| From bippy-5f407fcff5a0 Mon Sep 17 00:00:00 2001 |
| From: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| To: <linux-cve-announce@vger.kernel.org> |
| Reply-to: <cve@kernel.org>, <linux-kernel@vger.kernel.org> |
| Subject: CVE-2024-41085: cxl/mem: Fix no cxl_nvd during pmem region auto-assembling |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| cxl/mem: Fix no cxl_nvd during pmem region auto-assembling |
| |
| When CXL subsystem is auto-assembling a pmem region during cxl |
| endpoint port probing, always hit below calltrace. |
| |
| BUG: kernel NULL pointer dereference, address: 0000000000000078 |
| #PF: supervisor read access in kernel mode |
| #PF: error_code(0x0000) - not-present page |
| RIP: 0010:cxl_pmem_region_probe+0x22e/0x360 [cxl_pmem] |
| Call Trace: |
| <TASK> |
| ? __die+0x24/0x70 |
| ? page_fault_oops+0x82/0x160 |
| ? do_user_addr_fault+0x65/0x6b0 |
| ? exc_page_fault+0x7d/0x170 |
| ? asm_exc_page_fault+0x26/0x30 |
| ? cxl_pmem_region_probe+0x22e/0x360 [cxl_pmem] |
| ? cxl_pmem_region_probe+0x1ac/0x360 [cxl_pmem] |
| cxl_bus_probe+0x1b/0x60 [cxl_core] |
| really_probe+0x173/0x410 |
| ? __pfx___device_attach_driver+0x10/0x10 |
| __driver_probe_device+0x80/0x170 |
| driver_probe_device+0x1e/0x90 |
| __device_attach_driver+0x90/0x120 |
| bus_for_each_drv+0x84/0xe0 |
| __device_attach+0xbc/0x1f0 |
| bus_probe_device+0x90/0xa0 |
| device_add+0x51c/0x710 |
| devm_cxl_add_pmem_region+0x1b5/0x380 [cxl_core] |
| cxl_bus_probe+0x1b/0x60 [cxl_core] |
| |
| The cxl_nvd of the memdev needs to be available during the pmem region |
| probe. Currently the cxl_nvd is registered after the endpoint port probe. |
| The endpoint probe, in the case of autoassembly of regions, can cause a |
| pmem region probe requiring the not yet available cxl_nvd. Adjust the |
| sequence so this dependency is met. |
| |
| This requires adding a port parameter to cxl_find_nvdimm_bridge() that |
| can be used to query the ancestor root port. The endpoint port is not |
| yet available, but will share a common ancestor with its parent, so |
| start the query from there instead. |
| |
| The Linux kernel CVE team has assigned CVE-2024-41085 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 6.2 with commit f17b558d6663101f876a1d9cbbad3de0c8f4ce4d and fixed in 6.9.8 with commit 1d064e4fbebcf5b18dc10c1f3973487eb163b600 |
| Issue introduced in 6.2 with commit f17b558d6663101f876a1d9cbbad3de0c8f4ce4d and fixed in 6.10 with commit 84ec985944ef34a34a1605b93ce401aa8737af96 |
| |
| Please see https://www.kernel.org for a full list of currently supported |
| kernel versions by the kernel community. |
| |
| Unaffected versions might change over time as fixes are backported to |
| older supported kernel versions. The official CVE entry at |
| https://cve.org/CVERecord/?id=CVE-2024-41085 |
| will be updated if fixes are backported, please check that for the most |
| up to date information about this issue. |
| |
| |
| Affected files |
| ============== |
| |
| The file(s) affected by this issue are: |
| drivers/cxl/core/pmem.c |
| drivers/cxl/core/region.c |
| drivers/cxl/cxl.h |
| drivers/cxl/mem.c |
| |
| |
| Mitigation |
| ========== |
| |
| The Linux kernel CVE team recommends that you update to the latest |
| stable kernel version for this, and many other bugfixes. Individual |
| changes are never tested alone, but rather are part of a larger kernel |
| release. Cherry-picking individual commits is not recommended or |
| supported by the Linux kernel community at all. If however, updating to |
| the latest release is impossible, the individual changes to resolve this |
| issue can be found at these commits: |
| https://git.kernel.org/stable/c/1d064e4fbebcf5b18dc10c1f3973487eb163b600 |
| https://git.kernel.org/stable/c/84ec985944ef34a34a1605b93ce401aa8737af96 |
