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? > > 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
