Re: [PATCH] block: fix BLKSECDISCARD zero-length range causing page cache invalidation

[Zizhi Wo]

在 2026/7/25 3:39, Bart Van Assche 写道:
> On 7/4/26 12:39 AM, Zizhi Wo wrote:
> > Commit 697ba0b6ec4a ("block: fix integer overflow in BLKSECDISCARD") 
> > fixed
> > the start+len overflow via check_add_overflow() but did not handle the
> > start=0, len=0 case. There, start + len = 0, so end = 0 passes all 
> > checks,
> > and truncate_bdev_range()->truncate_inode_pages_range() is then called 
> > with
> > lend=UINT64_MAX, whitch is the "truncate to the end of file" sentinel, so
> > the entire page cache is invalidated.
> >
> > Fix this by replacing the validation with blk_validate_byte_range(), 
> > which
> > already rejects a zero-length range and is what BLKDISCARD uses. This 
> > also
> > switches the alignment check from a hardcoded 512 to
> > bdev_logical_block_size().
>
> A Fixes: tag is missing. Once this has been addressed, feel free to add:
>
> Reviewed-by: Bart Van Assche <bvanassche@xxxxxxx>


Thanks for the reminder, I will add a fixtag in the second version.

Thanks,
Zizhi Wo