Josef Bacik 1cd8334a4f trace: Fix epoll hang when we race with new entries ... commit 4ce97dbf50 upstream. Epoll on trace_pipe can sometimes hang in a weird case. If the ring buffer is empty when we set waiters_pending but an event shows up exactly at that moment we can miss being woken up by the ring buffers irq work. Since ring_buffer_empty() is inherently racey we will sometimes think that the buffer is not empty. So we don't get woken up and we don't think there are any events even though there were some ready when we added the watch, which makes us hang. This patch fixes this by making sure that we are actually on the wait list before we set waiters_pending, and add a memory barrier to make sure ring_buffer_empty() is going to be correct. Link: http://lkml.kernel.org/p/1408989581-23727-1-git-send-email-jbacik@fb.com Cc: Martin Lau <kafai@fb.com> Signed-off-by: Josef Bacik <jbacik@fb.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		2014-10-05 14:52:11 -07:00
..
cpu	sched/preempt: Fix up missed PREEMPT_NEED_RESCHED folding	2014-01-13 17:38:55 +01:00
debug	kgdb/kdb: Fix no KDB config problem	2014-01-25 08:55:09 +01:00
events	perf: Do not allow optimized switch for non-cloned events	2014-07-28 08:06:02 -07:00
gcov	gcov: reuse kbasename helper	2013-11-13 12:09:34 +09:00
irq	genirq: Sanitize spurious interrupt detection of threaded irqs	2014-06-30 20:12:00 -07:00
locking	rtmutex: Plug slow unlock race	2014-06-30 20:11:58 -07:00
power	PM / sleep: Fix request_firmware() error at resume	2014-07-28 08:06:03 -07:00
printk	printk: rename printk_sched to printk_deferred	2014-08-07 14:52:37 -07:00
rcu	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs	2014-01-28 08:38:04 -08:00
sched	sched: Fix sched_setparam() policy == -1 logic	2014-09-05 16:34:13 -07:00
time	timer: Fix lock inversion between hrtimer_bases.lock and scheduler locks	2014-08-07 14:52:38 -07:00
trace	trace: Fix epoll hang when we race with new entries	2014-10-05 14:52:11 -07:00
.gitignore	Ignore generated file kernel/x509_certificate_list	2013-12-10 18:21:34 +00:00
acct.c
async.c
audit_tree.c	inotify: Fix reporting of cookies for inotify events	2014-02-18 11:17:17 +01:00
audit_watch.c	inotify: Fix reporting of cookies for inotify events	2014-02-18 11:17:17 +01:00
audit.c	CAPABILITIES: remove undefined caps from all processes	2014-09-17 09:19:09 -07:00
audit.h	audit: Use struct net not pid_t to remember the network namespce to reply in	2014-02-28 04:04:33 -08:00
auditfilter.c	audit: Update kdoc for audit_send_reply and audit_list_rules_send	2014-03-08 15:31:54 -08:00
auditsc.c	audit: remove superfluous new- prefix in AUDIT_LOGIN messages	2014-07-09 11:18:28 -07:00
backtracetest.c
bounds.c	mm: do not allocate page->ptl dynamically, if spinlock_t fits to long	2013-12-20 12:25:45 -08:00
capability.c	CAPABILITIES: remove undefined caps from all processes	2014-09-17 09:19:09 -07:00
cgroup_freezer.c	cgroup: replace cftype->read_seq_string() with cftype->seq_show()	2013-12-05 12:28:04 -05:00
cgroup.c	cgroup: fix a failure path in create_css()	2014-03-18 17:15:36 -04:00
compat.c
configs.c
context_tracking.c	context_tracking: Wrap static key check into more intuitive function name	2013-12-02 20:43:14 +01:00
cpu_pm.c
cpu.c	sched: Fix hotplug vs. set_cpus_allowed_ptr()	2014-06-11 11:54:11 -07:00
cpuset.c	cpuset,mempolicy: fix sleeping function called from invalid context	2014-07-17 16:21:03 -07:00
crash_dump.c
cred.c
delayacct.c	kernel/delayacct.c: remove redundant checking in __delayacct_add_tsk()	2013-11-13 12:09:12 +09:00
dma.c
elfcore.c	switch elf_core_write_extra_phdrs() to dump_emit()	2013-11-09 00:16:23 -05:00
exec_domain.c
exit.c	exit: call disassociate_ctty() before exit_task_namespaces()	2014-04-26 17:19:07 -07:00
extable.c	kernel/extable: fix address-checks for core_kernel and init areas	2013-11-28 09:49:41 -08:00
fork.c	tracing: Fix syscall_*regfunc() vs copy_process() race	2014-07-06 18:57:29 -07:00
freezer.c	libata, freezer: avoid block device removal while system is frozen	2013-12-19 13:50:32 -05:00
futex_compat.c
futex.c	futex: Make lookup_pi_state more robust	2014-06-07 10:28:29 -07:00
groups.c	userns: Kill nsown_capable it makes the wrong thing easy	2013-08-30 23:44:11 -07:00
hrtimer.c	hrtimer: Set expiry time before switch_hrtimer_base()	2014-06-07 10:28:12 -07:00
hung_task.c	hung_task: Display every hung task warning	2014-01-25 12:13:33 +01:00
