Alexandre Courbot c18e49ad50 lib/decompressors: fix "no limit" output buffer length ... commit 1431574a1c upstream. When decompressing into memory, the output buffer length is set to some arbitrarily high value (0x7fffffff) to indicate the output is, virtually, unlimited in size. The problem with this is that some platforms have their physical memory at high physical addresses (0x80000000 or more), and that the output buffer address and its "unlimited" length cannot be added without overflowing. An example of this can be found in inflate_fast(): /* next_out is the output buffer address */ out = strm->next_out - OFF; /* avail_out is the output buffer size. end will overflow if the output * address is >= 0x80000104 */ end = out + (strm->avail_out - 257); This has huge consequences on the performance of kernel decompression, since the following exit condition of inflate_fast() will be always true: } while (in < last && out < end); Indeed, "end" has overflowed and is now always lower than "out". As a result, inflate_fast() will return after processing one single byte of input data, and will thus need to be called an unreasonably high number of times. This probably went unnoticed because kernel decompression is fast enough even with this issue. Nonetheless, adjusting the output buffer length in such a way that the above pointer arithmetic never overflows results in a kernel decompression that is about 3 times faster on affected machines. Signed-off-by: Alexandre Courbot <acourbot@nvidia.com> Tested-by: Jon Medhurst <tixy@linaro.org> Cc: Stephen Warren <swarren@wwwdotorg.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mark Brown <broonie@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		2014-02-06 11:08:12 -08:00
..
lzo	lib/lzo: Update LZO compression to current upstream version	2013-02-20 19:36:01 +01:00
mpi	lib/mpi/mpicoder.c: looping issue, need stop when equal to zero, found by 'EXTRA_FLAGS=-W'.	2013-06-12 16:29:44 -07:00
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	argv_split(): teach it to handle mutable strings	2013-04-29 18:28:19 -07:00
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_test.c
atomic64.c	lib: atomic64: Initialize locks statically to fix early users	2012-12-20 13:50:16 -08:00
audit.c
average.c
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
btree.c
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
checksum.c	asm-generic headers: Allow yet more arch overrides in checksum.h	2013-02-11 20:00:33 +05:30
clz_tab.c
cmdline.c
cordic.c
cpu_rmap.c	lib: cpu_rmap: avoid flushing all workqueues	2013-01-11 14:54:54 -08:00
cpu-notifier-error-inject.c
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
crc16.c
crc32.c	sections: fix const sections for crc32 table	2012-10-06 03:04:46 +09:00
crc32defs.h
ctype.c
debug_locks.c
debugobjects.c	hlist: drop the node parameter from iterators	2013-02-27 19:10:24 -08:00
dec_and_lock.c
decompress_bunzip2.c
decompress_inflate.c	lib/decompressors: fix "no limit" output buffer length	2014-02-06 11:08:12 -08:00
decompress_unlzma.c
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
decompress.c	lib/decompress.c: fix initconst	2013-04-30 17:04:09 -07:00
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	Revert "math64: New div64_u64_rem helper"	2013-04-30 19:13:05 +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	dump_stack: consolidate dump_stack() implementations and unify their behaviors	2013-04-30 17:04:02 -07:00
dynamic_debug.c	dynamic_debug: reuse generic string_unescape function	2013-04-30 17:04:03 -07:00
dynamic_queue_limits.c
earlycpio.c	lib: Add early cpio decoder	2012-09-30 18:02:20 -07:00
extable.c
fault-inject.c	lib/: rename random32() to prandom_u32()	2013-04-29 18:28:42 -07:00
fdt_ro.c
fdt_rw.c
fdt_strerror.c
fdt_sw.c
fdt_wip.c
fdt.c
find_last_bit.c
find_next_bit.c
flex_array.c
