4.19-stable review patch. If anyone has any objections, please let me know.
------------------ From: Masami Hiramatsu <[email protected]> commit 2e62024c265aa69315ed02835623740030435380 upstream. The following commit: a19b2e3d7839 ("kprobes/x86: Remove IRQ disabling from ftrace-based/optimized kprobes”) removed local_irq_save/restore() from optimized_callback(), the handler might be interrupted by the rescheduling interrupt and might be rescheduled - so we must not use the preempt_enable_no_resched() macro. Use preempt_enable() instead, to not lose preemption events. [ mingo: Improved the changelog. ] Reported-by: Nadav Amit <[email protected]> Signed-off-by: Masami Hiramatsu <[email protected]> Acked-by: Peter Zijlstra (Intel) <[email protected]> Cc: <[email protected]> Cc: Alexei Starovoitov <[email protected]> Cc: Andy Lutomirski <[email protected]> Cc: Borislav Petkov <[email protected]> Cc: Linus Torvalds <[email protected]> Cc: Oleg Nesterov <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: [email protected] Fixes: a19b2e3d7839 ("kprobes/x86: Remove IRQ disabling from ftrace-based/optimized kprobes”) Link: http://lkml.kernel.org/r/154002887331.7627.10194920925792947001.stgit@devbox Signed-off-by: Ingo Molnar <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- arch/x86/kernel/kprobes/opt.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/arch/x86/kernel/kprobes/opt.c +++ b/arch/x86/kernel/kprobes/opt.c @@ -179,7 +179,7 @@ optimized_callback(struct optimized_kpro opt_pre_handler(&op->kp, regs); __this_cpu_write(current_kprobe, NULL); } - preempt_enable_no_resched(); + preempt_enable(); } NOKPROBE_SYMBOL(optimized_callback);
