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authorSascha Hauer <s.hauer@pengutronix.de>2023-09-08 14:29:13 +0300
committerPaolo Abeni <pabeni@redhat.com>2023-09-12 15:58:44 +0300
commit403f0e771457e2b8811dc280719d11b9bacf10f4 (patch)
tree666063b49439cd85e7e2305600800d8b3562ae4a
parentcfaa80c91f6f99b9342b6557f0f0e1143e434066 (diff)
downloadlinux-403f0e771457e2b8811dc280719d11b9bacf10f4.tar.xz
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 | #2: ffff000004f01578 (&pl->state_mutex){+.+.}-{4:4}, at: phylink_resolve+0x44/0x4e8 | #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 #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: 633e98a711ac0 ("net: macb: use resolved link config in mac_link_up()") Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> Link: https://lore.kernel.org/r/20230908112913.1701766-1-s.hauer@pengutronix.de Signed-off-by: Paolo Abeni <pabeni@redhat.com>
-rw-r--r--drivers/net/ethernet/cadence/macb_main.c5
1 files changed, 3 insertions, 2 deletions
diff --git a/drivers/net/ethernet/cadence/macb_main.c b/drivers/net/ethernet/cadence/macb_main.c
index 31f664ee4d77..b940dcd3ace6 100644
--- a/drivers/net/ethernet/cadence/macb_main.c
+++ b/drivers/net/ethernet/cadence/macb_main.c
@@ -756,8 +756,6 @@ static void macb_mac_link_up(struct phylink_config *config,
if (rx_pause)
ctrl |= MACB_BIT(PAE);
- macb_set_tx_clk(bp, speed);
-
/* Initialize rings & buffers as clearing MACB_BIT(TE) in link down
* cleared the pipeline and control registers.
*/
@@ -777,6 +775,9 @@ static void macb_mac_link_up(struct phylink_config *config,
spin_unlock_irqrestore(&bp->lock, flags);
+ if (!(bp->caps & MACB_CAPS_MACB_IS_EMAC))
+ macb_set_tx_clk(bp, speed);
+
/* Enable Rx and Tx; Enable PTP unicast */
ctrl = macb_readl(bp, NCR);
if (gem_has_ptp(bp))