On Mon, 19 Dec 2022 17:19:24 +0000, Sean Christopherson wrote:
> 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
>
> [...]
Applied to kvm-x86 generic, the plan is that Wei will send the bigger
cleanup on top. Thanks!
[1/1] KVM: Destroy target device if coalesced MMIO unregistration fails
https://github.com/kvm-x86/linux/commit/b1cb1fac22ab
--
https://github.com/kvm-x86/linux/tree/next
https://github.com/kvm-x86/linux/tree/fixes
