linux-kernel - Re: [PATCH] MIPS: Add ksig argument to rseq_{signal_deliver,handle_notify

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Date:   Sun, 24 Jun 2018 13:08:26 -0400 (EDT)
From:   Mathieu Desnoyers <mathieu.desnoyers@...icios.com>
To:     Paul Burton <paul.burton@...s.com>
Cc:     linux-mips <linux-mips@...ux-mips.org>,
        James Hogan <jhogan@...nel.org>,
        Ralf Baechle <ralf@...ux-mips.org>,
        Peter Zijlstra <peterz@...radead.org>,
        "Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>,
        Boqun Feng <boqun.feng@...il.com>,
        Will Deacon <will.deacon@....com>,
        linux-kernel <linux-kernel@...r.kernel.org>,
        Thomas Gleixner <tglx@...utronix.de>
Subject: Re: [PATCH] MIPS: Add ksig argument to
 rseq_{signal_deliver,handle_notify_resume}

----- On Jun 24, 2018, at 12:58 PM, Paul Burton paul.burton@...s.com wrote:

> Commit 784e0300fe9f ("rseq: Avoid infinite recursion when delivering
> SIGSEGV") added a new ksig argument to the rseq_signal_deliver() &
> rseq_handle_notify_resume() functions, and was merged in v4.18-rc2.
> Meanwhile MIPS support for restartable sequences was also merged in
> v4.18-rc2 with commit 9ea141ad5471 ("MIPS: Add support for restartable
> sequences"), and therefore didn't get updated for the API change.
> 
> This results in build failures like the following:
> 
>    CC      arch/mips/kernel/signal.o
>  arch/mips/kernel/signal.c: In function 'handle_signal':
>  arch/mips/kernel/signal.c:804:22: error: passing argument 1 of
>    'rseq_signal_deliver' from incompatible pointer type
>    [-Werror=incompatible-pointer-types]
>    rseq_signal_deliver(regs);
>                        ^~~~
>  In file included from ./include/linux/context_tracking.h:5,
>                   from arch/mips/kernel/signal.c:12:
>  ./include/linux/sched.h:1811:56: note: expected 'struct ksignal *' but
>    argument is of type 'struct pt_regs *'
>    static inline void rseq_signal_deliver(struct ksignal *ksig,
>                                           ~~~~~~~~~~~~~~~~^~~~
>  arch/mips/kernel/signal.c:804:2: error: too few arguments to function
>    'rseq_signal_deliver'
>    rseq_signal_deliver(regs);
>    ^~~~~~~~~~~~~~~~~~~
> 
> Fix this by adding the ksig argument as was done for other architectures
> in commit 784e0300fe9f ("rseq: Avoid infinite recursion when delivering
> SIGSEGV").

Looks like we both noticed the same issue. Your commit message is more
exhaustive than mine, so yours should be merged rather than mine.

Acked-by: Mathieu Desnoyers <mathieu.desnoyers@...icios.com>

Thanks!

Mathieu

> 
> Signed-off-by: Paul Burton <paul.burton@...s.com>
> Cc: James Hogan <jhogan@...nel.org>
> Cc: Ralf Baechle <ralf@...ux-mips.org>
> Cc: Mathieu Desnoyers <mathieu.desnoyers@...icios.com>
> Cc: Peter Zijlstra <peterz@...radead.org>
> Cc: Paul E. McKenney <paulmck@...ux.vnet.ibm.com>
> Cc: Boqun Feng <boqun.feng@...il.com>
> Cc: Will Deacon <will.deacon@....com>
> Cc: linux-mips@...ux-mips.org
> Cc: linux-kernel@...r.kernel.org
> ---
> 
> arch/mips/kernel/signal.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/mips/kernel/signal.c b/arch/mips/kernel/signal.c
> index 00f2535d2226..0a9cfe7a0372 100644
> --- a/arch/mips/kernel/signal.c
> +++ b/arch/mips/kernel/signal.c
> @@ -801,7 +801,7 @@ static void handle_signal(struct ksignal *ksig, struct
> pt_regs *regs)
> 		regs->regs[0] = 0;		/* Don't deal with this again.	*/
> 	}
> 
> -	rseq_signal_deliver(regs);
> +	rseq_signal_deliver(ksig, regs);
> 
> 	if (sig_uses_siginfo(&ksig->ka, abi))
> 		ret = abi->setup_rt_frame(vdso + abi->vdso->off_rt_sigreturn,
> @@ -870,7 +870,7 @@ asmlinkage void do_notify_resume(struct pt_regs *regs, void
> *unused,
> 	if (thread_info_flags & _TIF_NOTIFY_RESUME) {
> 		clear_thread_flag(TIF_NOTIFY_RESUME);
> 		tracehook_notify_resume(regs);
> -		rseq_handle_notify_resume(regs);
> +		rseq_handle_notify_resume(NULL, regs);
> 	}
> 
> 	user_enter();
> --
> 2.17.1

-- 
Mathieu Desnoyers
EfficiOS Inc.
http://www.efficios.com