Commit-ID: 2e62024c265aa69315ed02835623740030435380 Gitweb: https://git.kernel.org/tip/2e62024c265aa69315ed02835623740030435380 Author: Masami Hiramatsu mhiramat@kernel.org AuthorDate: Sat, 20 Oct 2018 18:47:53 +0900 Committer: Ingo Molnar mingo@kernel.org CommitDate: Mon, 22 Oct 2018 03:31:01 +0200

kprobes/x86: Use preempt_enable() in optimized_callback()

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 namit@vmware.com Signed-off-by: Masami Hiramatsu mhiramat@kernel.org Acked-by: Peter Zijlstra (Intel) peterz@infradead.org Cc: stable@vger.kernel.org Cc: Alexei Starovoitov alexei.starovoitov@gmail.com Cc: Andy Lutomirski luto@kernel.org Cc: Borislav Petkov bp@alien8.de Cc: Linus Torvalds torvalds@linux-foundation.org Cc: Oleg Nesterov oleg@redhat.com Cc: Thomas Gleixner tglx@linutronix.de Cc: dwmw@amazon.co.uk 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 mingo@kernel.org --- arch/x86/kernel/kprobes/opt.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kernel/kprobes/opt.c b/arch/x86/kernel/kprobes/opt.c index eaf02f2e7300..40b16b270656 100644 --- a/arch/x86/kernel/kprobes/opt.c +++ b/arch/x86/kernel/kprobes/opt.c @@ -179,7 +179,7 @@ optimized_callback(struct optimized_kprobe *op, struct pt_regs *regs) opt_pre_handler(&op->kp, regs); __this_cpu_write(current_kprobe, NULL); } - preempt_enable_no_resched(); + preempt_enable(); } NOKPROBE_SYMBOL(optimized_callback);