irq_work.c
itimer.c
jump_label.c	static_key: WARN on usage before jump_label_init was called	2013-10-19 19:45:35 -04:00
kallsyms.c
kcmp.c
Kconfig.freezer
Kconfig.hz	kernel: remove CONFIG_USE_GENERIC_SMP_HELPERS	2013-11-15 09:32:22 +09:00
Kconfig.locks	locking/mutex: Disable optimistic spinning on some architectures	2014-07-28 08:06:03 -07:00
Kconfig.preempt
kexec.c	powerpc, kexec: Fix "Processor X is stuck" issue during kexec from ST mode	2014-06-07 10:28:28 -07:00
kmod.c	execve: use 'struct filename *' for executable name passing	2014-02-05 12:54:53 -08:00
kprobes.c	kprobes: use KSYM_NAME_LEN to size identifier buffers	2013-11-13 12:09:26 +09:00
ksysfs.c	kdump: fix exported size of vmcoreinfo note	2014-01-23 16:37:03 -08:00
kthread.c	kthread: fix return value of kthread_create() upon SIGKILL.	2014-06-30 20:11:53 -07:00
latencytop.c
Makefile	KEYS: Remove files generated when SYSTEM_TRUSTED_KEYRING=y	2013-12-13 15:59:11 +00:00
module_signing.c	keys: change asymmetric keys to use common hash definitions	2013-10-25 17:15:18 -04:00
module-internal.h	KEYS: Separate the kernel signature checking keyring from module signing	2013-09-25 17:17:01 +01:00
module.c	module: remove warning about waiting module removal.	2014-06-07 10:28:11 -07:00
notifier.c
nsproxy.c	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.c	padata: Fix wrong usage of rcu_dereference()	2013-12-05 21:28:42 +08:00
panic.c	panic: Make panic_timeout configurable	2013-11-26 12:12:26 +01:00
params.c	params: improve standard definitions	2013-12-04 14:09:46 +10:30
pid_namespace.c	pid_namespace: pidns_get() should check task_active_pid_ns() != NULL	2014-04-26 17:19:04 -07:00
pid.c	pidns: fix free_pid() to handle the first fork failure	2013-09-30 14:31:03 -07:00
posix-cpu-timers.c	posix-timers: Convert abuses of BUG_ON to WARN_ON	2013-12-09 16:56:29 +01:00
posix-timers.c
profile.c	mm: fix GFP_THISNODE callers and clarify	2014-03-10 17:26:19 -07:00
ptrace.c	exec/ptrace: fix get_dumpable() incorrect tests	2013-11-13 12:09:33 +09:00
range.c
reboot.c	kexec: migrate to reboot cpu	2013-12-18 19:04:50 -08:00
relay.c
res_counter.c	memcg: reduce function dereference	2013-09-12 15:38:02 -07:00
resource.c
seccomp.c
signal.c	kernel/signal.c: change do_signal_stop/do_sigaction to use while_each_thread()	2014-01-23 16:37:02 -08:00
smp.c	kernel/smp.c:on_each_cpu_cond(): fix warning in fallback path	2014-09-17 09:19:09 -07:00
smpboot.c
smpboot.h
softirq.c	Merge branch 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2014-01-31 09:02:51 -08:00
stacktrace.c
stop_machine.c	stop_machine: Fix^2 race between stop_two_cpus() and stop_cpus()	2014-03-11 11:33:47 +01:00
sys_ni.c
sys.c	kernel/sys.c: k_getrusage() can use while_each_thread()	2014-01-23 16:37:02 -08:00
sysctl_binary.c	kernel/sysctl_binary.c: use scnprintf() instead of snprintf()	2013-11-13 12:09:33 +09:00
sysctl.c	mm, pcp: allow restoring percpu_pagelist_fraction default	2014-07-09 11:18:26 -07:00
system_certificates.S	KEYS: correct alignment of system_certificate_list content in assembly file	2013-12-10 18:25:28 +00:00
system_keyring.c	KEYS: correct alignment of system_certificate_list content in assembly file	2013-12-10 18:25:28 +00:00
task_work.c	task_work: documentation	2013-09-11 15:58:27 -07:00
taskstats.c	genetlink: only pass array to genl_register_family_with_ops()	2013-11-19 16:39:05 -05:00
test_kprobes.c
time.c
timeconst.bc
timer.c	timer: Prevent overflow in apply_slack	2014-06-07 10:28:09 -07:00
tracepoint.c	tracepoint: Do not waste memory on mods with no tracepoints	2014-05-31 13:20:28 -07:00
tsacct.c
uid16.c	userns: Kill nsown_capable it makes the wrong thing easy	2013-08-30 23:44:11 -07:00
up.c	kernel: provide a __smp_call_function_single stub for !CONFIG_SMP	2013-11-15 09:32:22 +09:00
user_namespace.c	user namespace: fix incorrect memory barriers	2014-04-26 17:19:02 -07:00
user-return-notifier.c
user.c	KEYS: fix uninitialized persistent_keyring_register_sem	2013-12-13 15:59:11 +00:00
utsname_sysctl.c
utsname.c	userns: Kill nsown_capable it makes the wrong thing easy	2013-08-30 23:44:11 -07:00
watchdog.c	kernel/watchdog.c: remove preemption restrictions when restarting lockup detector	2014-07-06 18:57:27 -07:00
workqueue_internal.h
workqueue.c	workqueue: zero cpumask of wq_numa_possible_cpumask on init	2014-07-17 16:21:03 -07:00