Hi, Here is the 3rd version of the series to improve preempt related behavior in kprobes/x86. This actually includes many enhancements/fixes from the 2nd version, which is
https://lkml.org/lkml/2017/9/11/482 With the previous patch, lkp-bot reported that an issue ( https://lkml.org/lkml/2017/9/14/3 ) and I couldn't reproduce it. However, I found a suspicious bug and fixed it ([2/7]). Also, while I was checking the correct condition for *probe handlers in Documentation/kprobes.txt, I also found that current implementations for ftrace-based kprobe and optprobe were mis-reading the document. >From the document, handlers must be run with preempt- disabled, but interrupt disabling is not guaranteed. So in the middle of this series, patches ([4/7],[5/7], [6/7]) adding preempt-disabling and removing irq-disabling. And at last, I placed the original patch (Enable optprobe with CONFIG_PREEMPT). The others are just for making sure this fix works well. - [1/7] is just adding preemptible checker in kprobe smake tests so that we can easily find mistake. - [3/7] is adding an assert if user tries to change execution path in optprobe, which is obviously prohibited in the document (there also be how to avoid it.) Thank you, --- Masami Hiramatsu (7): kprobes: Improve smoke test to check preemptible kprobes/x86: Move get_kprobe_ctlblk in irq-disabled block kprobes: Warn if optprobe handler tries to change execution path kprobes/x86: Disable preempt in optprobe kprobes/x86: Disable preempt ftrace-based jprobe kprobes/x86: Remove disable_irq from ftrace-based/optimized kprobe kprobes: Use synchronize_rcu_tasks() for optprobe with CONFIG_PREEMPT arch/Kconfig | 2 +- arch/x86/kernel/kprobes/ftrace.c | 32 ++++++++++++++++---------------- arch/x86/kernel/kprobes/opt.c | 8 +++----- kernel/kprobes.c | 23 +++++++++++++++++------ kernel/test_kprobes.c | 20 ++++++++++++++++++++ 5 files changed, 57 insertions(+), 28 deletions(-) -- Masami Hiramatsu
