Path: csiph.com!aioe.org!bofh.it!news.nic.it!robomod From: Kamal Mostafa Newsgroups: linux.kernel Subject: [PATCH 3.19.y-ckt 029/251] spi: fix race freeing dummy_tx/rx before it is unmapped Date: Thu, 16 Jul 2015 04:20:01 +0200 Message-ID: References: X-Original-To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com X-Mailer: git-send-email 1.9.1 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Extended-Stable: 3.19 Sender: robomod@news.nic.it List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Approved: robomod@news.nic.it Lines: 67 Organization: linux.* mail to news gateway X-Original-Cc: Martin Sperl , Mark Brown , Kamal Mostafa X-Original-Date: Wed, 15 Jul 2015 18:05:50 -0700 X-Original-Message-ID: <1437008972-9140-30-git-send-email-kamal@canonical.com> X-Original-References: <1437008972-9140-1-git-send-email-kamal@canonical.com> X-Original-Sender: linux-kernel-owner@vger.kernel.org Xref: aioe.org linux.kernel:1185395 3.19.8-ckt4 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Martin Sperl commit 8e76ef88f607174082023f50b87fe12dcdbe5db5 upstream. Fix a race (with some kernel configurations) where a queued master->pump_messages runs and frees dummy_tx/rx before spi_unmap_msg is running (or is finished). This results in the following messages: BUG: Bad page state in process page:db7ba030 count:0 mapcount:0 mapping: (null) index:0x0 flags: 0x200(arch_1) page dumped because: PAGE_FLAGS_CHECK_AT_PREP flag set ... Reported-by: Noralf Trønnes Suggested-by: Noralf Trønnes Tested-by: Noralf Trønnes Signed-off-by: Martin Sperl Signed-off-by: Mark Brown Signed-off-by: Kamal Mostafa --- drivers/spi/spi.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c index a17f533..bfa47d5 100644 --- a/drivers/spi/spi.c +++ b/drivers/spi/spi.c @@ -1059,9 +1059,6 @@ void spi_finalize_current_message(struct spi_master *master) spin_lock_irqsave(&master->queue_lock, flags); mesg = master->cur_msg; - master->cur_msg = NULL; - - queue_kthread_work(&master->kworker, &master->pump_messages); spin_unlock_irqrestore(&master->queue_lock, flags); spi_unmap_msg(master, mesg); @@ -1074,9 +1071,13 @@ void spi_finalize_current_message(struct spi_master *master) } } - trace_spi_message_done(mesg); - + spin_lock_irqsave(&master->queue_lock, flags); + master->cur_msg = NULL; master->cur_msg_prepared = false; + queue_kthread_work(&master->kworker, &master->pump_messages); + spin_unlock_irqrestore(&master->queue_lock, flags); + + trace_spi_message_done(mesg); mesg->state = NULL; if (mesg->complete) -- 1.9.1 -- 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/