From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 CA1406FB5 for ; Sun, 17 Sep 2023 20:33:57 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 059BEC433C8; Sun, 17 Sep 2023 20:33:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1694982837; bh=pLjZLOEsJDCUsZMyqHU3NQTpJJiTTtv+XoIP1xOTFbg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=qyo7lzQ/w93UcToWrTCKA+pBQc/BUVg2Oz8iqYJVXhmtNrff0Aaz2lpD92OTkBvMQ YoyHvTBXSZAN46YsWKVVrUoWWH7HG8TaebZccsfOAzf96H85CBaRmcVMbvC8QAb6r8 XlP+lZ29hCGyjRJXw3l4A03MuZYCa92eHtwwTRJE= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Yu Zhang , Jack Wang , Ingo Molnar , Jarkko Sakkinen , Kai Huang , Haitao Huang Subject: [PATCH 5.15 366/511] x86/sgx: Break up long non-preemptible delays in sgx_vepc_release() Date: Sun, 17 Sep 2023 21:13:13 +0200 Message-ID: <20230917191122.646318550@linuxfoundation.org> X-Mailer: git-send-email 2.42.0 In-Reply-To: <20230917191113.831992765@linuxfoundation.org> References: <20230917191113.831992765@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jack Wang commit 3d7d72a34e05b23e21bafc8bfb861e73c86b31f3 upstream. On large enclaves we hit the softlockup warning with following call trace: xa_erase() sgx_vepc_release() __fput() task_work_run() do_exit() The latency issue is similar to the one fixed in: 8795359e35bc ("x86/sgx: Silence softlockup detection when releasing large enclaves") The test system has 64GB of enclave memory, and all is assigned to a single VM. Release of 'vepc' takes a longer time and causes long latencies, which triggers the softlockup warning. Add cond_resched() to give other tasks a chance to run and reduce latencies, which also avoids the softlockup detector. [ mingo: Rewrote the changelog. ] Fixes: 540745ddbc70 ("x86/sgx: Introduce virtual EPC for use by KVM guests") Reported-by: Yu Zhang Signed-off-by: Jack Wang Signed-off-by: Ingo Molnar Tested-by: Yu Zhang Reviewed-by: Jarkko Sakkinen Reviewed-by: Kai Huang Acked-by: Haitao Huang Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman --- arch/x86/kernel/cpu/sgx/virt.c | 3 +++ 1 file changed, 3 insertions(+) --- a/arch/x86/kernel/cpu/sgx/virt.c +++ b/arch/x86/kernel/cpu/sgx/virt.c @@ -167,6 +167,7 @@ static int sgx_vepc_release(struct inode continue; xa_erase(&vepc->page_array, index); + cond_resched(); } /* @@ -185,6 +186,7 @@ static int sgx_vepc_release(struct inode list_add_tail(&epc_page->list, &secs_pages); xa_erase(&vepc->page_array, index); + cond_resched(); } /* @@ -206,6 +208,7 @@ static int sgx_vepc_release(struct inode if (sgx_vepc_free_page(epc_page)) list_add_tail(&epc_page->list, &secs_pages); + cond_resched(); } if (!list_empty(&secs_pages))