* [PATCH net] net: dsa: mt7530: fix .get_stats64 sleeping in atomic context
@ 2026-04-17 3:55 Daniel Golle
2026-04-17 7:35 ` Chester A. Unal
` (2 more replies)
0 siblings, 3 replies; 6+ messages in thread
From: Daniel Golle @ 2026-04-17 3:55 UTC (permalink / raw)
To: Chester A. Unal, Daniel Golle, Andrew Lunn, Vladimir Oltean,
David S. Miller, Eric Dumazet, Jakub Kicinski, Paolo Abeni,
Matthias Brugger, AngeloGioacchino Del Regno, Russell King,
Christian Marangi, netdev, linux-kernel, linux-arm-kernel,
linux-mediatek
Cc: Frank Wunderlich, John Crispin
The .get_stats64 callback runs in atomic context, but on
MDIO-connected switches every register read acquires the MDIO bus
mutex, which can sleep:
[ 12.645973] BUG: sleeping function called from invalid context at kernel/locking/mutex.c:609
[ 12.654442] in_atomic(): 0, irqs_disabled(): 0, non_block: 0, pid: 759, name: grep
[ 12.663377] preempt_count: 0, expected: 0
[ 12.667410] RCU nest depth: 1, expected: 0
[ 12.671511] INFO: lockdep is turned off.
[ 12.675441] CPU: 0 UID: 0 PID: 759 Comm: grep Tainted: G S W 7.0.0+ #0 PREEMPT
[ 12.675453] Tainted: [S]=CPU_OUT_OF_SPEC, [W]=WARN
[ 12.675456] Hardware name: Bananapi BPI-R64 (DT)
[ 12.675459] Call trace:
[ 12.675462] show_stack+0x14/0x1c (C)
[ 12.675477] dump_stack_lvl+0x68/0x8c
[ 12.675487] dump_stack+0x14/0x1c
[ 12.675495] __might_resched+0x14c/0x220
[ 12.675504] __might_sleep+0x44/0x80
[ 12.675511] __mutex_lock+0x50/0xb10
[ 12.675523] mutex_lock_nested+0x20/0x30
[ 12.675532] mt7530_get_stats64+0x40/0x2ac
[ 12.675542] dsa_user_get_stats64+0x2c/0x40
[ 12.675553] dev_get_stats+0x44/0x1e0
[ 12.675564] dev_seq_printf_stats+0x24/0xe0
[ 12.675575] dev_seq_show+0x14/0x3c
[ 12.675583] seq_read_iter+0x37c/0x480
[ 12.675595] seq_read+0xd0/0xec
[ 12.675605] proc_reg_read+0x94/0xe4
[ 12.675615] vfs_read+0x98/0x29c
[ 12.675625] ksys_read+0x54/0xdc
[ 12.675633] __arm64_sys_read+0x18/0x20
[ 12.675642] invoke_syscall.constprop.0+0x54/0xec
[ 12.675653] do_el0_svc+0x3c/0xb4
[ 12.675662] el0_svc+0x38/0x200
[ 12.675670] el0t_64_sync_handler+0x98/0xdc
[ 12.675679] el0t_64_sync+0x158/0x15c
For MDIO-connected switches, poll MIB counters asynchronously using a
delayed workqueue every second and let .get_stats64 return the cached
values under a per-port spinlock. A mod_delayed_work() call on each
read triggers an immediate refresh so counters stay responsive when
queried more frequently.
MMIO-connected switches (MT7988, EN7581, AN7583) are not affected
because their regmap does not sleep, so they continue to read MIB
counters directly in .get_stats64.
Fixes: 88c810f35ed5 ("net: dsa: mt7530: implement .get_stats64")
Signed-off-by: Daniel Golle <daniel@makrotopia.org>
---
This bug highlights a bigger problem and the actual cause:
Locking in the mt7530 driver deserves a cleanup, and refactoring
towards cleanly and directly using the regmap API.
