From: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Date: Fri, 4 Oct 2019 19:04:13 +0000 (-0400)
Subject: Fix: fd tracker: provide async-signal-safety for close wrapper
X-Git-Tag: v2.11.0-rc5~4
X-Git-Url: http://git.liburcu.org/?a=commitdiff_plain;h=8ca5fb48f84862619c4b780beaf37b347494b372;hp=8ca5fb48f84862619c4b780beaf37b347494b372;p=lttng-ust.git

Fix: fd tracker: provide async-signal-safety for close wrapper

close(3) is part of the async-signal-safe functions. Therefore, it is
expected that the close wrapper provided by liblttng-ust-fd-tracker
behaves in a async-signal-safe way.

Use a similar strategy as ust_lock() does: disable signals when taking
and releasing the lock, and keep track of nesting with a TLS variable.
This ensures signals are restored to their original state when close(3)
ends up being invoked.

Fixes: #1199
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
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