Linus Torvalds
a49b7e82ca
kobject: fix kset_find_obj() race with concurrent last kobject_put()
...
Anatol Pomozov identified a race condition that hits module unloading
and re-loading. To quote Anatol:
"This is a race codition that exists between kset_find_obj() and
kobject_put(). kset_find_obj() might return kobject that has refcount
equal to 0 if this kobject is freeing by kobject_put() in other
thread.
Here is timeline for the crash in case if kset_find_obj() searches for
an object tht nobody holds and other thread is doing kobject_put() on
the same kobject:
THREAD A (calls kset_find_obj()) THREAD B (calls kobject_put())
splin_lock()
atomic_dec_return(kobj->kref), counter gets zero here
... starts kobject cleanup ....
spin_lock() // WAIT thread A in kobj_kset_leave()
iterate over kset->list
atomic_inc(kobj->kref) (counter becomes 1)
spin_unlock()
spin_lock() // taken
// it does not know that thread A increased counter so it
remove obj from list
spin_unlock()
vfree(module) // frees module object with containing kobj
// kobj points to freed memory area!!
kobject_put(kobj) // OOPS!!!!
The race above happens because module.c tries to use kset_find_obj()
when somebody unloads module. The module.c code was introduced in
commit 6494a93d55 "
Anatol supplied a patch specific for module.c that worked around the
problem by simply not using kset_find_obj() at all, but rather than make
a local band-aid, this just fixes kset_find_obj() to be thread-safe
using the proper model of refusing the get a new reference if the
refcount has already dropped to zero.
See examples of this proper refcount handling not only in the kref
documentation, but in various other equivalent uses of this pattern by
grepping for atomic_inc_not_zero().
[ Side note: the module race does indicate that module loading and
unloading is not properly serialized wrt sysfs information using the
module mutex. That may require further thought, but this is the
correct fix at the kobject layer regardless. ]
Reported-analyzed-and-tested-by: Anatol Pomozov <anatol.pomozov@gmail.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: stable@vger.kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-04-13 15:15:30 -07:00
..
lzo
lib/lzo: Update LZO compression to current upstream version
2013-02-20 19:36:01 +01:00
mpi
mpilib: use DIV_ROUND_UP and remove unused macros
2013-02-01 16:28:32 +11:00
raid6
lib/raid6: build proper files on corresponding arch
2012-12-13 19:51:04 +11:00
reed_solomon
xz
decompressors: fix typo "POWERPC"
2013-03-13 15:21:48 -07:00
zlib_deflate
zlib_inflate
.gitignore
X.509: Implement simple static OID registry
2012-10-08 13:50:18 +10:30
argv_split.c
lib: reduce the use of module.h wherever possible
2012-03-07 15:04:04 -05:00
asn1_decoder.c
Nothing all that exciting; a new module-from-fd syscall for those who want
2012-12-19 07:55:08 -08:00
atomic64.c
lib: atomic64: Initialize locks statically to fix early users
2012-12-20 13:50:16 -08:00
atomic64_test.c
atomic64_test: simplify the #ifdef for atomic64_dec_if_positive() test
2012-07-30 17:25:16 -07:00
audit.c
audit: support the "standard" <asm-generic/unistd.h>
2011-05-04 14:41:28 -04:00
average.c
lib: reduce the use of module.h wherever possible
2012-03-07 15:04:04 -05:00
bcd.c
usb/core: use bin2bcd() for bcdDevice in RH
2012-09-10 11:13:16 -07:00
bch.c
bitmap.c
propagate name change to comments in kernel source
2012-12-06 10:39:54 +01:00
bitrev.c
bsearch.c
lib: reduce the use of module.h wherever possible
2012-03-07 15:04:04 -05:00
btree.c
btree: catch NULL value before it does harm
2012-06-07 14:43:55 -07:00
bug.c
taint: add explicit flag to show whether lock dep is still OK.
