[PATCH 1/1] sandbox: unblock signal before calling execv()

[Heinrich Schuchardt]

The following faulty behavior was observed. The sandbox configured with
CONFIG_SANDBOX_CRASH_RESET=y was invoked with

    ./u-boot -T -S

After executing `exception undefined' the sandbox reboots.
When executing `exception undefined' the sandbox exits with SIGSEGV.

The expected behavior is that the sandbox should reboot again.

If we are relaunching the sandbox in a signal handler, we have to unblock
the respective signal before calling execv(). See signal(7) man-page.

Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt at canonical.com>
---
 arch/sandbox/cpu/os.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/arch/sandbox/cpu/os.c b/arch/sandbox/cpu/os.c
index f937991139..2c7aeea070 100644
--- a/arch/sandbox/cpu/os.c
+++ b/arch/sandbox/cpu/os.c
@@ -1012,8 +1012,24 @@ void *os_find_text_base(void)
 	return base;
 }
 
+/**
+ * os_unblock_signals() - unblock all signals
+ *
+ * If we are relaunching the sandbox in a signal handler, we have to unblock
+ * the respective signal before calling execv(). See signal(7) man-page.
+ */
+static void os_unblock_signals(void)
+{
+	sigset_t sigs;
+
+	sigfillset(&sigs);
+	sigprocmask(SIG_UNBLOCK, &sigs, NULL);
+}
+
 void os_relaunch(char *argv[])
 {
+	os_unblock_signals();
+
 	execv(argv[0], argv);
 	os_exit(1);
 }
-- 
2.37.2