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authorReinette Chatre <reinette.chatre@intel.com>2022-12-07 14:52:22 -0800
committerVinod Koul <vkoul@kernel.org>2022-12-28 16:24:50 +0530
commit6744a030d81e456883bfbb627ac1f30465c1a989 (patch)
tree5a90827a4aba31b3ceb9c109df3b73ae1a176191
parent1beeec45f9ac31eba52478379f70a5fa9c2ad005 (diff)
downloadlinux-6744a030d81e456883bfbb627ac1f30465c1a989.tar.bz2
dmaengine: idxd: Do not call DMX TX callbacks during workqueue disable
On driver unload any pending descriptors are flushed and pending DMA descriptors are explicitly completed: idxd_dmaengine_drv_remove() -> drv_disable_wq() -> idxd_wq_free_irq() -> idxd_flush_pending_descs() -> idxd_dma_complete_txd() With this done during driver unload any remaining descriptor is likely stuck and can be dropped. Even so, the descriptor may still have a callback set that could no longer be accessible. An example of such a problem is when the dmatest fails and the dmatest module is unloaded. The failure of dmatest leaves descriptors with dma_async_tx_descriptor::callback pointing to code that no longer exist. This causes a page fault as below at the time the IDXD driver is unloaded when it attempts to run the callback: BUG: unable to handle page fault for address: ffffffffc0665190 #PF: supervisor instruction fetch in kernel mode #PF: error_code(0x0010) - not-present page Fix this by clearing the callback pointers on the transmit descriptors only when workqueue is disabled. Fixes: 403a2e236538 ("dmaengine: idxd: change MSIX allocation based on per wq activation") Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Dave Jiang <dave.jiang@intel.com> Reviewed-by: Fenghua Yu <fenghua.yu@intel.com> Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/37d06b772aa7f8863ca50f90930ea2fd80b38fc3.1670452419.git.reinette.chatre@intel.com Signed-off-by: Vinod Koul <vkoul@kernel.org>
-rw-r--r--drivers/dma/idxd/device.c11
1 files changed, 11 insertions, 0 deletions
diff --git a/drivers/dma/idxd/device.c b/drivers/dma/idxd/device.c
index cd792f3f9873..29dbb0f52e18 100644
--- a/drivers/dma/idxd/device.c
+++ b/drivers/dma/idxd/device.c
@@ -1172,8 +1172,19 @@ static void idxd_flush_pending_descs(struct idxd_irq_entry *ie)
spin_unlock(&ie->list_lock);
list_for_each_entry_safe(desc, itr, &flist, list) {
+ struct dma_async_tx_descriptor *tx;
+
list_del(&desc->list);
ctype = desc->completion->status ? IDXD_COMPLETE_NORMAL : IDXD_COMPLETE_ABORT;
+ /*
+ * wq is being disabled. Any remaining descriptors are
+ * likely to be stuck and can be dropped. callback could
+ * point to code that is no longer accessible, for example
+ * if dmatest module has been unloaded.
+ */
+ tx = &desc->txd;
+ tx->callback = NULL;
+ tx->callback_result = NULL;
idxd_dma_complete_txd(desc, ctype, true);
}
}