Date: Mon, 15 Sep 2014 15:47:41 -0600 From: "Justin T. Gibbs" <gibbs@scsiguy.com> To: Konstantin Belousov <kostikbel@gmail.com> Cc: "Ivan A. Kosarev" <ivan@ivan-labs.com>, freebsd-current@freebsd.org Subject: Re: libthr and main thread stack size Message-ID: <FEB60EB5-546D-454D-AE62-B2483246E42C@scsiguy.com> In-Reply-To: <20140808112201.GC93733@kib.kiev.ua> References: <53E36E84.4060806@ivan-labs.com> <20140808052807.GB93733@kib.kiev.ua> <53E48B38.9010607@ivan-labs.com> <20140808112201.GC93733@kib.kiev.ua>
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[-- Attachment #1 --] On Aug 8, 2014, at 5:22 AM, Konstantin Belousov <kostikbel@gmail.com> wrote: … > Below is the patch which adds environment variable LIBPTHREAD_BIGSTACK_MAIN. > Setting it to any value results in the main thread stack left as is, and > other threads allocate stack below the area of RLIMIT_STACK. Try it. > I do not want to set this behaviour as default. Is there a reason this should not be the default? Looking at the getrlimit() page on the OpenGroup’s site they say: RLIMIT_STACK This is the maximum size of the initial thread's stack, in bytes. The implementation does not automatically grow the stack beyond this limit. If this limit is exceeded, SIGSEGV shall be generated for the thread. If the thread is blocking SIGSEGV, or the process is ignoring or catching SIGSEGV and has not made arrangements to use an alternate stack, the disposition of SIGSEGV shall be set to SIG_DFL before it is generated. Does posix say something different? I ran into this issue when debugging a segfault on Postgres when running an (arguably quite bogus) query that should have fit within both the configured stack rlimit and Postgres’ configured stack limit. The Postgres backend is really just single threaded, but happens to pull in libpthread due to the threading support in some of the libraries it uses. The segfault definitely violates POLA. — Justin [-- Attachment #2 --] -----BEGIN PGP SIGNATURE----- Comment: GPGTools - http://gpgtools.org iQEcBAEBAgAGBQJUF159AAoJED9n8CuvaSf4rikIAId5wOQQ2j3/kP6ilnInpmNp PH8YkuKrB2aWt7FFJkIw12VKMq75asmUPYz/Vxud/VAC73QMurrkWsxRowouHVO0 XLkJfcOwFtHOja0MmD5sGEgkShetv3yI2ZgjEQa0MXjI/rzxBCJQOviSNuVyH723 t3qtjnN72hj6QTSK39c0aoN9beXgjICDZkE+7PVuGO6m13dsJcqu2CqAfA9ycFKq qXo0G7iOFzM2QChXMO51Z9xz2hOnaqXmFY6iS3E0fVNlKNgzd8QMB0sLQvEajHbu 96N7QKp+JPMGObd+1pCzXqWuX3OCESMIqbNWKfolbgVV8qKMsGegws4CEPJ0ns4= =gypO -----END PGP SIGNATURE-----
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