Messages in this thread Patch in this message | | | Date | Mon, 3 Nov 2008 17:17:49 +0100 (CET) | From | Geert Uytterhoeven <> | Subject | [PATCH] jffs2: Fix race condition in jffs2_lzo_compress() |
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deflate_mutex protects the globals lzo_mem and lzo_compress_buf. However, jffs2_lzo_compress() unlocks deflate_mutex _before_ it has copied out the compressed data from lzo_compress_buf. Correct this by moving the mutex unlock after the copy. In addition, document what deflate_mutex actually protects.
Signed-off-by: Geert Uytterhoeven <Geert.Uytterhoeven@sonycom.com> --- Just noticed this when looking at the code. The patch is untested, except for a quick compile test.
fs/jffs2/compr_lzo.c | 15 +++++++++------ 1 file changed, 9 insertions(+), 6 deletions(-)
--- a/fs/jffs2/compr_lzo.c +++ b/fs/jffs2/compr_lzo.c @@ -19,7 +19,7 @@ static void *lzo_mem; static void *lzo_compress_buf; -static DEFINE_MUTEX(deflate_mutex); +static DEFINE_MUTEX(deflate_mutex); /* for lzo_mem and lzo_compress_buf */ static void free_workspace(void) { @@ -49,18 +49,21 @@ static int jffs2_lzo_compress(unsigned c mutex_lock(&deflate_mutex); ret = lzo1x_1_compress(data_in, *sourcelen, lzo_compress_buf, &compress_size, lzo_mem); - mutex_unlock(&deflate_mutex); - if (ret != LZO_E_OK) - return -1; + goto fail; if (compress_size > *dstlen) - return -1; + goto fail; memcpy(cpage_out, lzo_compress_buf, compress_size); - *dstlen = compress_size; + mutex_unlock(&deflate_mutex); + *dstlen = compress_size; return 0; + + fail: + mutex_unlock(&deflate_mutex); + return -1; } static int jffs2_lzo_decompress(unsigned char *data_in, unsigned char *cpage_out, With kind regards,
Geert Uytterhoeven Software Architect
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