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Date:   Mon,  9 Dec 2019 15:31:19 +0100
In-Reply-To: <20191209143120.60100-1-jannh@google.com>
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References: <20191209143120.60100-1-jannh@google.com>
Subject: [PATCH v6 3/4] x86/dumpstack: Split out header line printing from __die()
From:   Jann Horn <jannh@google.com>
To:     Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
        "H. Peter Anvin" <hpa@zytor.com>, x86@kernel.org,
        Andrey Ryabinin <aryabinin@virtuozzo.com>,
        Alexander Potapenko <glider@google.com>,
        Dmitry Vyukov <dvyukov@google.com>, kasan-dev@googlegroups.com,
        jannh@google.com
Cc:     linux-kernel@vger.kernel.org,
        Andrey Konovalov <andreyknvl@google.com>,
        Andy Lutomirski <luto@kernel.org>,
        Sean Christopherson <sean.j.christopherson@intel.com>
Content-Type: text/plain; charset="UTF-8"
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

Split __die() into __die_header() and __die_body(). This allows callers to
insert extra information below the header line that initiates the bug
report.

This can e.g. be used by __die() callers to allow KASAN to print additional
information below the header line of the bug report.

Signed-off-by: Jann Horn <jannh@google.com>
---

Notes:
    v3:
      new patch
    v4-v6:
      no changes

 arch/x86/include/asm/kdebug.h |  3 +++
 arch/x86/kernel/dumpstack.c   | 13 ++++++++++++-
 2 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/arch/x86/include/asm/kdebug.h b/arch/x86/include/asm/kdebug.h
index 75f1e35e7c15..a0050fabce42 100644
--- a/arch/x86/include/asm/kdebug.h
+++ b/arch/x86/include/asm/kdebug.h
@@ -33,6 +33,9 @@ enum show_regs_mode {
 };
 
 extern void die(const char *, struct pt_regs *,long);
+extern void __die_header(const char *str, struct pt_regs *regs, long err);
+extern int __must_check __die_body(const char *str, struct pt_regs *regs,
+				   long err);
 extern int __must_check __die(const char *, struct pt_regs *, long);
 extern void show_stack_regs(struct pt_regs *regs);
 extern void __show_regs(struct pt_regs *regs, enum show_regs_mode);
diff --git a/arch/x86/kernel/dumpstack.c b/arch/x86/kernel/dumpstack.c
index e07424e19274..6436f3f5f803 100644
--- a/arch/x86/kernel/dumpstack.c
+++ b/arch/x86/kernel/dumpstack.c
@@ -365,7 +365,7 @@ void oops_end(unsigned long flags, struct pt_regs *regs, int signr)
 }
 NOKPROBE_SYMBOL(oops_end);
 
-int __die(const char *str, struct pt_regs *regs, long err)
+void __die_header(const char *str, struct pt_regs *regs, long err)
 {
 	const char *pr = "";
 
@@ -384,7 +384,11 @@ int __die(const char *str, struct pt_regs *regs, long err)
 	       IS_ENABLED(CONFIG_KASAN)   ? " KASAN"           : "",
 	       IS_ENABLED(CONFIG_PAGE_TABLE_ISOLATION) ?
 	       (boot_cpu_has(X86_FEATURE_PTI) ? " PTI" : " NOPTI") : "");
+}
+NOKPROBE_SYMBOL(__die_header);
 
+int __die_body(const char *str, struct pt_regs *regs, long err)
+{
 	show_regs(regs);
 	print_modules();
 
@@ -394,6 +398,13 @@ int __die(const char *str, struct pt_regs *regs, long err)
 
 	return 0;
 }
+NOKPROBE_SYMBOL(__die_body);
+
+int __die(const char *str, struct pt_regs *regs, long err)
+{
+	__die_header(str, regs, err);
+	return __die_body(str, regs, err);
+}
 NOKPROBE_SYMBOL(__die);
 
 /*
-- 
2.24.0.393.g34dc348eaf-goog