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X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: hKIdHGk6xxFDbKq0wmafh3fJ2AaOayMdP6kuKugCIeFCgMwoJyZ8HSeWwA/2Hfu/05UlhQRep/d2bJ2h2ZGt32fJmKWcMHwmZIMIkJcgqeXFTZ7PGbnumjT2IrbP+j41mdtA+5lP6oyksSzdKU+E9X3dvB5xMfB1UmR9yohdMaOI4OWpsFKCFbuDr9QeCALY6ix1dkvOlEA39tHZSRW95M2jzXJK0DamOiDsZRJLExZ3xdaX51mqcsHoU8v2IwwzzdY0N+7KkV5vEmJjVdT+FCQ57mjrfX5+G4rvk5zIVDqoEy79ZZqaaO+8RV1rJIbtw4I63NkW81J+oBWMVdQbyUqutCl/zFF0GrbO4tn7w9Wmh7RAU8ch+yXXgugUouRnABnyaSL4xMgkH56LXKMLcR9/KcePwwpZ8M9hp+soRzZhc/0GT/G38tG8X5r4NG4X X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 20 Feb 2026 19:35:15.1816 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: 4b77df25-2523-4ca9-467a-08de70b72bf9 X-MS-Exchange-CrossTenant-Id: 3dd8961f-e488-4e60-8e11-a82d994e183d X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=3dd8961f-e488-4e60-8e11-a82d994e183d;Ip=[165.204.84.17];Helo=[satlexmb08.amd.com] X-MS-Exchange-CrossTenant-AuthSource: BN1PEPF00006000.namprd05.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: SJ2PR12MB9242 On 2/10/2026 4:46 PM, Davidlohr Bueso wrote: > When dev_dax_kmem_probe() partially succeeds (at least one range > is mapped) but a subsequent range fails request_mem_region() > or add_memory_driver_managed(), the probe silently continues, > ultimately returning success. I would mention the range resource gets NULL'ed out here. I think it would make the below easier to follow. > > However, dev_dax_kmem_remove() iterates care free on all ranges > where that remove_memory() returns 0 for "never added memory"; > as walk_memory_blocks() will never see it in the memory_blocks > xarray. So ultimately passing a nil pointer to remove_resource(), > which can go boom. Bit confusing imo. Maybe something like: "dev_dax_kmem_remove() iterates over all dax_device ranges regardless of if the underlying resource exists. When remove_memory() is called later it returns 0 because the memory was never added which causes dev_dax_kmem_remove() to incorrectly assume the (nonexistent) resource can be removed and attempts cleanup on a NULL pointer. As for the actual fix: Reviewed-by: Ben Cheatham > > Fix this by skipping these ranges altogether, with the consideration > that these are considered success, such that the cleanup is still > reached when all actually-added ranges are successfully removed. > > Fixes: 60e93dc097f7 ("device-dax: add dis-contiguous resource support") > Signed-off-by: Davidlohr Bueso > --- > drivers/dax/kmem.c | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/drivers/dax/kmem.c b/drivers/dax/kmem.c > index c036e4d0b610..edd62e68ffb7 100644 > --- a/drivers/dax/kmem.c > +++ b/drivers/dax/kmem.c > @@ -227,6 +227,12 @@ static void dev_dax_kmem_remove(struct dev_dax *dev_dax) > if (rc) > continue; > > + /* range was never added during probe */ > + if (!data->res[i]) { > + success++; > + continue; > + } > + > rc = remove_memory(range.start, range_len(&range)); > if (rc == 0) { > remove_resource(data->res[i]);