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From:   Ard Biesheuvel <ardb@kernel.org>
Date:   Thu, 16 Mar 2023 15:08:53 +0100
Message-ID: <CAMj1kXHKkK+6TDLebZw=H-ZZLVnwPGSRpNNKSbJoPwwA2vhG+w@mail.gmail.com>
Subject: Re: kernel 6.2 stuck at boot (efi_call_rts) on arm64
To:     Andrea Righi <andrea.righi@canonical.com>
Cc:     "Jason A. Donenfeld" <Jason@zx2c4.com>,
        Paolo Pisati <paolo.pisati@canonical.com>,
        linux-efi@vger.kernel.org, linux-kernel@vger.kernel.org,
        Darren Hart <darren@os.amperecomputing.com>
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

On Thu, 16 Mar 2023 at 15:06, Ard Biesheuvel <ardb@kernel.org> wrote:
>
> On Thu, 16 Mar 2023 at 14:59, Andrea Righi <andrea.righi@canonical.com> wrote:
> >
> > On Thu, Mar 16, 2023 at 02:53:24PM +0100, Ard Biesheuvel wrote:
> > > On Thu, 16 Mar 2023 at 14:50, Andrea Righi <andrea.righi@canonical.com> wrote:
> > > >
> > > > On Thu, Mar 16, 2023 at 02:45:49PM +0100, Ard Biesheuvel wrote:
> > > > > On Thu, 16 Mar 2023 at 13:50, Andrea Righi <andrea.righi@canonical.com> wrote:
> > > > > >
> > > > > > On Thu, Mar 16, 2023 at 01:43:32PM +0100, Ard Biesheuvel wrote:
> > > > > > > On Thu, 16 Mar 2023 at 13:41, Andrea Righi <andrea.righi@canonical.com> wrote:
> > > > > > > >
> > > > > > > > On Thu, Mar 16, 2023 at 01:38:30PM +0100, Ard Biesheuvel wrote:
> > > > > > > > > On Thu, 16 Mar 2023 at 13:21, Ard Biesheuvel <ardb@kernel.org> wrote:
> > > > > > > > > >
> > > > > > > > > > On Thu, 16 Mar 2023 at 12:34, Andrea Righi <andrea.righi@canonical.com> wrote:
> > > > > > > > > > >
> > > > > > > > > > > On Thu, Mar 16, 2023 at 11:18:21AM +0100, Ard Biesheuvel wrote:
> > > > > > > > > > > > On Thu, 16 Mar 2023 at 11:03, Andrea Righi <andrea.righi@canonical.com> wrote:
> > > > > > > > > > > > >
> > > > > > > > > > > > > On Thu, Mar 16, 2023 at 10:55:58AM +0100, Ard Biesheuvel wrote:
> > > > > > > > > > > > > > (cc Darren)
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > On Thu, 16 Mar 2023 at 10:45, Andrea Righi <andrea.righi@canonical.com> wrote:
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > On Thu, Mar 16, 2023 at 08:58:20AM +0100, Ard Biesheuvel wrote:
> > > > > > > > > > > > > > > > Hello Andrea,
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > On Thu, 16 Mar 2023 at 08:54, Andrea Righi <andrea.righi@canonical.com> wrote:
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > Hello,
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > the latest v6.2.6 kernel fails to boot on some arm64 systems, the kernel
> > > > > > > > > > > > > > > > > gets stuck and never completes the boot. On the console I see this:
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > [   72.043484] rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
> > > > > > > > > > > > > > > > > [   72.049571] rcu:     22-...0: (30 GPs behind) idle=b10c/1/0x4000000000000000 softirq=164/164 fqs=6443
> > > > > > > > > > > > > > > > > [   72.058520]     (detected by 28, t=15005 jiffies, g=449, q=174 ncpus=32)
> > > > > > > > > > > > > > > > > [   72.064949] Task dump for CPU 22:
> > > > > > > > > > > > > > > > > [   72.068251] task:kworker/u64:5   state:R  running task     stack:0     pid:447   ppid:2      flags:0x0000000a
> > > > > > > > > > > > > > > > > [   72.078156] Workqueue: efi_rts_wq efi_call_rts
> > > > > > > > > > > > > > > > > [   72.082595] Call trace:
> > > > > > > > > > > > > > > > > [   72.085029]  __switch_to+0xbc/0x100
> > > > > > > > > > > > > > > > > [   72.088508]  0xffff80000fe83d4c
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > After that, as a consequence, I start to get a lot of hung task timeout traces.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > I tried to bisect the problem and I found that the offending commit is
> > > > > > > > > > > > > > > > > this one:
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >  e7b813b32a42 ("efi: random: refresh non-volatile random seed when RNG is initialized")
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > I've reverted this commit for now and everything works just fine, but I
> > > > > > > > > > > > > > > > > was wondering if the problem could be caused by a lack of entropy on
> > > > > > > > > > > > > > > > > these arm64 boxes or something else.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > Any suggestion? Let me know if you want me to do any specific test.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > Thanks for the report.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > This is most likely the EFI SetVariable() call going off into the
> > > > > > > > > > > > > > > > weeds and never returning.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > Is this an Ampere Altra system by any chance? Do you see it on
> > > > > > > > > > > > > > > > different types of hardware?
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > This is: Ampere eMAG / Lenovo ThinkSystem HR330a.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > Could you check whether SetVariable works on this system? E.g. by
