Messages in this thread Patch in this message | | | From | <> | Subject | [PATCH] kernel/dma: Fix panic caused by passing swiotlb to command line | Date | Mon, 17 Sep 2018 11:27:11 +0800 |
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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 */ -- 2.7.4
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