wifi: brcmfmac: initialize SDIO data work before cleanup

Overview

In the Linux kernel, the following vulnerability has been resolved:

wifi: brcmfmac: initialize SDIO data work before cleanup

brcmf_sdio_probe() stores the newly allocated bus in sdiodev->bus before allocating the ordered workqueue. If that allocation fails, the function jumps to fail and calls brcmf_sdio_remove().

brcmf_sdio_remove() unconditionally cancels bus->datawork. Initialize the work item before the first failure path that can reach brcmf_sdio_remove(), so the cleanup path always observes a valid work object.

This issue was found by our static analysis tool and then confirmed by manual review of the probe error path and the remove-time work drain. The problem pattern is an early setup failure that reaches a cleanup helper which cancels an embedded work item before its initializer has run.

A QEMU PoC forced alloc_ordered_workqueue() to fail at the same point in brcmf_sdio_probe(), before INIT_WORK(&bus->datawork) is reached. The resulting fail path calls brcmf_sdio_remove(), and DEBUG_OBJECTS reports the invalid work drain with brcmf_sdio_probe() and brcmf_sdio_remove() in the stack.

Affected

• Linux >= 9982464379e81ece51ced03ebecbbcd34ea367a6 < 860887d22890417d43ef8298f0cc4865e29b54de
• Linux >= 9982464379e81ece51ced03ebecbbcd34ea367a6 < 9a4be91e5bb032b34cb3c962f6d4f82e7ef09364
• Linux >= 9982464379e81ece51ced03ebecbbcd34ea367a6 < fb12c87ae855346321af72e57a93c146205f1090
• Linux >= 9982464379e81ece51ced03ebecbbcd34ea367a6 < f50a2b9e57a751e70ae9a272875d80d39eaccd6a
• Linux >= 9982464379e81ece51ced03ebecbbcd34ea367a6 < 6bd21ec8549a5854dd64204a66289952917a924c
• Linux >= 9982464379e81ece51ced03ebecbbcd34ea367a6 < 5c342437ea44bb829680ca9e4f683dd5b325b219
• Linux >= 9982464379e81ece51ced03ebecbbcd34ea367a6 < c73c3fc1c7ca5a927639f0884624cb244ba791e4
• Linux >= 9982464379e81ece51ced03ebecbbcd34ea367a6 < 2a665946e0407a05a3f81bd56a08553c446498e0
• Linux 4.1

Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.