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:
1. ioport_unmap() is missing entirely, so this function will never
actually unmap a port.
2. 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@xxxxxxxxxxxxxxx> # v5.15+
Fixes: 316e8d79a095 ("pci_iounmap'2: Electric Boogaloo: try to make sense of it all")
Reported-by: Danilo Krummrich <dakr@xxxxxxxxxx>
Suggested-by: Arnd Bergmann <arnd@xxxxxxxxxx>
Signed-off-by: Philipp Stanner <pstanner@xxxxxxxxxx>
---
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.
---
lib/pci_iomap.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/lib/pci_iomap.c b/lib/pci_iomap.c
index ce39ce9f3526..6e144b017c48 100644
--- a/lib/pci_iomap.c
+++ b/lib/pci_iomap.c
@@ -168,10 +168,12 @@ void pci_iounmap(struct pci_dev *dev, void __iomem *p)
uintptr_t start = (uintptr_t) PCI_IOBASE;
uintptr_t addr = (uintptr_t) p;
- if (addr >= start && addr < start + IO_SPACE_LIMIT)
+ if (addr >= start && addr < start + IO_SPACE_LIMIT) {
+ ioport_unmap(p);
return;
- iounmap(p);
+ }
#endif
+ iounmap(p);
}
EXPORT_SYMBOL(pci_iounmap);
--
2.43.0