I've prepared this already and am going to submit a series doing
most of that using Coccinelle semantic patches once net-next opens
again.
drivers/net/dsa/mt7530.c | 54 +++++++++++++++++++++++++++++++++++++---
drivers/net/dsa/mt7530.h | 6 +++++
2 files changed, 57 insertions(+), 3 deletions(-)
diff --git a/drivers/net/dsa/mt7530.c b/drivers/net/dsa/mt7530.c
index b9423389c2ef0..786d3a8492bcb 100644
--- a/drivers/net/dsa/mt7530.c
+++ b/drivers/net/dsa/mt7530.c
@@ -25,6 +25,8 @@
#include "mt7530.h"
+#define MT7530_STATS_POLL_INTERVAL (1 * HZ)
+
static struct mt753x_pcs *pcs_to_mt753x_pcs(struct phylink_pcs *pcs)
{
return container_of(pcs, struct mt753x_pcs, pcs);
@@ -906,10 +908,9 @@ static void mt7530_get_rmon_stats(struct dsa_switch *ds, int port,
*ranges = mt7530_rmon_ranges;
}
-static void mt7530_get_stats64(struct dsa_switch *ds, int port,
- struct rtnl_link_stats64 *storage)
+static void mt7530_read_port_stats64(struct mt7530_priv *priv, int port,
+ struct rtnl_link_stats64 *storage)
{
- struct mt7530_priv *priv = ds->priv;
uint64_t data;
/* MIB counter doesn't provide a FramesTransmittedOK but instead
@@ -951,6 +952,43 @@ static void mt7530_get_stats64(struct dsa_switch *ds, int port,
&storage->rx_crc_errors);
}
+static void mt7530_stats_poll(struct work_struct *work)
+{
+ struct mt7530_priv *priv = container_of(work, struct mt7530_priv,
+ stats_work.work);
+ struct rtnl_link_stats64 stats = {};
+ struct dsa_port *dp;
+ int port;
+
+ dsa_switch_for_each_user_port(dp, priv->ds) {
+ port = dp->index;
+
+ mt7530_read_port_stats64(priv, port, &stats);
+
+ spin_lock(&priv->stats_lock);
+ priv->ports[port].stats = stats;
+ spin_unlock(&priv->stats_lock);
+ }
+
+ schedule_delayed_work(&priv->stats_work,
+ MT7530_STATS_POLL_INTERVAL);
+}
+
+static void mt7530_get_stats64(struct dsa_switch *ds, int port,
+ struct rtnl_link_stats64 *storage)
+{
+ struct mt7530_priv *priv = ds->priv;
+
+ if (priv->bus) {
+ spin_lock(&priv->stats_lock);
+ *storage = priv->ports[port].stats;
+ spin_unlock(&priv->stats_lock);
+ mod_delayed_work(system_wq, &priv->stats_work, 0);
+ } else {
+ mt7530_read_port_stats64(priv, port, storage);
+ }
+}
+
static void mt7530_get_eth_ctrl_stats(struct dsa_switch *ds, int port,
struct ethtool_eth_ctrl_stats *ctrl_stats)
{
@@ -3137,6 +3175,13 @@ mt753x_setup(struct dsa_switch *ds)
if (ret && priv->irq_domain)
mt7530_free_mdio_irq(priv);
+ if (!ret && priv->bus) {
+ spin_lock_init(&priv->stats_lock);
+ INIT_DELAYED_WORK(&priv->stats_work, mt7530_stats_poll);
+ schedule_delayed_work(&priv->stats_work,
+ MT7530_STATS_POLL_INTERVAL);
+ }
+
return ret;
}
@@ -3404,6 +3449,9 @@ EXPORT_SYMBOL_GPL(mt7530_probe_common);
void
mt7530_remove_common(struct mt7530_priv *priv)
{
+ if (priv->bus)
+ cancel_delayed_work_sync(&priv->stats_work);
+
if (priv->irq_domain)
mt7530_free_mdio_irq(priv);
diff --git a/drivers/net/dsa/mt7530.h b/drivers/net/dsa/mt7530.h
index 3e0090bed298d..44c1dc75baea8 100644
--- a/drivers/net/dsa/mt7530.h
+++ b/drivers/net/dsa/mt7530.h
@@ -796,6 +796,7 @@ struct mt7530_fdb {
* @pvid: The VLAN specified is to be considered a PVID at ingress. Any
* untagged frames will be assigned to the related VLAN.
