The patch titled
ptrace: x86: change syscall_trace_leave() to rely on tracehook when stepping
has been added to the -mm tree. Its filename is
ptrace-x86-change-syscall_trace_leave-to-rely-on-tracehook-when-stepping.patch
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------------------------------------------------------
Subject: ptrace: x86: change syscall_trace_leave() to rely on tracehook when stepping
From: Oleg Nesterov <oleg@xxxxxxxxxx>
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@xxxxxxxxxx>
Acked-by: Roland McGrath <roland@xxxxxxxxxx>
Cc: <linux-arch@xxxxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
arch/x86/kernel/ptrace.c | 21 +++++++--------------
1 file changed, 7 insertions(+), 14 deletions(-)
diff -puN arch/x86/kernel/ptrace.c~ptrace-x86-change-syscall_trace_leave-to-rely-on-tracehook-when-stepping arch/x86/kernel/ptrace.c
--- a/arch/x86/kernel/ptrace.c~ptrace-x86-change-syscall_trace_leave-to-rely-on-tracehook-when-stepping
+++ a/arch/x86/kernel/ptrace.c
@@ -1640,29 +1640,22 @@ 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);
}
_
Patches currently in -mm which might be from oleg@xxxxxxxxxx are
origin.patch
linux-next.patch
itimers-fix-racy-writes-to-cpu_itimer-fields.patch
posix-cpu-timers-optimize-and-document-timer_create-callback.patch
ptrace-cleanup-ptrace_init_task-ptrace_link-path.patch
ptrace-copy_process-should-disable-stepping.patch
ptrace-introduce-user_single_step_siginfo-helper.patch
ptrace-powerpc-implement-user_single_step_siginfo.patch
ptrace-change-tracehook_report_syscall_exit-to-handle-stepping.patch
ptrace-x86-implement-user_single_step_siginfo.patch
ptrace-x86-change-syscall_trace_leave-to-rely-on-tracehook-when-stepping.patch
signals-send_sig_noinfo-should-be-considered-as-si_fromuser.patch
signals-send_signal-use-si_fromuser-to-detect-from_ancestor_ns.patch
signals-cosmetic-collect_signal-use-si_user.patch
signals-kill-force_sig_specific.patch
signals-check-group_stop_count-after-tracehook_get_signal.patch
utrace-core.patch
do_wait-optimization-do-not-place-sub-threads-on-task_struct-children-list.patch
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