linux/drivers/cxl, branch master

cxl/region: Test CXL_DECODER_F_NORMALIZED_ADDRESSING as a bitmask

2026-02-24T15:33:30Z

The CXL decoder flags are defined as bitmasks, not bit indices. Using test_bit() to check them interprets the mask value as a bit index, which is the wrong test. For CXL_DECODER_F_NORMALIZED_ADDRESSING the test reads beyond the flags word, making the flag sometimes appear set and blocking creation of CXL region debugfs attributes that support poison operations. Replace test_bit() with a bitmask check. Found with cxl-test. Fixes: 208f432406b7 ("cxl: Disable HPA/SPA translation handlers for Normalized Addressing") Signed-off-by: Alison Schofield Reviewed-by: Gregory Price Tested-by: Gregory Price Link: https://patch.msgid.link/63fe4a6203e40e404347f1cdc7a1c55cb4959b86.1771873256.git.alison.schofield@intel.com Signed-off-by: Dave Jiang

cxl: Test CXL_DECODER_F_LOCK as a bitmask

2026-02-24T15:33:30Z

The CXL decoder flags are defined as bitmasks, not bit indices. Using test_bit() to check them interprets the mask value as a bit index, which is the wrong test. For CXL_DECODER_F_LOCK the test reads beyond the defined bits, causing the test to always return false and allowing resets that should have been blocked. Replace test_bit() with a bitmask check. Fixes: 2230c4bdc412 ("cxl: Add handling of locked CXL decoder") Signed-off-by: Alison Schofield Reviewed-by: Gregory Price Tested-by: Gregory Price Link: https://patch.msgid.link/98851c4770e4631753cf9f75b58a3a6daeca2ea2.1771873256.git.alison.schofield@intel.com Signed-off-by: Dave Jiang

cxl/mbox: validate payload size before accessing contents in cxl_payload_from_user_allowed()

2026-02-24T15:33:29Z

cxl_payload_from_user_allowed() casts and dereferences the input payload without first verifying its size. When a raw mailbox command is sent with an undersized payload (ie: 1 byte for CXL_MBOX_OP_CLEAR_LOG, which expects a 16-byte UUID), uuid_equal() reads past the allocated buffer, triggering a KASAN splat: BUG: KASAN: slab-out-of-bounds in memcmp+0x176/0x1d0 lib/string.c:683 Read of size 8 at addr ffff88810130f5c0 by task syz.1.62/2258 CPU: 2 UID: 0 PID: 2258 Comm: syz.1.62 Not tainted 6.19.0-dirty #3 PREEMPT(voluntary) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.17.0-0-gb52ca86e094d-prebuilt.qemu.org 04/01/2014 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0xab/0xe0 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0xce/0x650 mm/kasan/report.c:482 kasan_report+0xce/0x100 mm/kasan/report.c:595 memcmp+0x176/0x1d0 lib/string.c:683 uuid_equal include/linux/uuid.h:73 [inline] cxl_payload_from_user_allowed drivers/cxl/core/mbox.c:345 [inline] cxl_mbox_cmd_ctor drivers/cxl/core/mbox.c:368 [inline] cxl_validate_cmd_from_user drivers/cxl/core/mbox.c:522 [inline] cxl_send_cmd+0x9c0/0xb50 drivers/cxl/core/mbox.c:643 __cxl_memdev_ioctl drivers/cxl/core/memdev.c:698 [inline] cxl_memdev_ioctl+0x14f/0x190 drivers/cxl/core/memdev.c:713 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl fs/ioctl.c:583 [inline] __x64_sys_ioctl+0x18e/0x210 fs/ioctl.c:583 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xa8/0x330 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fdaf331ba79 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fdaf1d77038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007fdaf3585fa0 RCX: 00007fdaf331ba79 RDX: 00002000000001c0 RSI: 00000000c030ce02 RDI: 0000000000000003 RBP: 00007fdaf33749df R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fdaf3586038 R14: 00007fdaf3585fa0 R15: 00007ffced2af768 Add 'in_size' parameter to cxl_payload_from_user_allowed() and validate the payload is large enough. Fixes: 6179045ccc0c ("cxl/mbox: Block immediate mode in SET_PARTITION_INFO command") Fixes: 206f9fa9d555 ("cxl/mbox: Add Clear Log mailbox command") Signed-off-by: Davidlohr Bueso Reviewed-by: Alison Schofield Reviewed-by: Dave Jiang Link: https://patch.msgid.link/20260220001618.963490-2-dave@stgolabs.net Signed-off-by: Dave Jiang

