From: Nicholas Piggin Date: Sun, 27 Nov 2022 12:49:37 +0000 (+1000) Subject: powerpc: copy_thread fill in interrupt frame marker and back chain X-Git-Tag: v6.2-rc1~52^2~46 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=6895dfc0474170c492191c126fcfc420f7771a09;p=thirdparty%2Fkernel%2Fstable.git powerpc: copy_thread fill in interrupt frame marker and back chain Backtraces will not recognise the fork system call interrupt without the regs marker. And regular interrupt entry from userspace creates the back chain to the user stack, so do this for the initial fork frame too, to be consistent. Signed-off-by: Nicholas Piggin Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20221127124942.1665522-13-npiggin@gmail.com --- diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c index 0cb5296c6c41e..6b1d80bd370ea 100644 --- a/arch/powerpc/kernel/process.c +++ b/arch/powerpc/kernel/process.c @@ -1757,12 +1757,13 @@ int copy_thread(struct task_struct *p, const struct kernel_clone_args *args) /* Create initial stack frame. */ sp -= STACK_USER_INT_FRAME_SIZE; - ((unsigned long *)sp)[0] = 0; + *(unsigned long *)(sp + STACK_INT_FRAME_MARKER) = STACK_FRAME_REGS_MARKER; /* Copy registers */ childregs = (struct pt_regs *)(sp + STACK_INT_FRAME_REGS); if (unlikely(args->fn)) { /* kernel thread */ + ((unsigned long *)sp)[0] = 0; memset(childregs, 0, sizeof(struct pt_regs)); childregs->gpr[1] = sp + STACK_USER_INT_FRAME_SIZE; /* function */ @@ -1782,6 +1783,7 @@ int copy_thread(struct task_struct *p, const struct kernel_clone_args *args) *childregs = *regs; if (usp) childregs->gpr[1] = usp; + ((unsigned long *)sp)[0] = childregs->gpr[1]; p->thread.regs = childregs; /* 64s sets this in ret_from_fork */ if (!IS_ENABLED(CONFIG_PPC_BOOK3S_64))