From: "Ondřej Bílka" <neleai@seznam.cz>
To: libc-alpha@sourceware.org
Subject: Deadlock in signal safe functions.
Date: Sat, 11 Jul 2015 11:41:00 -0000 [thread overview]
Message-ID: <20150711114053.GA31011@domone> (raw)
Hi,
I realized that there is possible deadlock when we call any signal-safe
function in signal handler. Its quite simple.
1. Create two threads to force locking in _dl_fixup with
THREAD_GSCOPE_SET_FLAG ();
2. Send signal and and with handler calling unresolved function, say
mkdir.
This causes deadlock unless we implement locking as signal-safe
recursive mutex, which isn't recursive on x64.
I don't have reproducer yet as I don't know how to force enough lookups
to make this condition likely.
reply other threads:[~2015-07-11 11:41 UTC|newest]
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