Linus Torvalds
69cd9eba38
futex: avoid race between requeue and wake ...
Jan Stancek reported:
"pthread_cond_broadcast/4-1.c testcase from openposix testsuite (LTP)
occasionally fails, because some threads fail to wake up.
Testcase creates 5 threads, which are all waiting on same condition.
Main thread then calls pthread_cond_broadcast() without holding mutex,
which calls:
futex(uaddr1, FUTEX_CMP_REQUEUE_PRIVATE, 1, 2147483647, uaddr2, ..)
This immediately wakes up single thread A, which unlocks mutex and
tries to wake up another thread:
futex(uaddr2, FUTEX_WAKE_PRIVATE, 1)
If thread A manages to call futex_wake() before any waiters are
requeued for uaddr2, no other thread is woken up"
The ordering constraints for the hash bucket waiter counting are that
the waiter counts have to be incremented _before_ getting the spinlock
(because the spinlock acts as part of the memory barrier), but the
"requeue" operation didn't honor those rules, and nobody had even
thought about that case.
This fairly simple patch just increments the waiter count for the target
hash bucket (hb2) when requeing a futex before taking the locks. It
then decrements them again after releasing the lock - the code that
actually moves the futex(es) between hash buckets will do the additional
required waiter count housekeeping.
Reported-and-tested-by: Jan Stancek <jstancek@redhat.com>
Acked-by: Davidlohr Bueso <davidlohr@hp.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org # 3.14
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-09 08:02:12 -07:00
mm: per-thread vma caching
2014-04-07 16:35:53 -07:00
Merge branch 'for-linus' of git://ftp.arm.linux.org.uk/~rmk/linux-arm
2014-04-05 13:20:43 -07:00
gcov: reuse kbasename helper
2013-11-13 12:09:34 +09:00
genirq: Export symbol no_action()
2014-03-22 11:33:09 +01:00
lglock: map to spinlock when !CONFIG_SMP
2014-04-07 16:36:14 -07:00
kernel: use macros from compiler.h instead of __attribute__((...))
2014-04-07 16:36:11 -07:00
printk: fix one circular lockdep warning about console_lock
2014-04-03 16:21:08 -07:00
Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
2014-03-31 11:21:19 -07:00
Merge branch 'akpm' (incoming from Andrew)
2014-04-07 16:38:06 -07:00
kernel: use macros from compiler.h instead of __attribute__((...))
2014-04-07 16:36:11 -07:00
Merge branch 'akpm' (incoming from Andrew)
2014-04-07 16:38:06 -07:00
Ignore generated file kernel/x509_certificate_list
2013-12-10 18:21:34 +00:00
AUDIT: Allow login in non-init namespaces
2014-03-30 17:02:53 -07:00
audit: Use struct net not pid_t to remember the network namespce to reply in
2014-02-28 04:04:33 -08:00
inotify: Fix reporting of cookies for inotify events
2014-02-18 11:17:17 +01:00
inotify: Fix reporting of cookies for inotify events
2014-02-18 11:17:17 +01:00
audit: Update kdoc for audit_send_reply and audit_list_rules_send
2014-03-08 15:31:54 -08:00
execve: use 'struct filename *' for executable name passing
2014-02-05 12:54:53 -08:00
mm: do not allocate page->ptl dynamically, if spinlock_t fits to long
2013-12-20 12:25:45 -08:00
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security
2014-04-03 09:26:18 -07:00
cgroup: newly created dirs and files should be owned by the creator
2014-04-07 16:44:47 -04:00
cgroup: drop const from @buffer of cftype->write_string()
2014-03-19 10:23:54 -04:00
Merge branch 'x86-x32-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
2014-04-02 12:51:41 -07:00
context_tracking: Wrap static key check into more intuitive function name
2013-12-02 20:43:14 +01:00
CPU hotplug: Provide lockless versions of callback registration functions
2014-03-20 13:43:40 +01:00
Merge branch 'akpm' (incoming from Andrew)
2014-04-03 16:22:16 -07:00
kernel/delayacct.c: remove redundant checking in __delayacct_add_tsk()
2013-11-13 12:09:12 +09:00
switch elf_core_write_extra_phdrs() to dump_emit()
2013-11-09 00:16:23 -05:00
wait: WSTOPPED|WCONTINUED doesn't work if a zombie leader is traced by another process
2014-04-07 16:36:06 -07:00
asmlinkage: Make main_extable_sort_needed visible
2014-02-13 18:13:22 -08:00
kernel: use macros from compiler.h instead of __attribute__((...))
2014-04-07 16:36:11 -07:00
libata, freezer: avoid block device removal while system is frozen
2013-12-19 13:50:32 -05:00
futex: avoid race between requeue and wake
2014-04-09 08:02:12 -07:00
compat: Get rid of (get|put)_compat_time(val|spec)
2014-02-02 14:09:12 -08:00
kernel/groups.c: remove return value of set_groups
2014-04-03 16:21:05 -07:00
timer: Remove code redundancy while calling get_nohz_timer_target()
2014-03-20 12:35:46 +01:00
kernel: audit/fix non-modular users of module_init in core code
2014-04-03 16:21:07 -07:00
perf/x86: Warn to early_printk() in case irq_work is too slow
2014-02-21 21:49:07 +01:00
static_key: WARN on usage before jump_label_init was called
2013-10-19 19:45:35 -04:00
kernel: use macros from compiler.h instead of __attribute__((...))
