> On Thu, Sep 11, 2025 at 06:13:33AM +0000, Farber, Eliav wrote:
> > > On Wed, Sep 10, 2025 at 05:31:38PM +0000, Eliav Farber wrote:
> > >> Fix a compilation failure when warnings are treated as errors:
> > >>
> > >> drivers/net/ethernet/intel/e1000e/ethtool.c: In function
> > >> ‘e1000_set_eeprom’:
> > >> ./include/linux/overflow.h:71:15: error: comparison of distinct pointer
> > >> types lacks a cast [-Werror]
> > >> 71 | (void) (&__a == __d); \
> > >> | ^~
> > >> drivers/net/ethernet/intel/e1000e/ethtool.c:582:6: note: in expansion of
> > >> macro ‘check_add_overflow’
> > >> 582 | if (check_add_overflow(eeprom->offset, eeprom->len, &total_len)
> > >> ||
> > >> | ^~~~~~~~~~~~~~~~~~
> > >>
> > >> To fix this, change total_len and max_len from size_t to u32 in
> > >> e1000_set_eeprom().
> > >> The check_add_overflow() helper requires that the first two operands
> > >> and the pointer to the result (third operand) all have the same type.
> > >> On 64-bit builds, using size_t caused a mismatch with the u32 fields
> > >> eeprom->offset and eeprom->len, leading to type check failures.
> > >>
> > >> Fixes: ce8829d3d44b ("e1000e: fix heap overflow in e1000_set_eeprom")
> > >> Signed-off-by: Eliav Farber <[email protected]>
> > >> ---
> > >> drivers/net/ethernet/intel/e1000e/ethtool.c | 2 +-
> > >> 1 file changed, 1 insertion(+), 1 deletion(-)
> > >>
> > >> diff --git a/drivers/net/ethernet/intel/e1000e/ethtool.c
> > >> b/drivers/net/ethernet/intel/e1000e/ethtool.c
> > >> index 4aca854783e2..584378291f3f 100644
> > >> --- a/drivers/net/ethernet/intel/e1000e/ethtool.c
> > >> +++ b/drivers/net/ethernet/intel/e1000e/ethtool.c
> > >> @@ -559,7 +559,7 @@ static int e1000_set_eeprom(struct net_device
> > >> *netdev, {
> > >> struct e1000_adapter *adapter = netdev_priv(netdev);
> > >> struct e1000_hw *hw = &adapter->hw;
> > >> - size_t total_len, max_len;
> > >> + u32 total_len, max_len;
> > >> u16 *eeprom_buff;
> > >> int ret_val = 0;
> > >> int first_word;
> > >> --
> > >> 2.47.3
> > >>
> > >
> > > Why is this not needed in Linus's tree?
> > Kernel 5.10.243 enforces the same type, but this enforcement is
> > absent from 5.15.192 and later:
> > /*
> > * For simplicity and code hygiene, the fallback code below insists on
> > * a, b and *d having the same type (similar to the min() and max()
> > * macros), whereas gcc's type-generic overflow checkers accept
> > * different types. Hence we don't just make check_add_overflow an
> > * alias for __builtin_add_overflow, but add type checks similar to
> > * below.
> > */
> > #define check_add_overflow(a, b, d) __must_check_overflow(({ \
>
> Yeah, the min() build warning mess is slowly propagating back to older
> kernels over time as we take these types of fixes backwards. I count 3
> such new warnings in the new 5.10 release, not just this single one.
>
> Overall, how about fixing this up so it doesn't happen anymore by
> backporting the min() logic instead? That should solve this build
> warning, and keep it from happening again in the future? I did that for
> newer kernel branches, but never got around to it for these.
I did backporting of 4 commits to bring include/linux/overflow.h in
line with v5.15.193 in order to pull commit 1d1ac8244c22 ("overflow:
Allow mixed type arguments").
I'll also check what can be done for include/linux/minmax.h.
---
Regards, Eliav
