diff options
Diffstat (limited to 'arch/x86/kernel/step.c')
| -rw-r--r-- | arch/x86/kernel/step.c | 15 |
1 files changed, 11 insertions, 4 deletions
diff --git a/arch/x86/kernel/step.c b/arch/x86/kernel/step.c index 60d2c3798ba2..3e2952679b88 100644 --- a/arch/x86/kernel/step.c +++ b/arch/x86/kernel/step.c @@ -6,7 +6,9 @@ #include <linux/sched/task_stack.h> #include <linux/mm.h> #include <linux/ptrace.h> + #include <asm/desc.h> +#include <asm/debugreg.h> #include <asm/mmu_context.h> unsigned long convert_ip_to_linear(struct task_struct *child, struct pt_regs *regs) @@ -127,12 +129,17 @@ static int enable_single_step(struct task_struct *child) regs->flags |= X86_EFLAGS_TF; /* - * Always set TIF_SINGLESTEP - this guarantees that - * we single-step system calls etc.. This will also + * Always set TIF_SINGLESTEP. This will also * cause us to set TF when returning to user mode. */ set_tsk_thread_flag(child, TIF_SINGLESTEP); + /* + * Ensure that a trap is triggered once stepping out of a system + * call prior to executing any user instruction. + */ + set_task_syscall_work(child, SYSCALL_EXIT_TRAP); + oflags = regs->flags; /* Set TF on the kernel stack.. */ @@ -175,8 +182,7 @@ void set_task_blockstep(struct task_struct *task, bool on) * * NOTE: this means that set/clear TIF_BLOCKSTEP is only safe if * task is current or it can't be running, otherwise we can race - * with __switch_to_xtra(). We rely on ptrace_freeze_traced() but - * PTRACE_KILL is not safe. + * with __switch_to_xtra(). We rely on ptrace_freeze_traced(). */ local_irq_disable(); debugctl = get_debugctlmsr(); @@ -230,6 +236,7 @@ void user_disable_single_step(struct task_struct *child) /* Always clear TIF_SINGLESTEP... */ clear_tsk_thread_flag(child, TIF_SINGLESTEP); + clear_task_syscall_work(child, SYSCALL_EXIT_TRAP); /* But touch TF only if it was set by us.. */ if (test_and_clear_tsk_thread_flag(child, TIF_FORCED_TF)) |