From: Eric W. Biederman ebiederm@xmission.com
commit 4a3d2717d140401df7501a95e454180831a0c5af upstream.
xtensa is the last user of the PT_SINGLESTEP flag. Changing tsk->ptrace in user_enable_single_step and user_disable_single_step without locking could potentiallly cause problems.
So use a thread info flag instead of a flag in tsk->ptrace. Use TIF_SINGLESTEP that xtensa already had defined but unused.
Remove the definitions of PT_SINGLESTEP and PT_BLOCKSTEP as they have no more users.
Cc: stable@vger.kernel.org Acked-by: Max Filippov jcmvbkbc@gmail.com Tested-by: Kees Cook keescook@chromium.org Reviewed-by: Oleg Nesterov oleg@redhat.com Link: https://lkml.kernel.org/r/20220505182645.497868-4-ebiederm@xmission.com Signed-off-by: "Eric W. Biederman" ebiederm@xmission.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/xtensa/kernel/ptrace.c | 4 ++-- arch/xtensa/kernel/signal.c | 4 ++-- include/linux/ptrace.h | 6 ------ 3 files changed, 4 insertions(+), 10 deletions(-)
--- a/arch/xtensa/kernel/ptrace.c +++ b/arch/xtensa/kernel/ptrace.c @@ -226,12 +226,12 @@ const struct user_regset_view *task_user
void user_enable_single_step(struct task_struct *child) { - child->ptrace |= PT_SINGLESTEP; + set_tsk_thread_flag(child, TIF_SINGLESTEP); }
void user_disable_single_step(struct task_struct *child) { - child->ptrace &= ~PT_SINGLESTEP; + clear_tsk_thread_flag(child, TIF_SINGLESTEP); }
/* --- a/arch/xtensa/kernel/signal.c +++ b/arch/xtensa/kernel/signal.c @@ -473,7 +473,7 @@ static void do_signal(struct pt_regs *re /* Set up the stack frame */ ret = setup_frame(&ksig, sigmask_to_save(), regs); signal_setup_done(ret, &ksig, 0); - if (current->ptrace & PT_SINGLESTEP) + if (test_thread_flag(TIF_SINGLESTEP)) task_pt_regs(current)->icountlevel = 1;
return; @@ -499,7 +499,7 @@ static void do_signal(struct pt_regs *re /* If there's no signal to deliver, we just restore the saved mask. */ restore_saved_sigmask();
- if (current->ptrace & PT_SINGLESTEP) + if (test_thread_flag(TIF_SINGLESTEP)) task_pt_regs(current)->icountlevel = 1; return; } --- a/include/linux/ptrace.h +++ b/include/linux/ptrace.h @@ -46,12 +46,6 @@ extern int ptrace_access_vm(struct task_ #define PT_EXITKILL (PTRACE_O_EXITKILL << PT_OPT_FLAG_SHIFT) #define PT_SUSPEND_SECCOMP (PTRACE_O_SUSPEND_SECCOMP << PT_OPT_FLAG_SHIFT)
-/* single stepping state bits (used on ARM and PA-RISC) */ -#define PT_SINGLESTEP_BIT 31 -#define PT_SINGLESTEP (1<<PT_SINGLESTEP_BIT) -#define PT_BLOCKSTEP_BIT 30 -#define PT_BLOCKSTEP (1<<PT_BLOCKSTEP_BIT) - extern long arch_ptrace(struct task_struct *child, long request, unsigned long addr, unsigned long data); extern int ptrace_readdata(struct task_struct *tsk, unsigned long src, char __user *dst, int len);