Kindly ping.
Zhe
On 12/3/18 6:22 PM, zhe...@windriver.com wrote:
> From: He Zhe <zhe...@windriver.com>
>
> setup_io_tlb_npages does not check input argument before passing it
> to isdigit. The argument would be a NULL pointer if "swiotlb", without
> its value, is set in command line and thus causes the following panic.
>
> PANIC: early exception 0xe3 IP 10:ffffffffbb9b8e9f error 0 cr2 0x0
> [ 0.000000] CPU: 0 PID: 0 Comm: swapper Not tainted
> 4.19.0-rc3-yocto-standard+ #9
> [ 0.000000] RIP: 0010:setup_io_tlb_npages+0xf/0x95
> ...
> [ 0.000000] Call Trace:
> [ 0.000000] do_early_param+0x57/0x8e
> [ 0.000000] parse_args+0x208/0x320
> [ 0.000000] ? rdinit_setup+0x30/0x30
> [ 0.000000] parse_early_options+0x29/0x2d
> [ 0.000000] ? rdinit_setup+0x30/0x30
> [ 0.000000] parse_early_param+0x36/0x4d
> [ 0.000000] setup_arch+0x336/0x99e
> [ 0.000000] start_kernel+0x6f/0x4e6
> [ 0.000000] x86_64_start_reservations+0x24/0x26
> [ 0.000000] x86_64_start_kernel+0x6f/0x72
> [ 0.000000] secondary_startup_64+0xa4/0xb0
>
> This patch adds a check to prevent the panic and sets it for 4MB by default.
>
> Signed-off-by: He Zhe <zhe...@windriver.com>
> Cc: sta...@vger.kernel.org
> Cc: konrad.w...@oracle.com
> Cc: h...@lst.de
> Cc: m.szyprow...@samsung.com
> Cc: robin.mur...@arm.com
>
> Signed-off-by: He Zhe <zhe...@windriver.com>
> ---
> v2: Set swiotlb for 4MB by default
>
> kernel/dma/swiotlb.c | 11 +++++++++++
> 1 file changed, 11 insertions(+)
>
> diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
> index 045930e..0e18cd4 100644
> --- a/kernel/dma/swiotlb.c
> +++ b/kernel/dma/swiotlb.c
> @@ -58,6 +58,9 @@
> */
> #define IO_TLB_MIN_SLABS ((1<<20) >> IO_TLB_SHIFT)
>
> +#define IO_TLB_DEFAULT_MB 4
> +#define IO_TLB_DEFAULT_SLABS ((IO_TLB_DEFAULT_MB<<20) >> IO_TLB_SHIFT)
> +
> enum swiotlb_force swiotlb_force;
>
> /*
> @@ -103,6 +106,14 @@ static int late_alloc;
> static int __init
> setup_io_tlb_npages(char *str)
> {
> + if (!str) {
> + pr_err("No value provided for swiotlb, "
> + "set it to %d slabs for %dMB by default.\n",
> + IO_TLB_DEFAULT_SLABS, IO_TLB_DEFAULT_MB);
> + io_tlb_nslabs = IO_TLB_DEFAULT_SLABS;
> + return 0;
> + }
> +
> if (isdigit(*str)) {
> io_tlb_nslabs = simple_strtoul(str, &str, 0);
> /* avoid tail segment of size < IO_TLB_SEGSIZE */
