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dmaengine: idxd: Prevent use after free on completion memory

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commit 1beeec45f9ac31eba52478379f70a5fa9c2ad005 upstream.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Reinette Chatre 2022-12-07 14:52:21 -08:00 committed by Greg Kroah-Hartman
parent 99dc4520b7
commit b9e8e3fcfe
1 changed files with 1 additions and 1 deletions
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2
drivers/dma/idxd/device.c
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@ -1408,11 +1408,11 @@ void drv_disable_wq(struct idxd_wq *wq)
dev_warn(dev, "Clients has claim on wq %d: %d\n", dev_warn(dev, "Clients has claim on wq %d: %d\n",
wq->id, idxd_wq_refcount(wq)); wq->id, idxd_wq_refcount(wq));
idxd_wq_free_resources(wq);
idxd_wq_unmap_portal(wq); idxd_wq_unmap_portal(wq);
idxd_wq_drain(wq); idxd_wq_drain(wq);
idxd_wq_free_irq(wq); idxd_wq_free_irq(wq);
idxd_wq_reset(wq); idxd_wq_reset(wq);
idxd_wq_free_resources(wq);
percpu_ref_exit(&wq->wq_active); percpu_ref_exit(&wq->wq_active);
wq->type = IDXD_WQT_NONE; wq->type = IDXD_WQT_NONE;
wq->client_count = 0; wq->client_count = 0;