linux-toradex.git/include/asm-generic/futex.h, branch v4.4.44

asm-generic/futex: Re-enable preemption in futex_atomic_cmpxchg_inatomic()

2016-05-04T21:48:43+00:00

commit fba7cd681b6155e2d93e7862fcd6f970336b83c3 upstream.

The recent decoupling of pagefault disable and preempt disable added an
explicit preempt_disable/enable() pair to the futex_atomic_cmpxchg_inatomic()
implementation in asm-generic/futex.h. But it forgot to add preempt_enable()
calls to the error handling code pathes, which results in a preemption count
imbalance.

This is observable on boot when the test for atomic_cmpxchg() is calling
futex_atomic_cmpxchg_inatomic() on a NULL pointer.

Add the missing preempt_enable() calls to the error handling code pathes.

[ tglx: Massaged changelog ]

Fixes: d9b9ff8c1889 ("sched/preempt, futex: Disable preemption in UP futex_atomic_cmpxchg_inatomic() explicitly")
Signed-off-by: Romain Perier 
Cc: linux-arch@vger.kernel.org
Cc: Thomas Petazzoni 
Cc: Arnd Bergmann 
Cc: Peter Zijlstra 
Link: http://lkml.kernel.org/r/1460640963-690-1-git-send-email-romain.perier@free-electrons.com
Signed-off-by: Thomas Gleixner 
Signed-off-by: Greg Kroah-Hartman

sched/preempt, futex: Disable preemption in UP futex_atomic_cmpxchg_inatomic() explicitly

2015-05-19T06:39:16+00:00

Let's explicitly disable/enable preemption in the !CONFIG_SMP version
of futex_atomic_cmpxchg_inatomic(), to prepare for pagefault_disable() not
touching preemption anymore. This is needed for this function to be
callable from both, atomic and non-atomic context.

Otherwise we might break mutual exclusion when relying on a get_user()/
put_user() implementation.

Reviewed-and-tested-by: Thomas Gleixner 
Signed-off-by: David Hildenbrand 
Signed-off-by: Peter Zijlstra (Intel) 
Cc: David.Laight@ACULAB.COM
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: airlied@linux.ie
Cc: akpm@linux-foundation.org
Cc: benh@kernel.crashing.org
Cc: bigeasy@linutronix.de
Cc: borntraeger@de.ibm.com
Cc: daniel.vetter@intel.com
Cc: heiko.carstens@de.ibm.com
Cc: herbert@gondor.apana.org.au
Cc: hocko@suse.cz
Cc: hughd@google.com
Cc: mst@redhat.com
Cc: paulus@samba.org
Cc: ralf@linux-mips.org
Cc: schwidefsky@de.ibm.com
Cc: yang.shi@windriver.com
Link: http://lkml.kernel.org/r/1431359540-32227-10-git-send-email-dahi@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar

sched/preempt, futex: Disable preemption in UP futex_atomic_op_inuser() explicitly

2015-05-19T06:39:16+00:00

Let's explicitly disable/enable preemption in the !CONFIG_SMP version
of futex_atomic_op_inuser, to prepare for pagefault_disable() not
touching preemption anymore.

Otherwise we might break mutual exclusion when relying on a get_user()/
put_user() implementation.

Reviewed-and-tested-by: Thomas Gleixner 
Signed-off-by: David Hildenbrand 
Signed-off-by: Peter Zijlstra (Intel) 
Cc: David.Laight@ACULAB.COM
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: airlied@linux.ie
Cc: akpm@linux-foundation.org
Cc: benh@kernel.crashing.org
Cc: bigeasy@linutronix.de
Cc: borntraeger@de.ibm.com
Cc: daniel.vetter@intel.com
Cc: heiko.carstens@de.ibm.com
Cc: herbert@gondor.apana.org.au
Cc: hocko@suse.cz
Cc: hughd@google.com
Cc: mst@redhat.com
Cc: paulus@samba.org
Cc: ralf@linux-mips.org
Cc: schwidefsky@de.ibm.com
Cc: yang.shi@windriver.com
Link: http://lkml.kernel.org/r/1431359540-32227-9-git-send-email-dahi@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar

asm-generic: add generic futex for !CONFIG_SMP

2014-12-08T04:55:48+00:00

Follow m68k futex implementation for !CONFIG_SMP.

