linux-kernel - [PATCH] x86/kprobe: unbalanced preempt counter in kprobe_{fault,debug}

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Date:   Mon, 15 Jan 2018 12:28:28 +0800
From:   Yang Bo <yangbo@...pin.com>
To:     Thomas Gleixner <tglx@...utronix.de>
Cc:     Ingo Molnar <mingo@...hat.com>, "H. Peter Anvin" <hpa@...or.com>,
        x86@...nel.org, Masami Hiramatsu <mhiramat@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Laura Abbott <labbott@...hat.com>,
        linux-kernel@...r.kernel.org, Yang Bo <yangbo@...pin.com>
Subject: [PATCH] x86/kprobe: unbalanced preempt counter in kprobe_{fault,debug}_handler

Don't see any preempt_disable() in do_debug() and do_page_fault(),
there is no need to call preempt_enable_no_resched() here.

Signed-off-by: Yang Bo <yangbo@...pin.com>
---
 arch/x86/kernel/kprobes/core.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c
index 1ea5c9caa8f1..6f2c43e33674 100644
--- a/arch/x86/kernel/kprobes/core.c
+++ b/arch/x86/kernel/kprobes/core.c
@@ -969,7 +969,6 @@ int kprobe_debug_handler(struct pt_regs *regs)
 	}
 	reset_current_kprobe();
 out:
-	preempt_enable_no_resched();
 
 	/*
 	 * if somebody else is singlestepping across a probe point, flags
@@ -1017,7 +1016,6 @@ int kprobe_fault_handler(struct pt_regs *regs, int trapnr)
 			restore_previous_kprobe(kcb);
 		else
 			reset_current_kprobe();
-		preempt_enable_no_resched();
 	} else if (kcb->kprobe_status == KPROBE_HIT_ACTIVE ||
 		   kcb->kprobe_status == KPROBE_HIT_SSDONE) {
 		/*
-- 
2.15.1