Revision 3b6b7813b198b578aa7e04e4047ddb8225c37b7f authored by Mikulas Patocka on 20 March 2013, 17:21:25 UTC, committed by Alasdair G Kergon on 20 March 2013, 17:21:25 UTC
A deadlock was found in the prefetch code in the dm verity map function. This patch fixes this by transferring the prefetch to a worker thread and skipping it completely if kmalloc fails. If generic_make_request is called recursively, it queues the I/O request on the current->bio_list without making the I/O request and returns. The routine making the recursive call cannot wait for the I/O to complete. The deadlock occurs when one thread grabs the bufio_client mutex and waits for an I/O to complete but the I/O is queued on another thread's current->bio_list and is waiting to get the mutex held by the first thread. The fix recognises that prefetching is not essential. If memory can be allocated, it queues the prefetch request to the worker thread, but if not, it does nothing. Signed-off-by: Paul Taysom <taysom@chromium.org> Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com> Cc: stable@kernel.org
1 parent 58051b9
decompress_unlzma.c
/* Lzma decompressor for Linux kernel. Shamelessly snarfed
*from busybox 1.1.1
*
*Linux kernel adaptation
*Copyright (C) 2006 Alain < alain@knaff.lu >
*
*Based on small lzma deflate implementation/Small range coder
*implementation for lzma.
*Copyright (C) 2006 Aurelien Jacobs < aurel@gnuage.org >
*
*Based on LzmaDecode.c from the LZMA SDK 4.22 (http://www.7-zip.org/)
*Copyright (C) 1999-2005 Igor Pavlov
*
*Copyrights of the parts, see headers below.
*
*
*This program is free software; you can redistribute it and/or
*modify it under the terms of the GNU Lesser General Public
*License as published by the Free Software Foundation; either
*version 2.1 of the License, or (at your option) any later version.
*
*This program is distributed in the hope that it will be useful,
*but WITHOUT ANY WARRANTY; without even the implied warranty of
*MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
*Lesser General Public License for more details.
*
*You should have received a copy of the GNU Lesser General Public
*License along with this library; if not, write to the Free Software
*Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
#ifdef STATIC
#define PREBOOT
#else
#include <linux/decompress/unlzma.h>
#endif /* STATIC */
#include <linux/decompress/mm.h>
#define MIN(a, b) (((a) < (b)) ? (a) : (b))
static long long INIT read_int(unsigned char *ptr, int size)
{
int i;
long long ret = 0;
for (i = 0; i < size; i++)
ret = (ret << 8) | ptr[size-i-1];
return ret;
}
#define ENDIAN_CONVERT(x) \
x = (typeof(x))read_int((unsigned char *)&x, sizeof(x))
/* Small range coder implementation for lzma.
*Copyright (C) 2006 Aurelien Jacobs < aurel@gnuage.org >
*
*Based on LzmaDecode.c from the LZMA SDK 4.22 (http://www.7-zip.org/)
*Copyright (c) 1999-2005 Igor Pavlov
*/
#include <linux/compiler.h>
#define LZMA_IOBUF_SIZE 0x10000
struct rc {
