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Commit 67ae7cf1 authored by Ben Hutchings's avatar Ben Hutchings Committed by David S. Miller
Browse files

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
a77f5db3 ('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: default avatarKalle Valo <kvalo@qca.qualcomm.com>
Signed-off-by: default avatarBen Hutchings <bhutchings@solarflare.com>
Cc: stable@kernel.org [2.6.37+]
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 1511022c

net/core/ethtool.c

+2 −2
Original line number Original line Diff line number Diff line
@@ -923,7 +923,7 @@ static int ethtool_get_regs(struct net_device *dev, char __user *useraddr) 
		regs.len = reglen;

		regs.len = reglen;





	regbuf = vzalloc(reglen);

	regbuf = vzalloc(reglen);

	if (!regbuf)

	if (reglen && !regbuf)

		return -ENOMEM;

		return -ENOMEM;





	ops->get_regs(dev, &regs, regbuf);

	ops->get_regs(dev, &regs, regbuf);
@@ -932,7 +932,7 @@ static int ethtool_get_regs(struct net_device *dev, char __user *useraddr) 
	if (copy_to_user(useraddr, &regs, sizeof(regs)))

	if (copy_to_user(useraddr, &regs, sizeof(regs)))

		goto out;

		goto out;

	useraddr += offsetof(struct ethtool_regs, data);

	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;

		goto out;

	ret = 0;

	ret = 0;