diff options
author | David Arinzon <darinzon@amazon.com> | 2024-04-10 12:13:55 +0300 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2024-04-17 12:19:32 +0300 |
commit | 4d142dda057ae72d9b7a18515748e409577dfde2 (patch) | |
tree | 6f3042a8e5d7e265490d54d43ce673a1ce9b4c11 /drivers | |
parent | 507cc232ffe53a352847893f8177d276c3b532a9 (diff) | |
download | linux-4d142dda057ae72d9b7a18515748e409577dfde2.tar.xz |
net: ena: Fix potential sign extension issue
[ Upstream commit 713a85195aad25d8a26786a37b674e3e5ec09e3c ]
Small unsigned types are promoted to larger signed types in
the case of multiplication, the result of which may overflow.
In case the result of such a multiplication has its MSB
turned on, it will be sign extended with '1's.
This changes the multiplication result.
Code example of the phenomenon:
-------------------------------
u16 x, y;
size_t z1, z2;
x = y = 0xffff;
printk("x=%x y=%x\n",x,y);
z1 = x*y;
z2 = (size_t)x*y;
printk("z1=%lx z2=%lx\n", z1, z2);
Output:
-------
x=ffff y=ffff
z1=fffffffffffe0001 z2=fffe0001
The expected result of ffff*ffff is fffe0001, and without the
explicit casting to avoid the unwanted sign extension we got
fffffffffffe0001.
This commit adds an explicit casting to avoid the sign extension
issue.
Fixes: 689b2bdaaa14 ("net: ena: add functions for handling Low Latency Queues in ena_com")
Signed-off-by: Arthur Kiyanovski <akiyano@amazon.com>
Signed-off-by: David Arinzon <darinzon@amazon.com>
Reviewed-by: Shannon Nelson <shannon.nelson@amd.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'drivers')
-rw-r--r-- | drivers/net/ethernet/amazon/ena/ena_com.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/net/ethernet/amazon/ena/ena_com.c b/drivers/net/ethernet/amazon/ena/ena_com.c index 633b321d7fdd..4db689372980 100644 --- a/drivers/net/ethernet/amazon/ena/ena_com.c +++ b/drivers/net/ethernet/amazon/ena/ena_com.c @@ -362,7 +362,7 @@ static int ena_com_init_io_sq(struct ena_com_dev *ena_dev, ENA_COM_BOUNCE_BUFFER_CNTRL_CNT; io_sq->bounce_buf_ctrl.next_to_use = 0; - size = io_sq->bounce_buf_ctrl.buffer_size * + size = (size_t)io_sq->bounce_buf_ctrl.buffer_size * io_sq->bounce_buf_ctrl.buffers_num; dev_node = dev_to_node(ena_dev->dmadev); |