From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from ozlabs.org (ozlabs.org [103.22.144.67]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 5C8F71A099B for ; Thu, 9 Oct 2014 11:19:10 +1100 (EST) Received: from e23smtp09.au.ibm.com (e23smtp09.au.ibm.com [202.81.31.142]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id E1F9D1400D5 for ; Thu, 9 Oct 2014 11:19:09 +1100 (EST) Received: from /spool/local by e23smtp09.au.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Thu, 9 Oct 2014 10:19:07 +1000 From: "Ian Munsie" To: mpe 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> In-Reply-To: <1412764803-sup-6790@delenn.ozlabs.ibm.com> References: <1412764803-sup-6790@delenn.ozlabs.ibm.com> Cc: cbe-oss-dev , mikey , arnd , "Aneesh Kumar K.V" , greg , linux-kernel , linuxppc-dev , anton , imunsie , jk List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , 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