Paul E. McKenney
237c80c5c8
rcu: Fix TREE_PREEMPT_RCU CPU_HOTPLUG bad-luck hang ...
If the following sequence of events occurs, then
TREE_PREEMPT_RCU will hang waiting for a grace period to
complete, eventually OOMing the system:
o A TREE_PREEMPT_RCU build of the kernel is booted on a system
with more than 64 physical CPUs present (32 on a 32-bit system).
Alternatively, a TREE_PREEMPT_RCU build of the kernel is booted
with RCU_FANOUT set to a sufficiently small value that the
physical CPUs populate two or more leaf rcu_node structures.
o A task is preempted in an RCU read-side critical section
while running on a CPU corresponding to a given leaf rcu_node
structure.
o All CPUs corresponding to this same leaf rcu_node structure
record quiescent states for the current grace period.
o All of these same CPUs go offline (hence the need for enough
physical CPUs to populate more than one leaf rcu_node structure).
This causes the preempted task to be moved to the root rcu_node
structure.
At this point, there is nothing left to cause the quiescent
state to be propagated up the rcu_node tree, so the current
grace period never completes.
The simplest fix, especially after considering the deadlock
possibilities, is to detect this situation when the last CPU is
offlined, and to set that CPU's ->qsmask bit in its leaf
rcu_node structure. This will cause the next invocation of
force_quiescent_state() to end the grace period.
Without this fix, this hang can be triggered in an hour or so on
some machines with rcutorture and random CPU onlining/offlining.
With this fix, these same machines pass a full 10 hours of this
sort of abuse.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: laijs@cn.fujitsu.com
Cc: dipankar@in.ibm.com
Cc: mathieu.desnoyers@polymtl.ca
Cc: josh@joshtriplett.org
Cc: dvhltc@us.ibm.com
Cc: niv@us.ibm.com
Cc: peterz@infradead.org
Cc: rostedt@goodmis.org
Cc: Valdis.Kletnieks@vt.edu
Cc: dhowells@redhat.com
LKML-Reference: <20091015162614.GA19131@linux.vnet.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-10-15 20:33:01 +02:00
microblaze: Enable GCOV_PROFILE_ALL
2009-09-21 14:29:21 +02:00
Merge branch 'irq-threaded-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
2009-09-11 13:21:31 -07:00
headers: utsname.h redux
2009-09-23 18:13:10 -07:00
NOHZ: update idle state also when NOHZ is inactive
2009-10-07 13:05:05 +02:00
Merge branch 'tracing-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
2009-10-08 12:06:09 -07:00
bsdacct: switch credentials for writing to the accounting file
2009-08-24 11:33:40 +10:00
Audit: send signal info if selinux is disabled
2009-09-24 03:50:26 -04:00
Fix rule eviction order for AUDIT_DIR
2009-06-24 00:02:38 -04:00
Fix rule eviction order for AUDIT_DIR
2009-06-24 00:02:38 -04:00
Audit: reorganize struct audit_watch to save 8 bytes
2009-09-24 03:50:25 -04:00
Audit: clean up all op= output to include string quoting
2009-06-24 00:00:52 -04:00
Audit: rearrange audit_context to save 16 bytes per struct
2009-09-24 03:50:26 -04:00
cgroup: catch bad css refcnt at css_put
2009-10-01 16:11:12 -07:00
cgroups: let ss->can_attach and ss->attach do whole threadgroups at a time
2009-09-24 07:20:58 -07:00
Merge branch 'x86-pat-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
2009-09-15 09:19:38 -07:00
cgroups: let ss->can_attach and ss->attach do whole threadgroups at a time
2009-09-24 07:20:58 -07:00
creds_are_invalid() needs to be exported for use by modules:
2009-09-23 11:02:26 -07:00
headers: taskstats_kern.h trim
2009-09-18 09:48:52 -07:00
Merge branch 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
2009-10-08 12:16:35 -07:00
Merge branch 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
2009-10-08 12:16:35 -07:00
sched: fix nr_uninterruptible accounting of frozen tasks really
2009-07-18 14:19:53 +02:00
futex: Check for NULL keys in match_futex
2009-10-14 22:00:14 +02:00
futex: Fix compat_futex to be same as futex for REQUEUE_PI
2009-08-10 15:41:12 +02:00
Merge branch 'timers-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
2009-10-05 12:04:16 -07:00
sysctl: remove "struct file *" argument of ->proc_handler
2009-09-24 07:21:04 -07:00
itimers: Add tracepoints for itimer
2009-08-29 14:10:07 +02:00
kallsyms: use new arch_is_kernel_text()
2009-09-23 07:39:30 -07:00
kexec: fix omitting offset in extended crashkernel syntax
2009-07-29 19:10:34 -07:00
kfifo: Use "const" definitions
2009-09-19 13:13:17 -07:00
Revert "kmod: fix race in usermodehelper code"
2009-09-23 18:12:10 -07:00
const: constify remaining file_operations
2009-10-01 16:11:11 -07:00
sched: Keep kthreads at default priority
2009-09-09 17:30:06 +02:00
lockdep: Use cpu_clock() for lockstat
2009-10-09 15:56:44 +02:00
lockdep: BFS cleanup
2009-07-24 10:53:29 +02:00
seq_file: constify seq_operations
2009-09-23 07:39:29 -07:00
cgroups: move the cgroup debug subsys into cgroup.c to access internal state
2009-09-24 07:20:57 -07:00
module: fix up CONFIG_KALLSYMS=n build.
