a8f40111d1
The remoteproc_core and remoteproc drivers all initialize with module_init(). However remoteproc drivers need the rproc_class during their probe. If one of the remoteproc drivers runs init and gets through probe before remoteproc_init() runs, a NULL pointer access of rproc_class's `glue_dirs` spinlock occurs. > Unable to handle kernel NULL pointer dereference at virtual address 000000dc > pgd = c0004000 > [000000dc] *pgd=00000000 > Internal error: Oops: 5 [#1] PREEMPT ARM > Modules linked in: > CPU: 0 PID: 1 Comm: swapper Tainted: G W 4.14.106-rt56 #1 > Hardware name: Generic OMAP36xx (Flattened Device Tree) > task: c6050000 task.stack: c604a000 > PC is at rt_spin_lock+0x40/0x6c > LR is at rt_spin_lock+0x28/0x6c > pc : [<c0523c90>] lr : [<c0523c78>] psr: 60000013 > sp : c604bdc0 ip : 00000000 fp : 00000000 > r10: 00000000 r9 : c61c7c10 r8 : c6269c20 > r7 : c0905888 r6 : c6269c20 r5 : 00000000 r4 : 000000d4 > r3 : 000000dc r2 : c6050000 r1 : 00000002 r0 : 000000d4 > Flags: nZCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment none ... > [<c0523c90>] (rt_spin_lock) from [<c03b65a4>] (get_device_parent+0x54/0x17c) > [<c03b65a4>] (get_device_parent) from [<c03b6bec>] (device_add+0xe0/0x5b4) > [<c03b6bec>] (device_add) from [<c042adf4>] (rproc_add+0x18/0xd8) > [<c042adf4>] (rproc_add) from [<c01110e4>] (my_rproc_probe+0x158/0x204) > [<c01110e4>] (my_rproc_probe) from [<c03bb6b8>] (platform_drv_probe+0x34/0x70) > [<c03bb6b8>] (platform_drv_probe) from [<c03b9dd4>] (driver_probe_device+0x2c8/0x420) > [<c03b9dd4>] (driver_probe_device) from [<c03ba02c>] (__driver_attach+0x100/0x11c) > [<c03ba02c>] (__driver_attach) from [<c03b7d08>] (bus_for_each_dev+0x7c/0xc0) > [<c03b7d08>] (bus_for_each_dev) from [<c03b910c>] (bus_add_driver+0x1cc/0x264) > [<c03b910c>] (bus_add_driver) from [<c03ba714>] (driver_register+0x78/0xf8) > [<c03ba714>] (driver_register) from [<c010181c>] (do_one_initcall+0x100/0x190) > [<c010181c>] (do_one_initcall) from [<c0800de8>] (kernel_init_freeable+0x130/0x1d0) > [<c0800de8>] (kernel_init_freeable) from [<c051eee8>] (kernel_init+0x8/0x114) > [<c051eee8>] (kernel_init) from [<c01175b0>] (ret_from_fork+0x14/0x24) > Code: e2843008 e3c2203f f5d3f000 e5922010 (e193cf9f) > ---[ end trace 0000000000000002 ]--- Signed-off-by: Brandon Maier <brandon.maier@rockwellcollins.com> Link: https://lore.kernel.org/r/20190530225223.136420-1-brandon.maier@rockwellcollins.com Signed-off-by: Bjorn Andersson <bjorn.andersson@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.