Re: [PATCH] stat: don't fail if the major number is >= 256

[Andreas Schwab]

On Apr 11 2022, Linus Torvalds wrote:

>> For me, the failure happens in cp_compat_stat (I have a 64-bit kernel). In
>> struct compat_stat in arch/x86/include/asm/compat.h, st_dev and st_rdev
>> are compat_dev_t which is 16-bit. But they are followed by 16-bit
>> paddings, so they could be extended.
>
> Ok, that actually looks like a bug.
>
> The compat structure should match the native structure.  Those "u16
> __padX" fields seem to be just a symptom of the bug.

Looks like the move to 32-bit st_[r]dev was never applied to struct
compat_stat, see commit e95b206567 ("[PATCH] struct stat - support
larger dev_t") from tglx/history.git.

-- 
Andreas Schwab, schwab@xxxxxxxxxxxxxx
GPG Key fingerprint = 7578 EB47 D4E5 4D69 2510  2552 DF73 E780 A9DA AEC1
"And now for something completely different."