Commit 35c74226 authored by Jeremy Fitzhardinge's avatar Jeremy Fitzhardinge Committed by Andi Kleen

[PATCH] x86: deflate stack usage in lib/inflate.c

inflate_fixed and huft_build together use around 2.7k of stack.  When
using 4k stacks, I saw stack overflows from interrupts arriving while
unpacking the root initrd:

do_IRQ: stack overflow: 384
 [<c0106b64>] show_trace_log_lvl+0x1a/0x30
 [<c01075e6>] show_trace+0x12/0x14
 [<c010763f>] dump_stack+0x16/0x18
 [<c0107ca4>] do_IRQ+0x6d/0xd9
 [<c010202b>] xen_evtchn_do_upcall+0x6e/0xa2
 [<c0106781>] xen_hypervisor_callback+0x25/0x2c
 [<c010116c>] xen_restore_fl+0x27/0x29
 [<c0330f63>] _spin_unlock_irqrestore+0x4a/0x50
 [<c0117aab>] change_page_attr+0x577/0x584
 [<c0117b45>] kernel_map_pages+0x8d/0xb4
 [<c016a314>] cache_alloc_refill+0x53f/0x632
 [<c016a6c2>] __kmalloc+0xc1/0x10d
 [<c0463d34>] malloc+0x10/0x12
 [<c04641c1>] huft_build+0x2a7/0x5fa
 [<c04645a5>] inflate_fixed+0x91/0x136
 [<c04657e2>] unpack_to_rootfs+0x5f2/0x8c1
 [<c0465acf>] populate_rootfs+0x1e/0xe4

(This was under Xen, but there's no reason it couldn't happen on bare
  hardware.)

This patch mallocs the local variables, thereby reducing the stack
usage to sane levels.

