Messages in this thread | | | Date | Mon, 7 Dec 2020 18:22:02 -0500 | From | Steven Rostedt <> | Subject | Re: [PATCH] x86/kprobes: Restore BTF if the single-stepping is cancelled |
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Did this patch fall through the cracks?
-- Steve
On Wed, 28 Oct 2020 23:31:10 +0900 Masami Hiramatsu <mhiramat@kernel.org> wrote:
> Fix to restore BTF if single-stepping causes a page fault and > it is cancelled. > > Usually the BTF flag was restored when the single stepping is done > (in resume_execution()). However, if a page fault happens on the > single stepping instruction, the fault handler is invoked and > the single stepping is cancelled. Thus, the BTF flag is not > restored. > > Fixes: 1ecc798c6764 ("x86: debugctlmsr kprobes") > Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> > --- > arch/x86/kernel/kprobes/core.c | 5 +++++ > 1 file changed, 5 insertions(+) > > diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c > index 547c7abb39f5..39f7d8c3c064 100644 > --- a/arch/x86/kernel/kprobes/core.c > +++ b/arch/x86/kernel/kprobes/core.c > @@ -937,6 +937,11 @@ int kprobe_fault_handler(struct pt_regs *regs, int trapnr) > * So clear it by resetting the current kprobe: > */ > regs->flags &= ~X86_EFLAGS_TF; > + /* > + * Since the single step (trap) has been cancelled, > + * we need to restore BTF here. > + */ > + restore_btf(); > > /* > * If the TF flag was set before the kprobe hit,
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