linux-kernel - [PATCH] x86/MCE: Cast rIP to respective width before printing

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Date:   Sat, 10 Feb 2018 15:53:14 +0100
From:   Borislav Petkov <bp@...en8.de>
To:     X86 ML <x86@...nel.org>
Cc:     Tony Luck <tony.luck@...el.com>,
        LKML <linux-kernel@...r.kernel.org>,
        Sergey Senozhatsky <sergey.senozhatsky.work@...il.com>
Subject: [PATCH] x86/MCE: Cast rIP to respective width before printing

From: Borislav Petkov <bp@...e.de>

7b6061627eb8 ("x86: do not use print_symbol()") got rid of
print_symbol() uses in favor of passing a %pS format specifier to
printk() in order to print "symbolic direct pointers with offset".

We use this to print the RIP as part of the MCE record. And %pS requires
a void *.

However, mce.ip is u64 and casting it to a void * on 32-bit rightfully
warns:

  arch/x86/kernel/cpu/mcheck/mce.c:237:21: warning: cast to pointer from integer \
	  of different size [-Wint-to-pointer-cast]
      pr_cont("{%pS}", (void *)m->ip);
                       ^

about the size mismatch.

So cast the RIP to the machine-specific unsigned long address width
first.

Signed-off-by: Borislav Petkov <bp@...e.de>
Cc: Sergey Senozhatsky <sergey.senozhatsky.work@...il.com>
Fixes: 7b6061627eb8 ("x86: do not use print_symbol()")
---
 arch/x86/kernel/cpu/mcheck/mce.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kernel/cpu/mcheck/mce.c b/arch/x86/kernel/cpu/mcheck/mce.c
index 3a8e88a611eb..75f405ac085c 100644
--- a/arch/x86/kernel/cpu/mcheck/mce.c
+++ b/arch/x86/kernel/cpu/mcheck/mce.c
@@ -234,7 +234,7 @@ static void __print_mce(struct mce *m)
 			m->cs, m->ip);
 
 		if (m->cs == __KERNEL_CS)
-			pr_cont("{%pS}", (void *)m->ip);
+			pr_cont("{%pS}", (void *)(unsigned long)m->ip);
 		pr_cont("\n");
 	}
 
-- 
2.13.0