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From:   Marco Elver <elver@google.com>
Date:   Sat, 1 May 2021 12:45:49 +0200
Message-ID: <CANpmjNP32SRsnJBBfhjX63fcMyPAMgj8VDuMPdJXeut_+g2x_A@mail.gmail.com>
Subject: Re: [PATCH 6/3] signal: Factor force_sig_perf out of perf_sigtrap
To:     "Eric W. Biederman" <ebiederm@xmission.com>
Cc:     Arnd Bergmann <arnd@arndb.de>, Florian Weimer <fweimer@redhat.com>,
        "David S. Miller" <davem@davemloft.net>,
        Peter Zijlstra <peterz@infradead.org>,
        Ingo Molnar <mingo@kernel.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Peter Collingbourne <pcc@google.com>,
        Dmitry Vyukov <dvyukov@google.com>,
        Alexander Potapenko <glider@google.com>,
        sparclinux <sparclinux@vger.kernel.org>,
        linux-arch <linux-arch@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Linux API <linux-api@vger.kernel.org>,
        kasan-dev <kasan-dev@googlegroups.com>
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On Sat, 1 May 2021 at 01:43, Eric W. Biederman <ebiederm@xmission.com> wrote:
>
> Separate generating the signal from deciding it needs to be sent.
>
> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
> ---
>  include/linux/sched/signal.h |  1 +
>  kernel/events/core.c         | 11 ++---------
>  kernel/signal.c              | 13 +++++++++++++
>  3 files changed, 16 insertions(+), 9 deletions(-)
>
> diff --git a/include/linux/sched/signal.h b/include/linux/sched/signal.h
> index 7daa425f3055..1e2f61a1a512 100644
> --- a/include/linux/sched/signal.h
> +++ b/include/linux/sched/signal.h
> @@ -318,6 +318,7 @@ int send_sig_mceerr(int code, void __user *, short, struct task_struct *);
>
>  int force_sig_bnderr(void __user *addr, void __user *lower, void __user *upper);
>  int force_sig_pkuerr(void __user *addr, u32 pkey);
> +int force_sig_perf(void __user *addr, u32 type, u64 sig_data);
>
>  int force_sig_fault_trapno(int sig, int code, void __user *addr, int trapno);
>  int send_sig_fault_trapno(int sig, int code, void __user *addr, int trapno,
> diff --git a/kernel/events/core.c b/kernel/events/core.c
> index 928b166d888e..48ea8863183b 100644
> --- a/kernel/events/core.c
> +++ b/kernel/events/core.c
> @@ -6394,8 +6394,6 @@ void perf_event_wakeup(struct perf_event *event)
>
>  static void perf_sigtrap(struct perf_event *event)
>  {
> -       struct kernel_siginfo info;
> -
>         /*
>          * We'd expect this to only occur if the irq_work is delayed and either
>          * ctx->task or current has changed in the meantime. This can be the
> @@ -6410,13 +6408,8 @@ static void perf_sigtrap(struct perf_event *event)
>         if (current->flags & PF_EXITING)
>                 return;
>
> -       clear_siginfo(&info);
> -       info.si_signo = SIGTRAP;
> -       info.si_code = TRAP_PERF;
> -       info.si_errno = event->attr.type;
> -       info.si_perf = event->attr.sig_data;
> -       info.si_addr = (void __user *)event->pending_addr;
> -       force_sig_info(&info);
> +       force_sig_perf((void __user *)event->pending_addr,
> +                      event->attr.type, event->attr.sig_data);
>  }
>
>  static void perf_pending_event_disable(struct perf_event *event)
> diff --git a/kernel/signal.c b/kernel/signal.c
> index 690921960d8b..5b1ad7f080ab 100644
> --- a/kernel/signal.c
> +++ b/kernel/signal.c
> @@ -1753,6 +1753,19 @@ int force_sig_pkuerr(void __user *addr, u32 pkey)
>  }
>  #endif
>
> +int force_sig_perf(void __user *pending_addr, u32 type, u64 sig_data)

s/pending_addr/addr/

to match force_sig_perf() declaration.

> +{
> +       struct kernel_siginfo info;
> +
> +       clear_siginfo(&info);
> +       info.si_signo = SIGTRAP;
> +       info.si_errno = type;
> +       info.si_code  = TRAP_PERF;
> +       info.si_addr  = pending_addr;
> +       info.si_perf  = sig_data;
> +       return force_sig_info(&info);
> +}
> +
>  #if IS_ENABLED(SPARC)
>  int force_sig_fault_trapno(int sig, int code, void __user *addr, int trapno)
>  {
> --
> 2.30.1