* @sgmii_pcs: Pointer to PCS instance for SerDes ports
+ * @stats: Cached port statistics for MDIO-connected switches
*/
struct mt7530_port {
bool enable;
@@ -803,6 +804,7 @@ struct mt7530_port {
u32 pm;
u16 pvid;
struct phylink_pcs *sgmii_pcs;
+ struct rtnl_link_stats64 stats;
};
/* Port 5 mode definitions of the MT7530 switch */
@@ -875,6 +877,8 @@ struct mt753x_info {
* @create_sgmii: Pointer to function creating SGMII PCS instance(s)
* @active_cpu_ports: Holding the active CPU ports
* @mdiodev: The pointer to the MDIO device structure
+ * @stats_lock: Protects cached per-port stats from concurrent access
+ * @stats_work: Delayed work for polling MIB counters on MDIO switches
*/
struct mt7530_priv {
struct device *dev;
@@ -900,6 +904,8 @@ struct mt7530_priv {
int (*create_sgmii)(struct mt7530_priv *priv);
u8 active_cpu_ports;
struct mdio_device *mdiodev;
+ spinlock_t stats_lock; /* protects cached stats counters */
+ struct delayed_work stats_work;
};
struct mt7530_hw_vlan_entry {
--
2.53.0
^ permalink raw reply related [flat|nested] 6+ messages in thread* Re: [PATCH net] net: dsa: mt7530: fix .get_stats64 sleeping in atomic context
2026-04-17 3:55 [PATCH net] net: dsa: mt7530: fix .get_stats64 sleeping in atomic context Daniel Golle
@ 2026-04-17 7:35 ` Chester A. Unal
2026-04-17 12:08 ` Daniel Golle
2026-04-17 12:06 ` Andrew Lunn
2026-04-17 17:46 ` Breno Leitao
2 siblings, 1 reply; 6+ messages in thread
From: Chester A. Unal @ 2026-04-17 7:35 UTC (permalink / raw)
To: Daniel Golle, Andrew Lunn, Vladimir Oltean, David S. Miller,
Eric Dumazet, Jakub Kicinski, Paolo Abeni, Matthias Brugger,
AngeloGioacchino Del Regno, Russell King, Christian Marangi,
netdev, linux-kernel, linux-arm-kernel, linux-mediatek
Cc: Frank Wunderlich, John Crispin
On 17 April 2026 04:55:57 WEST, Daniel Golle <daniel@makrotopia.org> wrote:
>The .get_stats64 callback runs in atomic context, but on
>MDIO-connected switches every register read acquires the MDIO bus
>mutex, which can sleep:
>[ 12.645973] BUG: sleeping function called from invalid context at kernel/locking/mutex.c:609
>[ 12.654442] in_atomic(): 0, irqs_disabled(): 0, non_block: 0, pid: 759, name: grep
>[ 12.663377] preempt_count: 0, expected: 0
>[ 12.667410] RCU nest depth: 1, expected: 0
>[ 12.671511] INFO: lockdep is turned off.
