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net: macb: fix sleep inside spinlock
macb_set_tx_clk() is called under a spinlock but itself calls clk_set_rate() which can sleep. This results in: | BUG: sleeping function called from invalid context at kernel/locking/mutex.c:580 | pps pps1: new PPS source ptp1 | in_atomic(): 1, irqs_disabled(): 1, non_block: 0, pid: 40, name: kworker/u4:3 | preempt_count: 1, expected: 0 | RCU nest depth: 0, expected: 0 | 4 locks held by kworker/u4:3/40: | #0: ffff000003409148 | macb ff0c0000.ethernet: gem-ptp-timer ptp clock registered. | ((wq_completion)events_power_efficient){+.+.}-{0:0}, at: process_one_work+0x14c/0x51c | #1: ffff8000833cbdd8 ((work_completion)(&pl->resolve)){+.+.}-{0:0}, at: process_one_work+0x14c/0x51c | Rust-for-Linux#2: ffff000004f01578 (&pl->state_mutex){+.+.}-{4:4}, at: phylink_resolve+0x44/0x4e8 | Rust-for-Linux#3: ffff000004f06f50 (&bp->lock){....}-{3:3}, at: macb_mac_link_up+0x40/0x2ac | irq event stamp: 113998 | hardirqs last enabled at (113997): [<ffff800080e8503c>] _raw_spin_unlock_irq+0x30/0x64 | hardirqs last disabled at (113998): [<ffff800080e84478>] _raw_spin_lock_irqsave+0xac/0xc8 | softirqs last enabled at (113608): [<ffff800080010630>] __do_softirq+0x430/0x4e4 | softirqs last disabled at (113597): [<ffff80008001614c>] ____do_softirq+0x10/0x1c | CPU: 0 PID: 40 Comm: kworker/u4:3 Not tainted 6.5.0-11717-g9355ce8b2f50-dirty Rust-for-Linux#368 | Hardware name: ... ZynqMP ... (DT) | Workqueue: events_power_efficient phylink_resolve | Call trace: | dump_backtrace+0x98/0xf0 | show_stack+0x18/0x24 | dump_stack_lvl+0x60/0xac | dump_stack+0x18/0x24 | __might_resched+0x144/0x24c | __might_sleep+0x48/0x98 | __mutex_lock+0x58/0x7b0 | mutex_lock_nested+0x24/0x30 | clk_prepare_lock+0x4c/0xa8 | clk_set_rate+0x24/0x8c | macb_mac_link_up+0x25c/0x2ac | phylink_resolve+0x178/0x4e8 | process_one_work+0x1ec/0x51c | worker_thread+0x1ec/0x3e4 | kthread+0x120/0x124 | ret_from_fork+0x10/0x20 The obvious fix is to move the call to macb_set_tx_clk() out of the protected area. This seems safe as rx and tx are both disabled anyway at this point. It is however not entirely clear what the spinlock shall protect. It could be the read-modify-write access to the NCFGR register, but this is accessed in macb_set_rx_mode() and macb_set_rxcsum_feature() as well without holding the spinlock. It could also be the register accesses done in mog_init_rings() or macb_init_buffers(), but again these functions are called without holding the spinlock in macb_hresp_error_task(). The locking seems fishy in this driver and it might deserve another look before this patch is applied. Fixes: 633e98a ("net: macb: use resolved link config in mac_link_up()") Signed-off-by: Sascha Hauer <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Paolo Abeni <[email protected]>
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