Quoting Brian Norris (2018-08-09 12:52:13) > Hi, > > On Thu, Aug 09, 2018 at 12:40:31PM -0700, Stephen Boyd wrote: > > Quoting Brian Norris (2018-08-09 10:49:38) > > > On Thu, Aug 09, 2018 at 10:17:17AM -0700, Stephen Boyd wrote: > > > > Both callers of coreboot_table_init() ioremap the pointer that comes in > > > > but they don't unmap the memory on failure. Both of them also fail probe > > > > immediately with the return value of coreboot_table_init(), leaking a > > > > mapping when it fails. Plug the leak so the mapping isn't left unused. > > > > > > > > Cc: Wei-Ning Huang <wnhu...@chromium.org> > > > > Cc: Julius Werner <jwer...@chromium.org> > > > > Cc: Brian Norris <briannor...@chromium.org> > > > > Cc: Samuel Holland <sam...@sholland.org> > > > > Fixes: 570d30c2823f ("firmware: coreboot: Expose the coreboot table as > > > > a bus") > > > > > > I suppose this is fair, since that commit introduced error paths and > > > didn't clean them up. But one warning below: > > > > > > > Signed-off-by: Stephen Boyd <swb...@chromium.org> > > > > --- > > > > drivers/firmware/google/coreboot_table.c | 3 +++ > > > > 1 file changed, 3 insertions(+) > > > > > > > > diff --git a/drivers/firmware/google/coreboot_table.c > > > > b/drivers/firmware/google/coreboot_table.c > > > > index 19db5709ae28..0d3e140444ae 100644 > > > > --- a/drivers/firmware/google/coreboot_table.c > > > > +++ b/drivers/firmware/google/coreboot_table.c > > > > @@ -138,6 +138,9 @@ int coreboot_table_init(struct device *dev, void > > > > __iomem *ptr) > > > > ptr_entry += entry.size; > > > > } > > > > > > > > + if (ret) > > > > + iounmap(ptr); > > > > > > This works because no sub-driver is using this mapping any more (i.e., > > > because we killed coreboot_table_find()). Otherwise, we'd need to > > > explicitly kill all the sub-devices first. IOW, if this gets backported > > > to older kernels, it would need to go along with this and its other > > > dependencies: > > > > The memory is copied out of the table. So do the devices actually use > > the memory that we remap here? I don't see how it's a problem if we > > unmap the table after we populate devices. > > No, the memory is (or was) copied each time. See: > > int coreboot_table_find(int tag, void *data, size_t data_size) > { > ... > memcpy_fromio(&header, ptr_header, sizeof(header)); > ... > > (where ptr_header is an alias for 'ptr') > > So before commit b616cf53aa7a and friends, this patch is a bad idea. > > Just to reiterate/clarify: none of this is a criticism of this patch as > applied to mainline. It's just a criticism of what might happen with the > 'Fixes' tag if we aren't careful. >
Ok. I misread your email. Either way, both of these commits we're talking about here are only in v4.18-rc series, so backporting for stable will be fine either way.