Re: RISC-V: patched kexec-tools on github for review/testing

[Alexandre Ghiti <alexandre.ghiti@canonical.com>]

On Sat, Oct 9, 2021 at 3:25 PM Nick Kossifidis <mick@ics.forth.gr> wrote:
>
> Στις 2021-10-06 14:10, Alexandre Ghiti έγραψε:
> >
> > So I followed the instructions here:
> > https://documentation.suse.com/fr-fr/sles/12-SP3/html/SLES-all/cha-tuning-kexec.html#cha-tuning-kexec-basic-usage,
> > below the output on an Unmatched board using a vmlinux stored on a sd
> > card:
> >
> > ubuntu@ubuntu:~$ sudo sbin/kexec -l vmlinux --append="$(cat
> > /proc/cmdline)" --initrd=/boot/initrd.img
> > Warning: No cmdline provided, using append string as cmdline
> > Warning: No dtb provided, using /sys/firmware/fdt
> > [ 1813.472671] INFO: task kworker/1:0:988 blocked for more than 120
> > seconds.
> > [ 1813.478751]       Not tainted 5.15.0-rc1+ #15
> > [ 1813.483110] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs"
> > disables this message.
> > Could not find a free area of memory of 0x3000 bytes...
> > locate_hole failed
> >
> > I used the Ubuntu kernel, so this is pretty large:
> > -rwxrwxr-x 1 ubuntu ubuntu 277M Oct  5 15:47 vmlinux
> > -rw-r--r-- 1 root root 98M Sep 21 03:25 /boot/initrd.img
> >
>
> ACK, I haven't tested initrd much TBH, I usually don't use an initrd,
> and when I do it's a small busybox-based rootfs.
>
> > Then if I don't load the initrd (I sometimes have the same warning as
> > above) I can at least kexec the new kernel but it fails to boot:
> >
> > ubuntu@ubuntu:~$ sudo ./sbin/kexec -e
> > Warning: No cmdline or append string provided
> > Warning: No dtb provided, using /sys/firmware/fdt
> > [...]
> > [    0.000000] SBI v0.2 HSM extension detected
> > [    0.000000] CPU with hartid=0 is not available
> > [    0.000000] ------------[ cut here ]------------
> > [    0.000000] kernel BUG at arch/riscv/kernel/smpboot.c:107!
> > [    0.000000] Kernel BUG [#1]
> > [    0.000000] Modules linked in:
> > [    0.000000] CPU: 0 PID: 0 Comm: swapper Not tainted 5.15.0-rc1+ #15
> > [    0.000000] Hardware name: SiFive HiFive Unmatched A00 (DT)
> > [    0.000000] epc : setup_smp+0xcc/0x142
> > [    0.000000]  ra : setup_smp+0xc4/0x142
> > [    0.000000] epc : ffffffff80a04080 ra : ffffffff80a04078 sp :
> > ffffffff81803ec0
> > [    0.000000]  gp : ffffffff81a23220 tp : ffffffff81810500 t0 :
> > ffffffff81a3551f
> > [    0.000000]  t1 : ffffffffffffffff t2 : 0000000000000000 s0 :
> > ffffffff81803f00
> > [    0.000000]  s1 : 0000000000000000 a0 : 0000000000000000 a1 :
> > 0000000000000000
> > [    0.000000]  a2 : 0000000000000000 a3 : 0000000000000001 a4 :
> > 0000000000000000
> > [    0.000000]  a5 : ffffffff80c64500 a6 : 0000000000000004 a7 :
> > 000000000000ff00
> > [    0.000000]  s2 : 0000000000000005 s3 : 0000000000000000 s4 :
> > ffffffff8118f9a8
> > [    0.000000]  s5 : 0000000000000007 s6 : ffffffff80c0b790 s7 :
> > 0000000080000200
> > [    0.000000]  s8 : 0000000000000fff s9 : 0000000081000200 s10:
> > 0000000000000018
> > [    0.000000]  s11: 000000000000000b t3 : 0000000000ff0000 t4 :
> > ffffffffffffffff
> > [    0.000000]  t5 : ffffffff80c0b7a0 t6 : ffffffff81803bd8
> > [    0.000000] status: 0000000200000100 badaddr: 0000000000000000
> > cause: 0000000000000003
> > [    0.000000] [<ffffffff80a04080>] setup_smp+0xcc/0x142
> > [    0.000000] [<ffffffff80a03d88>] setup_arch+0x56a/0x590
> > [    0.000000] [<ffffffff80a00aa2>] start_kernel+0xaa/0xa5c
> > [    0.000000] random: get_random_bytes called from
> > oops_exit+0x44/0x70 with crng_init=0
> > [    0.000000] ---[ end trace 0000000000000000 ]---
> > [    0.000000] Kernel panic - not syncing: Attempted to kill the idle
> > task!
> > [    0.000000] ---[ end Kernel panic - not syncing: Attempted to kill
> > the idle task! ]---
> >
> > This reliably fails here.
> >
>
> This looks weird, I'll check it out (we have an unmatched here so I'll
> try to get my hands on it sometime next week).
>
> Did you try kdump ? Do you get the same error ?

kdump works fine, it fails to find the rootfs but I think my setup is
faulty here.
I took a quick look at kexec_relocate.S, and the use of va_pa_offset
is also wrong here, we should use va_kernel_pa_offset as it is used to
modify a text address But fixing that did not work either.

Alex




>
> BTW this is what I use for testing most of the time:
>
> For kexec:
> kexec -l /mnt/shared/vmlinux --reuse-cmdline
> kexec -e
>
> For kdump:
> kexec -p /mnt/shared/vmlinux
> echo c > /proc/sysrq-trigger
>
> Thanks a lot for your time !
>
> Regards,
> Nick