Nick Piggin
5fbfb18d7a
Fix up possibly racy module refcounting
...
Module refcounting is implemented with a per-cpu counter for speed.
However there is a race when tallying the counter where a reference may
be taken by one CPU and released by another. Reference count summation
may then see the decrement without having seen the previous increment,
leading to lower than expected count. A module which never has its
actual reference drop below 1 may return a reference count of 0 due to
this race.
Module removal generally runs under stop_machine, which prevents this
race causing bugs due to removal of in-use modules. However there are
other real bugs in module.c code and driver code (module_refcount is
exported) where the callers do not run under stop_machine.
Fix this by maintaining running per-cpu counters for the number of
module refcount increments and the number of refcount decrements. The
increments are tallied after the decrements, so any decrement seen will
always have its corresponding increment counted. The final refcount is
the difference of the total increments and decrements, preventing a
low-refcount from being returned.
Signed-off-by: Nick Piggin <npiggin@suse.de>
Acked-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-04-05 19:50:02 -07:00
..
gcov
irq
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h
2010-03-30 22:02:32 +09:00
power
Merge branch 'master' into export-slabh
2010-04-05 11:37:28 +09:00
time
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h
2010-03-30 22:02:32 +09:00
trace
Merge branch 'master' into export-slabh
2010-04-05 11:37:28 +09:00
.gitignore
acct.c
copy_signal() cleanup: kill taskstats_tgid_init() and acct_init_pacct()
2010-03-12 15:52:39 -08:00
async.c
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h
2010-03-30 22:02:32 +09:00
audit.c
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h
2010-03-30 22:02:32 +09:00
audit.h
audit_tree.c
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h
2010-03-30 22:02:32 +09:00
audit_watch.c
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h
2010-03-30 22:02:32 +09:00
auditfilter.c
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h
2010-03-30 22:02:32 +09:00
auditsc.c
audit: preface audit printk with audit
2010-04-05 13:19:45 -07:00
backtracetest.c
bounds.c
kbuild: move bounds.h to include/generated
2009-12-12 13:08:14 +01:00
capability.c
capabilities: Use RCU to protect task lookup in sys_capget
2009-12-10 09:42:48 +11:00
cgroup.c
cgroups: remove duplicate include
2010-03-24 16:31:19 -07:00
cgroup_freezer.c
Merge branch 'master' into export-slabh
2010-04-05 11:37:28 +09:00
compat.c
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h
2010-03-30 22:02:32 +09:00
configs.c
cpu.c
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h
2010-03-30 22:02:32 +09:00
cpuset.c
cpuset: alloc nodemask_t on the heap rather than the stack
2010-03-24 16:31:21 -07:00
cred-internals.h
cred.c
Merge branch 'master' into export-slabh
2010-04-05 11:37:28 +09:00
delayacct.c
dma.c
early_res.c
x86: Do not free zero sized per cpu areas
2010-03-29 18:55:40 +02:00
elfcore.c
elf coredump: add extended numbering support
2010-03-06 11:26:46 -08:00
exec_domain.c
exit.c
Merge branch 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
2010-03-13 14:43:01 -08:00
extable.c
fork.c
Merge branch 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
2010-03-13 14:43:01 -08:00
freezer.c
futex.c
futex: Handle futex value corruption gracefully
2010-02-03 15:13:22 +01:00
futex_compat.c
futex: Protect pid lookup in compat code with RCU
2009-12-09 14:22:14 +01:00
groups.c
hrtimer.c
hrtimers: Convert to raw_spinlocks
