Patch "drop_monitor: replace spin_lock by raw_spin_lock" has been added to the 5.4-stable tree

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



This is a note to let you know that I've just added the patch titled

    drop_monitor: replace spin_lock by raw_spin_lock

to the 5.4-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     drop_monitor-replace-spin_lock-by-raw_spin_lock.patch
and it can be found in the queue-5.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 090c3a817d678d59bb30af1569bb869af0e088f1
Author: Wander Lairson Costa <wander@xxxxxxxxxx>
Date:   Thu Apr 11 11:13:46 2024 -0300

    drop_monitor: replace spin_lock by raw_spin_lock
    
    [ Upstream commit f1e197a665c2148ebc25fe09c53689e60afea195 ]
    
    trace_drop_common() is called with preemption disabled, and it acquires
    a spin_lock. This is problematic for RT kernels because spin_locks are
    sleeping locks in this configuration, which causes the following splat:
    
    BUG: sleeping function called from invalid context at kernel/locking/spinlock_rt.c:48
    in_atomic(): 1, irqs_disabled(): 1, non_block: 0, pid: 449, name: rcuc/47
    preempt_count: 1, expected: 0
    RCU nest depth: 2, expected: 2
    5 locks held by rcuc/47/449:
     #0: ff1100086ec30a60 ((softirq_ctrl.lock)){+.+.}-{2:2}, at: __local_bh_disable_ip+0x105/0x210
     #1: ffffffffb394a280 (rcu_read_lock){....}-{1:2}, at: rt_spin_lock+0xbf/0x130
     #2: ffffffffb394a280 (rcu_read_lock){....}-{1:2}, at: __local_bh_disable_ip+0x11c/0x210
     #3: ffffffffb394a160 (rcu_callback){....}-{0:0}, at: rcu_do_batch+0x360/0xc70
     #4: ff1100086ee07520 (&data->lock){+.+.}-{2:2}, at: trace_drop_common.constprop.0+0xb5/0x290
    irq event stamp: 139909
    hardirqs last  enabled at (139908): [<ffffffffb1df2b33>] _raw_spin_unlock_irqrestore+0x63/0x80
    hardirqs last disabled at (139909): [<ffffffffb19bd03d>] trace_drop_common.constprop.0+0x26d/0x290
    softirqs last  enabled at (139892): [<ffffffffb07a1083>] __local_bh_enable_ip+0x103/0x170
    softirqs last disabled at (139898): [<ffffffffb0909b33>] rcu_cpu_kthread+0x93/0x1f0
    Preemption disabled at:
    [<ffffffffb1de786b>] rt_mutex_slowunlock+0xab/0x2e0
    CPU: 47 PID: 449 Comm: rcuc/47 Not tainted 6.9.0-rc2-rt1+ #7
    Hardware name: Dell Inc. PowerEdge R650/0Y2G81, BIOS 1.6.5 04/15/2022
    Call Trace:
     <TASK>
     dump_stack_lvl+0x8c/0xd0
     dump_stack+0x14/0x20
     __might_resched+0x21e/0x2f0
     rt_spin_lock+0x5e/0x130
     ? trace_drop_common.constprop.0+0xb5/0x290
     ? skb_queue_purge_reason.part.0+0x1bf/0x230
     trace_drop_common.constprop.0+0xb5/0x290
     ? preempt_count_sub+0x1c/0xd0
     ? _raw_spin_unlock_irqrestore+0x4a/0x80
     ? __pfx_trace_drop_common.constprop.0+0x10/0x10
     ? rt_mutex_slowunlock+0x26a/0x2e0
     ? skb_queue_purge_reason.part.0+0x1bf/0x230
     ? __pfx_rt_mutex_slowunlock+0x10/0x10
     ? skb_queue_purge_reason.part.0+0x1bf/0x230
     trace_kfree_skb_hit+0x15/0x20
     trace_kfree_skb+0xe9/0x150
     kfree_skb_reason+0x7b/0x110
     skb_queue_purge_reason.part.0+0x1bf/0x230
     ? __pfx_skb_queue_purge_reason.part.0+0x10/0x10
     ? mark_lock.part.0+0x8a/0x520
    ...
    
    trace_drop_common() also disables interrupts, but this is a minor issue
    because we could easily replace it with a local_lock.
    
