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authorJoakim Tjernlund <joakim.tjernlund@transmode.se>2010-11-12 03:55:09 +0000
committerDavid S. Miller <davem@davemloft.net>2010-11-12 12:21:18 -0800
commit75e6047431872dadd0b13503b374e48ccd71a507 (patch)
tree89e698b4a01ba2debe2b16334f3e0b8baf6ccf54 /drivers/net
parent2040bd57b5f0c52dc4503e0e960b1dcafaf30a8b (diff)
ucc_geth: Fix deadlock
This script: while [ 1==1 ] ; do ifconfig eth0 up; usleep 1950000 ;ifconfig eth0 down; dmesg -c ;done causes in just a second or two: INFO: task ifconfig:572 blocked for more than 120 seconds. "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. ifconfig D 0ff65760 0 572 369 0x00000000 Call Trace: [c6157be0] [c6008460] 0xc6008460 (unreliable) [c6157ca0] [c0008608] __switch_to+0x4c/0x6c [c6157cb0] [c028fecc] schedule+0x184/0x310 [c6157ce0] [c0290e54] __mutex_lock_slowpath+0xa4/0x150 [c6157d20] [c0290c48] mutex_lock+0x44/0x48 [c6157d30] [c01aba74] phy_stop+0x20/0x70 [c6157d40] [c01aef40] ucc_geth_stop+0x30/0x98 [c6157d60] [c01b18fc] ucc_geth_close+0x9c/0xdc [c6157d80] [c01db0cc] __dev_close+0xa0/0xd0 [c6157d90] [c01deddc] __dev_change_flags+0x8c/0x148 [c6157db0] [c01def54] dev_change_flags+0x1c/0x64 [c6157dd0] [c0237ac8] devinet_ioctl+0x678/0x784 [c6157e50] [c0239a58] inet_ioctl+0xb0/0xbc [c6157e60] [c01cafa8] sock_ioctl+0x174/0x2a0 [c6157e80] [c009a16c] vfs_ioctl+0xcc/0xe0 [c6157ea0] [c009a998] do_vfs_ioctl+0xc4/0x79c [c6157f10] [c009b0b0] sys_ioctl+0x40/0x74 [c6157f40] [c00117c4] ret_from_syscall+0x0/0x38 The reason appears to be ucc_geth_stop meets adjust_link as the PHY reports PHY changes. I belive adjust_link hangs somewhere, holding the PHY lock, because ucc_geth_stop disabled the controller HW. Fix is to stop the PHY before disabling the controller. Signed-off-by: Joakim Tjernlund <Joakim.Tjernlund@transmode.se> Reviewed-by: Anton Vorontsov <cbouatmailru@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/net')
-rw-r--r--drivers/net/ucc_geth.c10
1 files changed, 7 insertions, 3 deletions
diff --git a/drivers/net/ucc_geth.c b/drivers/net/ucc_geth.c
index cf6653f71d23..acbdab3d66ca 100644
--- a/drivers/net/ucc_geth.c
+++ b/drivers/net/ucc_geth.c
@@ -2050,12 +2050,16 @@ static void ucc_geth_stop(struct ucc_geth_private *ugeth)
ugeth_vdbg("%s: IN", __func__);
+ /*
+ * Tell the kernel the link is down.
+ * Must be done before disabling the controller
+ * or deadlock may happen.
+ */
+ phy_stop(phydev);
+
/* Disable the controller */
ugeth_disable(ugeth, COMM_DIR_RX_AND_TX);
- /* Tell the kernel the link is down */
- phy_stop(phydev);
-
/* Mask all interrupts */
out_be32(ugeth->uccf->p_uccm, 0x00000000);