linux/lib
Frederic Weisbecker ba9f207c9f rcu: Fix unpaired rcu_irq_enter() from locking selftests
HARDIRQ_ENTER() maps to irq_enter() which calls rcu_irq_enter().
But HARDIRQ_EXIT() maps to __irq_exit() which doesn't call
rcu_irq_exit().

So for every locking selftest that simulates hardirq disabled,
we create an imbalance in the rcu extended quiescent state
internal state.

As a result, after the first missing rcu_irq_exit(), subsequent
irqs won't exit dyntick-idle mode after leaving the interrupt
handler.  This means that RCU won't see the affected CPU as being
in an extended quiescent state, resulting in long grace-period
delays (as in grace periods extending for hours).

To fix this, just use __irq_enter() to simulate the hardirq
context. This is sufficient for the locking selftests as we
don't need to exit any extended quiescent state or perform
any check that irqs normally do when they wake up from idle.

As a side effect, this patch makes it possible to restore
"rcu: Decrease memory-barrier usage based on semi-formal proof",
which eventually helped finding this bug.

Reported-and-tested-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Stable <stable@kernel.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2011-05-26 09:42:19 -07:00
..
lzo lib: add support for LZO-compressed kernels 2010-01-11 09:34:04 -08:00
raid6 Move .gitignore from drivers/md to lib/raid6 2010-08-30 17:35:52 +10:00
reed_solomon
xz XZ decompressor: Fix decoding of empty LZMA2 streams 2011-05-02 08:46:12 -07:00
zlib_deflate zlib: slim down zlib_deflate() workspace when possible 2011-03-22 17:44:17 -07:00
zlib_inflate inflate_fast: sout is already a short so ptr arith was off by one. 2010-03-12 15:52:44 -08:00
.gitignore
argv_split.c tree-wide: convert open calls to remove spaces to skip_spaces() lib function 2009-12-15 08:53:32 -08:00
atomic64_test.c ARM: 6213/1: atomic64_test: add ARM as supported architecture 2010-07-27 10:43:46 +01:00
atomic64.c lib: Fix atomic64_add_unless return value convention 2010-03-01 11:38:46 -08:00
audit.c
average.c lib: Improve EWMA efficiency by using bitshifts 2010-12-06 15:58:43 -05:00
bcd.c rtc: BCD codeshrink 2008-07-24 10:47:33 -07:00
bch.c lib: add shared BCH ECC library 2011-03-11 14:25:50 +00:00
bitmap.c Fix common misspellings 2011-03-31 11:26:23 -03:00
bitrev.c
btree.c Fix common misspellings 2011-03-31 11:26:23 -03:00
bug.c modules: Fix module_bug_list list corruption race 2010-10-05 11:29:27 -07:00
bust_spinlocks.c oops handling: ensure that any oops is flushed to the mtdoops console 2009-01-06 15:59:11 -08:00
check_signature.c
checksum.c lib/checksum: fix one more thinko 2009-11-03 16:06:53 +01:00
cmdline.c generic, memparse(): constify argument 2008-07-28 15:05:23 +02:00
cpu_rmap.c lib: cpu_rmap: CPU affinity reverse-mapping 2011-01-24 14:51:56 -08:00
cpu-notifier-error-inject.c fault-injection: add CPU notifier error injection module 2010-05-27 09:12:48 -07:00
cpumask.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
crc7.c
crc16.c
crc32.c revert "crc32: use __BYTE_ORDER macro for endian detection" 2010-05-26 08:19:23 -07:00
crc32defs.h
crc-ccitt.c
crc-itu-t.c
crc-t10dif.c
ctype.c ctype: constify read-only _ctype string 2009-12-15 08:53:32 -08:00
debug_locks.c Revert "debug_locks: set oops_in_progress if we will log messages." 2010-11-29 15:18:28 -08:00
