[PATCH net 2/4] net: sparx5: fix sleep in atomic context in MAC table access
From: Daniel Machon <daniel.machon@microchip.com>
Date: 2026-05-04 14:44:05
Also in:
linux-arm-kernel, linux-rt-devel, lkml
Subsystem:
networking drivers, the rest · Maintainers:
Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
sparx5_mact_learn() is called from .ndo_set_rx_mode with
netif_addr_lock_bh held, but takes sparx5->lock which is a mutex.
A mutex may block, which is not allowed from atomic context.
Convert sparx5->lock to a spinlock, switch the hardware completion poll
to readx_poll_timeout_atomic(), and use spin_lock_bh() since no caller
runs in hardirq context.
Observed with CONFIG_PROVE_LOCKING, CONFIG_DEBUG_SPINLOCK,
CONFIG_DEBUG_MUTEXES and CONFIG_DEBUG_ATOMIC_SLEEP enabled:
BUG: sleeping function called from invalid context at kernel/locking/mutex.c:591
in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 217, name: ip
preempt_count: 201, expected: 0
Call trace:
__might_resched+0x144/0x248
__might_sleep+0x48/0x7c
__mutex_lock+0x74/0x850
mutex_lock_nested+0x24/0x30
sparx5_mact_learn+0x78/0x100
sparx5_mc_sync+0x40/0x54
__hw_addr_sync_dev+0xc4/0x170
sparx5_set_rx_mode+0x4c/0x58
__dev_set_rx_mode+0x64/0xa4
__dev_open+0x1ec/0x26c
Fixes: b37a1bae742f ("net: sparx5: add mactable support")
Signed-off-by: Daniel Machon <daniel.machon@microchip.com>
---
.../ethernet/microchip/sparx5/sparx5_mactable.c | 24 +++++++++++-----------
.../net/ethernet/microchip/sparx5/sparx5_main.h | 2 +-
2 files changed, 13 insertions(+), 13 deletions(-)
diff --git a/drivers/net/ethernet/microchip/sparx5/sparx5_mactable.c b/drivers/net/ethernet/microchip/sparx5/sparx5_mactable.c
index 2bf9c5f64151..0797cfa32916 100644
--- a/drivers/net/ethernet/microchip/sparx5/sparx5_mactable.c
+++ b/drivers/net/ethernet/microchip/sparx5/sparx5_mactable.c@@ -50,7 +50,7 @@ static int sparx5_mact_wait_for_completion(struct sparx5 *sparx5) { u32 val; - return readx_poll_timeout(sparx5_mact_get_status, + return readx_poll_timeout_atomic(sparx5_mact_get_status, sparx5, val, LRN_COMMON_ACCESS_CTRL_MAC_TABLE_ACCESS_SHOT_GET(val) == 0, TABLE_UPDATE_SLEEP_US, TABLE_UPDATE_TIMEOUT_US);
@@ -92,7 +92,7 @@ int sparx5_mact_learn(struct sparx5 *sparx5, int pgid, addr = pgid - consts->n_ports; } - mutex_lock(&sparx5->lock); + spin_lock_bh(&sparx5->lock); sparx5_mact_select(sparx5, mac, vid);
@@ -111,7 +111,7 @@ int sparx5_mact_learn(struct sparx5 *sparx5, int pgid, ret = sparx5_mact_wait_for_completion(sparx5); - mutex_unlock(&sparx5->lock); + spin_unlock_bh(&sparx5->lock); return ret; }
@@ -164,7 +164,7 @@ bool sparx5_mact_getnext(struct sparx5 *sparx5, u32 cfg2; int ret; - mutex_lock(&sparx5->lock); + spin_lock_bh(&sparx5->lock); sparx5_mact_select(sparx5, mac, *vid);
@@ -183,7 +183,7 @@ bool sparx5_mact_getnext(struct sparx5 *sparx5, *pcfg2 = cfg2; } - mutex_unlock(&sparx5->lock); + spin_unlock_bh(&sparx5->lock); return ret == 0; }
@@ -194,7 +194,7 @@ int sparx5_mact_find(struct sparx5 *sparx5, int ret; u32 cfg2; - mutex_lock(&sparx5->lock); + spin_lock_bh(&sparx5->lock); sparx5_mact_select(sparx5, mac, vid);
@@ -212,7 +212,7 @@ int sparx5_mact_find(struct sparx5 *sparx5, ret = -ENOENT; } - mutex_unlock(&sparx5->lock); + spin_unlock_bh(&sparx5->lock); return ret; }
@@ -222,7 +222,7 @@ int sparx5_mact_forget(struct sparx5 *sparx5, { int ret; - mutex_lock(&sparx5->lock); + spin_lock_bh(&sparx5->lock); sparx5_mact_select(sparx5, mac, vid);
@@ -233,7 +233,7 @@ int sparx5_mact_forget(struct sparx5 *sparx5, ret = sparx5_mact_wait_for_completion(sparx5); - mutex_unlock(&sparx5->lock); + spin_unlock_bh(&sparx5->lock); return ret; }
@@ -440,7 +440,7 @@ static void sparx5_mact_pull_work(struct work_struct *work) vid = 0; memset(mac, 0, sizeof(mac)); do { - mutex_lock(&sparx5->lock); + spin_lock_bh(&sparx5->lock); sparx5_mact_select(sparx5, mac, vid); spx5_wr(LRN_SCAN_NEXT_CFG_SCAN_NEXT_UNTIL_FOUND_ENA_SET(1), sparx5, LRN_SCAN_NEXT_CFG);
@@ -451,7 +451,7 @@ static void sparx5_mact_pull_work(struct work_struct *work) ret = sparx5_mact_wait_for_completion(sparx5); if (ret == 0) ret = sparx5_mact_get(sparx5, mac, &vid, &cfg2); - mutex_unlock(&sparx5->lock); + spin_unlock_bh(&sparx5->lock); if (ret == 0) sparx5_mact_handle_entry(sparx5, mac, vid, cfg2); } while (ret == 0);
@@ -493,7 +493,7 @@ int sparx5_mact_init(struct sparx5 *sparx5) { char queue_name[32]; - mutex_init(&sparx5->lock); + spin_lock_init(&sparx5->lock); /* Flush MAC table */ spx5_wr(LRN_COMMON_ACCESS_CTRL_CPU_ACCESS_CMD_SET(MAC_CMD_CLEAR_ALL) |
diff --git a/drivers/net/ethernet/microchip/sparx5/sparx5_main.h b/drivers/net/ethernet/microchip/sparx5/sparx5_main.h
index d5e6644ff124..8ef4050ceecc 100644
--- a/drivers/net/ethernet/microchip/sparx5/sparx5_main.h
+++ b/drivers/net/ethernet/microchip/sparx5/sparx5_main.h@@ -373,7 +373,7 @@ struct sparx5 { u32 features; void __iomem *regs[NUM_TARGETS]; int port_count; - struct mutex lock; /* MAC reg lock */ + spinlock_t lock; /* MAC reg lock */ /* port structures are in net device */ struct sparx5_port *ports[SPX5_PORTS]; enum sparx5_core_clockfreq coreclock;
--
2.34.1