Tejun Heo
774a1221e8
module, async: async_synchronize_full() on module init iff async is used
...
If the default iosched is built as module, the kernel may deadlock
while trying to load the iosched module on device probe if the probing
was running off async. This is because async_synchronize_full() at
the end of module init ends up waiting for the async job which
initiated the module loading.
async A modprobe
1. finds a device
2. registers the block device
3. request_module(default iosched)
4. modprobe in userland
5. load and init module
6. async_synchronize_full()
Async A waits for modprobe to finish in request_module() and modprobe
waits for async A to finish in async_synchronize_full().
Because there's no easy to track dependency once control goes out to
userland, implementing properly nested flushing is difficult. For
now, make module init perform async_synchronize_full() iff module init
has queued async jobs as suggested by Linus.
This avoids the described deadlock because iosched module doesn't use
async and thus wouldn't invoke async_synchronize_full(). This is
hacky and incomplete. It will deadlock if async module loading nests;
however, this works around the known problem case and seems to be the
best of bad options.
For more details, please refer to the following thread.
http://thread.gmane.org/gmane.linux.kernel/1420814
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Alex Riesen <raa.lkml@gmail.com>
Tested-by: Ming Lei <ming.lei@canonical.com>
Tested-by: Alex Riesen <raa.lkml@gmail.com>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-01-16 09:05:33 -08:00
..
debug
KGDB/KDB fixes and cleanups
2012-10-13 11:16:58 +09:00
events
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace
2012-12-17 15:44:47 -08:00
gcov
irq
irq: tsk->comm is an array
2012-12-18 15:02:11 -08:00
power
Merge branch 'for-3.8' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup
2012-12-12 08:18:24 -08:00
sched
sched: numa: ksm: fix oops in task_numa_placment()
2012-12-20 07:06:56 -08:00
time
Merge tag 'kvm-3.8-1' of git://git.kernel.org/pub/scm/virt/kvm/kvm
2012-12-13 15:31:08 -08:00
trace
tracing: Fix regression of trace_pipe
2013-01-14 13:13:32 -05:00
.gitignore
acct.c
vfs: make path_openat take a struct filename pointer
2012-10-12 20:15:09 -04:00
async.c
module, async: async_synchronize_full() on module init iff async is used
2013-01-16 09:05:33 -08:00
audit.c
kernel/audit.c: avoid negative sleep durations
2013-01-11 14:54:56 -08:00
audit.h
audit: optimize audit_compare_dname_path
2012-10-12 00:32:02 -04:00
audit_tree.c
audit: catch possible NULL audit buffers
2013-01-11 14:54:55 -08:00
audit_watch.c
audit: catch possible NULL audit buffers
2013-01-11 14:54:55 -08:00
auditfilter.c
audit: fix auditfilter.c kernel-doc warnings
2013-01-10 14:35:23 -08:00
auditsc.c
audit: catch possible NULL audit buffers
2013-01-11 14:54:55 -08:00
backtracetest.c
bounds.c
capability.c
userns: Teach inode_capable to understand inodes whose uids map to other namespaces.
2012-05-15 14:59:24 -07:00
cgroup.c
Merge branch 'akpm' (Andrew's patch-bomb)
2012-12-17 20:58:12 -08:00
cgroup_freezer.c
cgroup: rename ->create/post_create/pre_destroy/destroy() to ->css_alloc/online/offline/free()
2012-11-19 08:13:38 -08:00
compat.c
compat: generic compat_sys_sched_rr_get_interval() implementation
2012-12-17 17:15:18 -08:00
configs.c
context_tracking.c
context_tracking: New context tracking susbsystem
2012-11-30 11:40:07 -08:00
cpu.c
Merge branch 'x86-bsp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
2012-12-11 19:56:33 -08:00
cpu_pm.c
kernel/cpu_pm.c: fix various typos
2012-05-31 17:49:27 -07:00
cpuset.c
cpuset: use N_MEMORY instead N_HIGH_MEMORY
2012-12-12 17:38:32 -08:00
crash_dump.c
cred.c
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace
2012-12-18 10:55:28 -08:00
delayacct.c
dma.c
Remove all #inclusions of asm/system.h
2012-03-28 18:30:03 +01:00
elfcore.c
exec_domain.c
exit.c
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace
2012-12-17 15:44:47 -08:00
extable.c
extable: Skip sorting if sorted at build time.
