From 0c958ecc69c277b25f38f72bc6d18ab145e8167c Mon Sep 17 00:00:00 2001 From: Tony Battersby Date: Thu, 16 Jul 2015 11:40:41 -0400 Subject: scsi: fix memory leak with scsi-mq Fix a memory leak with scsi-mq triggered by commands with large data transfer length. __sg_alloc_table() sets both table->nents and table->orig_nents to the same value. When the scatterlist is DMA-mapped, table->nents is overwritten with the (possibly smaller) size of the DMA-mapped scatterlist, while table->orig_nents retains the original size of the allocated scatterlist. scsi_free_sgtable() should therefore check orig_nents instead of nents, and all code that initializes sdb->table without calling __sg_alloc_table() should set both nents and orig_nents. Fixes: d285203cf647 ("scsi: add support for a blk-mq based I/O path.") Cc: # 3.17+ Signed-off-by: Tony Battersby Reviewed-by: Christoph Hellwig Reviewed-by: Ewan D. Milne Signed-off-by: James Bottomley --- drivers/scsi/scsi_lib.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'drivers/scsi/scsi_lib.c') diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c index b1a263137a23..448ebdaa3d69 100644 --- a/drivers/scsi/scsi_lib.c +++ b/drivers/scsi/scsi_lib.c @@ -583,7 +583,7 @@ static struct scatterlist *scsi_sg_alloc(unsigned int nents, gfp_t gfp_mask) static void scsi_free_sgtable(struct scsi_data_buffer *sdb, bool mq) { - if (mq && sdb->table.nents <= SCSI_MAX_SG_SEGMENTS) + if (mq && sdb->table.orig_nents <= SCSI_MAX_SG_SEGMENTS) return; __sg_free_table(&sdb->table, SCSI_MAX_SG_SEGMENTS, mq, scsi_sg_free); } @@ -597,8 +597,8 @@ static int scsi_alloc_sgtable(struct scsi_data_buffer *sdb, int nents, bool mq) if (mq) { if (nents <= SCSI_MAX_SG_SEGMENTS) { - sdb->table.nents = nents; - sg_init_table(sdb->table.sgl, sdb->table.nents); + sdb->table.nents = sdb->table.orig_nents = nents; + sg_init_table(sdb->table.sgl, nents); return 0; } first_chunk = sdb->table.sgl; -- cgit v1.2.3