git: 227d01c1bc7c - main - linux(4): On Linux SIGKILL can not be reset to default

The branch main has been updated by dchagin:

URL: https://cgit.FreeBSD.org/src/commit/?id=227d01c1bc7caf2e838ee6eef1e6a3cc81d79d1b

commit 227d01c1bc7caf2e838ee6eef1e6a3cc81d79d1b
Author:     Dmitry Chagin <dchagin@FreeBSD.org>
AuthorDate: 2023-09-18 14:53:01 +0000
Commit:     Dmitry Chagin <dchagin@FreeBSD.org>
CommitDate: 2023-09-18 14:53:01 +0000

    linux(4): On Linux SIGKILL can not be reset to default
    
    MFC after:              1 week
---
 sys/compat/linux/linux_signal.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/sys/compat/linux/linux_signal.c b/sys/compat/linux/linux_signal.c
index e3e3fc74a6a9..9a84700b3949 100644
--- a/sys/compat/linux/linux_signal.c
+++ b/sys/compat/linux/linux_signal.c
@@ -170,6 +170,7 @@ linux_do_sigaction(struct thread *td, int linux_sig, l_sigaction_t *linux_nsa,
 
 	if (!LINUX_SIG_VALID(linux_sig))
 		return (EINVAL);
+	sig = linux_to_bsd_signal(linux_sig);
 
 	osa = (linux_osa != NULL) ? &oact : NULL;
 	if (linux_nsa != NULL) {
@@ -180,9 +181,11 @@ linux_do_sigaction(struct thread *td, int linux_sig, l_sigaction_t *linux_nsa,
 			linux_ktrsigset(&linux_nsa->lsa_mask,
 			    sizeof(linux_nsa->lsa_mask));
 #endif
+		if ((sig == SIGKILL || sig == SIGSTOP) &&
+		    nsa->sa_handler == SIG_DFL)
+			return (EINVAL);
 	} else
 		nsa = NULL;
-	sig = linux_to_bsd_signal(linux_sig);
 
 	error = kern_sigaction(td, sig, nsa, osa, 0);
 	if (error != 0)