int (*fill)(void*, unsigned int);
uint8_t *ptr;
uint8_t *buffer;
uint8_t *buffer_end;
int buffer_size;
uint32_t code;
uint32_t range;
uint32_t bound;
void (*error)(char *);
};
#define RC_TOP_BITS 24
#define RC_MOVE_BITS 5
#define RC_MODEL_TOTAL_BITS 11
static int INIT nofill(void *buffer, unsigned int len)
{
return -1;
}
/* Called twice: once at startup and once in rc_normalize() */
static void INIT rc_read(struct rc *rc)
{
rc->buffer_size = rc->fill((char *)rc->buffer, LZMA_IOBUF_SIZE);
if (rc->buffer_size <= 0)
rc->error("unexpected EOF");
rc->ptr = rc->buffer;
rc->buffer_end = rc->buffer + rc->buffer_size;
}
/* Called once */
static inline void INIT rc_init(struct rc *rc,
int (*fill)(void*, unsigned int),
char *buffer, int buffer_size)
{
if (fill)
rc->fill = fill;
else
rc->fill = nofill;
rc->buffer = (uint8_t *)buffer;
rc->buffer_size = buffer_size;
rc->buffer_end = rc->buffer + rc->buffer_size;
rc->ptr = rc->buffer;
rc->code = 0;
rc->range = 0xFFFFFFFF;
}
static inline void INIT rc_init_code(struct rc *rc)
{
int i;
for (i = 0; i < 5; i++) {
if (rc->ptr >= rc->buffer_end)
rc_read(rc);
rc->code = (rc->code << 8) | *rc->ptr++;
}
}
/* Called twice, but one callsite is in inline'd rc_is_bit_0_helper() */
static void INIT rc_do_normalize(struct rc *rc)
{
if (rc->ptr >= rc->buffer_end)
rc_read(rc);
rc->range <<= 8;
rc->code = (rc->code << 8) | *rc->ptr++;
}
static inline void INIT rc_normalize(struct rc *rc)
{
if (rc->range < (1 << RC_TOP_BITS))
rc_do_normalize(rc);
}
/* Called 9 times */
/* Why rc_is_bit_0_helper exists?
*Because we want to always expose (rc->code < rc->bound) to optimizer
*/
static inline uint32_t INIT rc_is_bit_0_helper(struct rc *rc, uint16_t *p)
{
rc_normalize(rc);
rc->bound = *p * (rc->range >> RC_MODEL_TOTAL_BITS);
return rc->bound;
}
static inline int INIT rc_is_bit_0(struct rc *rc, uint16_t *p)
{
uint32_t t = rc_is_bit_0_helper(rc, p);
return rc->code < t;
}
/* Called ~10 times, but very small, thus inlined */
static inline void INIT rc_update_bit_0(struct rc *rc, uint16_t *p)
{
rc->range = rc->bound;
*p += ((1 << RC_MODEL_TOTAL_BITS) - *p) >> RC_MOVE_BITS;
}
static inline void INIT rc_update_bit_1(struct rc *rc, uint16_t *p)
{
rc->range -= rc->bound;
rc->code -= rc->bound;
*p -= *p >> RC_MOVE_BITS;
}
/* Called 4 times in unlzma loop */
static int INIT rc_get_bit(struct rc *rc, uint16_t *p, int *symbol)
{
if (rc_is_bit_0(rc, p)) {
rc_update_bit_0(rc, p);
*symbol *= 2;
return 0;
} else {
rc_update_bit_1(rc, p);
*symbol = *symbol * 2 + 1;
return 1;
}
}
/* Called once */
static inline int INIT rc_direct_bit(struct rc *rc)
{
rc_normalize(rc);
rc->range >>= 1;
if (rc->code >= rc->range) {
rc->code -= rc->range;
return 1;
}
return 0;
}
/* Called twice */
static inline void INIT
rc_bit_tree_decode(struct rc *rc, uint16_t *p, int num_levels, int *symbol)
{
int i = num_levels;
*symbol = 1;
while (i--)
rc_get_bit(rc, p + *symbol, symbol);
*symbol -= 1 << num_levels;
}
/*
* Small lzma deflate implementation.
