Messages in this thread Patch in this message | | | Date | Tue, 24 Nov 2009 21:01:52 +0100 | From | Oleg Nesterov <> | Subject | [RFC,PATCH 07/14] ptrace: x86: change syscall_trace_leave() to rely on tracehook when stepping |
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(already in mm: ptrace-x86-change-syscall_trace_leave-to-rely-on-tracehook-when-stepping.patch)
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> ---
arch/x86/kernel/ptrace.c | 21 +++++++-------------- 1 file changed, 7 insertions(+), 14 deletions(-)
--- V1/arch/x86/kernel/ptrace.c~7_X86_CONVERT_SYSCALL_LEAVE 2009-11-24 19:52:11.000000000 +0100 +++ V1/arch/x86/kernel/ptrace.c 2009-11-24 19:52:12.000000000 +0100 @@ -1528,29 +1528,22 @@ asmregparm long syscall_trace_enter(stru asmregparm void syscall_trace_leave(struct pt_regs *regs) { + bool step; + if (unlikely(current->audit_context)) audit_syscall_exit(AUDITSC_RESULT(regs->ax), regs->ax); if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT))) trace_sys_exit(regs, regs->ax); - if (test_thread_flag(TIF_SYSCALL_TRACE)) - tracehook_report_syscall_exit(regs, 0); - /* * If TIF_SYSCALL_EMU is set, we only get here because of * TIF_SINGLESTEP (i.e. this is PTRACE_SYSEMU_SINGLESTEP). * We already reported this syscall instruction in - * syscall_trace_enter(), so don't do any more now. - */ - if (unlikely(test_thread_flag(TIF_SYSCALL_EMU))) - return; - - /* - * If we are single-stepping, synthesize a trap to follow the - * system call instruction. + * syscall_trace_enter(). */ - if (test_thread_flag(TIF_SINGLESTEP) && - tracehook_consider_fatal_signal(current, SIGTRAP)) - send_sigtrap(current, regs, 0, TRAP_BRKPT); + step = unlikely(test_thread_flag(TIF_SINGLESTEP)) && + !test_thread_flag(TIF_SYSCALL_EMU); + if (step || test_thread_flag(TIF_SYSCALL_TRACE)) + tracehook_report_syscall_exit(regs, step); }
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