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	lib/genalloc.c: fix overflow of ending address of memory chunk	2013-12-11 22:36:28 -08:00
halfmd4.c
hexdump.c	dynamic_debug: dynamic hex dump	2013-01-17 12:19:09 -08:00
hweight.c
idr.c	idr: introduce idr_alloc_cyclic()	2013-04-29 18:28:41 -07:00
inflate.c
int_sqrt.c	lib/int_sqrt.c: optimize square root algorithm	2013-04-29 18:28:19 -07:00
interval_tree_test_main.c	random32: rename random32 to prandom	2012-12-17 17:15:26 -08:00
interval_tree.c	mm: interval tree updates	2012-10-09 16:22:40 +09:00
iomap_copy.c
iomap.c
iommu-helper.c
ioremap.c
iovec.c	Hoist memcpy_fromiovec/memcpy_toiovec into lib/	2013-05-20 10:24:22 +09:30
irq_regs.c
is_single_threaded.c
jedec_ddr_data.c
kasprintf.c	lib/kasprintf.c: use kmalloc_track_caller() to get accurate traces for kvasprintf	2012-10-11 08:50:15 +09:00
Kconfig	Move utf16 functions to kernel core and rename	2013-04-15 21:23:03 +01:00
Kconfig.debug	lib/Kconfig.debug: Restrict FRAME_POINTER for MIPS	2013-07-28 16:30:12 -07:00
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	klist: del waiter from klist_remove_waiters before wakeup waitting process	2013-05-21 10:16:39 -07:00
kobject_uevent.c	netlink: hide struct module parameter in netlink_kernel_create	2012-09-08 18:46:30 -04:00
kobject.c	kref: minor cleanup	2013-05-07 16:09:00 -07:00
kstrtox.c	kstrto*: add documentation	2012-12-17 17:15:22 -08:00
kstrtox.h
lcm.c
libcrc32c.c
list_debug.c
list_sort.c	lib/: rename random32() to prandom_u32()	2013-04-29 18:28:42 -07:00
llist.c
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	lru_cache: introduce lc_get_cumulative()	2013-03-22 22:17:36 -06:00
Makefile	lib: make iovec obj instead of lib	2013-05-23 09:17:11 -07:00
md5.c
memory-notifier-error-inject.c
memweight.c
nlattr.c	netlink: add minlen validation for the new signed types	2012-08-30 13:11:46 -04:00
notifier-error-inject.c	mode_t, whack-a-mole at 11...	2013-04-09 14:13:05 -04:00
notifier-error-inject.h
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	Give the OID registry file module info to avoid kernel tainting	2013-05-05 14:38:00 -07:00
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
percpu_counter.c
percpu-rwsem.c	percpu_rw_semaphore: add lockdep annotations	2012-12-17 17:15:18 -08:00
plist.c	lib/plist.c: make plist test announcements KERN_DEBUG	2012-10-06 03:04:58 +09:00
pm-notifier-error-inject.c
prio_heap.c
proportions.c
radix-tree.c
random32.c	random32: fix off-by-one in seeding requirement	2013-12-08 07:29:24 -08:00
ratelimit.c
rational.c
rbtree_test.c	rbtree_test: add __init/__exit annotations	2013-04-30 17:04:07 -07:00
rbtree.c	lib/rbtree.c: avoid the use of non-static __always_inline	2013-01-11 14:54:56 -08:00
reciprocal_div.c
rwsem-spinlock.c	rwsem: simplify __rwsem_do_wake	2013-05-07 07:20:16 -07:00
rwsem.c	rwsem: check counter to avoid cmpxchg calls	2013-05-07 16:11:51 -07:00
scatterlist.c	lib/scatterlist.c: don't flush_kernel_dcache_page on slab page	2013-11-13 12:05:33 +09:00
sha1.c
show_mem.c	mm, show_mem: suppress page counts in non-blockable contexts	2013-04-29 15:54:28 -07:00
smp_processor_id.c
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
string_helpers.c	lib/string_helpers: introduce generic string_unescape	2013-04-30 17:04:03 -07:00
string.c
strncpy_from_user.c
strnlen_user.c
swiotlb.c	x86, kdump: Set crashkernel_low automatically	2013-04-17 12:35:32 -07:00
syscall.c
test-kstrtox.c
test-string_helpers.c	lib/string_helpers: introduce generic string_unescape	2013-04-30 17:04:03 -07:00
textsearch.c
timerqueue.c
ts_bm.c
ts_fsm.c
ts_kmp.c
ucs2_string.c	Move utf16 functions to kernel core and rename	2013-04-15 21:23:03 +01:00
usercopy.c	Kconfig: consolidate CONFIG_DEBUG_STRICT_USER_COPY_CHECKS	2013-04-30 17:04:09 -07:00
uuid.c	uuid: use prandom_bytes()	2013-04-29 18:28:42 -07:00
vsprintf.c	vsprintf: check real user/group id for %pK	2013-12-04 10:56:06 -08:00