Messages in this thread | | | Date | Sun, 2 Dec 2018 07:30:34 -0500 | From | Konrad Rzeszutek Wilk <> | Subject | Re: [PATCH] kernel/dma: Fix panic caused by passing swiotlb to command line |
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On Tue, Oct 30, 2018 at 07:06:10PM +0800, He Zhe wrote: > > > 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.
One provided the paramter for a reason. I would just do a small one, say 4MB. > > Thanks, > Zhe > > > > > Zhe > > > >>> Thanks, > >>> Zhe > >>> > >>> On 2018年09月17日 11:27, zhe.he@windriver.com wrote: > >>>> From: He Zhe <zhe.he@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. > >>>> > >>>> Signed-off-by: He Zhe <zhe.he@windriver.com> > >>>> Cc: stable@vger.kernel.org > >>>> Cc: konrad.wilk@oracle.com > >>>> Cc: hch@lst.de > >>>> Cc: m.szyprowski@samsung.com > >>>> Cc: robin.murphy@arm.com > >>>> --- > >>>> 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 > >>> iommu@lists.linux-foundation.org > >>> https://lists.linuxfoundation.org/mailman/listinfo/iommu > > >
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