linux-kernel - [RESEND PATCH tip] x86/idt: Remove X86_TRAP_BP initialization in idt_setup

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Message-ID: <20171108192845.552709-1-yhs@fb.com>
Date:   Wed, 8 Nov 2017 11:28:45 -0800
From:   Yonghong Song <yhs@...com>
To:     <mingo@...nel.org>, <tglx@...utronix.de>, <oleg@...hat.com>,
        <luto@...nel.org>, <hpa@...or.com>, <a.p.zijlstra@...llo.nl>,
        <linux-kernel@...r.kernel.org>, <x86@...nel.org>, <ast@...com>
CC:     <kernel-team@...com>
Subject: [RESEND PATCH tip] x86/idt: Remove X86_TRAP_BP initialization in idt_setup_traps()

Commit b70543a0b2b6("x86/idt: Move regular trap init to tables")
moves regular trap init for each trap vector into a table based
initialization. It introduced the initialization for vector
X86_TRAP_BP which was not in the original change and it breaks
uprobe functionality for x86_32. A program with uprobe
instrumented can have segfault on x86_32 instead of normal finish.
Uprobe still works on x86_64 even with this commit.

This patch removes X86_TRAP_BP from the structure def_idts
which is used in idt_setup_traps(). It also removes a redundant
entry for X86_TRAP_NMI in def_idts. Tested on both x86_64 and x86_32,
uprobe works fine.

Fixes: b70543a0b2b6("x86/idt: Move regular trap init to tables")
Reported-and-tested-by: Yonghong Song <yhs@...com>
Signed-off-by: Yonghong Song <yhs@...com>
---
 arch/x86/kernel/idt.c | 2 --
 1 file changed, 2 deletions(-)

[RESEND with adding linux-kernel@...r.kernel.org as the recipient.]

diff --git a/arch/x86/kernel/idt.c b/arch/x86/kernel/idt.c
index 723fa97..d985cef 100644
--- a/arch/x86/kernel/idt.c
+++ b/arch/x86/kernel/idt.c
@@ -92,8 +92,6 @@ static const __initdata struct idt_data def_idts[] = {
 	INTG(X86_TRAP_DF,		double_fault),
 #endif
 	INTG(X86_TRAP_DB,		debug),
-	INTG(X86_TRAP_NMI,		nmi),
-	INTG(X86_TRAP_BP,		int3),

 #ifdef CONFIG_X86_MCE
 	INTG(X86_TRAP_MC,		&machine_check),
-- 
2.9.5