4.4-stable review patch. If anyone has any objections, please let me know. ------------------ [ Upstream commit 7ff1e34bbdc15acab823b1ee4240e94623d50ee8 ] Fixes: arch/um/os-Linux/skas/process.c:613:1: warning: control reaches end of non-void function [-Wreturn-type] longjmp() never returns but gcc still warns that the end of the function can be reached. Add a return code and debug aid to detect this impossible case. Signed-off-by: Richard Weinberger <richard@xxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- arch/um/os-Linux/skas/process.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/arch/um/os-Linux/skas/process.c b/arch/um/os-Linux/skas/process.c index b856c66ebd3a..6dbf27ffafc8 100644 --- a/arch/um/os-Linux/skas/process.c +++ b/arch/um/os-Linux/skas/process.c @@ -585,6 +585,11 @@ int start_idle_thread(void *stack, jmp_buf *switch_buf) fatal_sigsegv(); } longjmp(*switch_buf, 1); + + /* unreachable */ + printk(UM_KERN_ERR "impossible long jump!"); + fatal_sigsegv(); + return 0; } void initial_thread_cb_skas(void (*proc)(void *), void *arg) -- 2.17.1