From: Richard Weinberger <richard@nod.at>
To: user-mode-linux-devel@lists.sourceforge.net
Cc: linux-kernel@vger.kernel.org, miklos@szeredi.hu,
lftan@altera.com, arnd@arndb.de, geert@linux-m68k.org,
Richard Weinberger <richard@nod.at>
Subject: [PATCH] um: Skip futex_atomic_cmpxchg_inatomic() test
Date: Wed, 10 Dec 2014 14:02:15 +0100 [thread overview]
Message-ID: <1418216535-29295-1-git-send-email-richard@nod.at> (raw)
futex_atomic_cmpxchg_inatomic() does not work on UML because
it triggers a copy_from_user() in kernel context.
On UML copy_from_user() can only be used if the kernel was called
by a real user space process such that UML can use ptrace()
to fetch the value.
Reported-by: Miklos Szeredi <miklos@szeredi.hu>
Suggested-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Richard Weinberger <richard@nod.at>
---
arch/um/Kconfig.common | 1 +
1 file changed, 1 insertion(+)
diff --git a/arch/um/Kconfig.common b/arch/um/Kconfig.common
index 87bc868..d195a87 100644
--- a/arch/um/Kconfig.common
+++ b/arch/um/Kconfig.common
@@ -3,6 +3,7 @@ config UML
default y
select HAVE_ARCH_AUDITSYSCALL
select HAVE_UID16
+ select HAVE_FUTEX_CMPXCHG if FUTEX
select GENERIC_IRQ_SHOW
select GENERIC_CPU_DEVICES
select GENERIC_IO
--
2.1.0
next reply other threads:[~2014-12-10 13:02 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-12-10 13:02 Richard Weinberger [this message]
2014-12-15 10:27 ` [uml-devel] " Daniel Walter
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