 +0100 Message-ID: <20261028165949.000691679@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261028165947.349197979@linuxfoundation.org> References: <20261028165947.349197979@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 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Aviv Vaknin commit 81933038f5e273d17ed22792f906889393b204c5 upstream. 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: Greg Kroah-Hartman --- kernel/exit.c | 2 +- kernel/pid_namespace.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) --- a/kernel/exit.c +++ b/kernel/exit.c @@ -1696,7 +1696,7 @@ 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; --- a/kernel/pid_namespace.c +++ b/kernel/pid_namespace.c @@ -246,7 +246,7 @@ void zap_pid_ns_processes(struct pid_nam * 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; schedule();