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Addl loop prevention for traverse_parent_state #1414

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Merged
merged 2 commits into from
May 22, 2019
Merged

Addl loop prevention for traverse_parent_state #1414

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c925105
Addl loop prevention for traverse_parent_state
mstemm May 22, 2019
0e4c72f
Add more info to loop warning.
mstemm May 22, 2019
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16 changes: 11 additions & 5 deletions userspace/libsinsp/threadinfo.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -904,7 +904,8 @@ void sinsp_threadinfo::traverse_parent_state(visitor_func_t &visitor)
// Move fast to its parent
fast = (fast ? fast->get_parent_thread() : fast);

while(slow)
// The slow pointer must be valid and not have a tid of -1.
while(slow && slow->m_tid != -1)
{
if(!visitor(slow))
{
Expand All @@ -919,15 +920,20 @@ void sinsp_threadinfo::traverse_parent_state(visitor_func_t &visitor)
for (uint32_t i = 0; i < 2; i++) {
fast = (fast ? fast->get_parent_thread() : fast);

// If not at the end but fast == slow, there's a loop
// in the thread state.
if(slow && (slow == fast))
// If not at the end but fast == slow or if
// slow points to itself, there's a loop in
// the thread state.
if(slow && (slow == fast ||
slow->m_tid == slow->m_ptid))
{
// Note we only log a loop once for a given main thread, to avoid flooding logs.
if(!m_parent_loop_detected)
{
g_logger.log(string("Loop in parent thread state detected for pid ") +
std::to_string(m_pid), sinsp_logger::SEV_WARNING);
std::to_string(m_pid) +
". stopped at tid= " + std::to_string(slow->m_tid) +
" ptid=" + std::to_string(slow->m_ptid),
sinsp_logger::SEV_WARNING);
m_parent_loop_detected = true;
}
return;
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