2012-04-19 15:06:55 -07:00
fork.c
pidns: Outlaw thread creation after unshare(CLONE_NEWPID)
2012-12-24 22:53:14 -08:00
freezer.c
freezer: change ptrace_stop/do_signal_stop to use freezable_schedule()
2012-10-26 14:27:49 -07:00
futex.c
futex: avoid wake_futex() for a PI futex_q
2012-11-26 17:41:24 -08:00
futex_compat.c
futex: Mark get_robust_list as deprecated
2012-03-29 11:37:17 +02:00
groups.c
userns: Convert in_group_p and in_egroup_p to use kgid_t
2012-05-03 03:29:33 -07:00
hrtimer.c
hrtimer: Update hrtimer base offsets each hrtimer_interrupt
2012-07-11 23:34:39 +02:00
hung_task.c
hung task debugging: Inject NMI when hung and going to panic
2012-04-25 12:39:25 +02:00
irq_work.c
irq_work: fix compile failure on tile from missing include
2012-04-13 13:15:16 -04:00
itimer.c
itimer: Use printk_once instead of WARN_ONCE
2012-04-10 11:00:30 +02:00
jump_label.c
jump_label: Export jump_label_rate_limit()
2012-08-06 19:00:35 +03:00
kallsyms.c
vsprintf: fix %ps on non symbols when using kallsyms
2012-05-29 16:22:32 -07:00
kcmp.c
kcmp: include linux/ptrace.h
2012-12-20 17:40:19 -08:00
Kconfig.freezer
Kconfig.hz
Kconfig.locks
locking: Adjust spin lock inlining Kconfig options
2012-09-13 17:56:13 +02:00
Kconfig.preempt
locking/kconfig: Simplify INLINE_SPIN_UNLOCK usage
2012-03-23 13:18:57 +01:00
kexec.c
kdump: remove unneeded include
2012-10-06 03:05:19 +09:00
kfifo.c
[media] kernel:kfifo: export __kfifo_max_r symbol
2012-04-11 18:24:37 -03:00
kmod.c
Bury the conditionals from kernel_thread/kernel_execve series
2012-12-19 18:07:38 -05:00
kprobes.c
kprobes/x86: Fix to support jprobes on ftrace-based kprobe
2012-09-13 22:52:11 -04:00
ksysfs.c
Merge branch 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
2012-12-11 18:10:49 -08:00
kthread.c
kthread: use N_MEMORY instead N_HIGH_MEMORY
2012-12-12 17:38:33 -08:00
latencytop.c
lglock.c
brlocks/lglocks: turn into functions
2012-05-29 23:28:41 -04:00
lockdep.c
lockdep: Check if nested lock is actually held
2012-09-13 17:00:44 +02:00
lockdep_internals.h
lockdep_proc.c
lockdep: Use KSYM_NAME_LEN'ed buffer for __get_key_name()
2012-10-24 12:39:09 +02:00
lockdep_states.h
Makefile
Nothing all that exciting; a new module-from-fd syscall for those who want
2012-12-19 07:55:08 -08:00
modsign_certificate.S
MODSIGN: Avoid using .incbin in C source
2012-12-14 13:06:44 +10:30
modsign_pubkey.c
keys: use keyring_alloc() to create module signing keyring
2012-12-20 17:40:21 -08:00
module-internal.h
MODSIGN: Move the magic string to the end of a module and eliminate the search
2012-10-19 17:30:40 -07:00
module.c
module, async: async_synchronize_full() on module init iff async is used
2013-01-16 09:05:33 -08:00
module_signing.c
MODSIGN: Don't use enum-type bitfields in module signature info block
2012-12-05 11:27:24 +10:30
mutex-debug.c
mutex-debug.h
mutex.c
mutex.h
notifier.c
nsproxy.c
userns: Implement unshare of the user namespace
2012-11-20 04:18:14 -08:00
padata.c
padata: use __this_cpu_read per-cpu helper
2012-12-06 17:16:23 +08:00
panic.c
panic: fix a possible deadlock in panic()
2012-07-30 17:25:13 -07:00
params.c
params: replace printk(KERN_<LVL>...) with pr_<lvl>(...)
2012-05-04 17:28:18 -07:00
pid.c
pidns: Stop pid allocation when init dies
2012-12-25 16:10:05 -08:00
pid_namespace.c
pidns: Stop pid allocation when init dies
2012-12-25 16:10:05 -08:00
posix-cpu-timers.c
A few /dev/random improvements for the v3.8 merge window.