Signed-off-by: Ley Foon Tan 
Acked-by: Arnd Bergmann

futex: Sanitize futex ops argument types

2011-03-11T11:23:31+00:00

Change futex_atomic_op_inuser and futex_atomic_cmpxchg_inatomic
prototypes to use u32 types for the futex as this is the data type the
futex core code uses all over the place.

Signed-off-by: Michel Lespinasse 
Cc: Darren Hart 
Cc: Peter Zijlstra 
Cc: Matt Turner 
Cc: Russell King 
Cc: David Howells 
Cc: Tony Luck 
Cc: Michal Simek 
Cc: Ralf Baechle 
Cc: "James E.J. Bottomley" 
Cc: Benjamin Herrenschmidt 
Cc: Martin Schwidefsky 
Cc: Paul Mundt 
Cc: "David S. Miller" 
Cc: Chris Metcalf 
Cc: Linus Torvalds 
LKML-Reference: <20110311025058.GD26122@google.com>
Signed-off-by: Thomas Gleixner

futex: Sanitize cmpxchg_futex_value_locked API

2011-03-11T11:23:08+00:00

The cmpxchg_futex_value_locked API was funny in that it returned either
the original, user-exposed futex value OR an error code such as -EFAULT.
This was confusing at best, and could be a source of livelocks in places
that retry the cmpxchg_futex_value_locked after trying to fix the issue
by running fault_in_user_writeable().
    
This change makes the cmpxchg_futex_value_locked API more similar to the
get_futex_value_locked one, returning an error code and updating the
original value through a reference argument.
    
Signed-off-by: Michel Lespinasse 
Acked-by: Chris Metcalf   [tile]
Acked-by: Tony Luck   [ia64]
Acked-by: Thomas Gleixner 
Tested-by: Michal Simek   [microblaze]
Acked-by: David Howells  [frv]
Cc: Darren Hart 
Cc: Peter Zijlstra 
Cc: Matt Turner 
Cc: Russell King 
Cc: Ralf Baechle 
Cc: "James E.J. Bottomley" 
Cc: Benjamin Herrenschmidt 
Cc: Martin Schwidefsky 
Cc: Paul Mundt 
Cc: "David S. Miller" 
Cc: Linus Torvalds 
LKML-Reference: <20110311024851.GC26122@google.com>
Signed-off-by: Thomas Gleixner

remove KERNEL tests of unexported headers under asm-generic/

2008-04-30T15:29:54+00:00

Signed-off-by: Robert P. J. Day 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

asm-*/futex.h should include linux/uaccess.h

2008-04-30T15:29:52+00:00

Lots of asm-*/futex.h call pagefault_enable and pagefault_disable, which
are declared in linux/uaccess.h, without including linux/uaccess.h.

They all include asm/uaccess.h, so this patch replaces asm/uaccess.h
with linux/uaccess.h.

Signed-off-by: Jeff Dike 
Cc: "Luck, Tony" 
Cc: Ralf Baechle 
Cc: Kyle McMartin 
Cc: Paul Mackerras 
Cc: Benjamin Herrenschmidt 
Cc: Paul Mundt 
Cc: "David S. Miller" 
Cc: Ingo Molnar 
Cc: Thomas Gleixner 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] mm: pagefault_{disable,enable}()

2006-12-07T16:39:21+00:00

Introduce pagefault_{disable,enable}() and use these where previously we did
manual preempt increments/decrements to make the pagefault handler do the
atomic thing.

Currently they still rely on the increased preempt count, but do not rely on
the disabled preemption, this might go away in the future.

(NOTE: the extra barrier() in pagefault_disable might fix some holes on
       machines which have too many registers for their own good)

[heiko.carstens@de.ibm.com: s390 fix]
Signed-off-by: Peter Zijlstra 
Acked-by: Nick Piggin 
Cc: Martin Schwidefsky 
Signed-off-by: Heiko Carstens 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] lightweight robust futexes updates

2006-03-27T16:44:49+00:00

- fix: initialize the robust list(s) to NULL in copy_process.

- doc update

- cleanup: rename _inuser to _inatomic

- __user cleanups and other small cleanups

Signed-off-by: Ingo Molnar 
Cc: Thomas Gleixner 
Cc: Arjan van de Ven 
Cc: Ulrich Drepper 
Cc: Andi Kleen 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds