On Tue, Oct 17, 2017 at 01:54:35PM +0800, Bixuan Cui wrote: > Hi, Hi,
> I try to start the kernel(v4.14.0-rc4) by qemu while enable > CONFIG_ARM64_LSE_ATOMICS and KCOV_INSTRUMENT_ALL(use > arch/arm64/configs/defconfig) at the same time. Then > it hang: > qemu-system-aarch64 -kernel Image -m 2048 -smp 8 -initrd qemu-le.rootfs -cpu > cortex-a57 -nographic -machine virt,kernel_irqchip=on -append > 'console=ttyAMA0 root=/dev/ram rdinit=/sbin/init nohz_full=1 > earlycon=pl011,0x9000000' -rtc base=localtime -device > virtio-net-device,netdev=net0 -netdev > type=tap,id=net0,script=no,downscript=no,ifname=tap2 > [ 0.000000] Booting Linux on physical CPU 0x0 > [ 0.000000] Linux version 4.14.0-rc4 #24 SMP PREEMPT Mon Oct 16 11:02:11 > CST 2017 > [ 0.000000] Boot CPU: AArch64 Processor [411fd070] > [ 0.000000] Machine model: linux,dummy-virt > [ 0.000000] earlycon: pl11 at MMIO 0x0000000009000000 (options '') > [ 0.000000] bootconsole [pl11] enabled > [ 0.000000] efi: Getting EFI parameters from FDT: > [ 0.000000] efi: UEFI not found. > [ 0.000000] cma: Reserved 64 MiB at 0x00000000bc000000 This is a known issue [1,2] that's being worked on at the moment. The problem is that the out-of-line LL/SC atomics are built with a special ABI, but KCOV inserts calls to other code that does not follow this ABI, resulting in register corruption. When I saw this happen, this resulted in cmpxchg() spuriously failing somewhere in the page init code, which looks similar to what you're seeing. The patch at [1] is sufficient to work around this for the time being. Thanks, Mark. [1] http://lists.infradead.org/pipermail/linux-arm-kernel/2017-September/533105.html [2] http://lists.infradead.org/pipermail/linux-arm-kernel/2017-October/537018.html > > After I try kernel v4.13 and it's the same result. > I trace the code and find it stop at the end of '__init_single_page(page, > pfn, zone, nid)' in memmap_init_zone() of mm/page_alloc.c ： > > static void __meminit __init_single_page(struct page *page, unsigned long pfn, > unsigned long zone, int nid) > { > set_page_links(page, zone, nid, pfn); > init_page_count(page); > page_mapcount_reset(page); > page_cpupid_reset_last(page); > > INIT_LIST_HEAD(&page->lru); > > #ifdef WANT_PAGE_VIRTUAL > /* The shift won't overflow because ZONE_NORMAL is below 4G. */ > if (!is_highmem_idx(zone)) > set_page_address(page, __va(pfn << PAGE_SHIFT)); > #endif > // printk("stop here\n"); > } > > Anyone can give me advice? > > Thanks, > Bixuan Cui > > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-ker...@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
