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Message-ID: <tencent_7C50F304C14CB2A5133317F8A13D1F544D0A@qq.com>
Date: Fri, 23 Feb 2024 21:41:21 +0800
From: Wen Yang <wenyang.linux@...mail.com>
To: Oleg Nesterov <oleg@...hat.com>, Andrew Morton <akpm@...ux-foundation.org>
Cc: "Eric W. Biederman" <ebiederm@...ssion.com>,
Christian Brauner <brauner@...nel.org>, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] get_signal: simplify/cleanup the the usage of ksig->info
On 2024/2/23 18:50, Oleg Nesterov wrote:
> get_signal() uses signr or ksig->info.si_signo in a chaotic way, this
> looks confusing. Change it to always use signr.
>
> This allows us to simplify the SIGNAL_GROUP_EXIT/group_exec_task branch,
> it no longer needs to touch ksig at all.
>
> Signed-off-by: Oleg Nesterov <oleg@...hat.com>
> ---
> kernel/signal.c | 15 +++++++++------
> 1 file changed, 9 insertions(+), 6 deletions(-)
>
> diff --git a/kernel/signal.c b/kernel/signal.c
> index c9c57d053ce4..690982e6595e 100644
> --- a/kernel/signal.c
> +++ b/kernel/signal.c
> @@ -2727,12 +2727,15 @@ bool get_signal(struct ksignal *ksig)
> /* Has this task already been marked for death? */
> if ((signal->flags & SIGNAL_GROUP_EXIT) ||
> signal->group_exec_task) {
> - clear_siginfo(&ksig->info);
> - ksig->info.si_signo = signr = SIGKILL;
> + signr = SIGKILL;
> sigdelset(¤t->pending.signal, SIGKILL);
> trace_signal_deliver(SIGKILL, SEND_SIG_NOINFO,
> - &sighand->action[SIGKILL - 1]);
> + &sighand->action[SIGKILL - 1]);
> recalc_sigpending();
> + /*
> + * implies do_group_exit(), no need to initialize
> + * ksig->info
> + */
> goto fatal;
There is little question:
If the this conditions is met:
current->flags & PF_USER_WORKER
It may execute “goto out“ instead of do_group_exit().
--
Best wishes,
Wen
> }
>
> @@ -2842,7 +2845,7 @@ bool get_signal(struct ksignal *ksig)
> spin_lock_irq(&sighand->siglock);
> }
>
> - if (likely(do_signal_stop(ksig->info.si_signo))) {
> + if (likely(do_signal_stop(signr))) {
> /* It released the siglock. */
> goto relock;
> }
> @@ -2866,7 +2869,7 @@ bool get_signal(struct ksignal *ksig)
>
> if (sig_kernel_coredump(signr)) {
> if (print_fatal_signals)
> - print_fatal_signal(ksig->info.si_signo);
> + print_fatal_signal(signr);
> proc_coredump_connector(current);
> /*
> * If it was able to dump core, this kills all
> @@ -2890,7 +2893,7 @@ bool get_signal(struct ksignal *ksig)
> /*
> * Death signals, no core dump.
> */
> - do_group_exit(ksig->info.si_signo);
> + do_group_exit(signr);
> /* NOTREACHED */
> }
> spin_unlock_irq(&sighand->siglock);
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