From: Sean Christopherson seanjc@google.com
commit b1cb1fac22abf102ffeb29dd3eeca208a3869d54 upstream.
Destroy and free the target coalesced MMIO device if unregistering said device fails. As clearly noted in the code, kvm_io_bus_unregister_dev() does not destroy the target device.
BUG: memory leak unreferenced object 0xffff888112a54880 (size 64): comm "syz-executor.2", pid 5258, jiffies 4297861402 (age 14.129s) hex dump (first 32 bytes): 38 c7 67 15 00 c9 ff ff 38 c7 67 15 00 c9 ff ff 8.g.....8.g..... e0 c7 e1 83 ff ff ff ff 00 30 67 15 00 c9 ff ff .........0g..... backtrace: [<0000000006995a8a>] kmalloc include/linux/slab.h:556 [inline] [<0000000006995a8a>] kzalloc include/linux/slab.h:690 [inline] [<0000000006995a8a>] kvm_vm_ioctl_register_coalesced_mmio+0x8e/0x3d0 arch/x86/kvm/../../../virt/kvm/coalesced_mmio.c:150 [<00000000022550c2>] kvm_vm_ioctl+0x47d/0x1600 arch/x86/kvm/../../../virt/kvm/kvm_main.c:3323 [<000000008a75102f>] vfs_ioctl fs/ioctl.c:46 [inline] [<000000008a75102f>] file_ioctl fs/ioctl.c:509 [inline] [<000000008a75102f>] do_vfs_ioctl+0xbab/0x1160 fs/ioctl.c:696 [<0000000080e3f669>] ksys_ioctl+0x76/0xa0 fs/ioctl.c:713 [<0000000059ef4888>] __do_sys_ioctl fs/ioctl.c:720 [inline] [<0000000059ef4888>] __se_sys_ioctl fs/ioctl.c:718 [inline] [<0000000059ef4888>] __x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:718 [<000000006444fa05>] do_syscall_64+0x9f/0x4e0 arch/x86/entry/common.c:290 [<000000009a4ed50b>] entry_SYSCALL_64_after_hwframe+0x49/0xbe
BUG: leak checking failed
Fixes: 5d3c4c79384a ("KVM: Stop looking for coalesced MMIO zones if the bus is destroyed") Cc: stable@vger.kernel.org Reported-by: 柳菁峰 liujingfeng@qianxin.com Reported-by: Michal Luczaj mhal@rbox.co Link: https://lore.kernel.org/r/20221219171924.67989-1-seanjc@google.com Link: https://lore.kernel.org/all/20230118220003.1239032-1-mhal@rbox.co Signed-off-by: Sean Christopherson seanjc@google.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- virt/kvm/coalesced_mmio.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-)
--- a/virt/kvm/coalesced_mmio.c +++ b/virt/kvm/coalesced_mmio.c @@ -187,15 +187,17 @@ int kvm_vm_ioctl_unregister_coalesced_mm r = kvm_io_bus_unregister_dev(kvm, zone->pio ? KVM_PIO_BUS : KVM_MMIO_BUS, &dev->dev);
+ kvm_iodevice_destructor(&dev->dev); + /* * On failure, unregister destroys all devices on the * bus _except_ the target device, i.e. coalesced_zones - * has been modified. No need to restart the walk as - * there aren't any zones left. + * has been modified. Bail after destroying the target + * device, there's no need to restart the walk as there + * aren't any zones left. */ if (r) break; - kvm_iodevice_destructor(&dev->dev); } }