NeilBrown 9cff8adeaa sched: Prevent recursion in io_schedule() ... io_schedule() calls blk_flush_plug() which, depending on the contents of current->plug, can initiate arbitrary blk-io requests. Note that this contrasts with blk_schedule_flush_plug() which requires all non-trivial work to be handed off to a separate thread. This makes it possible for io_schedule() to recurse, and initiating block requests could possibly call mempool_alloc() which, in times of memory pressure, uses io_schedule(). Apart from any stack usage issues, io_schedule() will not behave correctly when called recursively as delayacct_blkio_start() does not allow for repeated calls. So: - use ->in_iowait to detect recursion. Set it earlier, and restore it to the old value. - move the call to "raw_rq" after the call to blk_flush_plug(). As this is some sort of per-cpu thing, we want some chance that we are on the right CPU - When io_schedule() is called recurively, use blk_schedule_flush_plug() which cannot further recurse. - as this makes io_schedule() a lot more complex and as io_schedule() must match io_schedule_timeout(), but all the changes in io_schedule_timeout() and make io_schedule a simple wrapper for that. Signed-off-by: NeilBrown <neilb@suse.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> [ Moved the now rudimentary io_schedule() into sched.h. ] Cc: Jens Axboe <axboe@kernel.dk> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Tony Battersby <tonyb@cybernetics.com> Link: http://lkml.kernel.org/r/20150213162600.059fffb2@notabene.brown Signed-off-by: Ingo Molnar <mingo@kernel.org>		2015-02-18 14:27:44 +01:00
..
bpf	Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net	2015-01-27 13:55:36 -08:00
configs
debug	Surprising number of fixes this merge window :(	2015-01-23 06:40:36 +12:00
events	perf: Decouple unthrottling and rotating	2015-02-04 08:07:16 +01:00
gcov	gcov: enable GCOV_PROFILE_ALL from ARCH Kconfigs	2014-12-13 12:42:51 -08:00
irq	genirq: Prevent proc race against freeing of irq descriptors	2014-12-13 13:33:07 +01:00
locking	Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2015-02-09 16:06:06 -08:00
power	rcu: Make SRCU optional by using CONFIG_SRCU	2015-01-06 11:04:29 -08:00
printk	This code is a fork from the trace-3.19 pull as it needed the trace_seq	2014-12-13 14:04:41 -08:00
rcu	Merge branches 'doc.2015.01.07a', 'fixes.2015.01.15a', 'preempt.2015.01.06a', 'srcu.2015.01.06a', 'stall.2015.01.16a' and 'torture.2015.01.11a' into HEAD	2015-01-15 23:34:34 -08:00
sched	sched: Prevent recursion in io_schedule()	2015-02-18 14:27:44 +01:00
time	Merge branch 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2015-02-09 16:33:07 -08:00
trace	Merge branch 'perf/urgent' into perf/core, to pick up fixes	2015-01-28 15:42:56 +01:00
.gitignore
acct.c	acct: eliminate compile warning	2014-10-09 22:26:04 -04:00
async.c	kernel/async.c: switch to pr_foo()	2014-10-09 22:26:04 -04:00
audit.c	Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net	2014-12-30 10:45:47 -08:00
audit.h	audit: reduce scope of audit_log_fcaps	2014-09-23 16:37:51 -04:00
audit_tree.c	fsnotify: unify inode and mount marks handling	2014-12-13 12:42:53 -08:00
audit_watch.c	audit: invalid op= values for rules	2014-09-23 16:37:53 -04:00
auditfilter.c	Merge branch 'upstream' of git://git.infradead.org/users/pcmoore/audit	2014-12-23 18:13:16 -08:00
auditsc.c	Merge branch 'upstream' of git://git.infradead.org/users/pcmoore/audit	2014-12-31 14:52:18 -08:00
backtracetest.c
bounds.c
capability.c
cgroup.c	cgroup: prevent mount hang due to memory controller lifetime	2015-01-22 10:26:43 -05:00
cgroup_freezer.c
compat.c
configs.c
context_tracking.c	sched: stop the unbound recursion in preempt_schedule_context()	2014-10-28 10:46:05 +01:00
cpu.c	hotplugcpu: Avoid deadlocks by waking active_writer	2015-01-06 11:01:14 -08:00
cpu_pm.c
cpuset.c	Merge branch 'for-3.19' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup	2014-12-11 18:57:19 -08:00
crash_dump.c
cred.c
delayacct.c
dma.c
elfcore.c
exec_domain.c
exit.c	exit: fix race between wait_consider_task() and wait_task_zombie()	2015-01-08 15:10:51 -08:00
