Messages in this thread | | | From | Dmitry Vyukov <> | Date | Fri, 27 May 2022 19:04:07 +0200 | Subject | Re: [syzbot] riscv/fixes test error: lost connection to test machine |
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On Fri, 27 May 2022 at 16:01, Alexandre Ghiti <alexandre.ghiti@canonical.com> wrote: > On Friday, May 27, 2022 at 3:55:24 PM UTC+2 Dmitry Vyukov wrote: >> >> On Fri, 27 May 2022 at 15:50, Alexandre Ghiti >> <alexand...@canonical.com> wrote: >> > On Friday, May 27, 2022 at 3:02:01 PM UTC+2 Dmitry Vyukov wrote: >> >> >> >> On Fri, 27 May 2022 at 14:55, syzbot >> >> <syzbot+2c5da6...@syzkaller.appspotmail.com> wrote: >> >> > >> >> > Hello, >> >> > >> >> > syzbot found the following issue on: >> >> > >> >> > HEAD commit: c932edeaf6d6 riscv: dts: microchip: fix gpio1 reg property.. >> >> > git tree: git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux.git fixes >> >> > console output: https://syzkaller.appspot.com/x/log.txt?x=1418add5f00000 >> >> > kernel config: https://syzkaller.appspot.com/x/.config?x=aa6b5702bdf14a17 >> >> > dashboard link: https://syzkaller.appspot.com/bug?extid=2c5da6a0a16a0c4f34aa >> >> > compiler: riscv64-linux-gnu-gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2 >> >> > userspace arch: riscv64 >> >> > >> >> > IMPORTANT: if you fix the issue, please add the following tag to the commit: >> >> > Reported-by: syzbot+2c5da6...@syzkaller.appspotmail.com >> >> >> >> The CONFIG_KASAN_VMALLOC allows riscv kernel to boot, but now Go >> >> processes started crashing with: >> >> >> >> 1970/01/01 00:06:55 fuzzer started >> >> runtime: lfstack.push invalid packing: node=0xffffff5908a940 cnt=0x1 >> >> packed=0xffff5908a9400001 -> node=0xffff5908a940 >> >> fatal error: lfstack.push >> >> runtime stack: >> >> runtime.throw({0x30884c, 0xc}) >> >> /usr/local/go/src/runtime/panic.go:1198 +0x60 >> >> runtime.(*lfstack).push(0xdb3850, 0xffffff5908a940) >> >> /usr/local/go/src/runtime/lfstack.go:30 +0x1a8 >> >> >> >> Go runtime tries to shove some data into the upper 16 bits of pointers >> >> assuming they are unused. >> >> However, the original pointer node=0xffffff5908a940 suggest riscv now >> >> has 56-bit users-space address space? >> > >> > >> > Yes, sv57 was merged recently. >> > >> >> >> >> Documentation/riscv/vm-layout.rst claims 48-bit pointers: >> >> " >> >> The RISC-V privileged architecture document states that the 64bit addresses >> >> "must have bits 63–48 all equal to bit 47, or else a page-fault exception will >> >> occur.": >> > >> > >> > Thanks for pointing that, I extracted that from the specification before sv57 was specified, I'll fix that. >> > >> > The current kernel code will use sv57 as it is supported and advertised by qemu, and to my knowledge, you can't downgrade to sv48 unless by re-compiling qemu using the following: >> > >> > diff --git a/target/riscv/csr.c b/target/riscv/csr.c >> > index 6dbe9b541f..a64b50ed75 100644 >> > --- a/target/riscv/csr.c >> > +++ b/target/riscv/csr.c >> > @@ -637,7 +637,7 @@ static const char valid_vm_1_10_64[16] = { >> > [VM_1_10_MBARE] = 1, >> > [VM_1_10_SV39] = 1, >> > [VM_1_10_SV48] = 1, >> > - [VM_1_10_SV57] = 1 >> > + [VM_1_10_SV57] = 0 >> > }; >> > >> > /* Machine Information Registers */ >> > >> >> ... >> >> 0000000000000000 | 0 | 0000003fffffffff | 256 GB | >> >> user-space virtual memory, different per mm >> >> " >> >> There is no kernel config to force SV48/39, right? > > > No, we rely on what the hardware advertises, if it supports sv57, we'll go for sv57, if not, we'll try sv48...etc. I had some patches to force the downgrade by using the device tree but they never got merged though.
+original CC list
FTR sent Go runtime change to support SV57: https://go-review.googlesource.com/c/go/+/409055
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