CVE-2024-41085: cxl/mem: Fix no cxl_nvd during pmem region auto-assembling
First published: Mon Jul 29 2024(Updated: )
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.
Credit: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 416baaa9-dc9f-4396-8d5f-8c081fb06d67
| Affected Software | Affected Version | How to fix |
|---|---|---|
| Linux Linux kernel | >=6.2<6.9.8 | |
| redhat/kernel | <6.9.8 | 6.9.8 |
| redhat/kernel | <6.10 | 6.10 |
| debian/linux | 5.10.223-1 5.10.226-1 6.1.115-1 6.1.112-1 6.11.7-1 6.11.9-1 |
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Reference Links
- https://git.kernel.org/stable/c/1d064e4fbebcf5b18dc10c1f3973487eb163b600
- https://git.kernel.org/stable/c/84ec985944ef34a34a1605b93ce401aa8737af96
- https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2024-41085
- https://nvd.nist.gov/vuln/detail/CVE-2024-41085
- https://launchpad.net/bugs/cve/CVE-2024-41085
- https://security-tracker.debian.org/tracker/CVE-2024-41085
- https://ubuntu.com/security/CVE-2024-41085
- https://git.kernel.org/linus/84ec985944ef34a34a1605b93ce401aa8737af96
- https://lore.kernel.org/linux-cve-announce/2024072951-CVE-2024-41085-9bbd@gregkh/T
- https://bugzilla.redhat.com/show_bug.cgi/show_bug.cgi?id=2301666
- https://access.redhat.com/errata/RHSA-2024:9315
- https://bugzilla.redhat.com/show_bug.cgi?id=2300481
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