Re: [PATCH v2] PCI: sysfs: Reject unaligned resource I/O port accesses

[sashiko-bot@kernel.org]

> pci_resource_io() validates that the requested port lies within the
> BAR but never checks that it is aligned to the access size. A
> pwrite64()/pread64() on a resourceN file with an odd offset and
> count=2 or count=4 reaches outw()/outl() with a misaligned address.
> On arm64 this becomes a store/load to a Device-memory mapping
> (PCI_IOBASE + port), which architecturally requires natural
> alignment, causing an alignment fault and kernel oops.
> 
> Reject misaligned 2- and 4-byte accesses before they reach the
> low-level accessor. With natural alignment enforced, an access that
> starts inside the BAR cannot extend past its end, so drop the
> port + count - 1 range check.
> 
> Reported-by: syzbot+7134530b25073b4ef373@syzkaller.appspotmail.com
> Closes: https://syzkaller.appspot.com/bug?extid=7134530b25073b4ef373
> Signed-off-by: Deepanshu Kartikey <kartikey406@gmail.com>

Sashiko has reviewed this patch and found no issues. It looks great!

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Sashiko AI review · https://sashiko.dev/#/patchset/20260928123036.7902-1-kartikey406@gmail.com?part=1