summaryrefslogtreecommitdiff
path: root/drivers/dma/idxd/device.c
diff options
context:
space:
mode:
authorReinette Chatre <reinette.chatre@intel.com>2022-12-08 01:52:21 +0300
committerVinod Koul <vkoul@kernel.org>2022-12-28 13:54:49 +0300
commit1beeec45f9ac31eba52478379f70a5fa9c2ad005 (patch)
tree4af7a99ced6fbde86c29838f3e30ae0df9e0c87f /drivers/dma/idxd/device.c
parentb51b75f0604f17c0f6f3b6f68f1a521a5cc6b04f (diff)
downloadlinux-1beeec45f9ac31eba52478379f70a5fa9c2ad005.tar.xz
dmaengine: idxd: Prevent use after free on completion memory
On driver unload any pending descriptors are flushed at the time the interrupt is freed: idxd_dmaengine_drv_remove() -> drv_disable_wq() -> idxd_wq_free_irq() -> idxd_flush_pending_descs(). If there are any descriptors present that need to be flushed this flow triggers a "not present" page fault as below: BUG: unable to handle page fault for address: ff391c97c70c9040 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page The address that triggers the fault is the address of the descriptor that was freed moments earlier via: drv_disable_wq()->idxd_wq_free_resources() Fix the use after free by freeing the descriptors after any possible usage. This is done after idxd_wq_reset() to ensure that the memory remains accessible during possible completion writes by the device. Fixes: 63c14ae6c161 ("dmaengine: idxd: refactor wq driver enable/disable operations") Suggested-by: Dave Jiang <dave.jiang@intel.com> 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/6c4657d9cff0a0a00501a7b928297ac966e9ec9d.1670452419.git.reinette.chatre@intel.com Signed-off-by: Vinod Koul <vkoul@kernel.org>
Diffstat (limited to 'drivers/dma/idxd/device.c')
-rw-r--r--drivers/dma/idxd/device.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/dma/idxd/device.c b/drivers/dma/idxd/device.c
index c5523ced2e3a..cd792f3f9873 100644
--- a/drivers/dma/idxd/device.c
+++ b/drivers/dma/idxd/device.c
@@ -1407,11 +1407,11 @@ void drv_disable_wq(struct idxd_wq *wq)
dev_warn(dev, "Clients has claim on wq %d: %d\n",
wq->id, idxd_wq_refcount(wq));
- idxd_wq_free_resources(wq);
idxd_wq_unmap_portal(wq);
idxd_wq_drain(wq);
idxd_wq_free_irq(wq);
idxd_wq_reset(wq);
+ idxd_wq_free_resources(wq);
percpu_ref_exit(&wq->wq_active);
wq->type = IDXD_WQT_NONE;
wq->client_count = 0;