diff options
| author | Masami Hiramatsu <mhiramat@kernel.org> | 2017-09-19 13:02:20 +0300 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2017-09-28 10:25:50 +0300 |
| commit | a19b2e3d783964d48d2b494439648e929bcdc976 (patch) | |
| tree | e9937278cf4c1555e28853edbfdb0c6de25ff68d /arch/x86/kernel/kprobes/ftrace.c | |
| parent | 5bb4fc2d8641219732eb2bb654206775a4219aca (diff) | |
| download | linux-a19b2e3d783964d48d2b494439648e929bcdc976.tar.xz | |
kprobes/x86: Remove IRQ disabling from ftrace-based/optimized kprobes
Kkprobes don't need to disable IRQs if they are called from the
ftrace/jump trampoline code, because Documentation/kprobes.txt says:
-----
Probe handlers are run with preemption disabled. Depending on the
architecture and optimization state, handlers may also run with
interrupts disabled (e.g., kretprobe handlers and optimized kprobe
handlers run without interrupt disabled on x86/x86-64).
-----
So let's remove IRQ disabling from those handlers.
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Alexei Starovoitov <ast@fb.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E . McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/150581534039.32348.11331736206004264553.stgit@devbox
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/kernel/kprobes/ftrace.c')
| -rw-r--r-- | arch/x86/kernel/kprobes/ftrace.c | 9 |
1 files changed, 2 insertions, 7 deletions
diff --git a/arch/x86/kernel/kprobes/ftrace.c b/arch/x86/kernel/kprobes/ftrace.c index bcfee4f69b0e..8dc0161cec8f 100644 --- a/arch/x86/kernel/kprobes/ftrace.c +++ b/arch/x86/kernel/kprobes/ftrace.c @@ -61,14 +61,11 @@ void kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip, { struct kprobe *p; struct kprobe_ctlblk *kcb; - unsigned long flags; - - /* Disable irq for emulating a breakpoint and avoiding preempt */ - local_irq_save(flags); + /* Preempt is disabled by ftrace */ p = get_kprobe((kprobe_opcode_t *)ip); if (unlikely(!p) || kprobe_disabled(p)) - goto end; + return; kcb = get_kprobe_ctlblk(); if (kprobe_running()) { @@ -91,8 +88,6 @@ void kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip, * resets current kprobe, and keep preempt count +1. */ } -end: - local_irq_restore(flags); } NOKPROBE_SYMBOL(kprobe_ftrace_handler); |