* Copyright (C) 2006 Aurelien Jacobs < aurel@gnuage.org >
*
* Based on LzmaDecode.c from the LZMA SDK 4.22 (http://www.7-zip.org/)
* Copyright (C) 1999-2005 Igor Pavlov
*/
struct lzma_header {
uint8_t pos;
uint32_t dict_size;
uint64_t dst_size;
} __attribute__ ((packed)) ;
#define LZMA_BASE_SIZE 1846
#define LZMA_LIT_SIZE 768
#define LZMA_NUM_POS_BITS_MAX 4
#define LZMA_LEN_NUM_LOW_BITS 3
#define LZMA_LEN_NUM_MID_BITS 3
#define LZMA_LEN_NUM_HIGH_BITS 8
#define LZMA_LEN_CHOICE 0
#define LZMA_LEN_CHOICE_2 (LZMA_LEN_CHOICE + 1)
#define LZMA_LEN_LOW (LZMA_LEN_CHOICE_2 + 1)
#define LZMA_LEN_MID (LZMA_LEN_LOW \
+ (1 << (LZMA_NUM_POS_BITS_MAX + LZMA_LEN_NUM_LOW_BITS)))
#define LZMA_LEN_HIGH (LZMA_LEN_MID \
+(1 << (LZMA_NUM_POS_BITS_MAX + LZMA_LEN_NUM_MID_BITS)))
#define LZMA_NUM_LEN_PROBS (LZMA_LEN_HIGH + (1 << LZMA_LEN_NUM_HIGH_BITS))
#define LZMA_NUM_STATES 12
#define LZMA_NUM_LIT_STATES 7
#define LZMA_START_POS_MODEL_INDEX 4
#define LZMA_END_POS_MODEL_INDEX 14
#define LZMA_NUM_FULL_DISTANCES (1 << (LZMA_END_POS_MODEL_INDEX >> 1))
#define LZMA_NUM_POS_SLOT_BITS 6
#define LZMA_NUM_LEN_TO_POS_STATES 4
#define LZMA_NUM_ALIGN_BITS 4
#define LZMA_MATCH_MIN_LEN 2
#define LZMA_IS_MATCH 0
#define LZMA_IS_REP (LZMA_IS_MATCH + (LZMA_NUM_STATES << LZMA_NUM_POS_BITS_MAX))
#define LZMA_IS_REP_G0 (LZMA_IS_REP + LZMA_NUM_STATES)
#define LZMA_IS_REP_G1 (LZMA_IS_REP_G0 + LZMA_NUM_STATES)
#define LZMA_IS_REP_G2 (LZMA_IS_REP_G1 + LZMA_NUM_STATES)
#define LZMA_IS_REP_0_LONG (LZMA_IS_REP_G2 + LZMA_NUM_STATES)
#define LZMA_POS_SLOT (LZMA_IS_REP_0_LONG \
+ (LZMA_NUM_STATES << LZMA_NUM_POS_BITS_MAX))
#define LZMA_SPEC_POS (LZMA_POS_SLOT \
+(LZMA_NUM_LEN_TO_POS_STATES << LZMA_NUM_POS_SLOT_BITS))
#define LZMA_ALIGN (LZMA_SPEC_POS \
+ LZMA_NUM_FULL_DISTANCES - LZMA_END_POS_MODEL_INDEX)
#define LZMA_LEN_CODER (LZMA_ALIGN + (1 << LZMA_NUM_ALIGN_BITS))
#define LZMA_REP_LEN_CODER (LZMA_LEN_CODER + LZMA_NUM_LEN_PROBS)
#define LZMA_LITERAL (LZMA_REP_LEN_CODER + LZMA_NUM_LEN_PROBS)
struct writer {
uint8_t *buffer;
uint8_t previous_byte;
size_t buffer_pos;
int bufsize;
size_t global_pos;
int(*flush)(void*, unsigned int);
struct lzma_header *header;
};
struct cstate {
int state;
uint32_t rep0, rep1, rep2, rep3;
};
static inline size_t INIT get_pos(struct writer *wr)
{
return
wr->global_pos + wr->buffer_pos;
}
static inline uint8_t INIT peek_old_byte(struct writer *wr,
uint32_t offs)
{
if (!wr->flush) {
int32_t pos;
while (offs > wr->header->dict_size)
offs -= wr->header->dict_size;
