From: Dan Williams dan.j.williams@intel.com
commit a90accb358ae33ea982a35595573f7a045993f8b upstream.
Some regions may not have any address space allocated. Skip them when validating HPA order otherwise a crash like the following may result:
devm_cxl_add_region: cxl_acpi cxl_acpi.0: decoder3.4: created region9 BUG: kernel NULL pointer dereference, address: 0000000000000000 [..] RIP: 0010:store_targetN+0x655/0x1740 [cxl_core] [..] Call Trace: <TASK> kernfs_fop_write_iter+0x144/0x200 vfs_write+0x24a/0x4d0 ksys_write+0x69/0xf0 do_syscall_64+0x3a/0x90
store_targetN+0x655/0x1740: alloc_region_ref at drivers/cxl/core/region.c:676 (inlined by) cxl_port_attach_region at drivers/cxl/core/region.c:850 (inlined by) cxl_region_attach at drivers/cxl/core/region.c:1290 (inlined by) attach_target at drivers/cxl/core/region.c:1410 (inlined by) store_targetN at drivers/cxl/core/region.c:1453
Cc: stable@vger.kernel.org Fixes: 384e624bb211 ("cxl/region: Attach endpoint decoders") Reviewed-by: Vishal Verma vishal.l.verma@intel.com Reviewed-by: Dave Jiang dave.jiang@intel.com Link: https://lore.kernel.org/r/166752182461.947915.497032805239915067.stgit@dwill... Signed-off-by: Dan Williams dan.j.williams@intel.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/cxl/core/region.c | 3 +++ 1 file changed, 3 insertions(+)
--- a/drivers/cxl/core/region.c +++ b/drivers/cxl/core/region.c @@ -657,6 +657,9 @@ static struct cxl_region_ref *alloc_regi xa_for_each(&port->regions, index, iter) { struct cxl_region_params *ip = &iter->region->params;
+ if (!ip->res) + continue; + if (ip->res->start > p->res->start) { dev_dbg(&cxlr->dev, "%s: HPA order violation %s:%pr vs %pr\n",