2009-10-01 16:11:11 -07:00
cgroups: let ss->can_attach and ss->attach do whole threadgroups at a time
2009-09-24 07:20:58 -07:00
Merge branch 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
2009-10-08 12:16:35 -07:00
param: allow whitespace as kernel parameter separator
2009-09-25 00:32:58 +09:30
perf_event: Provide vmalloc() based mmap() backing
2009-10-06 14:21:50 +02:00
mm: also use alloc_large_system_hash() for the PID hash table
2009-09-22 07:17:38 -07:00
pidns: deny CLONE_PARENT|CLONE_NEWPID combination
2009-09-24 07:21:04 -07:00
itimers: Add tracepoints for itimer
2009-08-29 14:10:07 +02:00
time: Introduce CLOCK_REALTIME_COARSE
2009-08-21 21:43:46 +02:00
printk: add printk_delay to make messages readable for some scenarios
2009-09-23 07:39:28 -07:00
kernel/profile.c: Switch /proc/irq/prof_cpu_mask to seq_file
2009-09-20 20:15:40 +02:00
ptrace: __ptrace_detach: do __wake_up_parent() if we reap the tracee
2009-09-24 07:20:59 -07:00
rcu: Move rcu_barrier() to rcutree
2009-10-07 08:11:20 +02:00
rcu: Clean up code to address Ingo's checkpatch feedback
2009-09-23 19:46:30 +02:00
rcu: Fix TREE_PREEMPT_RCU CPU_HOTPLUG bad-luck hang
2009-10-15 20:33:01 +02:00
rcu: Fix TREE_PREEMPT_RCU CPU_HOTPLUG bad-luck hang
2009-10-15 20:33:01 +02:00
rcu: Fix TREE_PREEMPT_RCU CPU_HOTPLUG bad-luck hang
2009-10-15 20:33:01 +02:00
rcu: Make hot-unplugged CPU relinquish its own RCU callbacks
2009-10-07 08:11:20 +02:00
const: mark struct vm_struct_operations
2009-09-27 11:39:25 -07:00
memcg: some modification to softlimit under hierarchical memory reclaim.
2009-10-01 16:11:13 -07:00
walk system ram range
2009-09-23 07:39:41 -07:00
rtmutex: Avoid deadlock in rt_mutex_start_proxy_lock()
2009-08-06 05:50:21 +02:00
sched: Set correct normal_prio and prio values in sched_fork()
2009-10-05 13:42:20 +02:00
sched_clock: Fix atomicity/continuity bug by using cmpxchg64()
2009-09-30 22:56:10 +02:00
sched: Add new prio to cpupri before removing old prio
2009-08-02 14:26:09 +02:00
sched: Add new wakeup preemption mode: WAKEUP_RUNNING
2009-09-17 10:17:25 +02:00
sysctl: remove "struct file *" argument of ->proc_handler
2009-09-24 07:21:04 -07:00
sched: Add new wakeup preemption mode: WAKEUP_RUNNING
2009-09-17 10:17:25 +02:00
sched: Simplify sys_sched_rr_get_interval() system call
2009-09-21 09:53:55 +02:00
sched: Simplify sys_sched_rr_get_interval() system call
2009-09-21 09:53:55 +02:00
signals: inline __fatal_signal_pending
2009-09-24 07:21:01 -07:00
sysctl: remove "struct file *" argument of ->proc_handler
2009-09-24 07:21:04 -07:00
cpumask: remove arch_send_call_function_ipi
2009-09-24 09:34:47 +09:30
softirq: add BLOCK_IOPOLL to softirq_to_name
2009-09-17 15:53:44 -04:00
sysctl: remove "struct file *" argument of ->proc_handler
2009-09-24 07:21:04 -07:00
locking: Allow arch-inlined spinlocks
2009-08-31 18:08:50 +02:00
Merge branch 'hwpoison' of git://git.kernel.org/pub/scm/linux/kernel/git/ak/linux-mce-2.6
2009-09-24 07:53:22 -07:00
Merge branch 'master' of /home/davem/src/GIT/linux-2.6/
2009-09-24 15:13:11 -07:00
Merge branch 'hwpoison' of git://git.kernel.org/pub/scm/linux/kernel/git/ak/linux-mce-2.6
2009-09-24 07:53:22 -07:00
genetlink: make netns aware
2009-07-12 14:03:27 -07:00
time: Prevent 32 bit overflow with set_normalized_timespec()
2009-09-15 10:17:30 +02:00
Merge branch 'timers-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
2009-09-23 09:46:15 -07:00
trivial: fix typo "to to" in multiple files
2009-09-21 15:14:55 +02:00
headers: utsname.h redux
2009-09-23 18:13:10 -07:00
sysctl: remove "struct file *" argument of ->proc_handler
2009-09-24 07:21:04 -07:00
locking, sched: Give waitqueue spinlocks their own lockdep classes
2009-08-10 14:43:09 +02:00
Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
2009-09-11 13:23:18 -07:00
237c80c5c8