2013-01-21 17:17:57 +10:30
build_OID_registry
X.509: Implement simple static OID registry
2012-10-08 13:50:18 +10:30
bust_spinlocks.c
printk: Provide a wake_up_klogd() off-case
2013-03-22 16:41:20 -07:00
check_signature.c
lib: reduce the use of module.h wherever possible
2012-03-07 15:04:04 -05:00
checksum.c
asm-generic headers: Allow yet more arch overrides in checksum.h
2013-02-11 20:00:33 +05:30
clz_tab.c
lib: Fix multiple definitions of clz_tab
2012-02-02 10:34:23 +11:00
cmdline.c
lib: reduce the use of module.h wherever possible
2012-03-07 15:04:04 -05:00
cordic.c
Docs: wording: functions -> algorithm
2011-10-29 21:20:22 +02:00
cpu-notifier-error-inject.c
cpu: rewrite cpu-notifier-error-inject module
2012-07-30 17:25:22 -07:00
cpu_rmap.c
lib: cpu_rmap: avoid flushing all workqueues
2013-01-11 14:54:54 -08:00
cpumask.c
bootmem: fix wrong call parameter for free_bootmem()
2012-12-11 17:22:28 -08:00
crc-ccitt.c
crc-itu-t.c
crc-t10dif.c
crc7.c
crc8.c
lib: crc8: add new library module providing crc8 algorithm
2011-06-03 15:01:06 -04:00
crc16.c
crc32.c
sections: fix const sections for crc32 table
2012-10-06 03:04:46 +09:00
crc32defs.h
crc32: select an algorithm via Kconfig
2012-03-23 16:58:38 -07:00
ctype.c
lib: reduce the use of module.h wherever possible
2012-03-07 15:04:04 -05:00
debug_locks.c
lib: reduce the use of module.h wherever possible
2012-03-07 15:04:04 -05:00
debugobjects.c
hlist: drop the node parameter from iterators
2013-02-27 19:10:24 -08:00
dec_and_lock.c
lib: reduce the use of module.h wherever possible
2012-03-07 15:04:04 -05:00
decompress.c
lib/decompress.c add __init to decompress_method and data
2012-10-06 03:05:32 +09:00
decompress_bunzip2.c
decompress_bunzip2: remove invalid vi modeline
2011-12-06 10:00:05 +01:00
decompress_inflate.c
decompress_unlzma.c
treewide: Fix comment and string typo 'bufer'
2011-12-06 09:53:40 +01:00
decompress_unlzo.c
lib/lzo: Rename lzo1x_decompress.c to lzo1x_decompress_safe.c
2013-02-20 19:36:00 +01:00
decompress_unxz.c
Fix common misspellings
2011-03-31 11:26:23 -03:00
devres.c
lib/devres.c: fix misplaced #endif
2013-02-27 19:10:09 -08:00
digsig.c
Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security
2013-02-21 08:18:12 -08:00
div64.c
lib: correct link to the original source for div64_u64
2012-06-28 11:51:39 +02:00
dma-debug.c
dma-debug: update DMA debug API to better handle multiple mappings of a buffer
2013-03-22 16:41:20 -07:00
dump_stack.c
lib: reduce the use of module.h wherever possible
2012-03-07 15:04:04 -05:00
dynamic_debug.c
dynamic_debug: add pr_errs before -EINVALs
2013-01-17 12:19:09 -08:00
dynamic_queue_limits.c
bql: Avoid possible inconsistent calculation.
2012-05-31 18:18:17 -04:00
earlycpio.c
lib: Add early cpio decoder
2012-09-30 18:02:20 -07:00
extable.c
fault-inject.c
fault-inject: avoid call to random32() if fault injection is disabled
2012-06-20 14:39:36 -07:00
fdt.c
of/lib: Allow scripts/dtc/libfdt to be used from kernel code
2012-07-23 13:54:52 +01:00
fdt_ro.c
of/lib: Allow scripts/dtc/libfdt to be used from kernel code
2012-07-23 13:54:52 +01:00
fdt_rw.c
of/lib: Allow scripts/dtc/libfdt to be used from kernel code
2012-07-23 13:54:52 +01:00
