CVE-2021-47341 KVM: mmio: Fix use-after-free Read in kvm_vm_ioctl_unregister_coalesced_mmio

In the Linux kernel, the following vulnerability has been resolved:

KVM: mmio: Fix use-after-free Read in kvm_vm_ioctl_unregister_coalesced_mmio

BUG: KASAN: use-after-free in kvm_vm_ioctl_unregister_coalesced_mmio+0x7c/0x1ec arch/arm64/kvm/…/…/…/virt/kvm/coalesced_mmio.c:183
Read of size 8 at addr ffff0000c03a2500 by task syz-executor083/4269

CPU: 5 PID: 4269 Comm: syz-executor083 Not tainted 5.10.0 #7
Hardware name: linux,dummy-virt (DT)
Call trace:
dump_backtrace+0x0/0x2d0 arch/arm64/kernel/stacktrace.c:132
show_stack+0x28/0x34 arch/arm64/kernel/stacktrace.c:196
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x110/0x164 lib/dump_stack.c:118
print_address_description+0x78/0x5c8 mm/kasan/report.c:385
__kasan_report mm/kasan/report.c:545 [inline]
kasan_report+0x148/0x1e4 mm/kasan/report.c:562
check_memory_region_inline mm/kasan/generic.c:183 [inline]
__asan_load8+0xb4/0xbc mm/kasan/generic.c:252
kvm_vm_ioctl_unregister_coalesced_mmio+0x7c/0x1ec arch/arm64/kvm/…/…/…/virt/kvm/coalesced_mmio.c:183
kvm_vm_ioctl+0xe30/0x14c4 arch/arm64/kvm/…/…/…/virt/kvm/kvm_main.c:3755
vfs_ioctl fs/ioctl.c:48 [inline]
__do_sys_ioctl fs/ioctl.c:753 [inline]
__se_sys_ioctl fs/ioctl.c:739 [inline]
__arm64_sys_ioctl+0xf88/0x131c fs/ioctl.c:739
__invoke_syscall arch/arm64/kernel/syscall.c:36 [inline]
invoke_syscall arch/arm64/kernel/syscall.c:48 [inline]
el0_svc_common arch/arm64/kernel/syscall.c:158 [inline]
do_el0_svc+0x120/0x290 arch/arm64/kernel/syscall.c:220
el0_svc+0x1c/0x28 arch/arm64/kernel/entry-common.c:367
el0_sync_handler+0x98/0x170 arch/arm64/kernel/entry-common.c:383
el0_sync+0x140/0x180 arch/arm64/kernel/entry.S:670

Allocated by task 4269:
stack_trace_save+0x80/0xb8 kernel/stacktrace.c:121
kasan_save_stack mm/kasan/common.c:48 [inline]
kasan_set_track mm/kasan/common.c:56 [inline]
__kasan_kmalloc+0xdc/0x120 mm/kasan/common.c:461
kasan_kmalloc+0xc/0x14 mm/kasan/common.c:475
kmem_cache_alloc_trace include/linux/slab.h:450 [inline]
kmalloc include/linux/slab.h:552 [inline]
kzalloc include/linux/slab.h:664 [inline]
kvm_vm_ioctl_register_coalesced_mmio+0x78/0x1cc arch/arm64/kvm/…/…/…/virt/kvm/coalesced_mmio.c:146
kvm_vm_ioctl+0x7e8/0x14c4 arch/arm64/kvm/…/…/…/virt/kvm/kvm_main.c:3746
vfs_ioctl fs/ioctl.c:48 [inline]
__do_sys_ioctl fs/ioctl.c:753 [inline]
__se_sys_ioctl fs/ioctl.c:739 [inline]
__arm64_sys_ioctl+0xf88/0x131c fs/ioctl.c:739
__invoke_syscall arch/arm64/kernel/syscall.c:36 [inline]
invoke_syscall arch/arm64/kernel/syscall.c:48 [inline]
el0_svc_common arch/arm64/kernel/syscall.c:158 [inline]
do_el0_svc+0x120/0x290 arch/arm64/kernel/syscall.c:220
el0_svc+0x1c/0x28 arch/arm64/kernel/entry-common.c:367
el0_sync_handler+0x98/0x170 arch/arm64/kernel/entry-common.c:383
el0_sync+0x140/0x180 arch/arm64/kernel/entry.S:670

Freed by task 4269:
stack_trace_save+0x80/0xb8 kernel/stacktrace.c:121
kasan_save_stack mm/kasan/common.c:48 [inline]
kasan_set_track+0x38/0x6c mm/kasan/common.c:56
kasan_set_free_info+0x20/0x40 mm/kasan/generic.c:355
__kasan_slab_free+0x124/0x150 mm/kasan/common.c:422
kasan_slab_free+0x10/0x1c mm/kasan/common.c:431
slab_free_hook mm/slub.c:1544 [inline]
slab_free_freelist_hook mm/slub.c:1577 [inline]
slab_free mm/slub.c:3142 [inline]
kfree+0x104/0x38c mm/slub.c:4124
coalesced_mmio_destructor+0x94/0xa4 arch/arm64/kvm/…/…/…/virt/kvm/coalesced_mmio.c:102
kvm_iodevice_destructor include/kvm/iodev.h:61 [inline]
kvm_io_bus_unregister_dev+0x248/0x280 arch/arm64/kvm/…/…/…/virt/kvm/kvm_main.c:4374
kvm_vm_ioctl_unregister_coalesced_mmio+0x158/0x1ec arch/arm64/kvm/…/…/…/virt/kvm/coalesced_mmio.c:186
kvm_vm_ioctl+0xe30/0x14c4 arch/arm64/kvm/…/…/…/virt/kvm/kvm_main.c:3755
vfs_ioctl fs/ioctl.c:48 [inline]
__do_sys_ioctl fs/ioctl.c:753 [inline]
__se_sys_ioctl fs/ioctl.c:739 [inline]
__arm64_sys_ioctl+0xf88/0x131c fs/ioctl.c:739
__invoke_syscall arch/arm64/kernel/syscall.c:36 [inline]
invoke_syscall arch/arm64/kernel/sys
—truncated—