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=1792774654; b=ksRw/+1VTwsplDqU2/nRs9GyRa2oZ+cC5M7XIzWrAj21r1VzXZuzZP59nirg59jMpj5g 7QdusH99VqJsl+YHfvkT3gY2e93TjZ1h1PBLXlhNT44RCjBLShi2UfRRRTU6W7d5klF+d 7RfL+To7wHZf6AnjLLt2vfIv8joc+YMcNAeNrpqN2J+i00WUH+A7Weg6KYsVRIJs0m9If t6zfC9woKm+OwHmPR+mBqWoLm6pcBEOOIdKNok5n7y3uMzfG92h1ou4pnWVQTLDR8cnFV nAY19nr6BrhQ0s5bb+CuZZY/AwtzgweFhQOMl5/XxRYx2S9nm3h6IV5poO2EZdmEGaw== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1792774654; 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=25m3RgPO7Ww9GDCOHeWLHRAmkeAtY7WFHQ+HXwinn4M=; b=mCgTSgNjsCXj+meYryl0dVHsFsgfUnKdfqYLDoQ+mCze9YvHnLowPzSgXRrZ6C3md9+m /MA5EzAE/bqiPFUAfFVNzI30UZelmNiW7Xe5A+xIlkAZT3Ly+tKne19VcfX6oJr443tiQ u3iOXqDMmRT+qHjXFeUF/zfiCjAtKIePqV0WrLbvyM1s7grYAiYAEvjlaMQirzaB9NxyO UNOadCARkSxCNNo2X/32A8GV0ZE/nIK2vqVPjCbXhqGzEkT8YqN59+IvPPCs8MMvmZs6R y1aHLXUwL+2Qhhy1IR+YdHIOCXh00vgPTB25LJ1h9ekNiBS+3qgNWlQfLThxP05Vnyg== 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="u/ijncWR"; 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 5D612606A31D; Fri, 23 Oct 2026 16:57:33 +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=u/ijncWR Received: by smtp.kernel.org (Postfix) with ESMTPSA id AA9211F01825; Fri, 23 Oct 2026 16:57:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1792774653; bh=25m3RgPO7Ww9GDCOHeWLHRAmkeAtY7WFHQ+HXwinn4M=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=u/ijncWReSsuIZLx9DmwYtq/bVJ/mar7ruMiyrqQAeUN6gi/d5bplzuEblzKJXayR q9CO8J7r0185cMU6jKQOMpan5pRqGEqCq8nVm/jNqEfwmTczwSBcVTM9JiRi4CIB9C mEKNL4PBgqde6orPVFPhqOlYU2e/erYzIVD0hzxg= 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 7.2 113/242] pid_namespace: make zap_pid_ns_processes() freezable Date: Fri, 23 Oct 2026 18:39:15 +0200 Message-ID: <20261023163716.452153964@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261023163713.816071858@linuxfoundation.org> References: <20261023163713.816071858@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 7.2-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 @@ -1730,7 +1730,7 @@ 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 @@ -268,7 +268,7 @@ 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();