x86/dumpstack: Add a show_ip() function

... which shows the Instruction Pointer along with the insn bytes around
it. Use it whenever rIP is printed. Drop the rIP < PAGE_OFFSET check since
probe_kernel_read() can handle any address properly.

Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Link: https://lkml.kernel.org/r/20180417161124.5294-8-bp@alien8.de

diff --git a/arch/x86/include/asm/stacktrace.h b/arch/x86/include/asm/stacktrace.h
index 0630eeb18bbc51e5ba943bfffae7363b913e4989..b6dc698f992a54646266ba7a4dc2901e7bdfa109 100644 (file)
--- a/arch/x86/include/asm/stacktrace.h
+++ b/arch/x86/include/asm/stacktrace.h
@@ -112,4 +112,5 @@ static inline unsigned long caller_frame_pointer(void)
 }
 
 void show_opcodes(u8 *rip, const char *loglvl);
+void show_ip(struct pt_regs *regs, const char *loglvl);
 #endif /* _ASM_X86_STACKTRACE_H */

diff --git a/arch/x86/kernel/dumpstack.c b/arch/x86/kernel/dumpstack.c
index 1592d0c3ebb5dc7efacb35a84c51f06cd83956a6..82da808b5c3686315a3064fe373300fe7ffe3b33 100644 (file)
--- a/arch/x86/kernel/dumpstack.c
+++ b/arch/x86/kernel/dumpstack.c
@@ -94,9 +94,19 @@ void show_opcodes(u8 *rip, const char *loglvl)
        pr_cont("\n");
 }
 
+void show_ip(struct pt_regs *regs, const char *loglvl)
+{
+#ifdef CONFIG_X86_32
+       printk("%sEIP: %pS\n", loglvl, (void *)regs->ip);
+#else
+       printk("%sRIP: %04x:%pS\n", loglvl, (int)regs->cs, (void *)regs->ip);
+#endif
+       show_opcodes((u8 *)regs->ip, loglvl);
+}
+
 void show_iret_regs(struct pt_regs *regs)
 {
-       printk(KERN_DEFAULT "RIP: %04x:%pS\n", (int)regs->cs, (void *)regs->ip);
+       show_ip(regs, KERN_DEFAULT);
        printk(KERN_DEFAULT "RSP: %04x:%016lx EFLAGS: %08lx", (int)regs->ss,
                regs->sp, regs->flags);
 }
@@ -392,15 +402,8 @@ void show_regs(struct pt_regs *regs)
        __show_regs(regs, all);
 
        /*
-        * When in-kernel, we also print out the stack and code at the
-        * time of the fault..
+        * When in-kernel, we also print out the stack at the time of the fault..
         */
-       if (!user_mode(regs)) {
+       if (!user_mode(regs))
                show_trace_log_lvl(current, regs, NULL, KERN_DEFAULT);
-
-               if (regs->ip < PAGE_OFFSET)
-                       printk(KERN_DEFAULT "Code: Bad RIP value.\n");
-               else
-                       show_opcodes((u8 *)regs->ip, KERN_DEFAULT);
-       }
 }

diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c
index 5224c609918416337b97440eb2d515d8052463ae..0ae659de21eb241313e667321cd47c75cb3a148a 100644 (file)
--- a/arch/x86/kernel/process_32.c
+++ b/arch/x86/kernel/process_32.c
@@ -76,16 +76,14 @@ void __show_regs(struct pt_regs *regs, int all)
                savesegment(gs, gs);
        }
 
-       printk(KERN_DEFAULT "EIP: %pS\n", (void *)regs->ip);
-       printk(KERN_DEFAULT "EFLAGS: %08lx CPU: %d\n", regs->flags,
-               raw_smp_processor_id());
+       show_ip(regs, KERN_DEFAULT);
 
        printk(KERN_DEFAULT "EAX: %08lx EBX: %08lx ECX: %08lx EDX: %08lx\n",
                regs->ax, regs->bx, regs->cx, regs->dx);
        printk(KERN_DEFAULT "ESI: %08lx EDI: %08lx EBP: %08lx ESP: %08lx\n",
                regs->si, regs->di, regs->bp, sp);
-       printk(KERN_DEFAULT " DS: %04x ES: %04x FS: %04x GS: %04x SS: %04x\n",
-              (u16)regs->ds, (u16)regs->es, (u16)regs->fs, gs, ss);
+       printk(KERN_DEFAULT "DS: %04x ES: %04x FS: %04x GS: %04x SS: %04x EFLAGS: %08lx\n",
+              (u16)regs->ds, (u16)regs->es, (u16)regs->fs, gs, ss, regs->flags);
 
        if (!all)
                return;