From: Oleg Nesterov Date: Sat, 19 Apr 2014 16:10:09 +0000 (+0200) Subject: uprobes/x86: Fix is_64bit_mm() with CONFIG_X86_X32 X-Git-Url: http://git.lede-project.org./?a=commitdiff_plain;h=b24dc8dace74708fd849312722090169c5da97d3;p=openwrt%2Fstaging%2Fblogic.git uprobes/x86: Fix is_64bit_mm() with CONFIG_X86_X32 is_64bit_mm() assumes that mm->context.ia32_compat means the 32-bit instruction set, this is not true if the task is TIF_X32. Change set_personality_ia32() to initialize mm->context.ia32_compat by TIF_X32 or TIF_IA32 instead of 1. This allows to fix is_64bit_mm() without affecting other users, they all treat ia32_compat as "bool". TIF_ in ->ia32_compat looks a bit strange, but this is grep-friendly and avoids the new define's. Signed-off-by: Oleg Nesterov Reviewed-by: Jim Keniston Acked-by: Srikar Dronamraju --- diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c index 9c0280f93d05..9b53940981b7 100644 --- a/arch/x86/kernel/process_64.c +++ b/arch/x86/kernel/process_64.c @@ -413,12 +413,11 @@ void set_personality_ia32(bool x32) set_thread_flag(TIF_ADDR32); /* Mark the associated mm as containing 32-bit tasks. */ - if (current->mm) - current->mm->context.ia32_compat = 1; - if (x32) { clear_thread_flag(TIF_IA32); set_thread_flag(TIF_X32); + if (current->mm) + current->mm->context.ia32_compat = TIF_X32; current->personality &= ~READ_IMPLIES_EXEC; /* is_compat_task() uses the presence of the x32 syscall bit flag to determine compat status */ @@ -426,6 +425,8 @@ void set_personality_ia32(bool x32) } else { set_thread_flag(TIF_IA32); clear_thread_flag(TIF_X32); + if (current->mm) + current->mm->context.ia32_compat = TIF_IA32; current->personality |= force_personality32; /* Prepare the first "return" to user space */ current_thread_info()->status |= TS_COMPAT; diff --git a/arch/x86/kernel/uprobes.c b/arch/x86/kernel/uprobes.c index 892975b3c99c..ecbffd16d090 100644 --- a/arch/x86/kernel/uprobes.c +++ b/arch/x86/kernel/uprobes.c @@ -245,7 +245,7 @@ static int uprobe_init_insn(struct arch_uprobe *auprobe, struct insn *insn, bool static inline bool is_64bit_mm(struct mm_struct *mm) { return !config_enabled(CONFIG_IA32_EMULATION) || - !mm->context.ia32_compat; + !(mm->context.ia32_compat == TIF_IA32); } /* * If arch_uprobe->insn doesn't use rip-relative addressing, return