d6c931ea32
Scatter-gather needs to be disabled when using dma_declare_coherent_memory and HCD_LOCAL_MEM. Andrea Righi made the equivalent fix for EHCI drivers in commit 4307a28eb01284 "USB: EHCI: fix NULL pointer dererence in HCDs that use HCD_LOCAL_MEM". The following NULL pointer WARN_ON_ONCE triggered with OHCI drivers: ------------[ cut here ]------------ WARNING: CPU: 0 PID: 49 at drivers/usb/core/hcd.c:1379 hcd_alloc_coherent+0x4c/0xc8 Modules linked in: CPU: 0 PID: 49 Comm: usb-storage Not tainted 4.15.0+ #1014 Stack : 00000000 00000000 805a78d2 0000003a 81f5c2cc 8053d367 804d77fc 00000031 805a3a08 00000563 81ee9400 805a0000 00000000 10058c00 81f61b10 805c0000 00000000 00000000 805a0000 00d9038e 00000004 803ee818 00000006 312e3420 805c0000 00000000 00000073 81f61958 00000000 00000000 802eb380 804fd538 00000009 00000563 81ee9400 805a0000 00000002 80056148 00000000 805a0000 ... Call Trace: [<578af360>] show_stack+0x74/0x104 [<2f3702c6>] __warn+0x118/0x120 [<ae93fc9e>] warn_slowpath_null+0x44/0x58 [<a891a517>] hcd_alloc_coherent+0x4c/0xc8 [<3578fa36>] usb_hcd_map_urb_for_dma+0x4d8/0x534 [<110bc94c>] usb_hcd_submit_urb+0x82c/0x834 [<02eb5baf>] usb_sg_wait+0x14c/0x1a0 [<ccd09e85>] usb_stor_bulk_transfer_sglist.part.1+0xac/0x124 [<87a5c34c>] usb_stor_bulk_srb+0x40/0x60 [<ff1792ac>] usb_stor_Bulk_transport+0x160/0x37c [<b9e2709c>] usb_stor_invoke_transport+0x3c/0x500 [<004754f4>] usb_stor_control_thread+0x258/0x28c [<22edf42e>] kthread+0x134/0x13c [<a419ffd0>] ret_from_kernel_thread+0x14/0x1c ---[ end trace bcdb825805eefdcc ]--- Signed-off-by: Fredrik Noring <noring@nocrew.org> Acked-by: Alan Stern <stern@rowland.harvard.edu> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. 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.