On Wed, May 15, 2019 at 11:14:31PM +0000, Dexuan Cui wrote:
From: gregkh@xxxxxxxxxxxxxxxxxxx <gregkh@xxxxxxxxxxxxxxxxxxx> Sent: Wednesday, May 15, 2019 1:35 AM To: Dexuan Cui <decui@xxxxxxxxxxxxx>; lorenzo.pieralisi@xxxxxxx; Michael Kelley <mikelley@xxxxxxxxxxxxx>; stephen@xxxxxxxxxxxxxxxxxx Cc: stable@xxxxxxxxxxxxxxx Subject: FAILED: patch "[PATCH] PCI: hv: Fix a memory leak in hv_eject_device_work()" failed to apply to 4.9-stable tree The patch below does not apply to the 4.9-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable@xxxxxxxxxxxxxxx>. thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 05f151a73ec2b23ffbff706e5203e729a995cdc2 Mon Sep 17 00:00:00 2001 From: Dexuan Cui <decui@xxxxxxxxxxxxx> Date: Mon, 4 Mar 2019 21:34:48 +0000 Subject: [PATCH] PCI: hv: Fix a memory leak in hv_eject_device_work() When a device is created in new_pcichild_device(), hpdev->refs is set to 2 (i.e. the initial value of 1 plus the get_pcichild()). When we hot remove the device from the host, in a Linux VM we first call hv_pci_eject_device(), which increases hpdev->refs by get_pcichild() and then schedules a work of hv_eject_device_work(), so hpdev->refs becomes 3 (let's ignore the paired get/put_pcichild() in other places). But in hv_eject_device_work(), currently we only call put_pcichild() twice, meaning the 'hpdev' struct can't be freed in put_pcichild(). Add one put_pcichild() to fix the memory leak. The device can also be removed when we run "rmmod pci-hyperv". On this path (hv_pci_remove() -> hv_pci_bus_exit() -> hv_pci_devices_present()), hpdev->refs is 2, and we do correctly call put_pcichild() twice in pci_devices_present_work(). Fixes: 4daace0d8ce8 ("PCI: hv: Add paravirtual PCI front-end for Microsoft Hyper-V VMs") Signed-off-by: Dexuan Cui <decui@xxxxxxxxxxxxx> [lorenzo.pieralisi@xxxxxxx: commit log rework] Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@xxxxxxx> Reviewed-by: Stephen Hemminger <stephen@xxxxxxxxxxxxxxxxxx> Reviewed-by: Michael Kelley <mikelley@xxxxxxxxxxxxx> Cc: stable@xxxxxxxxxxxxxxx diff --git a/drivers/pci/controller/pci-hyperv.c b/drivers/pci/controller/pci-hyperv.c index 95441a35eceb..30f16b882746 100644 --- a/drivers/pci/controller/pci-hyperv.c +++ b/drivers/pci/controller/pci-hyperv.c @@ -1900,6 +1900,9 @@ static void hv_eject_device_work(struct work_struct *work) sizeof(*ejct_pkt), (unsigned long)&ctxt.pkt, VM_PKT_DATA_INBAND, 0); + /* For the get_pcichild() in hv_pci_eject_device() */ + put_pcichild(hpdev); + /* For the two refs got in new_pcichild_device() */ put_pcichild(hpdev); put_pcichild(hpdev); put_hvpcibus(hpdev->hbus);Hi, I backported the patch for linux-4.9.y. Please use the attached patch. Thanks, -- Dexuan
Queued for 4.9, thanks. -- Thanks, Sasha
