linux-kernel - [PATCH v4] signal: trace_signal_deliver when signal_group

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Message-ID: <20190424125238.83264-1-weizhenliang@huawei.com>
Date:   Wed, 24 Apr 2019 20:52:38 +0800
From:   Zhenliang Wei <weizhenliang@...wei.com>
To:     <ebiederm@...ssion.com>, <oleg@...hat.com>, <colona@...sta.com>,
        <akpm@...ux-foundation.org>, <christian@...uner.io>,
        <arnd@...db.de>, <tglx@...utronix.de>, <deepa.kernel@...il.com>,
        <gregkh@...uxfoundation.org>
CC:     <linux-kernel@...r.kernel.org>, <stable@...r.kernel.org>,
        <weizhenliang@...wei.com>
Subject: [PATCH v4] signal: trace_signal_deliver when signal_group_exit

In the fixes commit, removing SIGKILL from each thread signal mask
and executing "goto fatal" directly will skip the call to
"trace_signal_deliver". At this point, the delivery tracking of the SIGKILL
signal will be inaccurate.

Therefore, we need to add trace_signal_deliver before "goto fatal"
after executing sigdelset.

Note: SEND_SIG_NOINFO matches the fact that SIGKILL doesn't have any info.

Acked-by: Christian Brauner <christian@...uner.io>
Reviewed-by: Oleg Nesterov <oleg@...hat.com>
Cc: <stable@...r.kernel.org>
Fixes: cf43a757fd4944 ("signal: Restore the stop PTRACE_EVENT_EXIT")
Reported-by: kbuild test robot <lkp@...el.com>
Signed-off-by: Zhenliang Wei <weizhenliang@...wei.com>
---
 kernel/signal.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/kernel/signal.c b/kernel/signal.c
index 227ba170298e..3edf526db7c6 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -2441,6 +2441,8 @@ bool get_signal(struct ksignal *ksig)
 	if (signal_group_exit(signal)) {
 		ksig->info.si_signo = signr = SIGKILL;
 		sigdelset(&current->pending.signal, SIGKILL);
+		trace_signal_deliver(SIGKILL, SEND_SIG_NOINFO,
+			&sighand->action[signr - 1]);
 		recalc_sigpending();
 		goto fatal;
 	}
-- 
2.14.1.windows.1