Re: [PATCH] Revert "mtd: spinand: Fix OOB read"

[Greg KH <gregkh@linuxfoundation.org>]

On Tue, Jan 05, 2021 at 11:40:11AM +0100, Felix Fietkau wrote:
> 
> On 2021-01-05 11:31, Greg KH wrote:
> > On Tue, Jan 05, 2021 at 11:18:21AM +0100, Felix Fietkau wrote:
> >> This reverts stable commit baad618d078c857f99cc286ea249e9629159901f.
> >> 
> >> This commit is adding lines to spinand_write_to_cache_op, wheras the upstream
> >> commit 868cbe2a6dcee451bd8f87cbbb2a73cf463b57e5 that this was supposed to
> >> backport was touching spinand_read_from_cache_op.
> >> It causes a crash on writing OOB data by attempting to write to read-only
> >> kernel memory.
> >> 
> >> Cc: Miquel Raynal <miquel.raynal@bootlin.com>
> >> Signed-off-by: Felix Fietkau <nbd@nbd.name>
> >> ---
> >>  drivers/mtd/nand/spi/core.c | 4 ----
> >>  1 file changed, 4 deletions(-)
> > 
> > So the backport to 5.10.y broke, but not the backport to 4.19.y or
> > 5.4.y?  Can you provide a "correct" backport for this instead of just
> > removing this fix?
> I just checked, it seems that 4.19.y and 5.4.y are broken in exactly the
> same way.
> 
> On a first glance, it seems that the upstream commit has a wrong Fixes
> line and is fixing 3d1f08b032dc ("mtd: spinand: Use the external ECC
> engine logic") instead, which is not in 5.10.
> If that is correct, then we don't need any stable backport at all.

Ah, then yes, this should be reverted everywhere.  If that is the case,
otherwise, I went off of the fixes: value in the original commit, which
is in the 4.19.0 release.

> In my opinion it's best to just revert the broken commit in all the
> stable trees as quickly as possible and let Miquel sort out the mess
> afterwards, if needed.

I can do that, but need an ack from the maintainer...

thanks,

greg k-h