CVE-2024-26762

In the Linux kernel, the following vulnerability has been resolved:
cxl/pci: Skip to handle RAS errors if CXL.mem device is detached The PCI
AER model is an awkward fit for CXL error handling. While the expectation
is that a PCI device can escalate to link reset to recover from an AER
event, the same reset on CXL amounts to a surprise memory hotplug of
massive amounts of memory. At present, the CXL error handler attempts some
optimistic error handling to unbind the device from the cxl_mem driver
after reaping some RAS register values. This results in a “hopeful” attempt
to unplug the memory, but there is no guarantee that will succeed. A
subsequent AER notification after the memdev unbind event can no longer
assume the registers are mapped. Check for memdev bind before reaping
status register values to avoid crashes of the form: BUG: unable to handle
page fault for address: ffa00000195e9100 #PF: supervisor read access in
kernel mode #PF: error_code(0x0000) - not-present page […] RIP:
0010:__cxl_handle_ras+0x30/0x110 [cxl_core] […] Call Trace: <TASK> ?
__die+0x24/0x70 ? page_fault_oops+0x82/0x160 ?
kernelmode_fixup_or_oops+0x84/0x110 ? exc_page_fault+0x113/0x170 ?
asm_exc_page_fault+0x26/0x30 ? __pfx_dpc_reset_link+0x10/0x10 ?
__cxl_handle_ras+0x30/0x110 [cxl_core] ? find_cxl_port+0x59/0x80 [cxl_core]
cxl_handle_rp_ras+0xbc/0xd0 [cxl_core] cxl_error_detected+0x6c/0xf0
[cxl_core] report_error_detected+0xc7/0x1c0 pci_walk_bus+0x73/0x90
pcie_do_recovery+0x23f/0x330 Longer term, the unbind and
PCI_ERS_RESULT_DISCONNECT behavior might need to be replaced with a new
PCI_ERS_RESULT_PANIC.