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Commit 1ee1184485df9c9a3503d3a684b911fb7c73d259

Authored by Oleg Nesterov
Committed by Linus Torvalds
1 parent 95a3540da9
Exists in master and in 7 other branches imx_3.0.35_4.1.0, imx_3.10.17_1.0.1_ga, imx_3.10.53_1.1.0_ga, imx_3.14.28_1.0.0_ga, smarc-imx_3.10.53_1.1.0_ga, smarc-imx_3.14.28_1.0.0_ga, smarc-l5.0.0_1.0.0-ga

ptrace_untrace: fix the SIGNAL_STOP_STOPPED check 

This bug is ancient too. ptrace_untrace() must not resume the task
if the group stop in progress, we should set TASK_STOPPED instead.

Unfortunately, we still have problems here:

	- if the process/thread was traced, SIGNAL_STOP_STOPPED
	  does not necessary means this thread group is stopped.

	- ptrace breaks the bookkeeping of ->group_stop_count.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Jerome Marchand <jmarchan@redhat.com>
Cc: Roland McGrath <roland@redhat.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Showing 1 changed file with 7 additions and 3 deletions Side-by-side Diff

... ... @@ -60,11 +60,15 @@
60 60 {
61 61 spin_lock(&child->sighand->siglock);
62 62 if (task_is_traced(child)) {
63   - if (child->signal->flags & SIGNAL_STOP_STOPPED) {
  63 + /*
  64 + * If the group stop is completed or in progress,
  65 + * this thread was already counted as stopped.
  66 + */
  67 + if (child->signal->flags & SIGNAL_STOP_STOPPED ||
  68 + child->signal->group_stop_count)
64 69 __set_task_state(child, TASK_STOPPED);
65   - } else {
  70 + else
66 71 signal_wake_up(child, 1);
67   - }
68 72 }
69 73 spin_unlock(&child->sighand->siglock);
70 74 }