From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Christoph Hellwig , Goldwyn Rodrigues , Mark Rutland , Jan Kara , Jens Axboe Subject: [PATCH 4.15 035/122] direct-io: Fix sleep in atomic due to sync AIO Date: Wed, 7 Mar 2018 11:37:27 -0800 Message-Id: <20180307191734.231518222@linuxfoundation.org> In-Reply-To: <20180307191729.190879024@linuxfoundation.org> References: <20180307191729.190879024@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: 4.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jan Kara commit d9c10e5b8863cfb6886d1640386455075c6e979d upstream. Commit e864f39569f4 "fs: add RWF_DSYNC aand RWF_SYNC" added additional way for direct IO to become synchronous and thus trigger fsync from the IO completion handler. Then commit 9830f4be159b "fs: Use RWF_* flags for AIO operations" allowed these flags to be set for AIO as well. However that commit forgot to update the condition checking whether the IO completion handling should be defered to a workqueue and thus AIO DIO with RWF_[D]SYNC set will call fsync() from IRQ context resulting in sleep in atomic. Fix the problem by checking directly iocb flags (the same way as it is done in dio_complete()) instead of checking all conditions that could lead to IO being synchronous. CC: Christoph Hellwig CC: Goldwyn Rodrigues CC: stable@vger.kernel.org Reported-by: Mark Rutland Tested-by: Mark Rutland Fixes: 9830f4be159b29399d107bffb99e0132bc5aedd4 Signed-off-by: Jan Kara Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman --- fs/direct-io.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) --- a/fs/direct-io.c +++ b/fs/direct-io.c @@ -1252,8 +1252,7 @@ do_blockdev_direct_IO(struct kiocb *iocb */ if (dio->is_async && iov_iter_rw(iter) == WRITE) { retval = 0; - if ((iocb->ki_filp->f_flags & O_DSYNC) || - IS_SYNC(iocb->ki_filp->f_mapping->host)) + if (iocb->ki_flags & IOCB_DSYNC) retval = dio_set_defer_completion(dio); else if (!dio->inode->i_sb->s_dio_done_wq) { /*