2009-12-14 23:55:34 +01:00
hung_task.c
softlockup: Fix hung_task_check_count sysctl
2009-11-27 06:21:57 +01:00
hw_breakpoint.c
Merge branch 'perf/core' into perf/urgent
2010-03-04 11:47:52 +01:00
itimer.c
itimers: Fix racy writes to cpu_itimer fields
2009-11-18 16:32:12 +01:00
kallsyms.c
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h
2010-03-30 22:02:32 +09:00
Kconfig.freezer
Kconfig.hz
Kconfig.locks
mutex: Better control mutex adaptive spinning config
2009-12-03 11:50:11 +01:00
Kconfig.preempt
kexec.c
percpu: add __percpu sparse annotations to core kernel subsystems
2010-02-17 11:17:38 +09:00
kfifo.c
kfifo: Don't use integer as NULL pointer
2010-02-16 15:11:08 -08:00
kgdb.c
kgdb: Turn off tracing while in the debugger
2010-04-02 14:58:19 -05:00
kmod.c
kmod: fix resource leak in call_usermodehelper_pipe()
2010-01-11 09:34:04 -08:00
kprobes.c
kprobes: Calculate the index correctly when freeing the out-of-line execution slot
2010-03-11 14:06:16 +01:00
ksysfs.c
Merge branch 'for-next' into for-linus
2010-03-08 16:55:37 +01:00
kthread.c
cpuset: fix the problem that cpuset_mem_spread_node() returns an offline node
2010-03-24 16:31:21 -07:00
latencytop.c
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h
2010-03-30 22:02:32 +09:00
lockdep.c
Merge branch 'slabh' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/misc
2010-04-05 09:39:11 -07:00
lockdep_internals.h
lockdep_proc.c
lockdep_states.h
Makefile
elf coredump: replace ELF_CORE_EXTRA_* macros by functions
2010-03-06 11:26:45 -08:00
module.c
Fix up possibly racy module refcounting
2010-04-05 19:50:02 -07:00
mutex-debug.c
headers: remove sched.h from interrupt.h
2009-10-11 11:20:58 -07:00
mutex-debug.h
locking: Implement new raw_spinlock
2009-12-14 23:55:32 +01:00
mutex.c
mutex: Better control mutex adaptive spinning config
2009-12-03 11:50:11 +01:00
mutex.h
notifier.c
sched: Use lockdep-based checking on rcu_dereference()
2010-02-25 10:34:26 +01:00
ns_cgroup.c
nsproxy.c
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h
2010-03-30 22:02:32 +09:00
padata.c
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h
2010-03-30 22:02:32 +09:00
panic.c
panic: fix panic_timeout accuracy when running on a hypervisor
2010-03-06 11:26:33 -08:00
params.c
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial
2010-03-12 16:04:50 -08:00
perf_event.c
Merge branch 'master' into export-slabh
2010-04-05 11:37:28 +09:00
pid.c
Merge branch 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
2010-03-13 14:43:01 -08:00
pid_namespace.c
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h
2010-03-30 22:02:32 +09:00
pm_qos_params.c
pm_qos: clean up racy global "name" variable
2009-10-14 15:31:10 +02:00
posix-cpu-timers.c
Merge branch 'timers-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
2010-03-26 15:10:38 -07:00
posix-timers.c
posix-timers.c: Don't export local functions
2010-02-05 14:54:10 +01:00
printk.c
printk: avoid warning when CONFIG_PRINTK is disabled
2010-03-06 11:26:33 -08:00
profile.c
ptrace.c
ptrace: Fix ptrace_regset() comments and diagnose errors specifically
2010-02-23 13:45:26 -08:00
range.c
x86: Change range end to start+size
2010-02-10 17:47:17 -08:00
rcupdate.c
rcu: Make rcu_read_lock_bh_held() allow for disabled BH
2010-03-16 09:57:49 +01:00
rcutiny.c
rcu: Eliminate unneeded function wrapping
2009-11-22 18:58:16 +01:00
rcutorture.c
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu
2010-03-03 07:34:18 -08:00
rcutree.c
rcu: Fix accelerated grace periods for last non-dynticked CPU
2010-02-27 09:53:52 +01:00
rcutree.h
rcu: Increase RCU CPU stall timeouts if PROVE_RCU
2010-03-11 13:38:01 +01:00
rcutree_plugin.h
