From: Florian Weimer <fweimer@redhat.com>
To: Adhemerval Zanella via Libc-alpha <libc-alpha@sourceware.org>
Subject: Re: [PATCH v4 1/5] support: Add support_stack_alloc
Date: Wed, 10 Mar 2021 17:10:37 +0100 [thread overview]
Message-ID: <875z1zrnuq.fsf@oldenburg.str.redhat.com> (raw)
In-Reply-To: <20210310152633.3916978-1-adhemerval.zanella@linaro.org> (Adhemerval Zanella via Libc-alpha's message of "Wed, 10 Mar 2021 12:26:29 -0300")
* Adhemerval Zanella via Libc-alpha:
> + /* Use MAP_NORESERVE so that RAM will not be wasted on the guard
> + bands; touch all the pages of the actual stack before returning,
> + so we know they are allocated. */
> + void *alloc_base = xmmap (0,
> + alloc_size,
> + PROT_READ|PROT_WRITE,
> + MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE|MAP_STACK,
> + -1);
> + xmprotect (alloc_base, guardsize, PROT_NONE);
> + xmprotect (alloc_base + guardsize + stacksize, guardsize, PROT_NONE);
The usual pattern is to map with PROT_NONE and then use
PROT_READ|PROT_WRITE with mprotect.
Rest looks okay, thanks.
Florian
next prev parent reply other threads:[~2021-03-10 16:10 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-10 15:26 Adhemerval Zanella
2021-03-10 15:26 ` [PATCH v4 2/5] support: Add xclone Adhemerval Zanella
2021-03-10 15:26 ` [PATCH v4 3/5] Linux: Add close_range Adhemerval Zanella
2021-03-24 22:42 ` Alyssa Ross
2021-03-10 15:26 ` [PATCH v4 4/5] io: Add closefrom [BZ #10353] Adhemerval Zanella
2021-03-10 21:54 ` Joseph Myers
2021-03-11 11:24 ` Adhemerval Zanella
2021-03-10 15:26 ` [PATCH v4 5/5] posix: Add posix_spawn_file_actions_closefrom_np Adhemerval Zanella
2021-03-10 16:10 ` Florian Weimer [this message]
2021-03-12 13:24 ` [PATCH v4 1/5] support: Add support_stack_alloc Adhemerval Zanella
2021-03-12 13:35 ` Florian Weimer
2021-03-12 14:01 ` Adhemerval Zanella
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