David Howells ce82653d6c radix_tree_tag_get() is not as safe as the docs make out [ver #2] ... radix_tree_tag_get() is not safe to use concurrently with radix_tree_tag_set() or radix_tree_tag_clear(). The problem is that the double tag_get() in radix_tree_tag_get(): if (!tag_get(node, tag, offset)) saw_unset_tag = 1; if (height == 1) { int ret = tag_get(node, tag, offset); may see the value change due to the action of set/clear. RCU is no protection against this as no pointers are being changed, no nodes are being replaced according to a COW protocol - set/clear alter the node directly. The documentation in linux/radix-tree.h, however, says that radix_tree_tag_get() is an exception to the rule that "any function modifying the tree or tags (...) must exclude other modifications, and exclude any functions reading the tree". The problem is that the next statement in radix_tree_tag_get() checks that the tag doesn't vary over time: BUG_ON(ret && saw_unset_tag); This has been seen happening in FS-Cache: https://www.redhat.com/archives/linux-cachefs/2010-April/msg00013.html To this end, remove the BUG_ON() from radix_tree_tag_get() and note in various comments that the value of the tag may change whilst the RCU read lock is held, and thus that the return value of radix_tree_tag_get() may not be relied upon unless radix_tree_tag_set/clear() and radix_tree_delete() are excluded from running concurrently with it. Reported-by: Romain DEGEZ <romain.degez@smartjog.com> Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Nick Piggin <npiggin@suse.de> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>		2010-04-09 10:12:03 -07:00
..
lzo	lib: add support for LZO-compressed kernels	2010-01-11 09:34:04 -08:00
reed_solomon	lib: Remove unnecessary inclusions of asm/semaphore.h	2008-04-18 22:17:17 -04:00
zlib_deflate	trivial: fix typo "to to" in multiple files	2009-09-21 15:14:55 +02:00
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.c	lib: export generic atomic64_t functions	2009-07-29 19:10:35 -07:00
audit.c
bcd.c	rtc: BCD codeshrink	2008-07-24 10:47:33 -07:00
bitmap.c	bitmap: use for_each_set_bit()	2010-03-06 11:26:35 -08:00
bitrev.c	lib: export bitrev16	2008-06-06 11:29:10 -07:00
btree.c	[LogFS] add new flash file system	2009-11-20 20:13:39 +01:00
bug.c	allow bug table entries to use relative pointers (and use it on x86-64)	2008-12-16 18:40:32 +01:00
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
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	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
crc32defs.h
crc-ccitt.c
crc-itu-t.c
crc-t10dif.c	[SCSI] lib: Add support for the T10 (SCSI) Data Integrity Field CRC	2008-07-12 08:22:32 -05:00
ctype.c	ctype: constify read-only _ctype string	2009-12-15 08:53:32 -08:00
debug_locks.c	rcu: Introduce lockdep-based checking to RCU read-side primitives	2010-02-25 09:40:59 +01:00
debugobjects.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
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	bzip2: Add missing checks for malloc returning NULL	2009-12-15 14:04:19 -08:00
decompress_inflate.c	lzma/gzip: fix potential oops when input data is truncated	2009-09-24 07:21:05 -07:00
decompress_unlzma.c	lzma/gzip: fix potential oops when input data is truncated	2009-09-24 07:21:05 -07:00
decompress_unlzo.c	lib: add support for LZO-compressed kernels	2010-01-11 09:34:04 -08:00
decompress.c	Add LZO compression support for initramfs and old-style initrd	2010-01-11 09:34:05 -08:00
devres.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
div64.c	add an inlined version of iter_div_u64_rem	2008-06-12 10:47:58 +02:00
dma-debug.c	Merge branches 'amd-iommu/fixes' and 'dma-debug/fixes' into iommu/fixes	2010-01-22 18:00:41 +01:00
dump_stack.c
dynamic_debug.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
