commit: 67ae7cf1eeda777f79259c4c6cb17a0bd28dee71
From: Ben Hutchings <[email protected]>
Date: Thu, 21 Jul 2011 15:25:30 -0700
Subject: [PATCH] ethtool: Allow zero-length register dumps again
Some drivers (ab)use the ethtool_ops::get_regs operation to expose
only a hardware revision ID. Commit
a77f5db361ed9953b5b749353ea2c7fed2bf8d93 ('ethtool: Allocate register
dump buffer with vmalloc()') had the side-effect of breaking these, as
vmalloc() returns a null pointer for size=0 whereas kmalloc() did not.
For backward-compatibility, allow zero-length dumps again.
Reported-by: Kalle Valo <[email protected]>
Signed-off-by: Ben Hutchings <[email protected]>
Cc: [email protected] [2.6.37+]
Signed-off-by: David S. Miller <[email protected]>
---
net/core/ethtool.c | 4 ++--
1 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/net/core/ethtool.c b/net/core/ethtool.c
index b7c12a6..6cdba5f 100644
--- a/net/core/ethtool.c
+++ b/net/core/ethtool.c
@@ -923,7 +923,7 @@ static int ethtool_get_regs(struct net_device *dev, char
__user *useraddr)
regs.len = reglen;
regbuf = vzalloc(reglen);
- if (!regbuf)
+ if (reglen && !regbuf)
return -ENOMEM;
ops->get_regs(dev, ®s, regbuf);
@@ -932,7 +932,7 @@ static int ethtool_get_regs(struct net_device *dev, char
__user *useraddr)
if (copy_to_user(useraddr, ®s, sizeof(regs)))
goto out;
useraddr += offsetof(struct ethtool_regs, data);
- if (copy_to_user(useraddr, regbuf, regs.len))
+ if (regbuf && copy_to_user(useraddr, regbuf, regs.len))
goto out;
ret = 0;
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