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Re: [Qemu-devel] [PATCH] linux-user: Fix sched_getaffinity mask size
From: |
Samuel Thibault |
Subject: |
Re: [Qemu-devel] [PATCH] linux-user: Fix sched_getaffinity mask size |
Date: |
Sat, 27 Jan 2018 03:15:19 +0100 |
User-agent: |
NeoMutt/20170113 (1.7.2) |
Laurent Vivier, on ven. 26 janv. 2018 21:34:38 +0100, wrote:
> Le 26/01/2018 à 19:36, Samuel Thibault a écrit :
> > We properly computed the capped mask size to be put to the application
> > buffer, but didn't actually it. Also, we need to return the capped mask
> > size instead of 0 on success.
> >
> > Signed-off-by: Samuel Thibault <address@hidden>
> > ---
> > linux-user/syscall.c | 7 ++++++-
> > 1 file changed, 6 insertions(+), 1 deletion(-)
> >
> > diff --git a/linux-user/syscall.c b/linux-user/syscall.c
> > index 74378947f0..cf2369aac2 100644
> > --- a/linux-user/syscall.c
> > +++ b/linux-user/syscall.c
> > @@ -10496,10 +10496,15 @@ abi_long do_syscall(void *cpu_env, int num,
> > abi_long arg1,
> > ret = -TARGET_EINVAL;
> > break;
> > }
> > - ret = arg2;
> > + } else if (arg2 > ret) {
> > + arg2 = ret;
> > }
> >
> > ret = host_to_target_cpu_mask(mask, mask_size, arg3, arg2);
> > +
> > + if (ret == 0) {
> > + ret = arg2;
> > + }
> > }
> > }
> > break;
> >
>
> Modified code was:
>
> if (copy_to_user(arg3, mask, ret)) {
> goto efault;
> }
>
> so the change should only be:
>
> if (host_to_target_cpu_mask(mask, mask_size, arg3, ret)) {
> goto efault;
> }
That depends whether host_to_target_cpu_mask wants to return something
else than -TARGET_EFAULT, but at some point I don't care about
bikeshedding.
Samuel