>[ 12.675441] CPU: 0 UID: 0 PID: 759 Comm: grep Tainted: G S W 7.0.0+ #0 PREEMPT
>[ 12.675453] Tainted: [S]=CPU_OUT_OF_SPEC, [W]=WARN
>[ 12.675456] Hardware name: Bananapi BPI-R64 (DT)
>[ 12.675459] Call trace:
>[ 12.675462] show_stack+0x14/0x1c (C)
>[ 12.675477] dump_stack_lvl+0x68/0x8c
>[ 12.675487] dump_stack+0x14/0x1c
>[ 12.675495] __might_resched+0x14c/0x220
>[ 12.675504] __might_sleep+0x44/0x80
>[ 12.675511] __mutex_lock+0x50/0xb10
>[ 12.675523] mutex_lock_nested+0x20/0x30
>[ 12.675532] mt7530_get_stats64+0x40/0x2ac
>[ 12.675542] dsa_user_get_stats64+0x2c/0x40
>[ 12.675553] dev_get_stats+0x44/0x1e0
>[ 12.675564] dev_seq_printf_stats+0x24/0xe0
>[ 12.675575] dev_seq_show+0x14/0x3c
>[ 12.675583] seq_read_iter+0x37c/0x480
>[ 12.675595] seq_read+0xd0/0xec
>[ 12.675605] proc_reg_read+0x94/0xe4
>[ 12.675615] vfs_read+0x98/0x29c
>[ 12.675625] ksys_read+0x54/0xdc
>[ 12.675633] __arm64_sys_read+0x18/0x20
>[ 12.675642] invoke_syscall.constprop.0+0x54/0xec
>[ 12.675653] do_el0_svc+0x3c/0xb4
>[ 12.675662] el0_svc+0x38/0x200
>[ 12.675670] el0t_64_sync_handler+0x98/0xdc
>[ 12.675679] el0t_64_sync+0x158/0x15c
>
>For MDIO-connected switches, poll MIB counters asynchronously using a
>delayed workqueue every second and let .get_stats64 return the cached
>values under a per-port spinlock. A mod_delayed_work() call on each
>read triggers an immediate refresh so counters stay responsive when
>queried more frequently.
>
>MMIO-connected switches (MT7988, EN7581, AN7583) are not affected
>because their regmap does not sleep, so they continue to read MIB
>counters directly in .get_stats64.
>
>Fixes: 88c810f35ed5 ("net: dsa: mt7530: implement .get_stats64")
>Signed-off-by: Daniel Golle <daniel@makrotopia.org>
>---
>This bug highlights a bigger problem and the actual cause:
>Locking in the mt7530 driver deserves a cleanup, and refactoring
>towards cleanly and directly using the regmap API.
>I've prepared this already and am going to submit a series doing
>most of that using Coccinelle semantic patches once net-next opens
>again.
Acked-by: Chester A. Unal <chester.a.unal@arinc9.com>
Chester A.
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH net] net: dsa: mt7530: fix .get_stats64 sleeping in atomic context
2026-04-17 7:35 ` Chester A. Unal
@ 2026-04-17 12:08 ` Daniel Golle
0 siblings, 0 replies; 6+ messages in thread
From: Daniel Golle @ 2026-04-17 12:08 UTC (permalink / raw)
To: Chester A. Unal
Cc: Andrew Lunn, Vladimir Oltean, David S. Miller, Eric Dumazet,
Jakub Kicinski, Paolo Abeni, Matthias Brugger,
AngeloGioacchino Del Regno, Russell King, Christian Marangi,
netdev, linux-kernel, linux-arm-kernel, linux-mediatek,
Frank Wunderlich, John Crispin
On Fri, Apr 17, 2026 at 07:35:46AM +0000, Chester A. Unal wrote:
> On 17 April 2026 04:55:57 WEST, Daniel Golle <daniel@makrotopia.org> wrote:
> >The .get_stats64 callback runs in atomic context, but on
> >MDIO-connected switches every register read acquires the MDIO bus
> >mutex, which can sleep:
> >[ 12.645973] BUG: sleeping function called from invalid context at kernel/locking/mutex.c:609
> >[ 12.654442] in_atomic(): 0, irqs_disabled(): 0, non_block: 0, pid: 759, name: grep
> >[ 12.663377] preempt_count: 0, expected: 0
> >[ 12.667410] RCU nest depth: 1, expected: 0
> >[ 12.671511] INFO: lockdep is turned off.
