Message-ID: <CAOnJCU+2QXdCkf7g_cnQ+yMoFABc7bfKZ8=5sOJk2uQhS8+Uww@mail.gmail.com>
Date:   Sun, 26 Jun 2022 23:47:34 -0700
From:   Atish Patra <atishp@...shpatra.org>
To:     Anup Patel <anup@...infault.org>
Cc:     Jisheng Zhang <jszhang@...nel.org>,
        Paul Walmsley <paul.walmsley@...ive.com>,
        Palmer Dabbelt <palmer@...belt.com>,
        Albert Ou <aou@...s.berkeley.edu>,
        Andrey Ryabinin <ryabinin.a.a@...il.com>,
        Alexander Potapenko <glider@...gle.com>,
        Andrey Konovalov <andreyknvl@...il.com>,
        Dmitry Vyukov <dvyukov@...gle.com>,
        Vincenzo Frascino <vincenzo.frascino@....com>,
        Alexandre Ghiti <alexandre.ghiti@...onical.com>,
        Atish Patra <atishp@...osinc.com>,
        linux-riscv <linux-riscv@...ts.infradead.org>,
        "linux-kernel@...r.kernel.org List" <linux-kernel@...r.kernel.org>,
        kasan-dev <kasan-dev@...glegroups.com>,
        Sunil V L <sunilvl@...tanamicro.com>
Subject: Re: [PATCH v4 1/2] riscv: move sbi_init() earlier before jump_label_init()

