linux-toradex.git/kernel/futex.c, branch v3.0-rc3

futex: Set FLAGS_HAS_TIMEOUT during futex_wait restart setup

2011-04-15T14:34:32+00:00

The FLAGS_HAS_TIMEOUT flag was not getting set, causing the restart_block to
restart futex_wait() without a timeout after a signal.

Commit b41277dc7a18ee332d in 2.6.38 introduced the regression by accidentally
removing the the FLAGS_HAS_TIMEOUT assignment from futex_wait() during the setup
of the restart block. Restore the originaly behavior.

Fixes: https://bugzilla.kernel.org/show_bug.cgi?id=32922

Reported-by: Tim Smith 
Reported-by: Torsten Hilbrich 
Signed-off-by: Darren Hart 
Signed-off-by: Eric Dumazet 
Cc: Peter Zijlstra 
Cc: John Kacur 
Cc: stable@kernel.org
Link: http://lkml.kernel.org/r/%3Cdaac0eb3af607f72b9a4d3126b2ba8fb5ed3b883.1302820917.git.dvhart%40linux.intel.com%3E
Signed-off-by: Thomas Gleixner

Merge branch 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

2011-03-26T00:52:22+00:00

* 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  futex: Fix WARN_ON() test for UP
  WARN_ON_SMP(): Allow use in if() statements on UP
  x86, dumpstack: Use %pB format specifier for stack trace
  vsprintf: Introduce %pB format specifier
  lockdep: Remove unused 'factor' variable from lockdep_stats_show()

futex: Fix WARN_ON() test for UP

2011-03-25T10:32:11+00:00

An update of the futex code had a

	WARN_ON(!spin_is_locked(q->lock_ptr))

But on UP, spin_is_locked() is always false, and will
trigger this warning, and even worse, it will exit the function
without doing the necessary work.

Converting this to a WARN_ON_SMP() fixes the problem.

Reported-by: Richard Weinberger 
Tested-by: Richard Weinberger 
Signed-off-by: Steven Rostedt 
Acked-by: Thomas Gleixner 
Acked-by: Peter Zijlstra 
Acked-by: Darren Hart 
Cc: Lai Jiangshan 
LKML-Reference: <20110317192208.682654502@goodmis.org>
Signed-off-by: Ingo Molnar

userns: user namespaces: convert several capable() calls

2011-03-24T02:47:08+00:00

CAP_IPC_OWNER and CAP_IPC_LOCK can be checked against current_user_ns(),
because the resource comes from current's own ipc namespace.

setuid/setgid are to uids in own namespace, so again checks can be against
current_user_ns().

Changelog:
	Jan 11: Use task_ns_capable() in place of sched_capable().
	Jan 11: Use nsown_capable() as suggested by Bastian Blank.
	Jan 11: Clarify (hopefully) some logic in futex and sched.c
	Feb 15: use ns_capable for ipc, not nsown_capable
	Feb 23: let copy_ipcs handle setting ipc_ns->user_ns
	Feb 23: pass ns down rather than taking it from current

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Serge E. Hallyn 
Acked-by: "Eric W. Biederman" 
Acked-by: Daniel Lezcano 
Acked-by: David Howells 
Cc: James Morris 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Merge branch 'core-locking-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

2011-03-16T01:28:30+00:00

* 'core-locking-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  rtmutex: tester: Remove the remaining BKL leftovers
  lockdep/timers: Explain in detail the locking problems del_timer_sync() may cause
  rtmutex: Simplify PI algorithm and make highest prio task get lock
  rwsem: Remove redundant asmregparm annotation
  rwsem: Move duplicate function prototypes to linux/rwsem.h
  rwsem: Unify the duplicate rwsem_is_locked() inlines
  rwsem: Move duplicate init macros and functions to linux/rwsem.h
  rwsem: Move duplicate struct rwsem declaration to linux/rwsem.h
  x86: Cleanup rwsem_count_t typedef
  rwsem: Cleanup includes
  locking: Remove deprecated lock initializers
  cred: Replace deprecated spinlock initialization
  kthread: Replace deprecated spinlock initialization
  xtensa: Replace deprecated spinlock initialization
  um: Replace deprecated spinlock initialization
  sparc: Replace deprecated spinlock initialization
  mips: Replace deprecated spinlock initialization
  cris: Replace deprecated spinlock initialization
  alpha: Replace deprecated spinlock initialization
  rtmutex-tester: Remove BKL tests

futex: Deobfuscate handle_futex_death()

2011-03-14T20:08:47+00:00

handle_futex_death() uses futex_atomic_cmpxchg_inatomic() without
disabling page faults. That's ok, but totally non obvious.

We don't hold locks so we actually can and want to fault here, because
the get_user() before futex_atomic_cmpxchg_inatomic() does not
guarantee a R/W mapping.

We could just add a big fat comment to explain this, but actually
changing the code so that the functionality is entirely clear is
better.

Use the helper function which disables page faults around the
futex_atomic_cmpxchg_inatomic() and handle a fault with a call to
fault_in_user_writeable() as all other places in the futex code do as
well.

Pointed-out-by: Linus Torvalds 
Signed-off-by: Thomas Gleixner 
Acked-by: Darren Hart 
Cc: Michel Lespinasse 
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 
LKML-Reference: 
Signed-off-by: Thomas Gleixner

Merge branch 'tip/futex/devel' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-2.6-rt into core/futexes

2011-03-12T10:43:32+00:00

 futex,plist: Pass the real head of the priority list to plist_del()
 futex,plist: Remove debug lock assignment from plist_node
 plist: Shrink struct plist_head
 plist: Add priority list test

futex,plist: Remove debug lock assignment from plist_node

2011-03-11T20:09:53+00:00

The original code uses &plist_node->plist as the fake head of
the priority list for plist_del(), these debug locks in
the fake head are needed for CONFIG_DEBUG_PI_LIST.

But now we always pass the real head to plist_del(), the debug locks
in plist_node will not be used, so we remove these assignments.

Acked-by: Darren Hart 
Signed-off-by:  Lai Jiangshan 
LKML-Reference: <4D10797E.7040803@cn.fujitsu.com>
Signed-off-by: Steven Rostedt

futex,plist: Pass the real head of the priority list to plist_del()

2011-03-11T20:09:52+00:00

Some plist_del()s in kernel/futex.c are passed a faked head of the
priority list.

It does not fail because the current code does not require the real head
in plist_del(). The current code of plist_del() just uses the head for checking,
so it will not cause a bad result even when we use a faked head.

But it is undocumented usage:

/**
 * plist_del - Remove a @node from plist.
 *
 * @node:	&struct plist_node pointer - entry to be removed
 * @head:	&struct plist_head pointer - list head
 */

The document says that the @head is the "list head" head of the priority list.

In futex code, several places use "plist_del(&q->list, &q->list.plist);",
they pass a fake head. We need to fix them all.

Thanks to Darren Hart for many suggestions.

Acked-by: Darren Hart 
Signed-off-by:  Lai Jiangshan 
LKML-Reference: <4D11984A.5030203@cn.fujitsu.com>
Signed-off-by: Steven Rostedt

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