[PATCH 5.10 46/93] e100: fix length calculation in e100_get_regs_len

Greg Kroah-Hartman
2021-10-04T13:22:57Z

From: Jacob Keller <jacob.e.keller@intel.com>

[ Upstream commit 4329c8dc110b25d5f04ed20c6821bb60deff279f ]

commit abf9b902059f ("e100: cleanup unneeded math") tried to simplify
e100_get_regs_len and remove a double 'divide and then multiply'
calculation that the e100_reg_regs_len function did.

This change broke the size calculation entirely as it failed to account
for the fact that the numbered registers are actually 4 bytes wide and
not 1 byte. This resulted in a significant under allocation of the
register buffer used by e100_get_regs.

Fix this by properly multiplying the register count by u32 first before
adding the size of the dump buffer.

Fixes: abf9b902059f ("e100: cleanup unneeded math")
Reported-by: Felicitas Hetzelt <felicitashetzelt@gmail.com>
Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/net/ethernet/intel/e100.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/intel/e100.c b/drivers/net/ethernet/intel/e100.c
index 609e47b8287d..fee329d98621 100644
--- a/drivers/net/ethernet/intel/e100.c
+++ b/drivers/net/ethernet/intel/e100.c
@@ -2435,7 +2435,11 @@ static void e100_get_drvinfo(struct net_device *netdev,
static int e100_get_regs_len(struct net_device *netdev)
{
struct nic *nic = netdev_priv(netdev);
- return 1 + E100_PHY_REGS + sizeof(nic->mem->dump_buf);
+
+ /* We know the number of registers, and the size of the dump buffer.
+ * Calculate the total size in bytes.
+ */
+ return (1 + E100_PHY_REGS) * sizeof(u32) + sizeof(nic->mem->dump_buf);
}

static void e100_get_regs(struct net_device *netdev,
--
2.33.0