On Tue, Aug 11, 2026 at 09:57:52AM +0530, Balaji Selvanathan wrote:
> Hi Tom,
>
> On 8/10/2026 11:46 PM, Tom Rini wrote:
> > On Mon, Aug 10, 2026 at 03:04:53PM +0530, Balaji Selvanathan wrote:
> >
> > > Before commit 623f6c5b6ab7 ("boot: image-fdt: free old dtb
> > > reservations"), boot_fdt_handle_region() filtered out -EEXIST and
> > > -EINVAL when reserving an FDT memory region, treating both as benign.
> > > That commit added the free/reserve toggle but dropped the filter, so
> > > these now print as errors.
> > >
> > > -EINVAL in particular is expected: when a reserved-memory region falls
> > > outside the available memory LMB knows about, _lmb_alloc_addr() returns
> > > -EINVAL. This happens when a carve-out described in the kernel DT lies
> > > in a range the platform does not report as usable RAM, so its
> > > reservation fails with -EINVAL and prints:
> > >
> > > ERROR: reserving fdt memory region failed (addr=91a80000 size=80000
> > > flags=2): -22
> > >
> > > on an otherwise clean boot. The region is still described in the
> > > kernel DT and Linux reserves it itself, so U-Boot failing to track it
> > > in LMB is harmless.
> > >
> > > Restore the old filter, scoped to the reserve path: print the error
> > > only when freeing, or when a reservation fails with something other
> > > than -EEXIST or -EINVAL. The "free ||" guard keeps free-path failures
> > > always visible.
> > >
> > > Fixes: 623f6c5b6ab7 ("boot: image-fdt: free old dtb reservations")
> > > Signed-off-by: Balaji Selvanathan <[email protected]>
> > This is the same as:
> > https://patchwork.ozlabs.org/project/uboot/patch/[email protected]/
> > So I've added people from that thread to this one.
> >
> > It seems to me like the last message there wasn't quite everyone being
> > in agreement on the next step, so, what is required next at this point?
> > This is clearly a problem in some cases, in terms of "scary" message to
> > the user which isn't meaningful.
>
> AFAIK, lmb_alloc_mem returns -EINVAL for 2 reasons: a NULL addr pointer, and
> "the region isn't part of the available LMB map" (_lmb_alloc_addr()).
>
> In boot_fdt_handle_region, I think we always pass a valid &addr and bail
> early on size 0, so the NULL-pointer -EINVAL can't be hit from here. So
> -EINVAL could only mean "the region isn't part of the available LMB map" in
> boot_fdt_handle_region.
>
> Maybe we can give "region outside the LMB map" its own return value
> (-EFAULT) as Rudolph suggested and have boot_fdt_handle_region() ignore that
> specific case (to make it more clean). That seems like a middle ground.OK. I think a patch doing that might help move the discussion forward, can you please do so? Thanks. -- Tom
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