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uprobes/x86: Fix is_64bit_mm() with CONFIG_X86_X32

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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 <oleg@redhat.com>
Reviewed-by: Jim Keniston <jkenisto@us.ibm.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
This commit is contained in:
Oleg Nesterov 2014-04-19 18:10:09 +02:00
parent 8dbacad93a
commit b24dc8dace
2 changed files with 5 additions and 4 deletions
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7
arch/x86/kernel/process_64.c
View file

@ -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;

2
arch/x86/kernel/uprobes.c
View file

@ -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