From 0f55a2f3d496133dd22f1e4e49fb7301da87c7bb Mon Sep 17 00:00:00 2001 From: Masami Hiramatsu Date: Thu, 14 Oct 2010 12:10:18 +0900 Subject: [PATCH] kprobes: Update document about irq disabled state in kprobe handler Update kprobes.txt about interrupts disabled state inside kprobes handlers, because optimized probe/boosted kretprobe run without disabling interrrupts on x86. Signed-off-by: Masami Hiramatsu Cc: Rusty Russell Cc: Ananth N Mavinakayanahalli Cc: 2nddept-manager@sdl.hitachi.co.jp LKML-Reference: <20101014031018.4100.64883.stgit@ltc236.sdl.hitachi.co.jp> Signed-off-by: Ingo Molnar --- Documentation/kprobes.txt | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/Documentation/kprobes.txt b/Documentation/kprobes.txt index 1762b81fcdf2..741fe66d6eca 100644 --- a/Documentation/kprobes.txt +++ b/Documentation/kprobes.txt @@ -542,9 +542,11 @@ Kprobes does not use mutexes or allocate memory except during registration and unregistration. Probe handlers are run with preemption disabled. Depending on the -architecture, handlers may also run with interrupts disabled. In any -case, your handler should not yield the CPU (e.g., by attempting to -acquire a semaphore). +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). In any case, +your handler should not yield the CPU (e.g., by attempting to acquire +a semaphore). Since a return probe is implemented by replacing the return address with the trampoline's address, stack backtraces and calls -- 2.20.1