> > > > > > > > > > > > > > > > updating the EFI boot timeout (sudo efibootmgr -t <n>)?
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > ubuntu@kuzzle:~$ sudo efibootmgr -t 10
> > > > > > > > > > > > > > > ^C^C^C^C
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > ^ Stuck there, so it really looks like SetVariable is the problem.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > Could you please share the output of
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > dmidecode -s bios
> > > > > > > > > > > > > > dmidecode -s system-family
> > > > > > > > > > > > >
> > > > > > > > > > > > > $ sudo dmidecode -s bios-vendor
> > > > > > > > > > > > > LENOVO
> > > > > > > > > > > > > $ sudo dmidecode -s bios-version
> > > > > > > > > > > > > hve104r-1.15
> > > > > > > > > > > > > $ sudo dmidecode -s bios-release-date
> > > > > > > > > > > > > 02/26/2021
> > > > > > > > > > > > > $ sudo dmidecode -s bios-revision
> > > > > > > > > > > > > 1.15
> > > > > > > > > > > > > $ sudo dmidecode -s system-family
> > > > > > > > > > > > > Lenovo ThinkSystem HR330A/HR350A
> > > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > > Thanks
> > > > > > > > > > > >
> > > > > > > > > > > > Mind checking if this patch fixes your issue as well?
> > > > > > > > > > > >
> > > > > > > > > > > > https://git.kernel.org/pub/scm/linux/kernel/git/ardb/linux.git/commit/?h=altra-fix&id=77fa99dd4741456da85049c13ec31a148f5f5ac0
> > > > > > > > > > >
> > > > > > > > > > > Unfortunately this doesn't seem to be enough, I'm still getting the same
> > > > > > > > > > > problem also with this patch applied.
> > > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > > Thanks for trying.
> > > > > > > > > >
> > > > > > > > > > How about the last 3 patches on this branch?
> > > > > > > > > >
> > > > > > > > > > https://git.kernel.org/pub/scm/linux/kernel/git/ardb/linux.git/log/?h=efi-smbios-altra-fix
> > > > > > > > >
> > > > > > > > > Actually, that may not match your hardware.
> > > > > > > > >
> > > > > > > > > Does your kernel log have a line like
> > > > > > > > >
> > > > > > > > > SMCCC: SOC_ID: ID = jep106:036b:0019 Revision = 0x00000102
> > > > > > > > >
> > > > > > > > > ?
> > > > > > > >
> > > > > > > > $ sudo dmesg | grep "SMCCC: SOC_ID"
> > > > > > > > [    5.320782] SMCCC: SOC_ID: ARCH_SOC_ID not implemented, skipping ....
> > > > > > > >
> > > > > > >
> > > > > > > Thanks. Could you share the entire dmidecode output somewhere? Or at
> > > > > > > least the type 4 record(s)?
> > > > > >
> > > > > > Sure, here's the full output of dmidecode:
> > > > > > https://pastebin.ubuntu.com/p/4ZmKmP2xTm/
> > > > > >
> > > > >
> > > > > Thanks. I have updated my SMBIOS patches to take the processor version
> > > > > 'eMAG' into account, which appears to be what these boxes are using.
> > > > >
> > > > > I have updated the efi/urgent branch here with the latest versions.
> > > > > Mind giving them a spin?
> > > > >
> > > > >
> > > > > In the mean time, just for the record - could you please run this as well?
> > > > >
> > > > > hexdump -C /sys/firmware/dmi/entries/4-0/raw
> > > > >
> > > > > (as root)
> > > >
> > > > hm.. I don't have that in /sys/firmware/, this is what I have:
> > > >
> > > > # ls -l /sys/firmware/dmi/
> > > > total 0
> > > > drwxr-xr-x 2 root root 0 Mar 16 13:26 tables
> > > > # ls -l /sys/firmware/dmi/tables/
> > > > total 0
> > > > -r-------- 1 root root 5004 Mar 16 13:26 DMI
> > > > -r-------- 1 root root   24 Mar 16 13:26 smbios_entry_point
> > > >
> > >
> > > You'll need to load the dmi_sysfs module for that. But no big deal
> > > otherwise, I'm pretty sure the word order is the correct on on your
> > > system in any case (it decodes the value correctly in the next line)
> >
> > ok, much better after modprobe dmi_sysfs. :)
> >
>
> Yeah better, thanks.
>
> > $ sudo hexdump -C /sys/firmware/dmi/entries/4-0/raw
> > 00000000  04 30 04 00 01 03 fe 02  02 00 3f 50 00 00 00 00  |.0........?P....|
> > 00000010  03 89 b8 0b e4 0c b8 0b  41 06 05 00 06 00 07 00  |........A.......|
> > 00000020  04 00 00 20 20 20 7c 00  01 01 00 00 00 00 00 00  |...   |.........|
> > 00000030  43 50 55 20 31 00 41 6d  70 65 72 65 28 54 4d 29  |CPU 1.Ampere(TM)|
> > 00000040  00 65 4d 41 47 20 00 30  30 30 30 30 30 30 30 30  |.eMAG .000000000|
>
> Darn, this means we have to match for "eMAG " (with the trailing
> space) so the branch i just pushed needs to be updated for this.
>

I.e.,

--- a/drivers/firmware/efi/libstub/arm64.c
+++ b/drivers/firmware/efi/libstub/arm64.c
@@ -36,7 +36,7 @@ static bool system_needs_vamap(void)
        default:
                version = efi_get_smbios_string(&record->header, 4,
                                                processor_version);
-               if (!version || strcmp(version, "eMAG"))
+               if (!version || strncmp(version, "eMAG", 4))
                        break;

                fallthrough;