Also, up the heap size for the kernel decompressor to deal with the
extra allocation.
Signed-off-by: default avatarJeremy Fitzhardinge <jeremy@xensource.com>
Signed-off-by: default avatarAndi Kleen <ak@suse.de>
Cc: Tim Yamin <plasmaroo@gentoo.org>
Cc: Andi Kleen <ak@suse.de>
Cc: Matt Mackall <mpm@selenic.com>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Ian Molton <spyro@f2s.com>
parent 4cdd9c89
...@@ -98,7 +98,7 @@ extern int end; ...@@ -98,7 +98,7 @@ extern int end;
static ulg free_mem_ptr; static ulg free_mem_ptr;
static ulg free_mem_ptr_end; static ulg free_mem_ptr_end;
#define HEAP_SIZE 0x2000 #define HEAP_SIZE 0x3000
#include "../../../lib/inflate.c" #include "../../../lib/inflate.c"
......
...@@ -239,7 +239,7 @@ extern int end; ...@@ -239,7 +239,7 @@ extern int end;
static ulg free_mem_ptr; static ulg free_mem_ptr;
static ulg free_mem_ptr_end; static ulg free_mem_ptr_end;
#define HEAP_SIZE 0x2000 #define HEAP_SIZE 0x3000
#include "../../../../lib/inflate.c" #include "../../../../lib/inflate.c"
......
...@@ -182,7 +182,7 @@ extern int end; ...@@ -182,7 +182,7 @@ extern int end;
static ulg free_mem_ptr; static ulg free_mem_ptr;
static ulg free_mem_ptr_end; static ulg free_mem_ptr_end;
#define HEAP_SIZE 0x2000 #define HEAP_SIZE 0x3000
#include "../../../../lib/inflate.c" #include "../../../../lib/inflate.c"
......
...@@ -189,7 +189,7 @@ static void putstr(const char *); ...@@ -189,7 +189,7 @@ static void putstr(const char *);
static unsigned long free_mem_ptr; static unsigned long free_mem_ptr;
static unsigned long free_mem_end_ptr; static unsigned long free_mem_end_ptr;
#define HEAP_SIZE 0x3000 #define HEAP_SIZE 0x4000
static char *vidmem = (char *)0xb8000; static char *vidmem = (char *)0xb8000;
static int vidport; static int vidport;
......
...@@ -189,7 +189,7 @@ static void putstr(const char *); ...@@ -189,7 +189,7 @@ static void putstr(const char *);
static long free_mem_ptr; static long free_mem_ptr;
static long free_mem_end_ptr; static long free_mem_end_ptr;
#define HEAP_SIZE 0x6000 #define HEAP_SIZE 0x7000
static char *vidmem = (char *)0xb8000; static char *vidmem = (char *)0xb8000;
static int vidport; static int vidport;
......
...@@ -292,7 +292,6 @@ STATIC int INIT huft_build( ...@@ -292,7 +292,6 @@ STATIC int INIT huft_build(
oversubscribed set of lengths), and three if not enough memory. */ oversubscribed set of lengths), and three if not enough memory. */
{ {
unsigned a; /* counter for codes of length k */ unsigned a; /* counter for codes of length k */
unsigned c[BMAX+1]; /* bit length count table */
unsigned f; /* i repeats in table every f entries */ unsigned f; /* i repeats in table every f entries */
int g; /* maximum code length */ int g; /* maximum code length */
int h; /* table level */ int h; /* table level */
...@@ -303,18 +302,33 @@ STATIC int INIT huft_build( ...@@ -303,18 +302,33 @@ STATIC int INIT huft_build(
register unsigned *p; /* pointer into c[], b[], or v[] */ register unsigned *p; /* pointer into c[], b[], or v[] */
register struct huft *q; /* points to current table */ register struct huft *q; /* points to current table */
struct huft r; /* table entry for structure assignment */ struct huft r; /* table entry for structure assignment */
struct huft *u[BMAX]; /* table stack */
unsigned v[N_MAX]; /* values in order of bit length */
register int w; /* bits before this table == (l * h) */ register int w; /* bits before this table == (l * h) */
unsigned x[BMAX+1]; /* bit offsets, then code stack */
unsigned *xp; /* pointer into x */ unsigned *xp; /* pointer into x */
int y; /* number of dummy codes added */ int y; /* number of dummy codes added */
unsigned z; /* number of entries in current table */ unsigned z; /* number of entries in current table */
struct {
unsigned c[BMAX+1]; /* bit length count table */
struct huft *u[BMAX]; /* table stack */
unsigned v[N_MAX]; /* values in order of bit length */
unsigned x[BMAX+1]; /* bit offsets, then code stack */
