From 47508cbfd8f4a503e7145ca5a677670f84ef98d4 Mon Sep 17 00:00:00 2001 From: Michael Holzheu Date: Thu, 17 Dec 2015 19:06:02 +0100 Subject: s390/dis: Fix handling of format specifiers commit 272fa59ccb4fc802af28b1d699c2463db6a71bf7 upstream. The print_insn() function returns strings like "lghi %r1,0". To escape the '%' character in sprintf() a second '%' is used. For example "lghi %%r1,0" is converted into "lghi %r1,0". After print_insn() the output string is passed to printk(). Because format specifiers like "%r" or "%f" are ignored by printk() this works by chance most of the time. But for instructions with control registers like "lctl %c6,%c6,780" this fails because printk() interprets "%c" as character format specifier. Fix this problem and escape the '%' characters twice. For example "lctl %%%%c6,%%%%c6,780" is then converted by sprintf() into "lctl %%c6,%%c6,780" and by printk() into "lctl %c6,%c6,780". Signed-off-by: Michael Holzheu Signed-off-by: Martin Schwidefsky [ luis: backported to 3.16: - drop condition with OPERAND_VR introduced only with commit 3585cb028065 ("s390/disassembler: add vector instructions") ] Signed-off-by: Luis Henriques --- arch/s390/kernel/dis.c | 15 +++++++++++---- 1 file changed, 11 insertions(+), 4 deletions(-) (limited to 'arch/s390') diff --git a/arch/s390/kernel/dis.c b/arch/s390/kernel/dis.c index 993efe6a887c..3d942314818b 100644 --- a/arch/s390/kernel/dis.c +++ b/arch/s390/kernel/dis.c @@ -1726,14 +1726,21 @@ static int print_insn(char *buffer, unsigned char *code, unsigned long addr) } if (separator) ptr += sprintf(ptr, "%c", separator); + /* + * Use four '%' characters below because of the + * following two conversions: + * + * 1) sprintf: %%%%r -> %%r + * 2) printk : %%r -> %r + */ if (operand->flags & OPERAND_GPR) - ptr += sprintf(ptr, "%%r%i", value); + ptr += sprintf(ptr, "%%%%r%i", value); else if (operand->flags & OPERAND_FPR) - ptr += sprintf(ptr, "%%f%i", value); + ptr += sprintf(ptr, "%%%%f%i", value); else if (operand->flags & OPERAND_AR) - ptr += sprintf(ptr, "%%a%i", value); + ptr += sprintf(ptr, "%%%%a%i", value); else if (operand->flags & OPERAND_CR) - ptr += sprintf(ptr, "%%c%i", value); + ptr += sprintf(ptr, "%%%%c%i", value); else if (operand->flags & OPERAND_PCREL) ptr += sprintf(ptr, "%lx", (signed int) value + addr); -- cgit v1.2.3