> All callers of follow_pfnmap_start() except s390_pci_mmio_write() > are following it, if they are doing a write, with a check that > args.writable is true; for s390_pci_mmio_write() that's a bug. > Also, most of them return -EFAULT if it is not. Pull the check > directly into follow_pfnmap_start() through another input parameter > args.write_fault, to eliminate the need to do it in the caller. > > This also fixes an issue where follow_pfnmap_start() would return > 0 for a PFN that is mapped read-only, and the caller would not > attempt to call fixup_user_fault() on it; this can happen with > vm_ops that set .pfn_mkwrite(), for example. Instead, now the > caller (for example hva_to_pfn_remapped()) sees an error, > does attempt to fix it, and only returns -EFAULT if the > fixup was fruitless. > > Reported-by: Sergio Lopez <[email protected]> > Fixes: 28e3918179aa ("drm/gem-shmem: Track folio accessed/dirty status in > mmap") > Link: > https://lore.kernel.org/kvm/CAAiTLFU1ALsDoJoKW3d9bUvv990AozAoX=behmfng54qyba...@mail.gmail.com/ > Cc: [email protected] > Signed-off-by: Paolo Bonzini <[email protected]>
Sashiko has reviewed this patch and found no issues. It looks great! -- Sashiko AI review ยท https://sashiko.dev/#/patchset/[email protected]?part=5
