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Subject[PATCH -tip v6 00/22] kprobes: introduce NOKPROBE_SYMBOL(), cleanup and fixes crash bugs
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Hi,
Here is the version 6 of NOKPROBE_SYMBOL series. :)

This includes small updates and introducing nokprobe_inline
macro to prevent probing on the static/inlined small
functions since NOKPROBE_SYMBOL will inhibit inlining
by referring function address.
This macro is more self-describing than normal
__always_inline. (Thanks to Steven Rostedt!)

This series also adds four new patches, the first is
prohibiting probes on memset/memcpy since probing it
freezes the kernel. The next is allowing kprobes on
text_poke/hw_breakpoint handler which is not related
to kprobes int3/debug handling path. And the third is
removing preempt disable/enable in kprobes/x86 code.
The last is original instruction recovery code for
bad kprobes (Thanks to Ingo Molnar!) This recovery
code is important to make the kprobes more robust.


Currently, kprobes uses __kprobes annotation and
internal symbol-name based blacklist to prohibit
probing on some functions, because to probe those
functions may cause an infinit recursive loop by
int3/debug exceptions.
However, current mechanisms have some problems
especially from the view point of maintaining code;
- __kprobes is easy to confuse the function is
used by kprobes, despite it just means "no kprobe
on it".
- __kprobes moves functions to different section
this will be not good for cache optimization.
- symbol-name based solution is not good at all,
since the symbol name easily be changed, and
we cannot notice it.
- it doesn't support functions in modules at all.

Thus, I decided to introduce new NOKPROBE_SYMBOL
macro for building an integrated kprobe blacklist.

The new macro stores the address of the given symbols
into _kprobe_blacklist section, and initialize the
blacklist based on the address list at boottime.
This is also applied for modules. When loading a
module, kprobes finds the blacklist symbols in
_kprobe_blacklist section in the module automatically.
This series replaces all __kprobes on x86 and generic
code with the NOKPROBE_SYMBOL() too.

Although, the new blacklist still support old-style
__kprobes by decoding .kprobes.text if exist, because
it still be used on arch-dependent code except for x86.

This series will fix the kernel crashable "qualitative"
bugs of kprobes even with lockdep. But we still have
"quantitative" issue which we are discussing on LKML.

https://lkml.org/lkml/2013/12/3/788

I'd like to send another series for solving this
"quantitative" issue.

Changes from the previous:
- [2/22] Introduce nokprobe_inline macro
- [6/22] Prohibit probing on memset/memcpy
- [11/22] Allow probing on text_poke/hw_breakpoint
- [12/22] Use nokprobe_inline macro instead of __always_inline
- [14/22] Ditto.
- [21/22] Remove preempt disable/enable from kprobes/x86
- [22/22] Add emergency int3 recovery code

Thank you,
---

Masami Hiramatsu (22):
kprobes: Prohibit probing on .entry.text code
kprobes: Introduce NOKPROBE_SYMBOL() macro for blacklist
[BUGFIX] kprobes/x86: Prohibit probing on debug_stack_*
[BUGFIX] x86: Prohibit probing on native_set_debugreg/load_idt
[BUGFIX] x86: Prohibit probing on thunk functions and restore
[BUGFIX] x86: Prohibit probing on memcpy/memset
kprobes/x86: Call exception handlers directly from do_int3/do_debug
kprobes/x86: Allow probe on some kprobe preparation functions
kprobes: Allow probe on some kprobe functions
ftrace/kprobes: Allow probing on some preparation functions
x86: Allow kprobes on text_poke/hw_breakpoint
x86: Use NOKPROBE_SYMBOL() instead of __kprobes annotation
kprobes: Use NOKPROBE_SYMBOL macro instead of __kprobes
ftrace/kprobes: Use NOKPROBE_SYMBOL macro in ftrace
notifier: Use NOKPROBE_SYMBOL macro in notifier
sched: Use NOKPROBE_SYMBOL macro in sched
kprobes: Show blacklist entries via debugfs
kprobes: Support blacklist functions in module
kprobes: Use NOKPROBE_SYMBOL() in sample modules
kprobes/x86: Use kprobe_blacklist for .kprobes.text and .entry.text
kprobes/x86: Remove unneeded preempt_disable/enable in interrupt handlers
[RFC] kprobes/x86: Add emergency recovery process for bad kprobes


Documentation/kprobes.txt | 24 +-
arch/x86/include/asm/asm.h | 7
arch/x86/include/asm/fixmap.h | 7
arch/x86/include/asm/kprobes.h | 3
arch/x86/include/asm/paravirt.h | 7
arch/x86/include/asm/processor.h | 2
arch/x86/include/asm/special_insns.h | 4
arch/x86/include/asm/string_32.h | 6
arch/x86/include/asm/tlbflush.h | 6
arch/x86/include/asm/traps.h | 2
arch/x86/kernel/alternative.c | 3
arch/x86/kernel/apic/hw_nmi.c | 3
arch/x86/kernel/cpu/common.c | 4
arch/x86/kernel/cpu/perf_event.c | 3
arch/x86/kernel/cpu/perf_event_amd_ibs.c | 3
arch/x86/kernel/dumpstack.c | 9 -
arch/x86/kernel/entry_32.S | 33 --
arch/x86/kernel/entry_64.S | 20 -
arch/x86/kernel/hw_breakpoint.c | 5
arch/x86/kernel/kprobes/core.c | 193 +++++++-----
arch/x86/kernel/kprobes/ftrace.c | 17 +
arch/x86/kernel/kprobes/opt.c | 32 +-
arch/x86/kernel/kvm.c | 4
arch/x86/kernel/nmi.c | 18 +
arch/x86/kernel/paravirt.c | 6
arch/x86/kernel/traps.c | 30 +-
arch/x86/lguest/boot.c | 1
arch/x86/lib/memcpy_32.c | 2
arch/x86/lib/memcpy_64.S | 4
arch/x86/lib/memset_64.S | 3
arch/x86/lib/thunk_32.S | 3
arch/x86/lib/thunk_64.S | 3
arch/x86/mm/fault.c | 28 +-
arch/x86/mm/pgtable.c | 3
include/asm-generic/vmlinux.lds.h | 9 +
include/linux/compiler.h | 2
include/linux/kprobes.h | 31 ++
include/linux/module.h | 5
kernel/kprobes.c | 466 +++++++++++++++++++-----------
kernel/module.c | 6
kernel/notifier.c | 22 +
kernel/sched/core.c | 7
kernel/trace/trace_event_perf.c | 5
kernel/trace/trace_kprobe.c | 53 ++-
kernel/trace/trace_probe.c | 78 +++--
kernel/trace/trace_probe.h | 4
samples/kprobes/jprobe_example.c | 1
samples/kprobes/kprobe_example.c | 3
samples/kprobes/kretprobe_example.c | 2
tools/perf/bench/mem-memcpy-x86-64-asm.S | 1
tools/perf/bench/mem-memset-x86-64-asm.S | 1
51 files changed, 747 insertions(+), 447 deletions(-)

--
Masami HIRAMATSU
IT Management Research Dept. Linux Technology Center
Hitachi, Ltd., Yokohama Research Laboratory
E-mail: masami.hiramatsu.pt@hitachi.com



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