Re: [PATCH] drivers: pci: Fix flexible array usage

[Purva Yeshi]

On 11/02/25 04:33, Keith Busch wrote:
> On Mon, Feb 10, 2025 at 06:57:40PM +0530, Purva Yeshi wrote:
> > Fix warning detected by smatch tool:
> > Array of flexible structure occurs in 'pci_saved_state' struct
> >
> > The warning occurs because struct pci_saved_state contains struct
> > pci_cap_saved_data cap[], where cap[] has a flexible array member (data[]).
> > Arrays of structures with flexible members are not allowed, leading to this
> > warning.
> >
> > Replaced cap[] with a pointer (*cap), allowing dynamic memory allocation
> > instead of embedding an invalid array of flexible structures.
> >
> > Signed-off-by: Purva Yeshi <purvayeshi550@xxxxxxxxx>
> > ---
> >   drivers/pci/pci.c | 2 +-
> >   1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
> > index 869d204a7..648a080ef 100644
> > --- a/drivers/pci/pci.c
> > +++ b/drivers/pci/pci.c
> > @@ -1929,7 +1929,7 @@ EXPORT_SYMBOL(pci_restore_state);
> >   
> >   struct pci_saved_state {
> >   	u32 config_space[16];
> > -	struct pci_cap_saved_data cap[];
> > +	struct pci_cap_saved_data *cap;
> >   };
>
> I don't think this is right. Previously the space for "cap" was
> allocated at the end of the pci_saved_state, but now it's just an
> uninitialized pointer.

Thanks for your feedback. I understand your concern about the 
uninitialized pointer. To verify this, I tested the file using 
'~/smatch/smatch_scripts/kchecker drivers/pci/pci.c' smatch command, and 
it did not report any errors indicating that cap was uninitialized. 
Based on this, I initially believed the change to be safe.