ptrace: x86: change syscall_trace_leave() to rely on tracehook when stepping
Suggested by Roland. Unlike powepc, x86 always calls tracehook_report_syscall_exit(step) with step = 0, and sends the trap by hand. This results in unnecessary SIGTRAP when PTRACE_SINGLESTEP follows the syscall-exit stop. Change syscall_trace_leave() to pass the correct "step" argument to tracehook and remove the send_sigtrap() logic. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Roland McGrath <roland@redhat.com> Cc: <linux-arch@vger.kernel.org> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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@ -1767,29 +1767,22 @@ asmregparm long syscall_trace_enter(struct pt_regs *regs)
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asmregparm void syscall_trace_leave(struct pt_regs *regs)
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{
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bool step;
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if (unlikely(current->audit_context))
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audit_syscall_exit(AUDITSC_RESULT(regs->ax), regs->ax);
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if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT)))
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trace_sys_exit(regs, regs->ax);
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if (test_thread_flag(TIF_SYSCALL_TRACE))
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tracehook_report_syscall_exit(regs, 0);
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/*
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* If TIF_SYSCALL_EMU is set, we only get here because of
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* TIF_SINGLESTEP (i.e. this is PTRACE_SYSEMU_SINGLESTEP).
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* We already reported this syscall instruction in
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* syscall_trace_enter(), so don't do any more now.
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* syscall_trace_enter().
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*/
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if (unlikely(test_thread_flag(TIF_SYSCALL_EMU)))
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return;
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/*
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* If we are single-stepping, synthesize a trap to follow the
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* system call instruction.
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*/
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if (test_thread_flag(TIF_SINGLESTEP) &&
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tracehook_consider_fatal_signal(current, SIGTRAP))
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send_sigtrap(current, regs, 0, TRAP_BRKPT);
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step = unlikely(test_thread_flag(TIF_SINGLESTEP)) &&
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!test_thread_flag(TIF_SYSCALL_EMU);
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if (step || test_thread_flag(TIF_SYSCALL_TRACE))
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tracehook_report_syscall_exit(regs, step);
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}
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