From: Jiri Olsa Date: Sun, 31 Jul 2016 12:52:53 +0000 (+0200) Subject: s390/ftrace/jprobes: Fix conflict between jprobes and function graph tracing X-Git-Tag: Ubuntu-5.2.0-15.16~8693^2 X-Git-Url: https://git.proxmox.com/?a=commitdiff_plain;h=e64a5470dcd2900ab8f8f83638c00098b10e6300;p=mirror_ubuntu-eoan-kernel.git s390/ftrace/jprobes: Fix conflict between jprobes and function graph tracing This fixes the same issue Steven already fixed for x86 in following commit: 237d28db036e ftrace/jprobes/x86: Fix conflict between jprobes and function graph tracing It fixes the crash, that happens when function graph tracing and jprobes are used simultaneously. Please refer to above commit for details. Signed-off-by: Jiri Olsa Signed-off-by: Martin Schwidefsky Acked-by: Steven Rostedt --- diff --git a/arch/s390/kernel/kprobes.c b/arch/s390/kernel/kprobes.c index 250f5972536a..dd6306c51bd6 100644 --- a/arch/s390/kernel/kprobes.c +++ b/arch/s390/kernel/kprobes.c @@ -690,6 +690,15 @@ int setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs) stack = (unsigned long) regs->gprs[15]; memcpy(kcb->jprobes_stack, (void *) stack, MIN_STACK_SIZE(stack)); + + /* + * jprobes use jprobe_return() which skips the normal return + * path of the function, and this messes up the accounting of the + * function graph tracer to get messed up. + * + * Pause function graph tracing while performing the jprobe function. + */ + pause_graph_tracing(); return 1; } NOKPROBE_SYMBOL(setjmp_pre_handler); @@ -705,6 +714,9 @@ int longjmp_break_handler(struct kprobe *p, struct pt_regs *regs) struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); unsigned long stack; + /* It's OK to start function graph tracing again */ + unpause_graph_tracing(); + stack = (unsigned long) kcb->jprobe_saved_regs.gprs[15]; /* Put the regs back */