CVE-2021-47283

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

net:sfc: fix non-freed irq in legacy irq mode

SFC driver can be configured via modparam to work using MSI-X, MSI or legacy IRQ interrupts. In the last one, the interrupt was not properly released on module remove.

It was not freed because the flag irqs_hooked was not set during initialization in the case of using legacy IRQ.

Example of (trimmed) trace during module remove without this fix:

remove_proc_entry: removing non-empty directory irq/125, leaking at least 0000:3b:00.1 WARNING: CPU: 39 PID: 3658 at fs/proc/generic.c:715 remove_proc_entry+0x15c/0x170 …trimmed… Call Trace: unregister_irq_proc+0xe3/0x100 free_desc+0x29/0x70 irq_free_descs+0x47/0x70 mp_unmap_irq+0x58/0x60 acpi_unregister_gsi_ioapic+0x2a/0x40 acpi_pci_irq_disable+0x78/0xb0 pci_disable_device+0xd1/0x100 efx_pci_remove+0xa1/0x1e0 [sfc] pci_device_remove+0x38/0xa0 __device_release_driver+0x177/0x230 driver_detach+0xcb/0x110 bus_remove_driver+0x58/0xd0 pci_unregister_driver+0x2a/0xb0 efx_exit_module+0x24/0xf40 [sfc] __do_sys_delete_module.constprop.0+0x171/0x280 ? exit_to_user_mode_prepare+0x83/0x1d0 do_syscall_64+0x3d/0x80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7f9f9385800b …trimmed…

Affected Software

References

• https://git.kernel.org/stable/c/81c4d1d83f88e15b26f4522a35cba6ffd8c5dfdd
• https://git.kernel.org/stable/c/8d717c9135a3340ae62d1699484850bfb4112b0c
• https://git.kernel.org/stable/c/8f03eeb6e0a0a0b8d617ee0a4bce729e47130036