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RedisPipeline ignore flush when call dtor from another thread. #736

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Merged
liuh-80 merged 2 commits into from
Jan 11, 2023
Merged

RedisPipeline ignore flush when call dtor from another thread. #736

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7e257ee
RedisPipeline ignore flush when call dtor from another thread.
liuh-80 Jan 9, 2023
c29788a
Add notice log in dtor
liuh-80 Jan 10, 2023
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18 changes: 17 additions & 1 deletion common/redispipeline.h
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Original file line number Diff line number Diff line change
Expand Up @@ -7,6 +7,10 @@
#include "rediscommand.h"
#include "dbconnector.h"

#include "unistd.h"
#include "sys/syscall.h"
#define gettid() syscall(SYS_gettid)
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@liuh-80 liuh-80 Jan 9, 2023

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there is no wrapper for gettid() in glibc <= 2.30, so we need use syscall(SYS_gettid)


namespace swss {

class RedisPipeline {
Expand All @@ -19,10 +23,16 @@ class RedisPipeline {
, m_remaining(0)
{
m_db = db->newConnector(NEWCONNECTOR_TIMEOUT);
initializeOwnerTid();
}

~RedisPipeline() {
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@qiluo-msft qiluo-msft Jan 9, 2023 •
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RedisPipeline

Thanks for fixing the bug. It is from the design that DBConnector could be used only in one thread. Do you find similar issues in other classes in swss-common? #Closed

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@liuh-80 liuh-80 Jan 10, 2023

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No, I check all dtor in swss-common only find RedisPipeline class run redis command in dtor.

flush();
if (m_ownerTid == gettid())
{
// call flush from different thread will trigger race condition issue.
flush();
}
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@qiluo-msft qiluo-msft Jan 9, 2023 •
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}

Add a notice logging in else branch. The message could be "RedisPipeline dtor is called from another thread, possibly due to exit()" #Closed

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@liuh-80 liuh-80 Jan 10, 2023

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Fixed


delete m_db;
}

Expand Down Expand Up @@ -125,10 +135,16 @@ class RedisPipeline {
return m_db;
}

void initializeOwnerTid()
{
m_ownerTid = gettid();
}

private:
DBConnector *m_db;
std::queue<int> m_expectedTypes;
size_t m_remaining;
long int m_ownerTid;

void mayflush()
{
Expand Down