Re: [PATCH]: bunzip2: Fix warning in get_next_block()

From: Prarit Bhargava
Date: Sat May 22 2010 - 14:12:47 EST

On 05/22/2010 10:07 AM, Al Viro wrote:
On Sat, May 22, 2010 at 10:04:07AM -0400, Prarit Bhargava wrote:
Fix checkstack compile warning in get_next_block():

lib/decompress_bunzip2.c: In function `get_next_block':
lib/decompress_bunzip2.c:511: warning: the frame size of 1920 bytes is larger than 1024 bytes

int dbufCount, nextSym, dbufSize, groupCount, selector,
- i, j, k, t, runPos, symCount, symTotal, nSelectors,
- byteCount[256];
- unsigned char uc, symToByte[256], mtfSymbol[256], *selectors;
+ i, j, k, t, runPos, symCount, symTotal, nSelectors;
+ static int byteCount[256];
+ unsigned char uc, *selectors;
+ static unsigned char symToByte[256], mtfSymbol[256];
unsigned int *dbuf, origPtr;
Um... Some details might be useful, starting with "why can't that function
be called from several processes at once"...

Al, to be honest, I'm not 100% if this is single-threaded or not :/. I was hoping that by throwing the patch out I would get either an ACK or a NAK on it because of the single threaded issue. It seems to me (and I admit I might be totally wrong) that the bunzip2 function is only called during early boot,

#ifdef PREBOOT
STATIC int INIT decompress(unsigned char *buf, int len,
int(*fill)(void*, unsigned int),
int(*flush)(void*, unsigned int),
unsigned char *outbuf,
int *pos,
void(*error_fn)(char *x))
return bunzip2(buf, len - 4, fill, flush, outbuf, pos, error_fn);

... which (again, if the assumptions I'm making are correct) means that only one cpu will be active.

/me hopes someone will correct him if he's wrong and that's why hpa and phillip are cc'd directly

If it isn't single threaded, then you're right -- a PREBOOT malloc is the way to go.

To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at
Please read the FAQ at