d8a1de3d5b
Since linux 4.9 it is not possible to use buffers on the stack for DMA transfers. During usb probe the driver crashes with "transfer buffer is on stack" message. This fix k-allocates a buffer to be used on "read_reg_atomic", which is a macro that calls "usb_control_msg" under the hood. Kernel 4.19 backtrace: usb_hcd_submit_urb+0x3e5/0x900 ? sched_clock+0x9/0x10 ? log_store+0x203/0x270 ? get_random_u32+0x6f/0x90 ? cache_alloc_refill+0x784/0x8a0 usb_submit_urb+0x3b4/0x550 usb_start_wait_urb+0x4e/0xd0 usb_control_msg+0xb8/0x120 hfcsusb_probe+0x6bc/0xb40 [hfcsusb] usb_probe_interface+0xc2/0x260 really_probe+0x176/0x280 driver_probe_device+0x49/0x130 __driver_attach+0xa9/0xb0 ? driver_probe_device+0x130/0x130 bus_for_each_dev+0x5a/0x90 driver_attach+0x14/0x20 ? driver_probe_device+0x130/0x130 bus_add_driver+0x157/0x1e0 driver_register+0x51/0xe0 usb_register_driver+0x5d/0x120 ? 0xf81ed000 hfcsusb_drv_init+0x17/0x1000 [hfcsusb] do_one_initcall+0x44/0x190 ? free_unref_page_commit+0x6a/0xd0 do_init_module+0x46/0x1c0 load_module+0x1dc1/0x2400 sys_init_module+0xed/0x120 do_fast_syscall_32+0x7a/0x200 entry_SYSENTER_32+0x6b/0xbe Signed-off-by: Juliana Rodrigueiro <juliana.rodrigueiro@intra2net.com> Signed-off-by: David S. Miller <davem@davemloft.net>
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.