rcu: Fix holdoff for accelerated GPs for last non-dynticked CPU
2010-02-28 09:17:42 +01:00
rcutree_trace.c
rcu: Stop overflowing signed integers
2010-02-25 10:34:57 +01:00
relay.c
splice: comparing unsigned int < 0
2010-03-06 11:26:32 -08:00
res_counter.c
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h
2010-03-30 22:02:32 +09:00
resource.c
resources: add interfaces that return conflict information
2010-03-23 13:33:50 -07:00
rtmutex-debug.c
sched: Convert pi_lock to raw_spinlock
2009-12-14 23:55:33 +01:00
rtmutex-debug.h
rtmutex-tester.c
rtmutex.c
rtmutes: Convert rtmutex.lock to raw_spinlock
2009-12-14 23:55:33 +01:00
rtmutex.h
rtmutex_common.h
rwsem.c
sched.c
Merge branch 'master' into export-slabh
2010-04-05 11:37:28 +09:00
sched_clock.c
sched: Fix cpu_clock() in NMIs, on !CONFIG_HAVE_UNSTABLE_SCHED_CLOCK
2009-12-15 09:04:36 +01:00
sched_cpupri.c
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h
2010-03-30 22:02:32 +09:00
sched_cpupri.h
sched: Convert cpupri lock to raw_spinlock
2009-12-14 23:55:33 +01:00
sched_debug.c
sched: Fix proc_sched_set_task()
2010-04-02 20:06:40 +02:00
sched_fair.c
sched, rcu: Fix rcu_dereference() for RCU-lockdep
2010-03-01 09:29:58 +01:00
sched_features.h
sched: Discard some old bits
2009-12-09 10:03:07 +01:00
sched_idletask.c
sched: Remove the sched_class load_balance methods
2010-01-21 13:40:09 +01:00
sched_rt.c
Merge branch 'sched-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
2010-03-13 14:46:18 -08:00
sched_stats.h
seccomp.c
semaphore.c
signal.c
kernel core: use helpers for rlimits
2010-03-06 11:26:33 -08:00
slow-work-debugfs.c
SLOW_WORK: Move slow_work's proc file to debugfs
2009-12-01 08:20:31 -08:00
slow-work.c
slow-work: use get_ref wrapper instead of directly calling get_ref
2010-03-29 09:13:30 -07:00
slow-work.h
SLOW_WORK: CONFIG_SLOW_WORK_PROC should be CONFIG_SLOW_WORK_DEBUG
2010-03-29 09:14:47 -07:00
smp.c
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h
2010-03-30 22:02:32 +09:00
softirq.c
hrtimer, softirq: Fix hrtimer->softirq trampoline
2010-02-03 18:17:40 +01:00
softlockup.c
softlockup: Stop spurious softlockup messages due to overflow
2010-03-21 19:30:13 +01:00
spinlock.c
locking: Cleanup the name space completely
2009-12-14 23:55:33 +01:00
srcu.c
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h
2010-03-30 22:02:32 +09:00
stacktrace.c
stop_machine.c
percpu: add __percpu sparse annotations to core kernel subsystems
2010-02-17 11:17:38 +09:00
sys.c
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h
2010-03-30 22:02:32 +09:00
sys_ni.c
Add generic sys_ipc wrapper
2010-03-12 15:52:32 -08:00
sysctl.c
sysctl extern cleanup: lockdep
2010-03-12 15:53:10 -08:00
sysctl_binary.c
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h
2010-03-30 22:02:32 +09:00
sysctl_check.c
ipv4 05/05: add sysctl to accept packets with local source addresses
2009-12-03 12:14:38 -08:00
taskstats.c
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h
2010-03-30 22:02:32 +09:00
test_kprobes.c
time.c
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h
2010-03-30 22:02:32 +09:00
timeconst.pl
timer.c
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h
2010-03-30 22:02:32 +09:00
tracepoint.c
tsacct.c
mm: clean up mm_counter
2010-03-06 11:26:23 -08:00
uid16.c
up.c
user-return-notifier.c
core: Clean up user return notifers use of per_cpu
2009-12-02 10:22:59 +01:00
user.c
sched: Remove USER_SCHED
2010-01-21 13:40:18 +01:00
user_namespace.c
utsname.c
utsname_sysctl.c
sysctl kernel: Remove binary sysctl logic
2009-11-12 02:04:55 -08:00
wait.c
workqueue.c
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq
2009-12-10 09:35:44 -08:00