linux-kernel - [PATCH v2 1/2] signal: add the "int si_code" arg to prepare_kill

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Date: Fri, 9 Feb 2024 14:06:20 +0100
From: Oleg Nesterov <oleg@...hat.com>
To: Christian Brauner <brauner@...nel.org>
Cc: Andy Lutomirski <luto@...capital.net>,
	"Eric W. Biederman" <ebiederm@...ssion.com>,
	Tycho Andersen <tycho@...ho.pizza>, linux-api@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH v2 1/2] signal: add the "int si_code" arg to
 prepare_kill_siginfo()

So that do_tkill() can use this helper too. This also simplifies
the next patch.

TODO: perhaps we can kill prepare_kill_siginfo() and change the
callers to use SEND_SIG_NOINFO,  but this needs some changes in
__send_signal_locked() and TP_STORE_SIGINFO().

Signed-off-by: Oleg Nesterov <oleg@...hat.com>
---
 kernel/signal.c | 15 +++++----------
 1 file changed, 5 insertions(+), 10 deletions(-)

diff --git a/kernel/signal.c b/kernel/signal.c
index c3fac06937e2..a8199fda0d61 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -3793,12 +3793,12 @@ COMPAT_SYSCALL_DEFINE4(rt_sigtimedwait_time32, compat_sigset_t __user *, uthese,
 #endif
 #endif
 
-static inline void prepare_kill_siginfo(int sig, struct kernel_siginfo *info)
+static void prepare_kill_siginfo(int sig, struct kernel_siginfo *info, int si_code)
 {
 	clear_siginfo(info);
 	info->si_signo = sig;
 	info->si_errno = 0;
-	info->si_code = SI_USER;
+	info->si_code = si_code;
 	info->si_pid = task_tgid_vnr(current);
 	info->si_uid = from_kuid_munged(current_user_ns(), current_uid());
 }
@@ -3812,7 +3812,7 @@ SYSCALL_DEFINE2(kill, pid_t, pid, int, sig)
 {
 	struct kernel_siginfo info;
 
-	prepare_kill_siginfo(sig, &info);
+	prepare_kill_siginfo(sig, &info, SI_USER);
 
 	return kill_something_info(sig, &info, pid);
 }
@@ -3925,7 +3925,7 @@ SYSCALL_DEFINE4(pidfd_send_signal, int, pidfd, int, sig,
 		    (kinfo.si_code >= 0 || kinfo.si_code == SI_TKILL))
 			goto err;
 	} else {
-		prepare_kill_siginfo(sig, &kinfo);
+		prepare_kill_siginfo(sig, &kinfo, SI_USER);
 	}
 
 	/* TODO: respect PIDFD_THREAD */
@@ -3970,12 +3970,7 @@ static int do_tkill(pid_t tgid, pid_t pid, int sig)
 {
 	struct kernel_siginfo info;
 
-	clear_siginfo(&info);
-	info.si_signo = sig;
-	info.si_errno = 0;
-	info.si_code = SI_TKILL;
-	info.si_pid = task_tgid_vnr(current);
-	info.si_uid = from_kuid_munged(current_user_ns(), current_uid());
+	prepare_kill_siginfo(sig, &info, SI_TKILL);
 
 	return do_send_specific(tgid, pid, sig, &info);
 }
-- 
2.25.1.362.g51ebf55