2012-12-19 20:23:37 -08:00
posix-timers.c
printk.c
printk: fix incorrect length from print_time() when seconds > 99999
2013-01-04 16:11:48 -08:00
profile.c
propagate name change to comments in kernel source
2012-12-06 10:39:54 +01:00
ptrace.c
Merge branch 'akpm' (Andrew's patch-bomb)
2012-12-17 20:58:12 -08:00
range.c
rcu.h
rcu: Add a module parameter to force use of expedited RCU primitives
2012-10-23 14:54:08 -07:00
rcupdate.c
rcu: Add a module parameter to force use of expedited RCU primitives
2012-10-23 14:54:08 -07:00
rcutiny.c
rcu: Fix TINY_RCU rcu_is_cpu_rrupt_from_idle check
2012-11-13 14:08:34 -08:00
rcutiny_plugin.h
rcu: Add a module parameter to force use of expedited RCU primitives
2012-10-23 14:54:08 -07:00
rcutorture.c
Merge branches 'urgent.2012.10.27a', 'doc.2012.11.16a', 'fixes.2012.11.13a', 'srcu.2012.10.27a', 'stall.2012.11.13a', 'tracing.2012.11.08a' and 'idle.2012.10.24a' into HEAD
2012-11-16 09:59:58 -08:00
rcutree.c
context_tracking: New context tracking susbsystem
2012-11-30 11:40:07 -08:00
rcutree.h
rcu: Separate accounting of callbacks from callback-free CPUs
2012-11-16 10:05:57 -08:00
rcutree_plugin.h
rcu: Separate accounting of callbacks from callback-free CPUs
2012-11-16 10:05:57 -08:00
rcutree_trace.c
rcu: Separate accounting of callbacks from callback-free CPUs
2012-11-16 10:05:57 -08:00
relay.c
splice: fix racy pipe->buffers uses
2012-06-13 21:16:42 +02:00
res_counter.c
res_counter: return amount of charges after res_counter_uncharge()
2012-12-18 15:02:12 -08:00
resource.c
kernel/resource.c: fix stack overflow in __reserve_region_with_split()
2012-10-06 03:05:31 +09:00
rtmutex-debug.c
rtmutex-debug.h
rtmutex-tester.c
rtmutex.c
rtmutex.h
rtmutex_common.h
rwsem.c
lockdep, rwsem: provide down_write_nest_lock()
2013-01-11 14:54:55 -08:00
seccomp.c
seccomp: Make syscall skipping and nr changes more consistent
2012-10-02 21:14:29 +10:00
semaphore.c
semaphore: fix improper comment reference to mutex
2012-04-05 17:15:55 -07:00
signal.c
signals: set_current_blocked() can use __set_current_blocked()
2013-01-05 19:34:54 -08:00
smp.c
smp: Remove ipi_call_lock[_irq]()/ipi_call_unlock[_irq]()
2012-06-05 17:27:14 +02:00
smpboot.c
hotplug: Fix UP bug in smpboot hotplug code
2012-08-13 17:01:07 +02:00
smpboot.h
smpboot: Provide infrastructure for percpu hotplug threads
2012-08-13 17:01:07 +02:00
softirq.c
cputime: Specialize irq vtime hooks
2012-10-29 21:31:32 +01:00
spinlock.c
locking/kconfig: Simplify INLINE_SPIN_UNLOCK usage
2012-03-23 13:18:57 +01:00
srcu.c
Merge branches 'urgent.2012.10.27a', 'doc.2012.11.16a', 'fixes.2012.11.13a', 'srcu.2012.10.27a', 'stall.2012.11.13a', 'tracing.2012.11.08a' and 'idle.2012.10.24a' into HEAD
2012-11-16 09:59:58 -08:00
stacktrace.c
stop_machine.c
sys.c
cputime: Rename thread_group_times to thread_group_cputime_adjusted
2012-11-28 17:07:57 +01:00
sys_ni.c
module: add syscall to load module from fd
2012-12-14 13:05:22 +10:30
sysctl.c
Automatic NUMA Balancing V11
2012-12-16 15:18:08 -08:00
sysctl_binary.c
pidns: Use task_active_pid_ns where appropriate
2012-11-19 05:59:09 -08:00
task_work.c
task_work: task_work_add() should not succeed after exit_task_work()
2012-09-13 16:47:34 +02:00
taskstats.c
taskstats: cgroupstats_user_cmd() may leak on error
2012-10-06 03:05:31 +09:00
test_kprobes.c
time.c
time: Move update_vsyscall definitions to timekeeper_internal.h
2012-09-24 12:38:06 -04:00
timeconst.pl
timer.c
timers: Fix endless looping between cascade() and internal_add_timer()
2012-10-09 21:27:14 +02:00
tracepoint.c
tsacct.c
userns: Convert taskstats to handle the user and pid namespaces.
2012-09-18 01:01:32 -07:00
uid16.c
userns: Convert setting and getting uid and gid system calls to use kuid and kgid
2012-05-03 03:28:41 -07:00
up.c
user-return-notifier.c
user.c
proc: Usable inode numbers for the namespace file descriptors.
2012-11-20 04:19:49 -08:00
user_namespace.c
userns: Fix typo in description of the limitation of userns_install
2012-12-14 18:36:36 -08:00
utsname.c
userns: Require CAP_SYS_ADMIN for most uses of setns.
2012-12-14 16:12:03 -08:00
utsname_sysctl.c
wait.c
propagate name change to comments in kernel source
2012-12-06 10:39:54 +01:00
watchdog.c
watchdog: Fix disable/enable regression
2012-12-19 12:10:33 -08:00
workqueue.c
Merge branch 'for-3.8' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq
2012-12-12 08:15:13 -08:00
workqueue_sched.h