    Replace the spin_lock with raw_spin_lock to avoid sleeping in atomic
    context.
    
    Signed-off-by: Wander Lairson Costa <wander@xxxxxxxxxx>
    Reported-by: Hu Chunyu <chuhu@xxxxxxxxxx>
    Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/net/core/drop_monitor.c b/net/core/drop_monitor.c
index feb946c954b65..b37465af47e4b 100644
--- a/net/core/drop_monitor.c
+++ b/net/core/drop_monitor.c
@@ -71,7 +71,7 @@ struct net_dm_hw_entries {
 };
 
 struct per_cpu_dm_data {
-	spinlock_t		lock;	/* Protects 'skb', 'hw_entries' and
+	raw_spinlock_t		lock;	/* Protects 'skb', 'hw_entries' and
 					 * 'send_timer'
 					 */
 	union {
@@ -165,9 +165,9 @@ static struct sk_buff *reset_per_cpu_data(struct per_cpu_dm_data *data)
 err:
 	mod_timer(&data->send_timer, jiffies + HZ / 10);
 out:
-	spin_lock_irqsave(&data->lock, flags);
+	raw_spin_lock_irqsave(&data->lock, flags);
 	swap(data->skb, skb);
-	spin_unlock_irqrestore(&data->lock, flags);
+	raw_spin_unlock_irqrestore(&data->lock, flags);
 
 	if (skb) {
 		struct nlmsghdr *nlh = (struct nlmsghdr *)skb->data;
@@ -222,7 +222,7 @@ static void trace_drop_common(struct sk_buff *skb, void *location)
 
 	local_irq_save(flags);
 	data = this_cpu_ptr(&dm_cpu_data);
-	spin_lock(&data->lock);
+	raw_spin_lock(&data->lock);
 	dskb = data->skb;
 
 	if (!dskb)
@@ -256,7 +256,7 @@ static void trace_drop_common(struct sk_buff *skb, void *location)
 	}
 
 out:
-	spin_unlock_irqrestore(&data->lock, flags);
+	raw_spin_unlock_irqrestore(&data->lock, flags);
 }
 
 static void trace_kfree_skb_hit(void *ignore, struct sk_buff *skb, void *location)
@@ -315,9 +315,9 @@ net_dm_hw_reset_per_cpu_data(struct per_cpu_dm_data *hw_data)
 		mod_timer(&hw_data->send_timer, jiffies + HZ / 10);
 	}
 
-	spin_lock_irqsave(&hw_data->lock, flags);
+	raw_spin_lock_irqsave(&hw_data->lock, flags);
 	swap(hw_data->hw_entries, hw_entries);
-	spin_unlock_irqrestore(&hw_data->lock, flags);
+	raw_spin_unlock_irqrestore(&hw_data->lock, flags);
 
 	return hw_entries;
 }
@@ -445,7 +445,7 @@ net_dm_hw_summary_probe(struct sk_buff *skb,
 	int i;
 
 	hw_data = this_cpu_ptr(&dm_hw_cpu_data);
-	spin_lock_irqsave(&hw_data->lock, flags);
+	raw_spin_lock_irqsave(&hw_data->lock, flags);
 	hw_entries = hw_data->hw_entries;
 
 	if (!hw_entries)
@@ -474,7 +474,7 @@ net_dm_hw_summary_probe(struct sk_buff *skb,
 	}
 
 out:
-	spin_unlock_irqrestore(&hw_data->lock, flags);
+	raw_spin_unlock_irqrestore(&hw_data->lock, flags);
 }
 
 static const struct net_dm_alert_ops net_dm_alert_summary_ops = {
@@ -1592,7 +1592,7 @@ static struct notifier_block dropmon_net_notifier = {
 
 static void __net_dm_cpu_data_init(struct per_cpu_dm_data *data)
 {
-	spin_lock_init(&data->lock);
+	raw_spin_lock_init(&data->lock);
 	skb_queue_head_init(&data->drop_queue);
 	u64_stats_init(&data->stats.syncp);
 }




[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[Index of Archives]     [Linux USB Devel]     [Linux Audio Users]     [Yosemite News]     [Linux Kernel]     [Linux SCSI]

  Powered by Linux