cxl: Fix race of nvdimm_bus object when creating nvdimm objects

2026-02-24T15:33:21Z

Found issue during running of cxl-translate.sh unit test. Adding a 3s sleep right before the test seems to make the issue reproduce fairly consistently. The cxl_translate module has dependency on cxl_acpi and causes orphaned nvdimm objects to reprobe after cxl_acpi is removed. The nvdimm_bus object is registered by the cxl_nvb object when cxl_acpi_probe() is called. With the nvdimm_bus object missing, __nd_device_register() will trigger NULL pointer dereference when accessing the dev->parent that points to &nvdimm_bus->dev. [ 192.884510] BUG: kernel NULL pointer dereference, address: 000000000000006c [ 192.895383] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS edk2-20250812-19.fc42 08/12/2025 [ 192.897721] Workqueue: cxl_port cxl_bus_rescan_queue [cxl_core] [ 192.899459] RIP: 0010:kobject_get+0xc/0x90 [ 192.924871] Call Trace: [ 192.925959] [ 192.926976] ? pm_runtime_init+0xb9/0xe0 [ 192.929712] __nd_device_register.part.0+0x4d/0xc0 [libnvdimm] [ 192.933314] __nvdimm_create+0x206/0x290 [libnvdimm] [ 192.936662] cxl_nvdimm_probe+0x119/0x1d0 [cxl_pmem] [ 192.940245] cxl_bus_probe+0x1a/0x60 [cxl_core] [ 192.943349] really_probe+0xde/0x380 This patch also relies on the previous change where devm_cxl_add_nvdimm_bridge() is called from drivers/cxl/pmem.c instead of drivers/cxl/core.c to ensure the dependency of cxl_acpi on cxl_pmem. 1. Set probe_type of cxl_nvb to PROBE_FORCE_SYNCHRONOUS to ensure the driver is probed synchronously when add_device() is called. 2. Add a check in __devm_cxl_add_nvdimm_bridge() to ensure that the cxl_nvb driver is attached during cxl_acpi_probe(). 3. Take the cxl_root uport_dev lock and the cxl_nvb->dev lock in devm_cxl_add_nvdimm() before checking nvdimm_bus is valid. 4. Set cxl_nvdimm flag to CXL_NVD_F_INVALIDATED so cxl_nvdimm_probe() will exit with -EBUSY. The removal of cxl_nvdimm devices should prevent any orphaned devices from probing once the nvdimm_bus is gone. [ dj: Fixed 0-day reported kdoc issue. ] [ dj: Fix cxl_nvb reference leak on error. Gregory (kreview-0811365) ] Suggested-by: Dan Williams Fixes: 8fdcb1704f61 ("cxl/pmem: Add initial infrastructure for pmem support") Tested-by: Alison Schofield Reviewed-by: Alison Schofield Link: https://patch.msgid.link/20260205001633.1813643-3-dave.jiang@intel.com Signed-off-by: Dave Jiang

cxl: Move devm_cxl_add_nvdimm_bridge() to cxl_pmem.ko

2026-02-23T18:29:05Z

Moving the symbol devm_cxl_add_nvdimm_bridge() to drivers/cxl/cxl_pmem.c, so that cxl_pmem can export a symbol that gives cxl_acpi a depedency on cxl_pmem kernel module. This is a prepatory patch to resolve the issue of a race for nvdimm_bus object that is created during cxl_acpi_probe(). No functional changes besides moving code. Suggested-by: Dan Williams Acked-by: Ira Weiny Tested-by: Alison Schofield Reviewed-by: Alison Schofield Link: https://patch.msgid.link/20260205001633.1813643-2-dave.jiang@intel.com Signed-off-by: Dave Jiang

cxl/port: Hold port host lock during dport adding.

