Messages in this thread Patch in this message | | | Date | Tue, 11 Nov 2008 16:23:25 -0800 | From | Greg KH <> | Subject | [patch 15/49] JFFS2: fix race condition in jffs2_lzo_compress() |
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2.6.27-stable review patch. If anyone has any objections, please let us know.
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From: Geert Uytterhoeven <Geert.Uytterhoeven@sonycom.com>
commit dc8a0843a435b2c0891e7eaea64faaf1ebec9b11 upstream
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> Acked-by: Richard Purdie <rpurdie@openedhand.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: David Woodhouse <David.Woodhouse@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
--- 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, --
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