On Mon, Oct 17, 2016 at 10:04:32AM -0700, Andy Lutomirski wrote:
> On Mon, Oct 17, 2016 at 7:35 AM, Mark Rutland <mark.rutland@xxxxxxx> wrote:
> > Back in commit f56141e3e2d9aabf ("all arches, signal: move restart_block
> > to struct task_struct"), all architectures and core code were changed to
> > use task_struct::restart_block. However, when h8300 support was
> > subsequently restored in v4.2, it was not updated to account for this,
> > and maintains thread_info::restart_block, which is not kept in sync.
> >
> > This patch drops the redundant restart_block from thread_info, and moves
> > h8300 to the common one in task_struct, ensuring that syscall restarting
> > always works as expected.
>
> This is Obviously Correct (tm). Should it have a cc: stable?
> > Cc: stable@xxxxxxxxxxxxxxx # v4.2+
Yes. ;)
I must've messed up with git-send-email for the "real" Cc list.
Thanks,
Mark.
> > Cc: uclinux-h8-devel@xxxxxxxxxxxxxxxxxxxx
> > ---
> > arch/h8300/include/asm/thread_info.h | 4 ----
> > arch/h8300/kernel/signal.c | 2 +-
> > 2 files changed, 1 insertion(+), 5 deletions(-)
> >
> > This was previously sent as a reply to another patch [1], and then subsequently
> > on its own [2], but I haven't heard anything for about three weeks since the
> > last posting.
> >
> > This happens to get in the way of moving thread_info into task_struct on some
> > architectures as it implicitly relies on include ordering in a core header. I
> > have a workaround for that, but this does seem like a major bug regardless...
> >
> > Mark.
> >
> > [1] http://lkml.kernel.org/r/20160919104254.GA12473@leverpostej
> > [2] http://lkml.kernel.org/r/1474918434-3870-1-git-send-email-mark.rutland@xxxxxxx
> >
> > diff --git a/arch/h8300/include/asm/thread_info.h b/arch/h8300/include/asm/thread_info.h
> > index b408fe6..3cef068 100644
> > --- a/arch/h8300/include/asm/thread_info.h
> > +++ b/arch/h8300/include/asm/thread_info.h
> > @@ -31,7 +31,6 @@ struct thread_info {
> > int cpu; /* cpu we're on */
> > int preempt_count; /* 0 => preemptable, <0 => BUG */
> > mm_segment_t addr_limit;
> > - struct restart_block restart_block;
> > };
> >
> > /*
> > @@ -44,9 +43,6 @@ struct thread_info {
> > .cpu = 0, \
> > .preempt_count = INIT_PREEMPT_COUNT, \
> > .addr_limit = KERNEL_DS, \
> > - .restart_block = { \
> > - .fn = do_no_restart_syscall, \
> > - }, \
> > }
> >
> > #define init_thread_info (init_thread_union.thread_info)
> > diff --git a/arch/h8300/kernel/signal.c b/arch/h8300/kernel/signal.c
> > index ad1f81f..7138303 100644
> > --- a/arch/h8300/kernel/signal.c
> > +++ b/arch/h8300/kernel/signal.c
> > @@ -79,7 +79,7 @@ struct rt_sigframe {
> > unsigned int er0;
> >
> > /* Always make any pending restarted system calls return -EINTR */
> > - current_thread_info()->restart_block.fn = do_no_restart_syscall;
> > + current->restart_block.fn = do_no_restart_syscall;
> >
> > /* restore passed registers */
> > #define COPY(r) do { err |= get_user(regs->r, &usc->sc_##r); } while (0)
> > --
> > 1.9.1
> >
>
> --
> Andy Lutomirski
> AMA Capital Management, LLC
>
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