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KVM: Destroy target device if coalesced MMIO unregistration fails

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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: 5d3c4c7938 ("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>
This commit is contained in:
Sean Christopherson 2022-12-19 17:19:24 +00:00
parent b9926482ab
commit b1cb1fac22
1 changed files with 5 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
virt/kvm/coalesced_mmio.c
View File

@ -187,15 +187,17 @@ int kvm_vm_ioctl_unregister_coalesced_mmio(struct kvm *kvm,
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);
}
}