Patch "vfio/pci: fix memory leaks of eventfd ctx" has been added to the 4.19-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    vfio/pci: fix memory leaks of eventfd ctx

to the 4.19-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     vfio-pci-fix-memory-leaks-of-eventfd-ctx.patch
and it can be found in the queue-4.19 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit c0a9076859244a30d3b669150ac1eee494dfb06b
Author: Qian Cai <cai@xxxxxx>
Date:   Mon May 11 00:34:50 2020 -0400

    vfio/pci: fix memory leaks of eventfd ctx
    
    [ Upstream commit 1518ac272e789cae8c555d69951b032a275b7602 ]
    
    Finished a qemu-kvm (-device vfio-pci,host=0001:01:00.0) triggers a few
    memory leaks after a while because vfio_pci_set_ctx_trigger_single()
    calls eventfd_ctx_fdget() without the matching eventfd_ctx_put() later.
    Fix it by calling eventfd_ctx_put() for those memory in
    vfio_pci_release() before vfio_device_release().
    
    unreferenced object 0xebff008981cc2b00 (size 128):
      comm "qemu-kvm", pid 4043, jiffies 4294994816 (age 9796.310s)
      hex dump (first 32 bytes):
        01 00 00 00 6b 6b 6b 6b 00 00 00 00 ad 4e ad de  ....kkkk.....N..
        ff ff ff ff 6b 6b 6b 6b ff ff ff ff ff ff ff ff  ....kkkk........
      backtrace:
        [<00000000917e8f8d>] slab_post_alloc_hook+0x74/0x9c
        [<00000000df0f2aa2>] kmem_cache_alloc_trace+0x2b4/0x3d4
        [<000000005fcec025>] do_eventfd+0x54/0x1ac
        [<0000000082791a69>] __arm64_sys_eventfd2+0x34/0x44
        [<00000000b819758c>] do_el0_svc+0x128/0x1dc
        [<00000000b244e810>] el0_sync_handler+0xd0/0x268
        [<00000000d495ef94>] el0_sync+0x164/0x180
    unreferenced object 0x29ff008981cc4180 (size 128):
      comm "qemu-kvm", pid 4043, jiffies 4294994818 (age 9796.290s)
      hex dump (first 32 bytes):
        01 00 00 00 6b 6b 6b 6b 00 00 00 00 ad 4e ad de  ....kkkk.....N..
        ff ff ff ff 6b 6b 6b 6b ff ff ff ff ff ff ff ff  ....kkkk........
      backtrace:
        [<00000000917e8f8d>] slab_post_alloc_hook+0x74/0x9c
        [<00000000df0f2aa2>] kmem_cache_alloc_trace+0x2b4/0x3d4
        [<000000005fcec025>] do_eventfd+0x54/0x1ac
        [<0000000082791a69>] __arm64_sys_eventfd2+0x34/0x44
        [<00000000b819758c>] do_el0_svc+0x128/0x1dc
        [<00000000b244e810>] el0_sync_handler+0xd0/0x268
        [<00000000d495ef94>] el0_sync+0x164/0x180
    
    Signed-off-by: Qian Cai <cai@xxxxxx>
    Signed-off-by: Alex Williamson <alex.williamson@xxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c
index 9f72a6ee13b53..86cd8bdfa9f28 100644
--- a/drivers/vfio/pci/vfio_pci.c
+++ b/drivers/vfio/pci/vfio_pci.c
@@ -409,6 +409,10 @@ static void vfio_pci_release(void *device_data)
 	if (!(--vdev->refcnt)) {
 		vfio_spapr_pci_eeh_release(vdev->pdev);
 		vfio_pci_disable(vdev);
+		if (vdev->err_trigger)
+			eventfd_ctx_put(vdev->err_trigger);
+		if (vdev->req_trigger)
+			eventfd_ctx_put(vdev->req_trigger);
 	}
 
 	mutex_unlock(&driver_lock);