[PATCH stable 6.12 6/9] um: Set parent death signal for userspace process

[Florian Fainelli]

From: Benjamin Berg <benjamin.berg@xxxxxxxxx>

commit 801e00d3a1b78b7f71675fae79946ff4aa3ee070 upstream

Enable PR_SET_PDEATHSIG so that the UML userspace process will be killed
when the kernel exits unexpectedly.

Signed-off-by: Benjamin Berg <benjamin.berg@xxxxxxxxx>
Link: https://patch.msgid.link/20240919124511.282088-4-benjamin@xxxxxxxxxxxxxxxx
Signed-off-by: Johannes Berg <johannes.berg@xxxxxxxxx>
[florian: upstream applies os_set_pdeathsig() in stub_exe.c, a file
introduced in v6.13 that does not exist in 6.12; applied instead to
userspace_tramp() in arch/um/os-Linux/skas/process.c, which is the
equivalent entry-point for the userspace process in 6.12]
Signed-off-by: Florian Fainelli <florian.fainelli@xxxxxxxxxxxx>
---
 arch/um/os-Linux/skas/process.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/um/os-Linux/skas/process.c b/arch/um/os-Linux/skas/process.c
index b6f656bcffb1..cca016b0b29b 100644
--- a/arch/um/os-Linux/skas/process.c
+++ b/arch/um/os-Linux/skas/process.c
@@ -214,6 +214,9 @@ static int userspace_tramp(void *stack)
 				     (unsigned long) stub_segv_handler -
 				     (unsigned long) __syscall_stub_start;
 
+	/* Make sure this process dies if the kernel dies */
+	os_set_pdeathsig();
+
 	ptrace(PTRACE_TRACEME, 0, 0, 0);
 
 	signal(SIGTERM, SIG_DFL);
-- 
2.34.1