From: Kevin Hao Date: Wed, 18 Mar 2026 06:36:59 +0000 (+0800) Subject: net: macb: Protect access to net_device::ip_ptr with RCU lock X-Git-Tag: v7.0-rc6~40^2~28^2 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=baa35a698cea26930679a20a7550bbb4c8319725;p=thirdparty%2Fkernel%2Flinux.git net: macb: Protect access to net_device::ip_ptr with RCU lock Access to net_device::ip_ptr and its associated members must be protected by an RCU lock. Since we are modifying this piece of code, let's also move it to execute only when WAKE_ARP is enabled. To minimize the duration of the RCU lock, a local variable is used to temporarily store the IP address. This change resolves the following RCU check warning: WARNING: suspicious RCU usage 7.0.0-rc3-next-20260310-yocto-standard+ #122 Not tainted ----------------------------- drivers/net/ethernet/cadence/macb_main.c:5944 suspicious rcu_dereference_check() usage! other info that might help us debug this: rcu_scheduler_active = 2, debug_locks = 1 5 locks held by rtcwake/518: #0: ffff000803ab1408 (sb_writers#5){.+.+}-{0:0}, at: vfs_write+0xf8/0x368 #1: ffff0008090bf088 (&of->mutex#2){+.+.}-{4:4}, at: kernfs_fop_write_iter+0xbc/0x1c8 #2: ffff00080098d588 (kn->active#70){.+.+}-{0:0}, at: kernfs_fop_write_iter+0xcc/0x1c8 #3: ffff800081c84888 (system_transition_mutex){+.+.}-{4:4}, at: pm_suspend+0x1ec/0x290 #4: ffff0008009ba0f8 (&dev->mutex){....}-{4:4}, at: device_suspend+0x118/0x4f0 stack backtrace: CPU: 3 UID: 0 PID: 518 Comm: rtcwake Not tainted 7.0.0-rc3-next-20260310-yocto-standard+ #122 PREEMPT Hardware name: ZynqMP ZCU102 Rev1.1 (DT) Call trace: show_stack+0x24/0x38 (C) __dump_stack+0x28/0x38 dump_stack_lvl+0x64/0x88 dump_stack+0x18/0x24 lockdep_rcu_suspicious+0x134/0x1d8 macb_suspend+0xd8/0x4c0 device_suspend+0x218/0x4f0 dpm_suspend+0x244/0x3a0 dpm_suspend_start+0x50/0x78 suspend_devices_and_enter+0xec/0x560 pm_suspend+0x194/0x290 state_store+0x110/0x158 kobj_attr_store+0x1c/0x30 sysfs_kf_write+0xa8/0xd0 kernfs_fop_write_iter+0x11c/0x1c8 vfs_write+0x248/0x368 ksys_write+0x7c/0xf8 __arm64_sys_write+0x28/0x40 invoke_syscall+0x4c/0xe8 el0_svc_common+0x98/0xf0 do_el0_svc+0x28/0x40 el0_svc+0x54/0x1e0 el0t_64_sync_handler+0x84/0x130 el0t_64_sync+0x198/0x1a0 Fixes: 0cb8de39a776 ("net: macb: Add ARP support to WOL") Signed-off-by: Kevin Hao Cc: stable@vger.kernel.org Reviewed-by: Théo Lebrun Link: https://patch.msgid.link/20260318-macb-irq-v2-2-f1179768ab24@gmail.com Signed-off-by: Jakub Kicinski --- diff --git a/drivers/net/ethernet/cadence/macb_main.c b/drivers/net/ethernet/cadence/macb_main.c index 1b95226ae696..944aab71795c 100644 --- a/drivers/net/ethernet/cadence/macb_main.c +++ b/drivers/net/ethernet/cadence/macb_main.c @@ -5776,9 +5776,9 @@ static int __maybe_unused macb_suspend(struct device *dev) struct macb_queue *queue; struct in_device *idev; unsigned long flags; + u32 tmp, ifa_local; unsigned int q; int err; - u32 tmp; if (!device_may_wakeup(&bp->dev->dev)) phy_exit(bp->phy); @@ -5787,14 +5787,21 @@ static int __maybe_unused macb_suspend(struct device *dev) return 0; if (bp->wol & MACB_WOL_ENABLED) { - /* Check for IP address in WOL ARP mode */ - idev = __in_dev_get_rcu(bp->dev); - if (idev) - ifa = rcu_dereference(idev->ifa_list); - if ((bp->wolopts & WAKE_ARP) && !ifa) { - netdev_err(netdev, "IP address not assigned as required by WoL walk ARP\n"); - return -EOPNOTSUPP; + if (bp->wolopts & WAKE_ARP) { + /* Check for IP address in WOL ARP mode */ + rcu_read_lock(); + idev = __in_dev_get_rcu(bp->dev); + if (idev) + ifa = rcu_dereference(idev->ifa_list); + if (!ifa) { + rcu_read_unlock(); + netdev_err(netdev, "IP address not assigned as required by WoL walk ARP\n"); + return -EOPNOTSUPP; + } + ifa_local = be32_to_cpu(ifa->ifa_local); + rcu_read_unlock(); } + spin_lock_irqsave(&bp->lock, flags); /* Disable Tx and Rx engines before disabling the queues, @@ -5833,7 +5840,7 @@ static int __maybe_unused macb_suspend(struct device *dev) if (bp->wolopts & WAKE_ARP) { tmp |= MACB_BIT(ARP); /* write IP address into register */ - tmp |= MACB_BFEXT(IP, be32_to_cpu(ifa->ifa_local)); + tmp |= MACB_BFEXT(IP, ifa_local); } spin_unlock_irqrestore(&bp->lock, flags);