pos = wr->buffer_pos - offs;
return wr->buffer[pos];
} else {
uint32_t pos = wr->buffer_pos - offs;
while (pos >= wr->header->dict_size)
pos += wr->header->dict_size;
return wr->buffer[pos];
}
}
static inline int INIT write_byte(struct writer *wr, uint8_t byte)
{
wr->buffer[wr->buffer_pos++] = wr->previous_byte = byte;
if (wr->flush && wr->buffer_pos == wr->header->dict_size) {
wr->buffer_pos = 0;
wr->global_pos += wr->header->dict_size;
if (wr->flush((char *)wr->buffer, wr->header->dict_size)
!= wr->header->dict_size)
return -1;
}
return 0;
}
static inline int INIT copy_byte(struct writer *wr, uint32_t offs)
{
return write_byte(wr, peek_old_byte(wr, offs));
}
static inline int INIT copy_bytes(struct writer *wr,
uint32_t rep0, int len)
{
do {
if (copy_byte(wr, rep0))
return -1;
len--;
} while (len != 0 && wr->buffer_pos < wr->header->dst_size);
return len;
}
static inline int INIT process_bit0(struct writer *wr, struct rc *rc,
struct cstate *cst, uint16_t *p,
int pos_state, uint16_t *prob,
int lc, uint32_t literal_pos_mask) {
int mi = 1;
rc_update_bit_0(rc, prob);
prob = (p + LZMA_LITERAL +
(LZMA_LIT_SIZE
* (((get_pos(wr) & literal_pos_mask) << lc)
+ (wr->previous_byte >> (8 - lc))))
);
if (cst->state >= LZMA_NUM_LIT_STATES) {
int match_byte = peek_old_byte(wr, cst->rep0);
do {
int bit;
uint16_t *prob_lit;
match_byte <<= 1;
bit = match_byte & 0x100;
prob_lit = prob + 0x100 + bit + mi;
if (rc_get_bit(rc, prob_lit, &mi)) {
if (!bit)
break;
} else {
if (bit)
break;
}
} while (mi < 0x100);
}
while (mi < 0x100) {
uint16_t *prob_lit = prob + mi;
rc_get_bit(rc, prob_lit, &mi);
}
if (cst->state < 4)
cst->state = 0;
else if (cst->state < 10)
cst->state -= 3;
else
cst->state -= 6;
return write_byte(wr, mi);
}
static inline int INIT process_bit1(struct writer *wr, struct rc *rc,
struct cstate *cst, uint16_t *p,
int pos_state, uint16_t *prob) {
int offset;
uint16_t *prob_len;
int num_bits;
int len;
rc_update_bit_1(rc, prob);
prob = p + LZMA_IS_REP + cst->state;
if (rc_is_bit_0(rc, prob)) {
rc_update_bit_0(rc, prob);
cst->rep3 = cst->rep2;
cst->rep2 = cst->rep1;
cst->rep1 = cst->rep0;
cst->state = cst->state < LZMA_NUM_LIT_STATES ? 0 : 3;
prob = p + LZMA_LEN_CODER;
} else {
rc_update_bit_1(rc, prob);
prob = p + LZMA_IS_REP_G0 + cst->state;
if (rc_is_bit_0(rc, prob)) {
rc_update_bit_0(rc, prob);
prob = (p + LZMA_IS_REP_0_LONG
+ (cst->state <<
LZMA_NUM_POS_BITS_MAX) +
pos_state);
if (rc_is_bit_0(rc, prob)) {
rc_update_bit_0(rc, prob);
cst->state = cst->state < LZMA_NUM_LIT_STATES ?