fdt_strerror.c
of/lib: Allow scripts/dtc/libfdt to be used from kernel code
2012-07-23 13:54:52 +01:00
fdt_sw.c
of/lib: Allow scripts/dtc/libfdt to be used from kernel code
2012-07-23 13:54:52 +01:00
fdt_wip.c
of/lib: Allow scripts/dtc/libfdt to be used from kernel code
2012-07-23 13:54:52 +01:00
find_last_bit.c
lib: reduce the use of module.h wherever possible
2012-03-07 15:04:04 -05:00
find_next_bit.c
lib: reduce the use of module.h wherever possible
2012-03-07 15:04:04 -05:00
flex_array.c
lib: reduce the use of module.h wherever possible
2012-03-07 15:04:04 -05:00
flex_proportions.c
lib/flex_proportions.c: fix corruption of denominator in flexible proportions
2012-09-25 08:59:21 -07:00
gcd.c
lib/gcd.c: prevent possible div by 0
2012-10-06 03:04:57 +09:00
gen_crc32table.c
sections: fix const sections for crc32 table
2012-10-06 03:04:46 +09:00
genalloc.c
genalloc: stop crashing the system when destroying a pool
2012-10-25 14:37:52 -07:00
halfmd4.c
lib: reduce the use of module.h wherever possible
2012-03-07 15:04:04 -05:00
hexdump.c
dynamic_debug: dynamic hex dump
2013-01-17 12:19:09 -08:00
hweight.c
lib: reduce the use of module.h wherever possible
2012-03-07 15:04:04 -05:00
idr.c
idr: idr_alloc() shouldn't trigger lowmem warning when preloaded
2013-03-13 15:21:49 -07:00
inflate.c
int_sqrt.c
lib: reduce the use of module.h wherever possible
2012-03-07 15:04:04 -05:00
interval_tree.c
mm: interval tree updates
2012-10-09 16:22:40 +09:00
interval_tree_test_main.c
random32: rename random32 to prandom
2012-12-17 17:15:26 -08:00
iomap.c
lib: reduce the use of module.h wherever possible
2012-03-07 15:04:04 -05:00
iomap_copy.c
lib: reduce the use of module.h wherever possible
2012-03-07 15:04:04 -05:00
iommu-helper.c
The following text was taken from the original review request:
2012-03-24 10:24:31 -07:00
ioremap.c
lib: reduce the use of module.h wherever possible
2012-03-07 15:04:04 -05:00
irq_regs.c
lib: reduce the use of module.h wherever possible
2012-03-07 15:04:04 -05:00
is_single_threaded.c
jedec_ddr_data.c
ddr: add LPDDR2 data from JESD209-2
2012-05-02 00:04:06 -07:00
kasprintf.c
lib/kasprintf.c: use kmalloc_track_caller() to get accurate traces for kvasprintf
2012-10-11 08:50:15 +09:00
Kconfig
lib: remove depends on CONFIG_EXPERIMENTAL
2013-01-17 12:11:27 -08:00
Kconfig.debug
ImgTec Meta architecture changes for v3.9-rc1
2013-03-03 12:06:09 -08:00
Kconfig.kgdb
KGDB/KDB fixes and cleanups
2013-03-02 08:31:39 -08:00
Kconfig.kmemcheck
kfifo.c
kfifo: fix kfifo_alloc() and kfifo_init()
2013-02-27 19:10:23 -08:00
klist.c
Revert "driver core: check start node in klist_iter_init_node"
2012-04-19 19:17:30 -07:00
kobject.c
kobject: fix kset_find_obj() race with concurrent last kobject_put()
2013-04-13 15:15:30 -07:00
kobject_uevent.c
netlink: hide struct module parameter in netlink_kernel_create
2012-09-08 18:46:30 -04:00
kstrtox.c
kstrto*: add documentation
2012-12-17 17:15:22 -08:00
kstrtox.h
lib/kstrtox: common code between kstrto*() and simple_strto*() functions
2011-10-31 17:30:56 -07:00
lcm.c
lib: reduce the use of module.h wherever possible
2012-03-07 15:04:04 -05:00
libcrc32c.c
list_debug.c
rcu: Fix broken strings in RCU's source code.
