From e0ad2cd8ff7fb957be867d17d44fb4b7093c91bd Mon Sep 17 00:00:00 2001 From: Anton Vorontsov Date: Thu, 27 Aug 2009 07:35:47 +0000 Subject: [PATCH] ucc_geth: Fix NULL pointer dereference in uec_get_ethtool_stats() In commit 3e73fc9a12679a546284d597c1f19165792d0b83 ("ucc_geth: Fix IO memory (un)mapping code") I fixed ug_regs IO memory leak by properly freeing the allocated memory. But ethtool_stats() callback doesn't check for ug_regs being NULL, and that causes following oops if 'ethtool -S' is executed on a closed eth device: Unable to handle kernel paging request for data at address 0x00000180 Faulting instruction address: 0xc0208228 Oops: Kernel access of bad area, sig: 11 [#1] ... NIP [c0208228] uec_get_ethtool_stats+0x38/0x140 LR [c02559a0] ethtool_get_stats+0xf8/0x23c Call Trace: [ef87bcd0] [c025597c] ethtool_get_stats+0xd4/0x23c (unreliable) [ef87bd00] [c025706c] dev_ethtool+0xfe8/0x11bc [ef87be00] [c0252b5c] dev_ioctl+0x454/0x6a8 ... ---[ end trace 77fff1162a9586b0 ]--- Segmentation fault This patch fixes the issue. Signed-off-by: Anton Vorontsov Signed-off-by: David S. Miller --- drivers/net/ucc_geth_ethtool.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/drivers/net/ucc_geth_ethtool.c b/drivers/net/ucc_geth_ethtool.c index 61fe80dda3e3..304128fa6058 100644 --- a/drivers/net/ucc_geth_ethtool.c +++ b/drivers/net/ucc_geth_ethtool.c @@ -319,9 +319,13 @@ static void uec_get_ethtool_stats(struct net_device *netdev, int i, j = 0; if (stats_mode & UCC_GETH_STATISTICS_GATHERING_MODE_HARDWARE) { - base = (u32 __iomem *)&ugeth->ug_regs->tx64; + if (ugeth->ug_regs) + base = (u32 __iomem *)&ugeth->ug_regs->tx64; + else + base = NULL; + for (i = 0; i < UEC_HW_STATS_LEN; i++) - data[j++] = in_be32(&base[i]); + data[j++] = base ? in_be32(&base[i]) : 0; } if (stats_mode & UCC_GETH_STATISTICS_GATHERING_MODE_FIRMWARE_TX) { base = (u32 __iomem *)ugeth->p_tx_fw_statistics_pram;