9 : 11;
return copy_byte(wr, cst->rep0);
} else {
rc_update_bit_1(rc, prob);
}
} else {
uint32_t distance;
rc_update_bit_1(rc, prob);
prob = p + LZMA_IS_REP_G1 + cst->state;
if (rc_is_bit_0(rc, prob)) {
rc_update_bit_0(rc, prob);
distance = cst->rep1;
} else {
rc_update_bit_1(rc, prob);
prob = p + LZMA_IS_REP_G2 + cst->state;
if (rc_is_bit_0(rc, prob)) {
rc_update_bit_0(rc, prob);
distance = cst->rep2;
} else {
rc_update_bit_1(rc, prob);
distance = cst->rep3;
cst->rep3 = cst->rep2;
}
cst->rep2 = cst->rep1;
}
cst->rep1 = cst->rep0;
cst->rep0 = distance;
}
cst->state = cst->state < LZMA_NUM_LIT_STATES ? 8 : 11;
prob = p + LZMA_REP_LEN_CODER;
}
prob_len = prob + LZMA_LEN_CHOICE;
if (rc_is_bit_0(rc, prob_len)) {
rc_update_bit_0(rc, prob_len);
prob_len = (prob + LZMA_LEN_LOW
+ (pos_state <<
LZMA_LEN_NUM_LOW_BITS));
offset = 0;
num_bits = LZMA_LEN_NUM_LOW_BITS;
} else {
rc_update_bit_1(rc, prob_len);
prob_len = prob + LZMA_LEN_CHOICE_2;
if (rc_is_bit_0(rc, prob_len)) {
rc_update_bit_0(rc, prob_len);
prob_len = (prob + LZMA_LEN_MID
+ (pos_state <<
LZMA_LEN_NUM_MID_BITS));
offset = 1 << LZMA_LEN_NUM_LOW_BITS;
num_bits = LZMA_LEN_NUM_MID_BITS;
} else {
rc_update_bit_1(rc, prob_len);
prob_len = prob + LZMA_LEN_HIGH;
offset = ((1 << LZMA_LEN_NUM_LOW_BITS)
+ (1 << LZMA_LEN_NUM_MID_BITS));
num_bits = LZMA_LEN_NUM_HIGH_BITS;
}
}
rc_bit_tree_decode(rc, prob_len, num_bits, &len);
len += offset;
if (cst->state < 4) {
int pos_slot;
cst->state += LZMA_NUM_LIT_STATES;
prob =
p + LZMA_POS_SLOT +
((len <
LZMA_NUM_LEN_TO_POS_STATES ? len :
LZMA_NUM_LEN_TO_POS_STATES - 1)
<< LZMA_NUM_POS_SLOT_BITS);
rc_bit_tree_decode(rc, prob,
LZMA_NUM_POS_SLOT_BITS,
&pos_slot);
if (pos_slot >= LZMA_START_POS_MODEL_INDEX) {
int i, mi;
num_bits = (pos_slot >> 1) - 1;
cst->rep0 = 2 | (pos_slot & 1);
if (pos_slot < LZMA_END_POS_MODEL_INDEX) {
cst->rep0 <<= num_bits;
prob = p + LZMA_SPEC_POS +
cst->rep0 - pos_slot - 1;
} else {
num_bits -= LZMA_NUM_ALIGN_BITS;
while (num_bits--)
cst->rep0 = (cst->rep0 << 1) |
rc_direct_bit(rc);
prob = p + LZMA_ALIGN;
cst->rep0 <<= LZMA_NUM_ALIGN_BITS;
num_bits = LZMA_NUM_ALIGN_BITS;
}
i = 1;
mi = 1;
while (num_bits--) {
if (rc_get_bit(rc, prob + mi, &mi))
cst->rep0 |= i;
i <<= 1;
}
} else
cst->rep0 = pos_slot;
if (++(cst->rep0) == 0)
return 0;
if (cst->rep0 > wr->header->dict_size
|| cst->rep0 > get_pos(wr))
return -1;
}
len += LZMA_MATCH_MIN_LEN;
return copy_bytes(wr, cst->rep0, len);
}
STATIC inline int INIT unlzma(unsigned char *buf, int in_len,
int(*fill)(void*, unsigned int),
int(*flush)(void*, unsigned int),
unsigned char *output,
int *posp,
void(*error)(char *x)
