On 10/2/23 18:07, Logan Gunthorpe wrote:
On 2023-10-01 15:08, Gustavo A. R. Silva wrote:`struct dev_pagemap` is a flexible structure, which means that it contains a flexible-array member at the bottom. This could potentially lead to an overwrite of the objects following `pgmap` in `struct pci_p2pdma_pagemap`, when `nr_range > 1`. Fix this by placing the declaration of object `pgmap` at the end of `struct pci_p2pdma_pagemap`. -Wflex-array-member-not-at-end is coming in GCC-14, and we are getting ready to enable it globally. Fixes: 0afea3814358 ("PCI/P2PDMA: Add provider's pci_dev to pci_p2pdma_pagemap struct") Fixes: a6e6fe6549f6 ("PCI/P2PDMA: Introduce private pagemap structure") Cc: [email protected] Signed-off-by: Gustavo A. R. Silva <[email protected]>Makes sense to me, thanks. Although, I'm not sure the fixes tags are appropriate. The flexible-array member was introduced in 5.10 (b7b3c01b19) and both the "fixed" commits predate that change by a number of releases.
You're right. I'll remove those tags.
Also, it's probably worth noting in the commit message that the p2pdma code hardcodes nr_ranges to 1 (in pci_p2pdma_add_resource); so there is no way to actually hit any bug with the current code.
Yep. I mention that in this part "This could potentially lead to an overwrite of the objects following `pgmap` in `struct pci_p2pdma_pagemap`, when `nr_range > 1`."
I totally agree that the patch should be applied to prevent possible bugs being introduced in the future: Reviewed-by: Logan Gunthorpe <[email protected]>
Thanks for the RB and the feedback. :) -- Gustavo
