[PATCH AUTOSEL 4.4 57/64] vfio/pci: fix memory leaks of eventfd ctx

Sasha Levin
2020-09-18T02:18:51Z

From: Qian Cai <cai@lca.pw>

[ 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@lca.pw>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/vfio/pci/vfio_pci.c | 4 ++++
1 file changed, 4 insertions(+)

diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c
index 7a82735d53087..ab765770e8dd6 100644
--- a/drivers/vfio/pci/vfio_pci.c
+++ b/drivers/vfio/pci/vfio_pci.c
@@ -255,6 +255,10 @@ 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);
--
2.25.1