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Kevin Hao
baa35a698c
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: 0cb8de39a7 ("net: macb: Add ARP support to WOL")
Signed-off-by: Kevin Hao <haokexin@gmail.com>
Cc: stable@vger.kernel.org
Reviewed-by: Théo Lebrun <theo.lebrun@bootlin.com>
Link: https://patch.msgid.link/20260318-macb-irq-v2-2-f1179768ab24@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>