debugobjects.c debugobjects: Add hint for better object identification 2011-03-08 16:10:38 +01:00
dec_and_lock.c atomic: only take lock when the counter drops to zero on UP as well 2009-06-16 19:47:47 -07:00
decompress_bunzip2.c Decompressors: include <linux/slab.h> in <linux/decompress/mm.h> 2011-01-13 08:03:23 -08:00
decompress_inflate.c decompressors: check input size in decompress_inflate.c 2011-01-13 08:03:25 -08:00
decompress_unlzma.c Decompressors: validate match distance in decompress_unlzma.c 2011-01-13 08:03:24 -08:00
decompress_unlzo.c Decompressors: fix callback-to-callback mode in decompress_unlzo.c 2011-01-13 08:03:24 -08:00
decompress_unxz.c Fix common misspellings 2011-03-31 11:26:23 -03:00
decompress.c decompressors: add boot-time XZ support 2011-01-13 08:03:25 -08:00
devres.c lib/devres.c: fix comment typo 2010-07-11 22:16:32 +02:00
div64.c div64_u64(): improve precision on 32bit platforms 2010-10-26 16:52:19 -07:00
dma-debug.c llseek: automatically add .llseek fop 2010-10-15 15:53:27 +02:00
dump_stack.c
dynamic_debug.c dynamic_debug: add #include <linux/sched.h> 2011-02-03 15:59:58 -08:00
extable.c module: trim exception table on init free. 2009-06-12 21:47:04 +09:30
fault-inject.c headers: remove sched.h from interrupt.h 2009-10-11 11:20:58 -07:00
find_last_bit.c bitmap: find_last_bit() 2009-01-01 10:12:19 +10:30
find_next_bit.c bitops: introduce CONFIG_GENERIC_FIND_BIT_LE 2011-03-23 19:46:14 -07:00
flex_array.c flex_array: export symbols to modules 2011-01-13 08:03:11 -08:00
gcd.c lib: add lib/gcd.c 2009-06-18 13:04:05 -07:00
gen_crc32table.c crc32: major optimization 2010-05-25 08:07:06 -07:00
genalloc.c genalloc: fix allocation from end of pool 2010-06-29 15:29:30 -07:00
halfmd4.c
hexdump.c include/linux/printk.h lib/hexdump.c: neatening and add CONFIG_PRINTK guard 2011-01-13 08:03:10 -08:00
hweight.c x86: Add optimized popcnt variants 2010-04-06 15:52:11 -07:00
idr.c docbook: add idr/ida to kernel-api docbook 2010-10-26 17:40:56 -07:00
inflate.c MN10300: Don't try and #include <linux/slab.h> in lib/inflate.c from bootloader 2010-08-12 09:51:35 -07:00
int_sqrt.c
iomap_copy.c
iomap.c Use WARN() in lib/ 2008-07-26 12:00:07 -07:00
iommu-helper.c iommu: inline iommu_num_pages 2010-08-09 20:45:05 -07:00
ioremap.c ACPI, APEI, Generic Hardware Error Source POLL/IRQ/NMI notification type support 2011-01-12 03:06:19 -05:00
irq_regs.c
is_single_threaded.c kernel: is_current_single_threaded: don't use ->mmap_sem 2009-07-17 09:11:31 +10:00
kasprintf.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 Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6 into for-linus-1 2011-03-25 17:41:20 +02:00
Kconfig.debug rcu: Enable DEBUG_OBJECTS_RCU_HEAD from !PREEMPT 2011-05-05 23:16:57 -07:00
Kconfig.kgdb mips,kgdb: kdb low level trap catch and stack trace 2010-05-20 21:04:26 -05:00
Kconfig.kmemcheck kmemcheck: depend on HAVE_ARCH_KMEMCHECK 2009-07-01 22:28:44 +02:00
klist.c driver core: Remove completion from struct klist_node 2009-01-06 10:44:30 -08:00
kobject_uevent.c kobject_uevent: fix typo in comments 2010-08-23 18:12:46 -07:00
kobject.c kobject: Introduce kset_find_obj_hinted. 2010-10-22 10:16:44 -07:00
kref.c kref: Add a kref_sub function 2010-11-22 13:25:13 +10:00
kstrtox.c kstrtox: simpler code in _kstrtoull() 2011-04-14 16:06:55 -07:00
lcm.c block: Fix overrun in lcm() and move it to lib 2010-03-15 12:47:59 +01:00