2012-07-06 06:01:49 -07:00
list_sort.c
llist.c
Disintegrate and delete asm/system.h
2012-03-28 15:58:21 -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
lockdep: Selftest: convert spinlock to raw spinlock
2013-02-19 08:43:35 +01:00
lru_cache.c
hlist: drop the node parameter from iterators
2013-02-27 19:10:24 -08:00
Makefile
kfifo: move kfifo.c from kernel/ to lib/
2013-02-27 19:10:23 -08:00
md5.c
lib: reduce the use of module.h wherever possible
2012-03-07 15:04:04 -05:00
memory-notifier-error-inject.c
memory: memory notifier error injection module
2012-07-30 17:25:22 -07:00
memweight.c
string: introduce memweight()
2012-07-30 17:25:16 -07:00
nlattr.c
netlink: add minlen validation for the new signed types
2012-08-30 13:11:46 -04:00
notifier-error-inject.c
fault-injection: notifier error injection
2012-07-30 17:25:22 -07:00
notifier-error-inject.h
fault-injection: notifier error injection
2012-07-30 17:25:22 -07:00
of-reconfig-notifier-error-inject.c
powerpc+of: Rename and fix OF reconfig notifier error inject module
2012-12-14 10:32:52 +11:00
oid_registry.c
X.509: Add utility functions to render OIDs as strings
2012-10-08 13:50:18 +10:30
parser.c
lib/parser.c: fix up comments for valid return values from match_number
2013-02-21 17:22:25 -08:00
pci_iomap.c
lib: add NO_GENERIC_PCI_IOPORT_MAP
2012-01-31 23:19:47 +02:00
percpu-rwsem.c
percpu_rw_semaphore: add lockdep annotations
2012-12-17 17:15:18 -08:00
percpu_counter.c
switch the protection of percpu_counter list to spinlock
2012-07-31 09:28:31 +04:00
plist.c
lib/plist.c: make plist test announcements KERN_DEBUG
2012-10-06 03:04:58 +09:00
pm-notifier-error-inject.c
PM: PM notifier error injection module
2012-07-30 17:25:22 -07:00
prio_heap.c
proportions.c
locking, lib/proportions: Annotate prop_local_percpu::lock as raw
2011-09-13 11:11:50 +02:00
radix-tree.c
radix-tree: fix contiguous iterator
2012-06-05 10:46:40 -07:00
random32.c
prandom: introduce prandom_bytes() and prandom_bytes_state()
2012-12-17 17:15:26 -08:00
ratelimit.c
lib: reduce the use of module.h wherever possible
2012-03-07 15:04:04 -05:00
rational.c
lib: Change mail address of Oskar Schirmer
2012-05-17 15:18:37 +02:00
rbtree.c
lib/rbtree.c: avoid the use of non-static __always_inline
2013-01-11 14:54:56 -08:00
rbtree_test.c
random32: rename random32 to prandom
2012-12-17 17:15:26 -08:00
reciprocal_div.c
sch_red: Adaptative RED AQM
2011-12-08 19:52:43 -05:00
rwsem-spinlock.c
rwsem-spinlock: Implement writer lock-stealing for better scalability
2013-02-19 08:43:39 +01:00
rwsem.c
rwsem: Implement writer lock-stealing for better scalability
2013-02-19 08:42:43 +01:00
scatterlist.c
lib/scatterlist: use page iterator in the mapping iterator
2013-02-27 19:10:10 -08:00
sha1.c
lib: reduce the use of module.h wherever possible
2012-03-07 15:04:04 -05:00
show_mem.c
arch, mm: filter disallowed nodes from arch specific show_mem functions
2011-05-25 08:39:03 -07:00
smp_processor_id.c
lib: reduce the use of module.h wherever possible
2012-03-07 15:04:04 -05:00
sort.c
spinlock_debug.c
lib/spinlock_debug: avoid livelock in do_raw_spin_lock()
2012-10-06 03:04:57 +09:00
stmp_device.c
lib: add support for stmp-style devices
2012-04-20 23:27:08 +02:00
string.c
The following text was taken from the original review request:
2012-03-24 10:24:31 -07:00
string_helpers.c
lib/string_helpers.c: make arrays static
2012-05-29 16:22:32 -07:00
strncpy_from_user.c
word-at-a-time: make the interfaces truly generic
2012-05-26 11:33:40 -07:00
strnlen_user.c
lib: Fix generic strnlen_user for 32-bit big-endian machines
2012-05-27 20:59:46 -07:00
swiotlb.c
x86: Don't panic if can not alloc buffer for swiotlb
2013-01-29 19:36:53 -08:00
syscall.c
lib: reduce the use of module.h wherever possible
2012-03-07 15:04:04 -05:00
test-kstrtox.c
lib/test-kstrtox.c: mark const init data with __initconst instead of __initdata
2012-05-29 16:22:32 -07:00
textsearch.c
timerqueue.c
The following text was taken from the original review request:
2012-03-24 10:24:31 -07:00
ts_bm.c
ts_fsm.c
ts_kmp.c
uuid.c
lib: reduce the use of module.h wherever possible
2012-03-07 15:04:04 -05:00
vsprintf.c
lib/vsprintf.c: add %pa format specifier for phys_addr_t types
2013-02-21 17:22:20 -08:00