On 2018/10/23 19:14, He Zhe wrote: > > On 2018/10/23 03:29, Konrad Rzeszutek Wilk wrote: >> On Sat, Sep 22, 2018 at 08:56:58PM +0800, He Zhe wrote: >>> May I have your input? >> Alternatively would it make more sense for it to assume some default >> value? > Maybe, but the original code has no default value and I have no idea > what default value is proper here.
Can anyone give some suggestions? Though I'd prefer to do nothing when no option is provided. Thanks, Zhe > > Zhe > >>> Thanks, >>> Zhe >>> >>> On 2018年09月17日 11:27, [email protected] wrote: >>>> From: He Zhe <[email protected]> >>>> >>>> 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. >>>> >>>> Signed-off-by: He Zhe <[email protected]> >>>> Cc: [email protected] >>>> Cc: [email protected] >>>> Cc: [email protected] >>>> Cc: [email protected] >>>> Cc: [email protected] >>>> --- >>>> kernel/dma/swiotlb.c | 5 +++++ >>>> 1 file changed, 5 insertions(+) >>>> >>>> diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c >>>> index 4f8a6db..46fc34e 100644 >>>> --- a/kernel/dma/swiotlb.c >>>> +++ b/kernel/dma/swiotlb.c >>>> @@ -109,6 +109,11 @@ static int late_alloc; >>>> static int __init >>>> setup_io_tlb_npages(char *str) >>>> { >>>> + if (!str) { >>>> + pr_err("Config string not provided\n"); >>>> + return -EINVAL; >>>> + } >>>> + >>>> if (isdigit(*str)) { >>>> io_tlb_nslabs = simple_strtoul(str, &str, 0); >>>> /* avoid tail segment of size < IO_TLB_SEGSIZE */ >>> _______________________________________________ >>> iommu mailing list >>> [email protected] >>> https://lists.linuxfoundation.org/mailman/listinfo/iommu > _______________________________________________ iommu mailing list [email protected] https://lists.linuxfoundation.org/mailman/listinfo/iommu