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: remove "optimizations"	2008-04-29 08:11:16 -07:00
flex_array.c	flex_array: add missing kerneldoc annotations	2009-09-22 07:17:47 -07:00
gcd.c	lib: add lib/gcd.c	2009-06-18 13:04:05 -07:00
gen_crc32table.c
genalloc.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
halfmd4.c
hexdump.c	hexdump: remove the trailing space	2009-06-16 19:47:51 -07:00
hweight.c	x86, core: Optimize hweight32()	2009-12-28 10:41:39 +01:00
idr.c	idr: Apply lockdep-based diagnostics to rcu_dereference() uses	2010-02-25 10:34:51 +01:00
inflate.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
int_sqrt.c
iomap_copy.c
iomap.c	Use WARN() in lib/	2008-07-26 12:00:07 -07:00
iommu-helper.c	iommu-helper: use bitmap library	2009-12-16 07:20:18 -08:00
ioremap.c
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	Revert "lib: build list_sort() only if needed"	2010-03-07 09:54:44 -08:00
Kconfig.debug	microblaze: Enable memory leak detector	2010-04-07 07:27:26 +02:00
Kconfig.kgdb	kgdb: remove the requirement for CONFIG_FRAME_POINTER	2008-08-01 08:39:34 -05:00
Kconfig.kmemcheck	kmemcheck: depend on HAVE_ARCH_KMEMCHECK	2009-07-01 22:28:44 +02:00
kernel_lock.c	bkl: Fixup core_lock fallout	2009-12-14 23:55:33 +01:00
klist.c	driver core: Remove completion from struct klist_node	2009-01-06 10:44:30 -08:00
kobject_uevent.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
kobject.c	Driver core: Constify struct sysfs_ops in struct kobj_type	2010-03-07 17:04:49 -08:00
kref.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
libcrc32c.c	libcrc32c: Fix "crc32c undefined" compilation error	2008-12-25 11:01:42 +11:00
list_debug.c	list debugging: use WARN() instead of BUG()	2008-07-25 10:53:29 -07:00
list_sort.c	lib: revise list_sort() header comment	2010-03-06 11:26:35 -08:00
lmb.c	lmb: Add lmb_free()	2010-02-03 17:39:50 +11:00
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	locking: rename trace_softirq_[enter|exit] => lockdep_softirq_[enter|exit]	2009-03-13 01:32:36 +01:00
lru_cache.c	The DRBD driver	2009-10-01 21:17:49 +02:00
Makefile	Revert "lib: build list_sort() only if needed"	2010-03-07 09:54:44 -08:00
nlattr.c	Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/kaber/nf-next-2.6	2009-03-26 22:45:23 -07:00
parser.c	parser: remove unnecessary strlen()	2009-12-15 08:53:33 -08:00
percpu_counter.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
plist.c	plist: Make plist debugging raw_spinlock aware	2009-12-14 23:55:33 +01:00
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_tag_get() is not as safe as the docs make out [ver #2]	2010-04-09 10:12:03 -07:00
random32.c	random32: seeding improvement	2008-07-30 16:29:19 -07:00
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	rb_tree: remove redundant if()-condition in rb_erase()	2009-06-16 19:47:56 -07:00
reciprocal_div.c
rwsem-spinlock.c	rwsem generic spinlock: use IRQ save/restore spinlocks	2010-04-07 16:15:05 -07:00
rwsem.c	x86: fix UML and -regparm=3	2008-01-30 13:33:00 +01:00
scatterlist.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
sha1.c
show_mem.c	mm: use the same log level for show_mem()	2010-03-06 11:26:27 -08:00
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	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
syscall.c	task_current_syscall	2008-07-26 12:00:10 -07:00
textsearch.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
ts_bm.c	textsearch: ts_bm: support case insensitive searching in Boyer-Moore algorithm	2008-07-08 02:37:54 -07:00
ts_fsm.c	textsearch: ts_fsm: return error on request for case insensitive search	2008-07-08 02:38:27 -07:00
ts_kmp.c	textsearch: ts_kmp: support case insensitive searching in Knuth-Morris-Pratt algorithm	2008-07-08 02:38:09 -07:00
vsprintf.c	resource: add window support	2010-03-14 20:08:36 -04:00