> >[ 12.675441] CPU: 0 UID: 0 PID: 759 Comm: grep Tainted: G S W 7.0.0+ #0 PREEMPT
> >[ 12.675453] Tainted: [S]=CPU_OUT_OF_SPEC, [W]=WARN
> >[ 12.675456] Hardware name: Bananapi BPI-R64 (DT)
> >[ 12.675459] Call trace:
> >[ 12.675462] show_stack+0x14/0x1c (C)
> >[ 12.675477] dump_stack_lvl+0x68/0x8c
> >[ 12.675487] dump_stack+0x14/0x1c
> >[ 12.675495] __might_resched+0x14c/0x220
> >[ 12.675504] __might_sleep+0x44/0x80
> >[ 12.675511] __mutex_lock+0x50/0xb10
> >[ 12.675523] mutex_lock_nested+0x20/0x30
> >[ 12.675532] mt7530_get_stats64+0x40/0x2ac
> >[ 12.675542] dsa_user_get_stats64+0x2c/0x40
> >[ 12.675553] dev_get_stats+0x44/0x1e0
> >[ 12.675564] dev_seq_printf_stats+0x24/0xe0
> >[ 12.675575] dev_seq_show+0x14/0x3c
> >[ 12.675583] seq_read_iter+0x37c/0x480
> >[ 12.675595] seq_read+0xd0/0xec
> >[ 12.675605] proc_reg_read+0x94/0xe4
> >[ 12.675615] vfs_read+0x98/0x29c
> >[ 12.675625] ksys_read+0x54/0xdc
> >[ 12.675633] __arm64_sys_read+0x18/0x20
> >[ 12.675642] invoke_syscall.constprop.0+0x54/0xec
> >[ 12.675653] do_el0_svc+0x3c/0xb4
> >[ 12.675662] el0_svc+0x38/0x200
> >[ 12.675670] el0t_64_sync_handler+0x98/0xdc
> >[ 12.675679] el0t_64_sync+0x158/0x15c
> >
> >For MDIO-connected switches, poll MIB counters asynchronously using a
> >delayed workqueue every second and let .get_stats64 return the cached
> >values under a per-port spinlock. A mod_delayed_work() call on each
^^^^^^^^^^^^^^^^^^^
Just noticed I forgot to update the commit message when changing the
implementation to use a single shared spinlock for all ports...
I'll send v2 tomorrow fixing that, and what ever else comes up, if
anything.
> >read triggers an immediate refresh so counters stay responsive when
> >queried more frequently.
> >
> >MMIO-connected switches (MT7988, EN7581, AN7583) are not affected
> >because their regmap does not sleep, so they continue to read MIB
> >counters directly in .get_stats64.
> >
> >Fixes: 88c810f35ed5 ("net: dsa: mt7530: implement .get_stats64")
> >Signed-off-by: Daniel Golle <daniel@makrotopia.org>
> >---
> >This bug highlights a bigger problem and the actual cause:
> >Locking in the mt7530 driver deserves a cleanup, and refactoring
> >towards cleanly and directly using the regmap API.
> >I've prepared this already and am going to submit a series doing
> >most of that using Coccinelle semantic patches once net-next opens
> >again.
>
> Acked-by: Chester A. Unal <chester.a.unal@arinc9.com>
>
> Chester A.