On Sat, Jun 25, 2022 at 9:33 PM Anup Patel <anup@...infault.org> wrote:
>
> On Sat, May 21, 2022 at 8:13 PM Jisheng Zhang <jszhang@...nel.org> wrote:
> >
> > We call jump_label_init() in setup_arch() is to use static key
> > mechanism earlier, but riscv jump label relies on the sbi functions,
> > If we enable static key before sbi_init(), the code path looks like:
> >   static_branch_enable()
> >     ..
> >       arch_jump_label_transform()
> >         patch_text_nosync()
> >           flush_icache_range()
> >             flush_icache_all()
> >               sbi_remote_fence_i() for CONFIG_RISCV_SBI case
> >                 __sbi_rfence()
> >
> > Since sbi isn't initialized, so NULL deference! Here is a typical
> > panic log:
> >
> > [    0.000000] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000
> > [    0.000000] Oops [#1]
> > [    0.000000] Modules linked in:
> > [    0.000000] CPU: 0 PID: 0 Comm: swapper Not tainted 5.18.0-rc7+ #79
> > [    0.000000] Hardware name: riscv-virtio,qemu (DT)
> > [    0.000000] epc : 0x0
> > [    0.000000]  ra : sbi_remote_fence_i+0x1e/0x26
> > [    0.000000] epc : 0000000000000000 ra : ffffffff80005826 sp : ffffffff80c03d50
> > [    0.000000]  gp : ffffffff80ca6178 tp : ffffffff80c0ad80 t0 : 6200000000000000
> > [    0.000000]  t1 : 0000000000000000 t2 : 62203a6b746e6972 s0 : ffffffff80c03d60
> > [    0.000000]  s1 : ffffffff80001af6 a0 : 0000000000000000 a1 : 0000000000000000
> > [    0.000000]  a2 : 0000000000000000 a3 : 0000000000000000 a4 : 0000000000000000
> > [    0.000000]  a5 : 0000000000000000 a6 : 0000000000000000 a7 : 0000000000080200
> > [    0.000000]  s2 : ffffffff808b3e48 s3 : ffffffff808bf698 s4 : ffffffff80cb2818
> > [    0.000000]  s5 : 0000000000000001 s6 : ffffffff80c9c345 s7 : ffffffff80895aa0
> > [    0.000000]  s8 : 0000000000000001 s9 : 000000000000007f s10: 0000000000000000
> > [    0.000000]  s11: 0000000000000000 t3 : ffffffff80824d08 t4 : 0000000000000022
> > [    0.000000]  t5 : 000000000000003d t6 : 0000000000000000
> > [    0.000000] status: 0000000000000100 badaddr: 0000000000000000 cause: 000000000000000c
> > [    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! ]---
> >
> > Fix this issue by moving sbi_init() earlier before jump_label_init()
> >
> > Signed-off-by: Jisheng Zhang <jszhang@...nel.org>
>
> We are seeing a similar crash when booting kernel via EDK2 with RNG enabled.
>
> Shell> fs0:\Image root=/dev/vda2 rootwait console=ttyS0
> earlycon=uart8250,mmio,0x10000000 initrd=\initramfs.cp
> EFI stub: Booting Linux Kernel...
> EFI stub: Using DTB from configuration table
> EFI stub: Exiting boot services...
> [    0.000000] Linux version 5.19.0-rc3 (oe-user@...host)
> (riscv64-unknown-linux-gnu-gcc (Ventana-2022.05.16) 12.1.0, GNU ld
> (Ventana-2022.05.16) 2.37.90.20220201) #1 SMP Thu Jun 23 05:33:13 UTC
> 2022
> [    0.000000] OF: fdt: Ignoring memory range 0x80000000 - 0x81200000
> [    0.000000] earlycon: uart8250 at MMIO 0x0000000010000000 (options '')
> [    0.000000] printk: bootconsole [uart8250] enabled
> [    0.000000] efi: EFI v2.70 by EDK II
> [    0.000000] efi: RNG=0xff94fd98 MEMRESERVE=0xfe658f18
> [    0.000000] efi: seeding entropy pool
> [    0.000000] Unable to handle kernel NULL pointer dereference at
> virtual address 0000000000000000
> [    0.000000] Oops [#1]
> [    0.000000] Modules linked in:
> [    0.000000] CPU: 0 PID: 0 Comm: swapper Not tainted 5.19.0-rc3 #1
> [    0.000000] epc : 0x0
> [    0.000000]  ra : sbi_remote_fence_i+0x1e/0x26
> [    0.000000] epc : 0000000000000000 ra : ffffffff800080f8 sp :
> ffffffff81203cd0
> [    0.000000]  gp : ffffffff812f1d40 tp : ffffffff8120da80 t0 :
> 0000000000cb8266
> [    0.000000]  t1 : 000000006d5e5146 t2 : 0000000058000000 s0 :
> ffffffff81203ce0
> [    0.000000]  s1 : ffffffff8047586a a0 : 0000000000000000 a1 :
> 0000000000000000
> [    0.000000]  a2 : 0000000000000000 a3 : 0000000000000000 a4 :
> 0000000000000000
> [    0.000000]  a5 : 0000000000000000 a6 : 0000000000000000 a7 :
> 0000000000000000
> [    0.000000]  s2 : ffffffff80dea320 s3 : ffffffff80deabb0 s4 :
> ffffffff81353d48
> [    0.000000]  s5 : 0000000000000001 s6 : 00000000fffde848 s7 :
> 0000000000000004
> [    0.000000]  s8 : 0000000081021714 s9 : 000000008101e6f0 s10:
> 00000000fffde780
> [    0.000000]  s11: 0000000000000004 t3 : 000000001467a415 t4 :
> 0000000000000000
> [    0.000000]  t5 : 00000000007627e0 t6 : ffffffffbc865574
> [    0.000000] status: 0000000200000100 badaddr: 0000000000000000
> cause: 000000000000000c
> [    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 patch fixes the above crash as well.
>

Thanks for the confirmation.

> Reviewed-by: Anup Patel <anup@...infault.org>
>
> Thanks,
> Anup
>
> > ---
> >  arch/riscv/kernel/setup.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/arch/riscv/kernel/setup.c b/arch/riscv/kernel/setup.c
> > index 834eb652a7b9..d150cedeb7e0 100644
> > --- a/arch/riscv/kernel/setup.c
> > +++ b/arch/riscv/kernel/setup.c
> > @@ -268,6 +268,7 @@ void __init setup_arch(char **cmdline_p)
> >         *cmdline_p = boot_command_line;
> >
> >         early_ioremap_setup();
> > +       sbi_init();
> >         jump_label_init();
> >         parse_early_param();
> >
> > @@ -284,7 +285,6 @@ void __init setup_arch(char **cmdline_p)
> >         misc_mem_init();
> >
> >         init_resources();
> > -       sbi_init();
> >
> >  #ifdef CONFIG_KASAN
> >         kasan_init();
> > --
> > 2.34.1
> >
>
> _______________________________________________
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Reviewed-by: Atish Patra <atishp@...osinc.com>

-- 
Regards,
Atish

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