The rtnl_mutex was held to protect calls to dev_uc_add and dev_uc_del. Holding rtnl is not required as those functions make use of the netif_addr_lock* API to protect the MAC changing. This change fixes the following regression by removing the rtnl usage when fcoe_update_src_mac is called. https://bugzilla.kernel.org/show_bug.cgi?id=42918 the existing dependency chain (in reverse order) is: -> #1 (&fip->ctlr_mutex){+.+...}: [<c1091f70>] lock_acquire+0x80/0x1b0 [<c147655d>] mutex_lock_nested+0x6d/0x340 [<f8970c32>] fcoe_ctlr_link_up+0x22/0x180 [libfcoe] [<f894620e>] fcoe_create+0x47e/0x6e0 [fcoe] [<f8973dd3>] fcoe_transport_create+0x143/0x250 [libfcoe] [<c10527e0>] param_attr_store+0x30/0x60 [<c1052696>] module_attr_store+0x26/0x40 [<c11a201e>] sysfs_write_file+0xae/0x100 [<c11449df>] vfs_write+0x8f/0x160 [<c1144cbd>] sys_write+0x3d/0x70 [<c147a0c4>] syscall_call+0x7/0xb -> #0 (rtnl_mutex){+.+.+.}: [<c109164b>] __lock_acquire+0x140b/0x1720 [<c1091f70>] lock_acquire+0x80/0x1b0 [<c147655d>] mutex_lock_nested+0x6d/0x340 [<c13a10c4>] rtnl_lock+0x14/0x20 [<f89445ac>] fcoe_update_src_mac+0x2c/0xb0 [fcoe] [<f8971712>] fcoe_ctlr_timer_work+0x712/0xb60 [libfcoe] [<c104fb69>] process_one_work+0x179/0x5d0 [<c10502f1>] worker_thread+0x121/0x2d0 [<c10550ed>] kthread+0x7d/0x90 [<c1481a82>] kernel_thread_helper+0x6/0x10 other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&fip->ctlr_mutex); lock(rtnl_mutex); lock(&fip->ctlr_mutex); lock(rtnl_mutex); *** DEADLOCK *** Signed-off-by: Robert Love <robert.w.love@xxxxxxxxx> --- drivers/scsi/fcoe/fcoe.c | 2 -- 1 files changed, 0 insertions(+), 2 deletions(-) diff --git a/drivers/scsi/fcoe/fcoe.c b/drivers/scsi/fcoe/fcoe.c index e959960..85b8203 100644 --- a/drivers/scsi/fcoe/fcoe.c +++ b/drivers/scsi/fcoe/fcoe.c @@ -539,13 +539,11 @@ static void fcoe_update_src_mac(struct fc_lport *lport, u8 *addr) struct fcoe_port *port = lport_priv(lport); struct fcoe_interface *fcoe = port->priv; - rtnl_lock(); if (!is_zero_ether_addr(port->data_src_addr)) dev_uc_del(fcoe->netdev, port->data_src_addr); if (!is_zero_ether_addr(addr)) dev_uc_add(fcoe->netdev, addr); memcpy(port->data_src_addr, addr, ETH_ALEN); - rtnl_unlock(); } /** -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