2014-04-07 16:36:11 -07:00
kernel: remove CONFIG_USE_GENERIC_SMP_HELPERS
2013-11-15 09:32:22 +09:00
kernel: use macros from compiler.h instead of __attribute__((...))
2014-04-07 16:36:11 -07:00
execve: use 'struct filename *' for executable name passing
2014-02-05 12:54:53 -08:00
kprobes: use KSYM_NAME_LEN to size identifier buffers
2013-11-13 12:09:26 +09:00
kernel: use macros from compiler.h instead of __attribute__((...))
2014-04-07 16:36:11 -07:00
kthread: ensure locality of task_struct allocations
2014-04-03 16:20:49 -07:00
Merge branch 'x86-asmlinkage-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
2014-03-31 14:13:25 -07:00
KEYS: Separate the kernel signature checking keyring from module signing
2013-09-25 17:17:01 +01:00
modules: use raw_cpu_write for initialization of per cpu refcount.
2014-04-07 16:36:14 -07:00
keys: change asymmetric keys to use common hash definitions
2013-10-25 17:15:18 -04:00
notifier: Substitute rcu_access_pointer() for rcu_dereference_raw()
2014-02-26 06:35:13 -08:00
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace
2013-09-07 14:35:32 -07:00
padata: Fix wrong usage of rcu_dereference()
2013-12-05 21:28:42 +08:00
kernel/panic.c: display reason at end + pr_emerg
2014-04-07 16:36:08 -07:00
params: improve standard definitions
2013-12-04 14:09:46 +10:30
pidns: fix free_pid() to handle the first fork failure
2013-09-30 14:31:03 -07:00
pid_namespace: pidns_get() should check task_active_pid_ns() != NULL
2014-04-02 16:20:21 -07:00
posix-timers: Convert abuses of BUG_ON to WARN_ON
2013-12-09 16:56:29 +01:00
CPU hotplug notifiers registration fixes for 3.15-rc1
2014-04-07 14:55:46 -07:00
kernel/compat: convert to COMPAT_SYSCALL_DEFINE
2014-03-06 15:35:10 +01:00
kexec: migrate to reboot cpu
2013-12-18 19:04:50 -08:00
treewide: Fix typo in Documentation/DocBook
2014-02-19 14:58:17 +01:00
res_counter: remove interface for locked charging and uncharging
2014-04-07 16:35:54 -07:00
kernel/resource.c: make reallocate_resource() static
2014-04-03 16:21:07 -07:00
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security
2014-04-03 09:26:18 -07:00
kernel: use macros from compiler.h instead of __attribute__((...))
2014-04-07 16:36:11 -07:00
smp: Rename __smp_call_function_single() to smp_call_function_single_async()
2014-02-24 14:47:15 -08:00
kernel: delete __cpuinit usage from all core kernel files
2013-07-14 19:36:59 -04:00
softirq: Add linux/irq.h to make it compile again
2014-03-19 11:28:14 +01:00
stop_machine: Fix^2 race between stop_two_cpus() and stop_cpus()
2014-03-11 11:33:47 +01:00
mm, thp: add VM_INIT_DEF_MASK and PRCTL_THP_DISABLE
2014-04-07 16:35:52 -07:00
fs, kernel: permit disabling the uselib syscall
2014-04-03 16:21:05 -07:00
hung_task: check the value of "sysctl_hung_task_timeout_sec"
2014-04-07 16:36:07 -07:00
kernel/sysctl_binary.c: use scnprintf() instead of snprintf()
2013-11-13 12:09:33 +09:00
KEYS: correct alignment of system_certificate_list content in assembly file
2013-12-10 18:25:28 +00:00
KEYS: correct alignment of system_certificate_list content in assembly file
2013-12-10 18:25:28 +00:00
task_work: documentation
2013-09-11 15:58:27 -07:00
genetlink: only pass array to genl_register_family_with_ops()
2013-11-19 16:39:05 -05:00
Merge branch 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
2014-04-01 11:00:07 -07:00
rcutorture: Gracefully handle NULL cleanup hooks
2014-02-23 09:04:39 -08:00
Nothing major: the stricter permissions checking for sysfs broke
2014-04-06 09:38:07 -07:00
userns: Kill nsown_capable it makes the wrong thing easy
2013-08-30 23:44:11 -07:00
smp: Rename __smp_call_function_single() to smp_call_function_single_async()
2014-02-24 14:47:15 -08:00
kernel: audit/fix non-modular users of module_init in core code
2014-04-03 16:21:07 -07:00
kernel: audit/fix non-modular users of module_init in core code
2014-04-03 16:21:07 -07:00
userns: Kill nsown_capable it makes the wrong thing easy
2013-08-30 23:44:11 -07:00
kernel/watchdog.c: touch_nmi_watchdog should only touch local cpu not every one
2014-04-03 16:20:58 -07:00
Merge branch 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
2014-04-01 11:00:07 -07:00
69cd9eba38