)
{
struct lzma_header header;
int lc, pb, lp;
uint32_t pos_state_mask;
uint32_t literal_pos_mask;
uint16_t *p;
int num_probs;
struct rc rc;
int i, mi;
struct writer wr;
struct cstate cst;
unsigned char *inbuf;
int ret = -1;
rc.error = error;
if (buf)
inbuf = buf;
else
inbuf = malloc(LZMA_IOBUF_SIZE);
if (!inbuf) {
error("Could not allocate input buffer");
goto exit_0;
}
cst.state = 0;
cst.rep0 = cst.rep1 = cst.rep2 = cst.rep3 = 1;
wr.header = &header;
wr.flush = flush;
wr.global_pos = 0;
wr.previous_byte = 0;
wr.buffer_pos = 0;
rc_init(&rc, fill, inbuf, in_len);
for (i = 0; i < sizeof(header); i++) {
if (rc.ptr >= rc.buffer_end)
rc_read(&rc);
((unsigned char *)&header)[i] = *rc.ptr++;
}
if (header.pos >= (9 * 5 * 5)) {
error("bad header");
goto exit_1;
}
mi = 0;
lc = header.pos;
while (lc >= 9) {
mi++;
lc -= 9;
}
pb = 0;
lp = mi;
while (lp >= 5) {
pb++;
lp -= 5;
}
pos_state_mask = (1 << pb) - 1;
literal_pos_mask = (1 << lp) - 1;
ENDIAN_CONVERT(header.dict_size);
ENDIAN_CONVERT(header.dst_size);
if (header.dict_size == 0)
header.dict_size = 1;
if (output)
wr.buffer = output;
else {
wr.bufsize = MIN(header.dst_size, header.dict_size);
wr.buffer = large_malloc(wr.bufsize);
}
if (wr.buffer == NULL)
goto exit_1;
num_probs = LZMA_BASE_SIZE + (LZMA_LIT_SIZE << (lc + lp));
p = (uint16_t *) large_malloc(num_probs * sizeof(*p));
if (p == 0)
goto exit_2;
num_probs = LZMA_LITERAL + (LZMA_LIT_SIZE << (lc + lp));
for (i = 0; i < num_probs; i++)
p[i] = (1 << RC_MODEL_TOTAL_BITS) >> 1;
rc_init_code(&rc);
while (get_pos(&wr) < header.dst_size) {
int pos_state = get_pos(&wr) & pos_state_mask;
uint16_t *prob = p + LZMA_IS_MATCH +
(cst.state << LZMA_NUM_POS_BITS_MAX) + pos_state;
if (rc_is_bit_0(&rc, prob)) {
if (process_bit0(&wr, &rc, &cst, p, pos_state, prob,
lc, literal_pos_mask)) {
error("LZMA data is corrupt");
goto exit_3;
}
} else {
if (process_bit1(&wr, &rc, &cst, p, pos_state, prob)) {
error("LZMA data is corrupt");
goto exit_3;
}
if (cst.rep0 == 0)
break;
}
if (rc.buffer_size <= 0)
goto exit_3;
}
if (posp)
*posp = rc.ptr-rc.buffer;
if (!wr.flush || wr.flush(wr.buffer, wr.buffer_pos) == wr.buffer_pos)
ret = 0;
exit_3:
large_free(p);
exit_2:
if (!output)
large_free(wr.buffer);
exit_1:
if (!buf)
free(inbuf);
exit_0:
return ret;
}
#ifdef PREBOOT
STATIC int INIT decompress(unsigned char *buf, int in_len,
int(*fill)(void*, unsigned int),
int(*flush)(void*, unsigned int),
unsigned char *output,
int *posp,
void(*error)(char *x)
)
{
return unlzma(buf, in_len - 4, fill, flush, output, posp, error);
}
#endif
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