{"id":"CVE-2026-64586","summary":"wifi: brcmfmac: drain bus_reset work on device removal","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nwifi: brcmfmac: drain bus_reset work on device removal\n\nbrcmf_fw_crashed() and the debugfs \"reset\" entry both schedule\ndrvr-\u003ebus_reset, whose callback recovers drvr through container_of()\nand dereferences it.  The removal path frees drvr (brcmf_free -\u003e\nwiphy_free) without draining the work, so a bus_reset callback pending\nor running during removal can outlive drvr.\n\nCancellation cannot live in brcmf_detach() or brcmf_free(): the work\ncallback reaches teardown through the bus .reset op (PCIe\nbrcmf_pcie_reset -\u003e brcmf_detach; SDIO brcmf_sdio_bus_reset -\u003e\nbrcmf_sdiod_remove -\u003e brcmf_free), so cancelling there would wait for\nthe running work and deadlock.\n\nAdd a per-bus mutex (bus_reset_lock) and route all arming through\nbrcmf_bus_schedule_reset(), which under the lock skips when the bus is\nmarked removing.  Each bus remove entry calls\nbrcmf_bus_cancel_reset_work(), which under the same lock sets removing\nand cancels the work.  Holding the mutex across cancel_work_sync() makes\nthe set-removing + drain step atomic.  Every producer reaches the arming\npath from process context -- the PCIe firmware-halt notification runs in\nthe threaded IRQ handler (brcmf_pcie_isr_thread) and the SDIO hostmail\npath runs from the data workqueue -- so the mutex is taken only in\nsleepable contexts.  Where applicable the remove entry first stops the\nfirmware-crash producer: on PCIe mask the mailbox and synchronize_irq;\non SDIO unregister the bus interrupt and cancel the data worker, which\nalso reports firmware halts through brcmf_fw_crashed().  The mutex is\ninitialized at bus allocation.  The SDIO suspend power-off path frees\ndrvr through the same brcmf_sdiod_remove() and takes the same lock;\nresume re-allows the work only on a successful re-probe.\n\nAlso guard brcmf_fw_crashed() against a NULL bus_if/drvr: it can fire\nbefore brcmf_attach() wires up drvr, and it dereferences drvr\n(bphy_err/brcmf_dev_coredump) before reaching the arming gate.\n\nThe bus_reset work is shared across buses, so the drain is applied to\nevery remove path: PCIe (the .reset op introduced by the Fixes commit),\nSDIO (arms the same work through brcmf_fw_crashed()), and USB (via the\ndebugfs \"reset\" entry).  cancel_work_sync() drains a running or pending\nbus_reset work item before removal frees drvr, and patch 1/2 makes the\nscratch-buffer release safe when reset teardown has already released\nthose DMA buffers.\n\nThis patch fixes the lifetime of the bus_reset work item itself.  It does\nnot attempt to address the separate, pre-existing lifetime of the\nasynchronous firmware completion started by the PCIe reset path.  That\ncallback needs its own lifetime/ownership protocol and is being tracked\nseparately.\n\nThis issue was found by an in-house static analysis tool.","modified":"2026-08-10T08:27:02.964136921Z","published":"2026-08-06T07:06:27.158Z","related":["openSUSE-SU-2026:11476-1"],"database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/64xxx/CVE-2026-64586.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/02d378828af8bb74f6c2f4d2bee3c77cf16c861e"},{"type":"WEB","url":"https://git.kernel.org/stable/c/177a25be1195f8bdc6160ba5f1a5699f7041c985"},{"type":"WEB","url":"https://git.kernel.org/stable/c/43b25879f004c98defa2776bedc6ca4763c51945"},{"type":"WEB","url":"https://git.kernel.org/stable/c/c268331845ee00dbdbccb000826bb612dff2bee7"},{"type":"WEB","url":"https://git.kernel.org/stable/c/e3815d1ffbb9be4f1605ddc3b427557893461683"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/64xxx/CVE-2026-64586.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-64586"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"4684997d9eea29380000e062755aa6d368d789a3"},{"fixed":"c268331845ee00dbdbccb000826bb612dff2bee7"},{"fixed":"e3815d1ffbb9be4f1605ddc3b427557893461683"},{"fixed":"02d378828af8bb74f6c2f4d2bee3c77cf16c861e"},{"fixed":"177a25be1195f8bdc6160ba5f1a5699f7041c985"},{"fixed":"43b25879f004c98defa2776bedc6ca4763c51945"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-64586.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"5.2.0"},{"fixed":"6.6.151"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.7.0"},{"fixed":"6.12.103"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.18.44"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"7.1.6"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-64586.json"}}],"schema_version":"1.8.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"}]}