Fix module shutdown crash during ZTS JIT shutdown #10835
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Commit a211956 fixed a leak by adding a TSRM destructor for the JIT globals in ZTS mode. In case the main thread shuts down the TSRM, it will call all the destructors. The JIT globals destructor will be invoked, but will always access the main thread globals using JIT_G. This means that instead of freeing the JIT globals in the different threads, the one in the main thread is freed repeatedly over and over, crashing PHP. Fix it by always passing the pointer instead of relying on JIT_G.
saundefined
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Mar 13, 2023
Commit a211956 fixed a leak by adding a TSRM destructor for the JIT globals in ZTS mode. In case the main thread shuts down the TSRM, it will call all the destructors. The JIT globals destructor will be invoked, but will always access the main thread globals using JIT_G. This means that instead of freeing the JIT globals in the different threads, the one in the main thread is freed repeatedly over and over, crashing PHP. Fix it by always passing the pointer instead of relying on JIT_G. Closes GH-10835. (cherry picked from commit b3e28e2)
patrickallaert
pushed a commit
that referenced
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Mar 14, 2023
Commit a211956 fixed a leak by adding a TSRM destructor for the JIT globals in ZTS mode. In case the main thread shuts down the TSRM, it will call all the destructors. The JIT globals destructor will be invoked, but will always access the main thread globals using JIT_G. This means that instead of freeing the JIT globals in the different threads, the one in the main thread is freed repeatedly over and over, crashing PHP. Fix it by always passing the pointer instead of relying on JIT_G. Closes GH-10835. (cherry picked from commit b3e28e2)
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Commit a211956 fixed a leak by adding a TSRM destructor for the JIT globals in ZTS mode. In case the main thread shuts down the TSRM, it will call all the destructors. The JIT globals destructor will be invoked, but will always access the main thread globals using JIT_G. This means that instead of freeing the JIT globals in the different threads, the one in the main thread is freed repeatedly over and over, crashing PHP. Fix it by always passing the pointer instead of relying on JIT_G.
This can be triggered reliably even when opcache is on. The JIT does not need to be enabled, because the JIT globals are always constructed. To reproduce this locally, I used an Apache worker/event MPM, and send a lot of requests using ApacheBench. Eventually you'll see the segfaults in the error_log file. You can also crash it by stopping the Apache server. Other SAPIs might be affected as well.
This bug exists only in 8.1.17RC1, 8.2.4RC1 and master.
Discovered while working on #10737