[PATCH 5.15 192/244] um: add "noreboot" command line option for PANIC_TIMEOUT=-1 setups

Greg Kroah-Hartman
2022-08-23T10:24:16Z

From: Jason A. Donenfeld <Jason@zx2c4.com>

[ Upstream commit dda520d07b95072a0b63f6c52a8eb566d08ea897 ]

QEMU has a -no-reboot option, which halts instead of reboots when the
guest asks to reboot. This is invaluable when used with
CONFIG_PANIC_TIMEOUT=-1 (and panic_on_warn), because it allows panics
and warnings to be caught immediately in CI. Implement this in UML too,
by way of a basic setup param.

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/um/os-Linux/skas/process.c | 17 ++++++++++++++++-
1 file changed, 16 insertions(+), 1 deletion(-)

diff --git a/arch/um/os-Linux/skas/process.c b/arch/um/os-Linux/skas/process.c
index 87d3129e7362..0df2ebcc97c0 100644
--- a/arch/um/os-Linux/skas/process.c
+++ b/arch/um/os-Linux/skas/process.c
@@ -5,6 +5,7 @@
*/

#include <stdlib.h>
+#include <stdbool.h>
#include <unistd.h>
#include <sched.h>
#include <errno.h>
@@ -707,10 +708,24 @@ void halt_skas(void)
UML_LONGJMP(&initial_jmpbuf, INIT_JMP_HALT);
}

+static bool noreboot;
+
+static int __init noreboot_cmd_param(char *str, int *add)
+{
+ noreboot = true;
+ return 0;
+}
+
+__uml_setup("noreboot", noreboot_cmd_param,
+"noreboot\n"
+" Rather than rebooting, exit always, akin to QEMU's -no-reboot option.\n"
+" This is useful if you're using CONFIG_PANIC_TIMEOUT in order to catch\n"
+" crashes in CI\n");
+
void reboot_skas(void)
{
block_signals_trace();
- UML_LONGJMP(&initial_jmpbuf, INIT_JMP_REBOOT);
+ UML_LONGJMP(&initial_jmpbuf, noreboot ? INIT_JMP_HALT : INIT_JMP_REBOOT);
}

void __switch_mm(struct mm_id *mm_idp)
--
2.35.1