Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755483AbaJIATT (ORCPT ); Wed, 8 Oct 2014 20:19:19 -0400 Received: from e23smtp06.au.ibm.com ([202.81.31.148]:42804 "EHLO e23smtp06.au.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753478AbaJIATJ (ORCPT ); Wed, 8 Oct 2014 20:19:09 -0400 From: "Ian Munsie" To: mpe Cc: greg , arnd , benh , mikey , anton , linux-kernel , linuxppc-dev , jk , imunsie , cbe-oss-dev , "Aneesh Kumar K.V" Subject: [PATCH] CXL: Fix afu_read() not doing finish_wait() on signal or non-blocking Date: Thu, 9 Oct 2014 11:17:46 +1100 Message-Id: <1412813866-22717-1-git-send-email-imunsie@au.ibm.com> X-Mailer: git-send-email 2.1.0 In-Reply-To: <1412764803-sup-6790@delenn.ozlabs.ibm.com> References: <1412764803-sup-6790@delenn.ozlabs.ibm.com> X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 14100900-0021-0000-0000-0000004F5BB4 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Ian Munsie If afu_read() returned due to a signal or the AFU file descriptor being opened non-blocking it would not call finish_wait() before returning, which could lead to a crash later when something else wakes up the wait queue. This patch restructures the wait logic to ensure that the cleanup is done correctly. Signed-off-by: Ian Munsie --- Resending with correct whitespace as my mailer decided to replace tabs with spaces on the last try. drivers/misc/cxl/file.c | 20 +++++++++++++++----- 1 file changed, 15 insertions(+), 5 deletions(-) diff --git a/drivers/misc/cxl/file.c b/drivers/misc/cxl/file.c index 847b7e6..378b099 100644 --- a/drivers/misc/cxl/file.c +++ b/drivers/misc/cxl/file.c @@ -273,6 +273,7 @@ static ssize_t afu_read(struct file *file, char __user *buf, size_t count, struct cxl_context *ctx = file->private_data; struct cxl_event event; unsigned long flags; + int rc; DEFINE_WAIT(wait); if (count < CXL_READ_MIN_SIZE) @@ -285,13 +286,17 @@ static ssize_t afu_read(struct file *file, char __user *buf, size_t count, if (ctx_event_pending(ctx)) break; - spin_unlock_irqrestore(&ctx->lock, flags); - if (file->f_flags & O_NONBLOCK) - return -EAGAIN; + if (file->f_flags & O_NONBLOCK) { + rc = -EAGAIN; + goto out; + } - if (signal_pending(current)) - return -ERESTARTSYS; + if (signal_pending(current)) { + rc = -ERESTARTSYS; + goto out; + } + spin_unlock_irqrestore(&ctx->lock, flags); pr_devel("afu_read going to sleep...\n"); schedule(); pr_devel("afu_read woken up\n"); @@ -336,6 +341,11 @@ static ssize_t afu_read(struct file *file, char __user *buf, size_t count, if (copy_to_user(buf, &event, event.header.size)) return -EFAULT; return event.header.size; + +out: + finish_wait(&ctx->wq, &wait); + spin_unlock_irqrestore(&ctx->lock, flags); + return rc; } static const struct file_operations afu_fops = { -- 2.1.0 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/