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Subject[PATCH v4 00/23] kprobes: Unify kretprobe trampoline handlers and make kretprobe lockless
Date
Hi,

Here is the 4th version of the series to unify the kretprobe trampoline handler
and make kretprobe lockless.

Previous version is here;

https://lkml.kernel.org/r/159854631442.736475.5062989489155389472.stgit@devnote2

In this version, I updated the generic trampoline handler a bit, merge
the Peter's lockless patches(*), and add an RFC "remove task scan" patch
as [20/23].

(*) https://lkml.kernel.org/r/20200827161237.889877377@infradead.org

I ran some tests and ftracetest on x86-64. Mostly OK, but hit a BUG in the
trampoline handler once. I'm trying to reproduce it but not succeeded yet.
So this may need a careful review and tests.

I did something like:

mount -t debugfs debug /sys/kernel/debug
cd /sys/kernel/debug/tracing/
echo r:event1 vfs_read >> kprobe_events
echo r:event2 vfs_read %ax >> kprobe_events
echo r:event3 rw_verify_area %ax >> kprobe_events
echo 1 > events/kprobes/enable
sleep 1
less trace
cat ../kprobes/list
cd ~/linux/tools/testing/selftests/ftrace
./ftracetest

Then hits a BUG_ON at kernel/kprobes.c:1893 (no test executed, maybe
it happened when removing kretprobes?)

Thank you,

---

Masami Hiramatsu (17):
kprobes: Add generic kretprobe trampoline handler
x86/kprobes: Use generic kretprobe trampoline handler
arm: kprobes: Use generic kretprobe trampoline handler
arm64: kprobes: Use generic kretprobe trampoline handler
arc: kprobes: Use generic kretprobe trampoline handler
csky: kprobes: Use generic kretprobe trampoline handler
ia64: kprobes: Use generic kretprobe trampoline handler
mips: kprobes: Use generic kretprobe trampoline handler
parisc: kprobes: Use generic kretprobe trampoline handler
powerpc: kprobes: Use generic kretprobe trampoline handler
s390: kprobes: Use generic kretprobe trampoline handler
sh: kprobes: Use generic kretprobe trampoline handler
sparc: kprobes: Use generic kretprobe trampoline handler
kprobes: Remove NMI context check
kprobes: Free kretprobe_instance with rcu callback
kprobes: Make local used functions static
[RFC] kprobes: Remove task scan for updating kretprobe_instance

Peter Zijlstra (6):
llist: Add nonatomic __llist_add()
sched: Fix try_invoke_on_locked_down_task() semantics
kprobes: Remove kretprobe hash
asm-generic/atomic: Add try_cmpxchg() fallbacks
freelist: Lock less freelist
kprobes: Replace rp->free_instance with freelist


arch/arc/kernel/kprobes.c | 54 ------
arch/arm/probes/kprobes/core.c | 78 ---------
arch/arm64/kernel/probes/kprobes.c | 78 ---------
arch/csky/kernel/probes/kprobes.c | 77 --------
arch/ia64/kernel/kprobes.c | 77 --------
arch/mips/kernel/kprobes.c | 54 ------
arch/parisc/kernel/kprobes.c | 76 --------
arch/powerpc/kernel/kprobes.c | 53 ------
arch/s390/kernel/kprobes.c | 79 ---------
arch/sh/kernel/kprobes.c | 58 ------
arch/sparc/kernel/kprobes.c | 51 ------
arch/x86/include/asm/atomic.h | 2
arch/x86/include/asm/atomic64_64.h | 2
arch/x86/include/asm/cmpxchg.h | 2
arch/x86/kernel/kprobes/core.c | 108 ------------
drivers/gpu/drm/i915/i915_request.c | 6 -
include/asm-generic/atomic-instrumented.h | 216 ++++++++++++++----------
include/linux/atomic-arch-fallback.h | 90 +++++++++-
include/linux/atomic-fallback.h | 90 +++++++++-
include/linux/freelist.h | 129 ++++++++++++++
include/linux/kprobes.h | 73 +++++---
include/linux/llist.h | 15 ++
include/linux/sched.h | 4
kernel/fork.c | 4
kernel/kprobes.c | 263 +++++++++++++----------------
kernel/sched/core.c | 9 -
kernel/trace/trace_kprobe.c | 3
scripts/atomic/gen-atomic-fallback.sh | 63 ++++++-
scripts/atomic/gen-atomic-instrumented.sh | 29 +++
29 files changed, 729 insertions(+), 1114 deletions(-)
create mode 100644 include/linux/freelist.h

--
Masami Hiramatsu (Linaro) <mhiramat@kernel.org>

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