Vulnerability CVE-2021-47060
Published: 2024-02-29   Modified: 2024-03-01

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

KVM: Stop looking for coalesced MMIO zones if the bus is destroyed

Abort the walk of coalesced MMIO zones if kvm_io_bus_unregister_dev()
fails to allocate memory for the new instance of the bus. If it can't
instantiate a new bus, unregister_dev() destroys all devices _except_ the
target device. But, it doesn't tell the caller that it obliterated the
bus and invoked the destructor for all devices that were on the bus. In
the coalesced MMIO case, this can result in a deleted list entry
dereference due to attempting to continue iterating on coalesced_zones
after future entries (in the walk) have been deleted.

Opportunistically add curly braces to the for-loop, which encompasses
many lines but sneaks by without braces due to the guts being a single
if statement.

 References:
https://git.kernel.org/stable/c/7d1bc32d6477ff96a32695ea4be8144e4513ab2d
https://git.kernel.org/stable/c/2a20592baff59c5351c5200ec667e1a2aa22af85
https://git.kernel.org/stable/c/168e82f640ed1891a700bdb43e37da354b2ab63c
https://git.kernel.org/stable/c/50cbad42bfea8c052b7ca590bd4126cdc898713c
https://git.kernel.org/stable/c/5d3c4c79384af06e3c8e25b7770b6247496b4417
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