x86/dumpstack: Introduce die_addr() for die() with #GP fault address

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

Introduce a new function die_addr() that behaves like die(), but is for
faults only and uses __die_header() and __die_body() so that a future
commit can print extra information after the header line.

 [ bp: Comment the KASAN-specific usage of gp_addr. ]

Signed-off-by: Jann Horn <[email protected]>
Signed-off-by: Borislav Petkov <[email protected]>
Cc: Alexander Potapenko <[email protected]>
Cc: Andrey Konovalov <[email protected]>
Cc: Andrey Ryabinin <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: Dmitry Vyukov <[email protected]>
Cc: "Eric W. Biederman" <[email protected]>
Cc: "H. Peter Anvin" <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: [email protected]
Cc: Masami Hiramatsu <[email protected]>
Cc: "Peter Zijlstra (Intel)" <[email protected]>
Cc: Sean Christopherson <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: x86-ml <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

1 files changed, 8 insertions, 1 deletions

diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
index 108ab1ee069f..2afd7d8d4007 100644
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -619,7 +619,14 @@ dotraplinkage void do_general_protection(struct pt_regs *regs, long error_code)
 				 "maybe for address",
 				 gp_addr);
 
-		die(desc, regs, error_code);
+		/*
+		 * KASAN is interested only in the non-canonical case, clear it
+		 * otherwise.
+		 */
+		if (hint != GP_NON_CANONICAL)
+			gp_addr = 0;
+
+		die_addr(desc, regs, error_code, gp_addr);
 		return;
 	}