From: Rich Felker <dalias@libc.org>
To: linux-kernel@vger.kernel.org
Cc: Thomas Gleixner <tglx@linutronix.de>,
Davidlohr Bueso <dave@stgolabs.net>,
Ingo Molnar <mingo@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Darren Hart <dvhart@linux.intel.com>,
Mel Gorman <mgorman@suse.de>,
Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
Greg Ungerer <gerg@uclinux.org>,
Geert Uytterhoeven <geert@linux-m68k.org>,
Yoshinori Sato <ysato@users.sourceforge.jp>
Subject: [PATCH] futex: fix shared futex operations on nommu
Date: Mon, 25 Apr 2016 21:03:03 -0400 [thread overview]
Message-ID: <20160426010303.GA3706@brightrain.aerifal.cx> (raw)
The shared get_futex_key code does not work on nommu, but is not
needed anyway because it's impossible for a given backing to have
multiple distinct virtual addresses on nommu. Simply disable these
code paths by refraining from setting FLAG_SHARED when CONFIG_MMU is
not enabled.
Signed-off-by: Rich Felker <dalias@libc.org>
---
kernel/futex.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/kernel/futex.c b/kernel/futex.c
index a5d2e74..ed6f475 100644
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -3131,8 +3131,10 @@ long do_futex(u32 __user *uaddr, int op, u32 val, ktime_t *timeout,
int cmd = op & FUTEX_CMD_MASK;
unsigned int flags = 0;
+#ifdef CONFIG_MMU
if (!(op & FUTEX_PRIVATE_FLAG))
flags |= FLAGS_SHARED;
+#endif
if (op & FUTEX_CLOCK_REALTIME) {
flags |= FLAGS_CLOCKRT;
--
2.8.1
next reply other threads:[~2016-04-26 1:03 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-04-26 1:03 Rich Felker [this message]
2016-04-26 9:55 ` Sebastian Andrzej Siewior
2016-04-26 15:53 ` Rich Felker
2016-04-26 16:11 ` Sebastian Andrzej Siewior
2016-04-26 16:27 ` Rich Felker
2016-04-26 22:27 ` Andrew Morton
2016-04-26 22:31 ` Rich Felker
2016-04-27 13:43 ` Thomas Gleixner
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