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Re: [PATCH] [BZ #22637] Fix stack guard size accounting
- From: Florian Weimer <fw at deneb dot enyo dot de>
- To: libc-alpha at sourceware dot org
- Date: Mon, 15 Jan 2018 16:20:32 +0100
- Subject: Re: [PATCH] [BZ #22637] Fix stack guard size accounting
- Authentication-results: sourceware.org; auth=none
- References: <20180115150839.4EA504034FFAF@oldenburg.str.redhat.com>
* Florian Weimer:
> From: Szabolcs Nagy <szabolcs.nagy@arm.com>
>
> Previously if user requested S stack and G guard when creating a
> thread, the total mapping was S and the actual available stack was
> S - G - static_tls, which is not what the user requested.
>
> This patch fixes the guard size accounting by pretending the user
> requested S+G stack. This way all later logic works out except
> when reporting the user requested stack size (pthread_getattr_np)
> or when computing the minimal stack size (__pthread_get_minstack).
>
> Normally this will increase thread stack allocations by one page.
> TLS accounting is not affected, that will require a separate fix.
>
> [BZ #22637]
> * nptl/descr.h (stackblock, stackblock_size): Update comments.
> * nptl/allocatestack.c (allocate_stack): Add guardsize to stacksize.
> * nptl/nptl-init.c (__pthread_get_minstack): Remove guardsize from
> stacksize.
> * nptl/pthread_getattr_np.c (pthread_getattr_np): Likewise.
>
> (cherry picked from commit 630f4cc3aa019ede55976ea561f1a7af2f068639)
Please disregard. Should have gone to libc-stable.