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH net] net: dsa: mt7530: fix .get_stats64 sleeping in atomic context
2026-04-17 3:55 [PATCH net] net: dsa: mt7530: fix .get_stats64 sleeping in atomic context Daniel Golle
2026-04-17 7:35 ` Chester A. Unal
@ 2026-04-17 12:06 ` Andrew Lunn
2026-04-17 17:46 ` Breno Leitao
2 siblings, 0 replies; 6+ messages in thread
From: Andrew Lunn @ 2026-04-17 12:06 UTC (permalink / raw)
To: Daniel Golle
Cc: Chester A. Unal, Vladimir Oltean, David S. Miller, Eric Dumazet,
Jakub Kicinski, Paolo Abeni, Matthias Brugger,
AngeloGioacchino Del Regno, Russell King, Christian Marangi,
netdev, linux-kernel, linux-arm-kernel, linux-mediatek,
Frank Wunderlich, John Crispin
On Fri, Apr 17, 2026 at 04:55:57AM +0100, Daniel Golle wrote:
> The .get_stats64 callback runs in atomic context, but on
> MDIO-connected switches every register read acquires the MDIO bus
> mutex, which can sleep:
> [ 12.645973] BUG: sleeping function called from invalid context at kernel/locking/mutex.c:609
> [ 12.654442] in_atomic(): 0, irqs_disabled(): 0, non_block: 0, pid: 759, name: grep
> [ 12.663377] preempt_count: 0, expected: 0
> [ 12.667410] RCU nest depth: 1, expected: 0
> [ 12.671511] INFO: lockdep is turned off.
> [ 12.675441] CPU: 0 UID: 0 PID: 759 Comm: grep Tainted: G S W 7.0.0+ #0 PREEMPT
> [ 12.675453] Tainted: [S]=CPU_OUT_OF_SPEC, [W]=WARN
> [ 12.675456] Hardware name: Bananapi BPI-R64 (DT)
> [ 12.675459] Call trace:
> [ 12.675462] show_stack+0x14/0x1c (C)
> [ 12.675477] dump_stack_lvl+0x68/0x8c
> [ 12.675487] dump_stack+0x14/0x1c
> [ 12.675495] __might_resched+0x14c/0x220
> [ 12.675504] __might_sleep+0x44/0x80
> [ 12.675511] __mutex_lock+0x50/0xb10
> [ 12.675523] mutex_lock_nested+0x20/0x30
> [ 12.675532] mt7530_get_stats64+0x40/0x2ac
> [ 12.675542] dsa_user_get_stats64+0x2c/0x40
> [ 12.675553] dev_get_stats+0x44/0x1e0
> [ 12.675564] dev_seq_printf_stats+0x24/0xe0
> [ 12.675575] dev_seq_show+0x14/0x3c
> [ 12.675583] seq_read_iter+0x37c/0x480
> [ 12.675595] seq_read+0xd0/0xec
> [ 12.675605] proc_reg_read+0x94/0xe4
> [ 12.675615] vfs_read+0x98/0x29c
> [ 12.675625] ksys_read+0x54/0xdc
> [ 12.675633] __arm64_sys_read+0x18/0x20
> [ 12.675642] invoke_syscall.constprop.0+0x54/0xec
> [ 12.675653] do_el0_svc+0x3c/0xb4
> [ 12.675662] el0_svc+0x38/0x200
> [ 12.675670] el0t_64_sync_handler+0x98/0xdc
> [ 12.675679] el0t_64_sync+0x158/0x15c
>
> For MDIO-connected switches, poll MIB counters asynchronously using a
> delayed workqueue every second and let .get_stats64 return the cached
> values under a per-port spinlock. A mod_delayed_work() call on each
> read triggers an immediate refresh so counters stay responsive when
> queried more frequently.
>
> MMIO-connected switches (MT7988, EN7581, AN7583) are not affected
> because their regmap does not sleep, so they continue to read MIB
> counters directly in .get_stats64.
