[PATCH] riscv: compat: Using seperated vdso_maps for compat_vdso_info

[Guo Ren]

On Thu, May 26, 2022 at 5:34 AM Palmer Dabbelt <palmer at dabbelt.com> wrote:
>
> On Wed, 25 May 2022 14:15:03 PDT (-0700), linux at roeck-us.net wrote:
> > On 5/25/22 09:04, guoren at kernel.org wrote:
> >> From: Guo Ren <guoren at linux.alibaba.com>
> >>
> >> This is a fixup for vdso implementation which caused musl to
> >> fail.
> >>
> >> [   11.600082] Run /sbin/init as init process
> >> [   11.628561] init[1]: unhandled signal 11 code 0x1 at
> >> 0x0000000000000000 in libc.so[ffffff8ad39000+a4000]
> >> [   11.629398] CPU: 0 PID: 1 Comm: init Not tainted
> >> 5.18.0-rc7-next-20220520 #1
> >> [   11.629462] Hardware name: riscv-virtio,qemu (DT)
> >> [   11.629546] epc : 00ffffff8ada1100 ra : 00ffffff8ada13c8 sp :
> >> 00ffffffc58199f0
> >> [   11.629586]  gp : 00ffffff8ad39000 tp : 00ffffff8ade0998 t0 :
> >> ffffffffffffffff
> >> [   11.629598]  t1 : 00ffffffc5819fd0 t2 : 0000000000000000 s0 :
> >> 00ffffff8ade0cc0
> >> [   11.629610]  s1 : 00ffffff8ade0cc0 a0 : 0000000000000000 a1 :
> >> 00ffffffc5819a00
> >> [   11.629622]  a2 : 0000000000000001 a3 : 000000000000001e a4 :
> >> 00ffffffc5819b00
> >> [   11.629634]  a5 : 00ffffffc5819b00 a6 : 0000000000000000 a7 :
> >> 0000000000000000
> >> [   11.629645]  s2 : 00ffffff8ade0ac8 s3 : 00ffffff8ade0ec8 s4 :
> >> 00ffffff8ade0728
> >> [   11.629656]  s5 : 00ffffff8ade0a90 s6 : 0000000000000000 s7 :
> >> 00ffffffc5819e40
> >> [   11.629667]  s8 : 00ffffff8ade0ca0 s9 : 00ffffff8addba50 s10:
> >> 0000000000000000
> >> [   11.629678]  s11: 0000000000000000 t3 : 0000000000000002 t4 :
> >> 0000000000000001
> >> [   11.629688]  t5 : 0000000000020000 t6 : ffffffffffffffff
> >> [   11.629699] status: 0000000000004020 badaddr: 0000000000000000
> >> cause: 000000000000000d
> >>
> >> The last __vdso_init(&compat_vdso_info) replaces the data in normal
> >> vdso_info. This is an obvious bug.
> >>
> >> Reported-by: Guenter Roeck <linux at roeck-us.net>
> >> Signed-off-by: Guo Ren <guoren at linux.alibaba.com>
> >> Signed-off-by: Guo Ren <guoren at kernel.org>
> >> Cc: Palmer Dabbelt <palmer at dabbelt.com>
> >> Cc: Heiko Stübner <heiko at sntech.de>
> >
> > Tested-by: Guenter Roeck <linux at roeck-us.net>
>
> Sorry I'm a bit buried right now, this is fixing the issue you pointed
> out earlier?
I've updated patch V2, please use that, thx.
https://lore.kernel.org/linux-riscv/20220526003339.2948309-1-guoren@kernel.org/T/#u

>
> >
> >> ---
> >>   arch/riscv/kernel/vdso.c | 15 +++++++++++++--
> >>   1 file changed, 13 insertions(+), 2 deletions(-)
> >>
> >> diff --git a/arch/riscv/kernel/vdso.c b/arch/riscv/kernel/vdso.c
> >> index 50fe4c877603..69b05b6c181b 100644
> >> --- a/arch/riscv/kernel/vdso.c
> >> +++ b/arch/riscv/kernel/vdso.c
> >> @@ -206,12 +206,23 @@ static struct __vdso_info vdso_info __ro_after_init = {
> >>   };
> >>
> >>   #ifdef CONFIG_COMPAT
> >> +static struct vm_special_mapping rv_compat_vdso_maps[] __ro_after_init = {
> >> +    [RV_VDSO_MAP_VVAR] = {
> >> +            .name   = "[vvar]",
> >> +            .fault = vvar_fault,
> >> +    },
> >> +    [RV_VDSO_MAP_VDSO] = {
> >> +            .name   = "[vdso]",
> >> +            .mremap = vdso_mremap,
> >> +    },
> >> +};
> >> +
> >>   static struct __vdso_info compat_vdso_info __ro_after_init = {
> >>      .name = "compat_vdso",
> >>      .vdso_code_start = compat_vdso_start,
> >>      .vdso_code_end = compat_vdso_end,
> >> -    .dm = &rv_vdso_maps[RV_VDSO_MAP_VVAR],
> >> -    .cm = &rv_vdso_maps[RV_VDSO_MAP_VDSO],
> >> +    .dm = &rv_compat_vdso_maps[RV_VDSO_MAP_VVAR],
> >> +    .cm = &rv_compat_vdso_maps[RV_VDSO_MAP_VDSO],
> >>   };
> >>   #endif
> >>



-- 
Best Regards
 Guo Ren

ML: https://lore.kernel.org/linux-csky/