From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5D291C43464 for ; Fri, 18 Sep 2020 03:02:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 27850206B6 for ; Fri, 18 Sep 2020 03:02:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600398165; bh=LIWOTdfHIdT6uVuD6J6B7XN5ftruP8Of0smGsGAHIvU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=lH9TWP85oGaHlzjoXFSoHYPgBeginF+hjOk8ktiZksllFe7nF9rvbBM5IybP7zasm sn7s280N8FglDu5fs3fU7PDjljxKJQDvXelnYELmtAXA+7F28EKCg8n3Bquw3hqeBN ovhFXFp3Vke7OqyDCi8MvDBEFZ8HUk0aYNh04QPo= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728798AbgIRDCn (ORCPT ); Thu, 17 Sep 2020 23:02:43 -0400 Received: from mail.kernel.org ([198.145.29.99]:53478 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727517AbgIRCFV (ORCPT ); Thu, 17 Sep 2020 22:05:21 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id C762E23770; Fri, 18 Sep 2020 02:05:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600394720; bh=LIWOTdfHIdT6uVuD6J6B7XN5ftruP8Of0smGsGAHIvU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=WXqNIsqOsCooXzT6ohJ9cEJned5WaLe8xhBISR/AshEpS0U1JeFxGGogLPTGreoMf uv21H82pQjGKTJA0SZ3mFO4AkEsmq2znvpFItWvCKOcJ38HSEuik+ZVKDJphQ4vtsn SxfzIDBV6W37JtWTaFjcGj/88SZR6EQFmUEFpO8k= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Bernd Edlinger , "Eric W . Biederman" , Sasha Levin Subject: [PATCH AUTOSEL 5.4 204/330] perf: Use new infrastructure to fix deadlocks in execve Date: Thu, 17 Sep 2020 21:59:04 -0400 Message-Id: <20200918020110.2063155-204-sashal@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200918020110.2063155-1-sashal@kernel.org> References: <20200918020110.2063155-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Bernd Edlinger [ Upstream commit 6914303824bb572278568330d72fc1f8f9814e67 ] This changes perf_event_set_clock to use the new exec_update_mutex instead of cred_guard_mutex. This should be safe, as the credentials are only used for reading. Signed-off-by: Bernd Edlinger Signed-off-by: Eric W. Biederman Signed-off-by: Sasha Levin --- kernel/events/core.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/kernel/events/core.c b/kernel/events/core.c index db1f5aa755f22..47646050efa0c 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -1253,7 +1253,7 @@ static void put_ctx(struct perf_event_context *ctx) * function. * * Lock order: - * cred_guard_mutex + * exec_update_mutex * task_struct::perf_event_mutex * perf_event_context::mutex * perf_event::child_mutex; @@ -11002,14 +11002,14 @@ SYSCALL_DEFINE5(perf_event_open, } if (task) { - err = mutex_lock_interruptible(&task->signal->cred_guard_mutex); + err = mutex_lock_interruptible(&task->signal->exec_update_mutex); if (err) goto err_task; /* * Reuse ptrace permission checks for now. * - * We must hold cred_guard_mutex across this and any potential + * We must hold exec_update_mutex across this and any potential * perf_install_in_context() call for this new event to * serialize against exec() altering our credentials (and the * perf_event_exit_task() that could imply). @@ -11298,7 +11298,7 @@ SYSCALL_DEFINE5(perf_event_open, mutex_unlock(&ctx->mutex); if (task) { - mutex_unlock(&task->signal->cred_guard_mutex); + mutex_unlock(&task->signal->exec_update_mutex); put_task_struct(task); } @@ -11334,7 +11334,7 @@ err_alloc: free_event(event); err_cred: if (task) - mutex_unlock(&task->signal->cred_guard_mutex); + mutex_unlock(&task->signal->exec_update_mutex); err_task: if (task) put_task_struct(task); @@ -11639,7 +11639,7 @@ static void perf_event_exit_task_context(struct task_struct *child, int ctxn) /* * When a child task exits, feed back event values to parent events. * - * Can be called with cred_guard_mutex held when called from + * Can be called with exec_update_mutex held when called from * install_exec_creds(). */ void perf_event_exit_task(struct task_struct *child) -- 2.25.1