>
> Fixes: 88c810f35ed5 ("net: dsa: mt7530: implement .get_stats64")
> Signed-off-by: Daniel Golle <daniel@makrotopia.org>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Andrew
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH net] net: dsa: mt7530: fix .get_stats64 sleeping in atomic context
2026-04-17 3:55 [PATCH net] net: dsa: mt7530: fix .get_stats64 sleeping in atomic context Daniel Golle
2026-04-17 7:35 ` Chester A. Unal
2026-04-17 12:06 ` Andrew Lunn
@ 2026-04-17 17:46 ` Breno Leitao
2026-04-17 18:03 ` Daniel Golle
2 siblings, 1 reply; 6+ messages in thread
From: Breno Leitao @ 2026-04-17 17:46 UTC (permalink / raw)
To: Daniel Golle
Cc: Chester A. Unal, Andrew Lunn, Vladimir Oltean, David S. Miller,
Eric Dumazet, Jakub Kicinski, Paolo Abeni, Matthias Brugger,
AngeloGioacchino Del Regno, Russell King, Christian Marangi,
netdev, linux-kernel, linux-arm-kernel, linux-mediatek,
Frank Wunderlich, John Crispin
On Fri, Apr 17, 2026 at 04:55:57AM +0100, Daniel Golle wrote:
> @@ -3404,6 +3449,9 @@ EXPORT_SYMBOL_GPL(mt7530_probe_common);
> void
> mt7530_remove_common(struct mt7530_priv *priv)
> {
> + if (priv->bus)
> + cancel_delayed_work_sync(&priv->stats_work);
> +
Shouldn't you cancel the work later, after dsa_unregister_switch()?
I am wondering if the following race cannot happen:
mt7530_remove_common() someone reading /proc/net/dev
cancel_delayed_work_sync()
/* returns: work neither pending
nor executing - true at this
instant */
mt7530_get_stats64()
mod_delayed_work(...)
/* work is queued again */
dsa_unregister_switch()
return
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH net] net: dsa: mt7530: fix .get_stats64 sleeping in atomic context
2026-04-17 17:46 ` Breno Leitao
@ 2026-04-17 18:03 ` Daniel Golle
0 siblings, 0 replies; 6+ messages in thread
From: Daniel Golle @ 2026-04-17 18:03 UTC (permalink / raw)
To: Breno Leitao
Cc: Chester A. Unal, Andrew Lunn, Vladimir Oltean, David S. Miller,
Eric Dumazet, Jakub Kicinski, Paolo Abeni, Matthias Brugger,
AngeloGioacchino Del Regno, Russell King, Christian Marangi,
netdev, linux-kernel, linux-arm-kernel, linux-mediatek,
Frank Wunderlich, John Crispin
On Fri, Apr 17, 2026 at 10:46:29AM -0700, Breno Leitao wrote:
> On Fri, Apr 17, 2026 at 04:55:57AM +0100, Daniel Golle wrote:
> > @@ -3404,6 +3449,9 @@ EXPORT_SYMBOL_GPL(mt7530_probe_common);
> > void
> > mt7530_remove_common(struct mt7530_priv *priv)
> > {
> > + if (priv->bus)
> > + cancel_delayed_work_sync(&priv->stats_work);
> > +
>
> Shouldn't you cancel the work later, after dsa_unregister_switch()?
>
> I am wondering if the following race cannot happen:
>
> mt7530_remove_common() someone reading /proc/net/dev
> cancel_delayed_work_sync()
> /* returns: work neither pending
> nor executing - true at this
> instant */
> mt7530_get_stats64()
> mod_delayed_work(...)
> /* work is queued again */
> dsa_unregister_switch()
> return
Thanks you for pointing this out.
cancel_delayed_work_sync() should be moved after dsa_unregister_switch()
to avoid this kind of race.
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2026-04-17 18:04 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2026-04-17 3:55 [PATCH net] net: dsa: mt7530: fix .get_stats64 sleeping in atomic context Daniel Golle
2026-04-17 7:35 ` Chester A. Unal
2026-04-17 12:08 ` Daniel Golle
2026-04-17 12:06 ` Andrew Lunn
2026-04-17 17:46 ` Breno Leitao
2026-04-17 18:03 ` Daniel Golle
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