1cada2f307
The hierarchical parts of MSM pinctrl/GPIO is only used when the device tree has a "wakeup-parent" as a phandle, but the .irq_eoi is anyway assigned leading to semantic problems on elder Qualcomm chipsets. When the drivers/mfd/qcom-pm8xxx.c driver calls chained_irq_exit() that call will in turn call chip->irq_eoi() which is set to irq_chip_eoi_parent() by default on a hierachical IRQ chip, and the parent is pinctrl-msm.c so that will in turn unconditionally call irq_chip_eoi_parent() again, but its parent is invalid so we get the following crash: Unnable to handle kernel NULL pointer dereference at virtual address 00000010 pgd = (ptrval) [00000010] *pgd=00000000 Internal error: Oops: 5 [#1] PREEMPT SMP ARM (...) PC is at irq_chip_eoi_parent+0x4/0x10 LR is at pm8xxx_irq_handler+0x1b4/0x2d8 If we solve this crash by avoiding to call up to irq_chip_eoi_parent(), the machine will hang and get reset by the watchdog, because of semantic issues, probably inside irq_chip. As a solution, just assign the .irq_eoi conditionally if we are actually using a wakeup parent. Cc: David Heidelberg <david@ixit.cz> Cc: Bjorn Andersson <bjorn.andersson@linaro.org> Cc: Lina Iyer <ilina@codeaurora.org> Cc: Stephen Boyd <swboyd@chromium.org> Cc: stable@vger.kernel.org Fixes: e35a6ae0eb3a ("pinctrl/msm: Setup GPIO chip in hierarchy") Link: https://lore.kernel.org/r/20200306121221.1231296-1-linus.walleij@linaro.org Link: https://lore.kernel.org/r/20200309125207.571840-1-linus.walleij@linaro.org Link: https://lore.kernel.org/r/20200309152604.585112-1-linus.walleij@linaro.org Tested-by: David Heidelberg <david@ixit.cz> Acked-by: Marc Zyngier <maz@kernel.org> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.