} *stk;
unsigned *c, *v, *x;
struct huft **u;
int ret;
DEBG("huft1 "); DEBG("huft1 ");
stk = malloc(sizeof(*stk));
if (stk == NULL)
return 3; /* out of memory */
c = stk->c;
v = stk->v;
x = stk->x;
u = stk->u;
/* Generate counts for each bit length */ /* Generate counts for each bit length */
memzero(c, sizeof(c)); memzero(stk->c, sizeof(stk->c));
p = b; i = n; p = b; i = n;
do { do {
Tracecv(*p, (stderr, (n-i >= ' ' && n-i <= '~' ? "%c %d\n" : "0x%x %d\n"), Tracecv(*p, (stderr, (n-i >= ' ' && n-i <= '~' ? "%c %d\n" : "0x%x %d\n"),
...@@ -326,7 +340,8 @@ DEBG("huft1 "); ...@@ -326,7 +340,8 @@ DEBG("huft1 ");
{ {
*t = (struct huft *)NULL; *t = (struct huft *)NULL;
*m = 0; *m = 0;
return 2; ret = 2;
goto out;
} }
DEBG("huft2 "); DEBG("huft2 ");
...@@ -351,10 +366,14 @@ DEBG("huft3 "); ...@@ -351,10 +366,14 @@ DEBG("huft3 ");
/* Adjust last length count to fill out codes, if needed */ /* Adjust last length count to fill out codes, if needed */
for (y = 1 << j; j < i; j++, y <<= 1) for (y = 1 << j; j < i; j++, y <<= 1)
if ((y -= c[j]) < 0) if ((y -= c[j]) < 0) {
return 2; /* bad input: more codes than bits */ ret = 2; /* bad input: more codes than bits */
if ((y -= c[i]) < 0) goto out;
return 2; }
if ((y -= c[i]) < 0) {
ret = 2;
goto out;
}
c[i] += y; c[i] += y;
DEBG("huft4 "); DEBG("huft4 ");
...@@ -428,7 +447,8 @@ DEBG1("3 "); ...@@ -428,7 +447,8 @@ DEBG1("3 ");
{ {
if (h) if (h)
huft_free(u[0]); huft_free(u[0]);
return 3; /* not enough memory */ ret = 3; /* not enough memory */
goto out;
} }
DEBG1("4 "); DEBG1("4 ");
hufts += z + 1; /* track memory usage */ hufts += z + 1; /* track memory usage */
...@@ -492,7 +512,11 @@ DEBG("h6f "); ...@@ -492,7 +512,11 @@ DEBG("h6f ");
DEBG("huft7 "); DEBG("huft7 ");
/* Return true (1) if we were given an incomplete table */ /* Return true (1) if we were given an incomplete table */
return y != 0 && g != 1; ret = y != 0 && g != 1;
out:
free(stk);
return ret;
} }
...@@ -705,10 +729,14 @@ STATIC int noinline INIT inflate_fixed(void) ...@@ -705,10 +729,14 @@ STATIC int noinline INIT inflate_fixed(void)
struct huft *td; /* distance code table */ struct huft *td; /* distance code table */
int bl; /* lookup bits for tl */ int bl; /* lookup bits for tl */
int bd; /* lookup bits for td */ int bd; /* lookup bits for td */
unsigned l[288]; /* length list for huft_build */ unsigned *l; /* length list for huft_build */
DEBG("<fix"); DEBG("<fix");
l = malloc(sizeof(*l) * 288);
if (l == NULL)
return 3; /* out of memory */
/* set up literal table */ /* set up literal table */
for (i = 0; i < 144; i++) for (i = 0; i < 144; i++)
l[i] = 8; l[i] = 8;
...@@ -719,9 +747,10 @@ DEBG("<fix"); ...@@ -719,9 +747,10 @@ DEBG("<fix");
for (; i < 288; i++) /* make a complete, but wrong code set */ for (; i < 288; i++) /* make a complete, but wrong code set */
l[i] = 8; l[i] = 8;
bl = 7; bl = 7;
if ((i = huft_build(l, 288, 257, cplens, cplext, &tl, &bl)) != 0) if ((i = huft_build(l, 288, 257, cplens, cplext, &tl, &bl)) != 0) {
free(l);
return i; return i;
}
/* set up distance table */ /* set up distance table */
for (i = 0; i < 30; i++) /* make an incomplete code set */ for (i = 0; i < 30; i++) /* make an incomplete code set */
...@@ -730,6 +759,7 @@ DEBG("<fix"); ...@@ -730,6 +759,7 @@ DEBG("<fix");
if ((i = huft_build(l, 30, 0, cpdist, cpdext, &td, &bd)) > 1) if ((i = huft_build(l, 30, 0, cpdist, cpdext, &td, &bd)) > 1)
{ {
huft_free(tl); huft_free(tl);
free(l);
DEBG(">"); DEBG(">");
return i; return i;
...@@ -737,11 +767,13 @@ DEBG("<fix"); ...@@ -737,11 +767,13 @@ DEBG("<fix");
/* decompress until an end-of-block code */ /* decompress until an end-of-block code */
if (inflate_codes(tl, td, bl, bd)) if (inflate_codes(tl, td, bl, bd)) {
free(l);
return 1; return 1;
}
/* free the decoding tables, return */ /* free the decoding tables, return */
free(l);
huft_free(tl); huft_free(tl);
huft_free(td); huft_free(td);
return 0; return 0;
......
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