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Commit b24dc8da authored by Oleg Nesterov's avatar Oleg Nesterov
Browse files

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: default avatarOleg Nesterov <oleg@redhat.com>
Reviewed-by: default avatarJim Keniston <jkenisto@us.ibm.com>
Acked-by: default avatarSrikar Dronamraju <srikar@linux.vnet.ibm.com>
parent 8dbacad9

arch/x86/kernel/process_64.c

+4 −3
Original line number Diff line number Diff line
@@ -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;

arch/x86/kernel/uprobes.c

+1 −1
Original line number Diff line number Diff line
@@ -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