cefe535a60
commit b08472db93b1ccff84a7adec5779d47f0e9d3a30 upstream.
A NULL pointer dereference was observed in the AMD64 AGP driver when
running in a virtualized environment (e.g. qemu/kvm) without a physical
AMD northbridge. The crash occurs in amd64_fetch_size() when attempting
to dereference the pointer returned by node_to_amd_nb(0).
The root cause of this crash is broken error propagation in
agp_amd64_probe(): When no AMD northbridges are found, cache_nbs()
correctly returns -ENODEV. However, the probe function erroneously
checks the return value against exactly -1, rather than < 0.
As a result, the hardware absence error is masked, allowing the driver
to improperly proceed with initialization. It eventually calls
agp_add_bridge(), which invokes amd64_fetch_size(). Since the hardware
does not exist, node_to_amd_nb(0) returns NULL, leading to a General
Protection Fault (GPF) when accessing its ->misc member.
Fix the issue by correcting the error check in agp_amd64_probe() to
abort properly when cache_nbs() returns any negative error code. This
prevents the driver from erroneously proceeding without hardware, thereby
avoiding the subsequent NULL pointer dereference at its source.
Fixes:
|
||
|---|---|---|
| .. | ||
| agp | ||
| hw_random | ||
| ipmi | ||
| tpm | ||
| xilinx_hwicap | ||
| xillybus | ||
| adi.c | ||
| apm-emulation.c | ||
| applicom.c | ||
| applicom.h | ||
| bsr.c | ||
| ds1620.c | ||
| dsp56k.c | ||
| dtlk.c | ||
| hangcheck-timer.c | ||
| hpet.c | ||
| Kconfig | ||
| lp.c | ||
| Makefile | ||
| mem.c | ||
| misc.c | ||
| misc_minor_kunit.c | ||
| nsc_gpio.c | ||
| nvram.c | ||
| nwbutton.c | ||
| nwbutton.h | ||
| nwflash.c | ||
| pc8736x_gpio.c | ||
| powernv-op-panel.c | ||
| ppdev.c | ||
| ps3flash.c | ||
| random.c | ||
| scx200_gpio.c | ||
| sonypi.c | ||
| tlclk.c | ||
| toshiba.c | ||
| ttyprintk.c | ||
| uv_mmtimer.c | ||
| virtio_console.c | ||