extable.c	ftrace/x86/extable: Add is_ftrace_trampoline() function	2014-11-19 15:25:26 -05:00
fork.c	mm: use new helper functions around the i_mmap_mutex	2014-12-13 12:42:45 -08:00
freezer.c	freezer: remove obsolete comments in __thaw_task()	2014-10-21 23:44:20 +02:00
futex.c	futex: Fix argument handling in futex_lock_pi() calls	2015-01-19 12:05:32 +01:00
futex_compat.c
groups.c	userns: Don't allow setgroups until a gid mapping has been setablished	2014-12-09 16:58:40 -06:00
hung_task.c
irq_work.c	percpu: Convert remaining __get_cpu_var uses in 3.18-rcX	2014-10-29 11:18:18 -04:00
jump_label.c
kallsyms.c	kernel/kallsyms.c: use __seq_open_private()	2014-10-14 02:18:16 +02:00
kcmp.c
Kconfig.freezer
Kconfig.hz
Kconfig.locks	locking/mcs: Better differentiate between MCS variants	2015-01-14 15:07:32 +01:00
Kconfig.preempt
kexec.c	kexec: remove unnecessary KERN_ERR from kexec.c	2014-12-13 12:42:51 -08:00
kmod.c	usermodehelper: kill the kmod_thread_locker logic	2014-12-10 17:41:17 -08:00
kprobes.c	module: remove mod arg from module_free, rename module_memfree().	2015-01-20 11:38:33 +10:30
ksysfs.c
kthread.c	kernel/kthread.c: partial revert of 81c98869fa ("kthread: ensure locality of task_struct allocations")	2014-10-09 22:25:51 -04:00
latencytop.c
Makefile	kernel: res_counter: remove the unused API	2014-12-10 17:41:04 -08:00
module-internal.h
module.c	module: make module_refcount() a signed integer.	2015-01-22 11:15:54 +10:30
module_signing.c
notifier.c	rcu: Make SRCU optional by using CONFIG_SRCU	2015-01-06 11:04:29 -08:00
nsproxy.c	bury struct proc_ns in fs/proc	2014-12-04 14:34:54 -05:00
padata.c
panic.c	kernel: add panic_on_warn	2014-12-10 17:41:10 -08:00
params.c	param: fix uninitialized read with CONFIG_DEBUG_LOCK_ALLOC	2015-01-20 11:38:31 +10:30
pid.c	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs	2014-12-16 15:53:03 -08:00
pid_namespace.c	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs	2014-12-16 15:53:03 -08:00
profile.c
ptrace.c	exit: ptrace: shift "reap dead" code from exit_ptrace() to forget_original_parent()	2014-12-10 17:41:10 -08:00
range.c	kernel: avoid overflow in cmp_range	2015-01-17 10:02:23 +13:00
reboot.c	kernel: add support for kernel restart handler call chain	2014-09-26 00:00:06 -07:00
relay.c
resource.c	x86: optimize resource lookups for ioremap	2014-10-14 02:18:22 +02:00
seccomp.c	Merge branch 'x86-seccomp-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2014-10-14 02:27:06 +02:00
signal.c	Merge branch 'x86-mpx-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2014-12-10 09:34:43 -08:00
smp.c	Merge branch 'for-3.18-consistent-ops' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu	2014-10-15 07:48:18 +02:00
smpboot.c	smpboot: Add missing get_online_cpus() in smpboot_register_percpu_thread()	2015-01-23 11:33:51 +01:00
smpboot.h
softirq.c	Merge branch 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2015-02-09 15:24:03 -08:00
stacktrace.c	stacktrace: introduce snprint_stack_trace for buffer output	2014-12-13 12:42:48 -08:00
stop_machine.c
sys.c	x86, mpx: Strictly enforce empty prctl() args	2015-01-22 21:11:06 +01:00
sys_ni.c	syscalls: implement execveat() system call	2014-12-13 12:42:51 -08:00
sysctl.c	As the merge window is still open, and this code was not as complex	2014-12-16 12:53:59 -08:00
sysctl_binary.c	kernel: add panic_on_warn	2014-12-10 17:41:10 -08:00
system_certificates.S
system_keyring.c
task_work.c
taskstats.c	kill f_dentry uses	2014-11-19 13:01:25 -05:00
test_kprobes.c
torture.c
tracepoint.c
tsacct.c
uid16.c	groups: Consolidate the setgroups permission checks	2014-12-05 17:19:27 -06:00
up.c
user-return-notifier.c
user.c	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace	2014-12-17 12:31:40 -08:00
user_namespace.c	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace	2014-12-17 12:31:40 -08:00
utsname.c	copy address of proc_ns_ops into ns_common	2014-12-04 14:34:47 -05:00
utsname_sysctl.c
watchdog.c	Merge branch 'for-3.18-consistent-ops' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu	2014-10-15 07:48:18 +02:00
workqueue.c	workqueue: fix subtle pool management issue which can stall whole worker_pool	2015-01-16 14:21:16 -05:00
workqueue_internal.h