libcrc32c.c libcrc32c: Fix "crc32c undefined" compilation error 2008-12-25 11:01:42 +11:00
list_debug.c Expand CONFIG_DEBUG_LIST to several other list operations 2011-02-18 11:32:28 -08:00
list_sort.c lib/list_sort: test: check element addresses 2010-10-26 16:52:19 -07:00
locking-selftest-hardirq.h
locking-selftest-mutex.h
locking-selftest-rlock-hardirq.h
locking-selftest-rlock-softirq.h
locking-selftest-rlock.h
locking-selftest-rsem.h
locking-selftest-softirq.h
locking-selftest-spin-hardirq.h
locking-selftest-spin-softirq.h
locking-selftest-spin.h
locking-selftest-wlock-hardirq.h
locking-selftest-wlock-softirq.h
locking-selftest-wlock.h
locking-selftest-wsem.h
locking-selftest.c rcu: Fix unpaired rcu_irq_enter() from locking selftests 2011-05-26 09:42:19 -07:00
lru_cache.c The DRBD driver 2009-10-01 21:17:49 +02:00
Makefile Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6 into for-linus-1 2011-03-25 17:41:20 +02:00
nlattr.c net: fix nla_policy_len to actually _iterate_ over the policy 2011-02-28 12:38:25 -08:00
parser.c Fix common misspellings 2011-03-31 11:26:23 -03:00
percpu_counter.c percpucounter: Optimize __percpu_counter_add a bit through the use of this_cpu() options. 2010-12-17 15:07:18 +01:00
plist.c plist: Add priority list test 2011-03-11 15:14:48 -05:00
prio_heap.c lib: fix sparse shadowed variable warning 2009-01-06 15:59:11 -08:00
prio_tree.c
proportions.c Merge branch 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2009-01-06 17:10:04 -08:00
radix-tree.c radix_tree: radix_tree_gang_lookup_tag_slot() may never return 2011-01-26 10:50:04 +10:00
random32.c Merge branch 'master' into for-next 2010-06-16 18:08:13 +02:00
ratelimit.c ratelimit: fix the return value when __ratelimit() fails to acquire the lock 2010-04-07 08:38:04 -07:00
rational.c lib/rational.c needs module.h 2010-01-11 09:34:05 -08:00
rbtree.c Export the augmented rbtree helper functions 2011-01-28 12:16:59 +10:00
reciprocal_div.c
rwsem-spinlock.c rwsem generic spinlock: use IRQ save/restore spinlocks 2010-04-07 16:15:05 -07:00
rwsem.c rwsem: Remove redundant asmregparm annotation 2011-01-27 12:30:40 +01:00
scatterlist.c scatterlist: prevent invalid free when alloc fails 2010-08-30 19:55:09 +02:00
sha1.c
show_mem.c lib, arch: add filter argument to show_mem and fix private implementations 2011-03-24 17:49:37 -07:00
smp_processor_id.c cpumask: convert lib/smp_processor_id to new cpumask ops 2009-01-30 15:47:34 +01:00
sort.c generic swap(): lib/sort.c: rename swap to swap_func 2009-01-08 08:31:14 -08:00
spinlock_debug.c locking: Further name space cleanups 2009-12-14 23:55:33 +01:00
string_helpers.c [SCSI] lib: string_get_size(): don't hang on zero; no decimals on exact 2008-10-23 11:42:20 -05:00
string.c lib/string.c: simplify strnstr() 2010-03-06 11:26:35 -08:00
swiotlb.c swiotlb: fix wrong panic 2011-02-25 15:07:36 -08:00
syscall.c task_current_syscall 2008-07-26 12:00:10 -07:00
test-kstrtox.c kstrtox: fix compile warnings in test 2011-04-14 16:06:54 -07:00
textsearch.c textsearch: doc - fix spelling in lib/textsearch.c. 2011-01-24 23:33:30 -08:00
timerqueue.c Fix common misspellings 2011-03-31 11:26:23 -03:00
ts_bm.c
ts_fsm.c
ts_kmp.c
uuid.c Unified UUID/GUID definition 2010-05-19 22:40:47 -04:00
vsprintf.c Merge branch 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2011-03-25 17:52:22 -07:00