[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-Id: <20220418121210.905523230@linuxfoundation.org>
Date: Mon, 18 Apr 2022 14:09:48 +0200
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-kernel@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
stable@...r.kernel.org,
Linus Torvalds <torvalds@...ux-foundation.org>,
Geert Uytterhoeven <geert+renesas@...der.be>,
Biju Das <biju.das.jz@...renesas.com>,
Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>,
Mark Brown <broonie@...nel.org>,
Sasha Levin <sashal@...nel.org>
Subject: [PATCH 4.14 007/284] spi: Fix erroneous sgs value with min_t()
From: Biju Das <biju.das.jz@...renesas.com>
[ Upstream commit ebc4cb43ea5ada3db46c80156fca58a54b9bbca8 ]
While computing sgs in spi_map_buf(), the data type
used in min_t() for max_seg_size is 'unsigned int' where
as that of ctlr->max_dma_len is 'size_t'.
min_t(unsigned int,x,y) gives wrong results if one of x/y is
'size_t'
Consider the below examples on a 64-bit machine (ie size_t is
64-bits, and unsigned int is 32-bit).
case 1) min_t(unsigned int, 5, 0x100000001);
case 2) min_t(size_t, 5, 0x100000001);
Case 1 returns '1', where as case 2 returns '5'. As you can see
the result from case 1 is wrong.
This patch fixes the above issue by using the data type of the
parameters that are used in min_t with maximum data length.
Fixes: commit 1a4e53d2fc4f68aa ("spi: Fix invalid sgs value")
Reported-by: Linus Torvalds <torvalds@...ux-foundation.org>
Suggested-by: Geert Uytterhoeven <geert+renesas@...der.be>
Signed-off-by: Biju Das <biju.das.jz@...renesas.com>
Reviewed-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>
Link: https://lore.kernel.org/r/20220316175317.465-1-biju.das.jz@bp.renesas.com
Signed-off-by: Mark Brown <broonie@...nel.org>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
drivers/spi/spi.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index d26aefed16ac..1031c8e38144 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -774,10 +774,10 @@ static int spi_map_buf(struct spi_controller *ctlr, struct device *dev,
int i, ret;
if (vmalloced_buf || kmap_buf) {
- desc_len = min_t(unsigned int, max_seg_size, PAGE_SIZE);
+ desc_len = min_t(unsigned long, max_seg_size, PAGE_SIZE);
sgs = DIV_ROUND_UP(len + offset_in_page(buf), desc_len);
} else if (virt_addr_valid(buf)) {
- desc_len = min_t(unsigned int, max_seg_size, ctlr->max_dma_len);
+ desc_len = min_t(size_t, max_seg_size, ctlr->max_dma_len);
sgs = DIV_ROUND_UP(len, desc_len);
} else {
return -EINVAL;
--
2.34.1
Powered by blists - more mailing lists