On Mon, Dec 4, 2023, at 13:38, Philipp Stanner wrote:
pci_iounmap() in lib/pci_iomap.c is supposed to check whether an address is within ioport-range IF the config specifies that ioports exist. If so, the port should be unmapped with ioport_unmap(). If not, it's a generic MMIO address that has to be passed to iounmap().
The bugs are:
- ioport_unmap() is missing entirely, so this function will never actually unmap a port.
- the #ifdef for the ioport-ranges accidentally also guards iounmap(), potentially compiling an empty function. This would cause the mapping to be leaked.
Implement the missing call to ioport_unmap().
Move the guard so that iounmap() will always be part of the function.
CC: stable@vger.kernel.org # v5.15+ Fixes: 316e8d79a095 ("pci_iounmap'2: Electric Boogaloo: try to make sense of it all") Reported-by: Danilo Krummrich dakr@redhat.com Suggested-by: Arnd Bergmann arnd@kernel.org Signed-off-by: Philipp Stanner pstanner@redhat.com
In case someone wants to look into that and provide patches for kernels older than v5.15: Note that this patch only applies to v5.15+ – the leaks, however, are older. I went through the log briefly and it seems f5810e5c32923 already contains them in asm-generic/io.h.
Reviewed-by: Arnd Bergmann arnd@arndb.de