Bug #20220: M:N threading needs to tell ASAN about stack switches

• Status: Closed
• Assignee: kjtsanaktsidis (KJ Tsanaktsidis)
• Target version: -
• Backport: 3.0: UNKNOWN, 3.1: UNKNOWN, 3.2: UNKNOWN, 3.3: UNKNOWN

[kjtsanaktsidis (KJ Tsanaktsidis)]

When switching stacks via coroutine_transfer in the M:N threading information, we need to tell ASAN about it in the same way that we do in cont.c. This is a matter of calling __sanitizer_start_switch_fiber in the transferring M:N thread, and then calling __sanitizer_finish_switch_fiber in the transferred-to M:N thread.

• Status changed from Open to Closed

Applied in changeset git|719db18b50a996f3df4f76854f7dc9d69f875582.

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notify ASAN about M:N threading stack switches

In a similar way to how we do it with fibers in cont.c, we need to call
__sanitize_start_switch_fiber and __sanitize_finish_switch_fiber around
the call to coroutine_transfer to let ASAN save & restore the fake stack
pointer.

When a M:N thread is exiting, we pass to_dead to the new
coroutine_transfer0 function, so that we can pass NULL for saving the
stack pointer. This signals to ASAN that the fake stack can be freed
(otherwise it would be leaked)

[Bug #20220]

[kjtsanaktsidis (KJ Tsanaktsidis)]

• Related to Misc #20387: Meta-ticket for ASAN support added