2026-02-23T16:31:22Z

CXL testing environment can trigger following trace Oops: general protection fault, probably for non-canonical address 0xdffffc0000000092: 0000 [#1] SMP KASAN NOPTI KASAN: null-ptr-deref in range [0x0000000000000490-0x0000000000000497] RIP: 0010:cxl_dpa_to_region+0x105/0x1f0 [cxl_core] Call Trace: cxl_event_trace_record+0xd1/0xa70 [cxl_core] __cxl_event_trace_record+0x12f/0x1e0 [cxl_core] cxl_mem_get_records_log+0x261/0x500 [cxl_core] cxl_mem_get_event_records+0x7c/0xc0 [cxl_core] cxl_mock_mem_probe+0xd38/0x1c60 [cxl_mock_mem] platform_probe+0x9d/0x130 really_probe+0x1c8/0x960 __driver_probe_device+0x187/0x3e0 driver_probe_device+0x45/0x120 __device_attach_driver+0x15d/0x280 When CXL subsystem adds a cxl port to a hierarchy, there is a small window where the new port becomes visible before it is bound to a driver. This happens because device_add() adds a device to bus device list before bus_probe_device() binds it to a driver. So if two cxl memdevs are trying to add a dport to a same port via devm_cxl_enumerate_ports(), the second cxl memdev may observe the port and attempt to add a dport, but fails because the port has not yet been attached to cxl port driver. That causes the memdev->endpoint can not be updated. The sequence is like: CPU 0 CPU 1 devm_cxl_enumerate_ports() # port not found, add it add_port_attach_ep() # hold the parent port lock # to add the new port devm_cxl_create_port() device_add() # Add dev to bus devs list bus_add_device() devm_cxl_enumerate_ports() # found the port find_cxl_port_by_uport() # hold port lock to add a dport device_lock(the port) find_or_add_dport() cxl_port_add_dport() return -ENXIO because port->dev.driver is NULL device_unlock(the port) bus_probe_device() # hold the port lock # for attaching device_lock(the port) attaching the new port device_unlock(the port) To fix this race, require that dport addition holds the host lock of the target port(the host of CXL root and all cxl host bridge ports is the platform firmware device, the host of all other ports is their parent port). The CXL subsystem already requires holding the host lock while attaching a new port. Therefore, successfully acquiring the host lock guarantees that port attaching has completed. Fixes: 4f06d81e7c6a ("cxl: Defer dport allocation for switch ports") Signed-off-by: Li Ming Reviewed-by: Dan Williams Tested-by: Alison Schofield Link: https://patch.msgid.link/20260210-fix-port-enumeration-failure-v3-2-06acce0b9ead@zohomail.com Signed-off-by: Dave Jiang

cxl/port: Introduce port_to_host() helper

2026-02-23T16:31:07Z

In CXL subsystem, a port has its own host device for the port creation and removal. The host of CXL root and all the first level ports is the platform firmware device, the host of other ports is their parent port's device. Create this new helper to much easier to get the host of a cxl port. Introduce port_to_host() and use it to replace all places where using open coded to get the host of a port. Remove endpoint_host() as its functionality can be replaced by port_to_host(). [dj: Squashed commit 1 and 3 in the series to commit 1. ] Signed-off-by: Li Ming Tested-by: Alison Schofield Reviewed-by: Dan Williams Link: https://patch.msgid.link/20260210-fix-port-enumeration-failure-v3-1-06acce0b9ead@zohomail.com Signed-off-by: Dave Jiang

cxl/memdev: fix deadlock in cxl_memdev_autoremove() on attach failure

2026-02-23T16:03:44Z

cxl_memdev_autoremove() takes device_lock(&cxlmd->dev) via guard(device) and then calls cxl_memdev_unregister() when the attach callback was provided but cxl_mem_probe() failed to bind. cxl_memdev_unregister() calls cdev_device_del() device_del() bus_remove_device() device_release_driver() This path is reached when a driver uses the @attach parameter to devm_cxl_add_memdev() and the CXL topology fails to enumerate (e.g. DVSEC range registers decode outside platform-defined CXL ranges, causing the endpoint port probe to fail). Add cxl_memdev_attach_failed() to set the scope of the check correctly. Reported-by: kreview-c94b85d6d2 Fixes: 29317f8dc6ed ("cxl/mem: Introduce cxl_memdev_attach for CXL-dependent operation") Signed-off-by: Gregory Price Reviewed-by: Dan Williams Reviewed-by: Davidlohr Bueso Link: https://patch.msgid.link/20260211192228.2148713-1-gourry@gourry.net Signed-off-by: Dave Jiang

Convert 'alloc_flex' family to use the new default GFP_KERNEL argument

2026-02-22T01:09:51Z

This is the exact same thing as the 'alloc_obj()' version, only much smaller because there are a lot fewer users of the *alloc_flex() interface. As with alloc_obj() version, this was done entirely with mindless brute force, using the same script, except using 'flex' in the pattern rather than 'objs*'. Signed-off-by: Linus Torvalds

Convert 'alloc_obj' family to use the new default GFP_KERNEL argument

2026-02-22T01:09:51Z

This was done entirely with mindless brute force, using git grep -l '\