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Message-Id: <20250403191913.2681831-16-sashal@kernel.org>
Date: Thu, 3 Apr 2025 15:19:09 -0400
From: Sasha Levin <sashal@...nel.org>
To: linux-kernel@...r.kernel.org,
stable@...r.kernel.org
Cc: Ryo Takakura <ryotkkr98@...il.com>,
"Luis Claudio R . Goncalves" <lgoncalv@...hat.com>,
Sebastian Andrzej Siewior <bigeasy@...utronix.de>,
Krzysztof Wilczyński <kwilczynski@...nel.org>,
Bjorn Helgaas <bhelgaas@...gle.com>,
Sasha Levin <sashal@...nel.org>,
nirmal.patel@...ux.intel.com,
lpieralisi@...nel.org,
kw@...ux.com,
clrkwllms@...nel.org,
rostedt@...dmis.org,
linux-pci@...r.kernel.org,
linux-rt-devel@...ts.linux.dev
Subject: [PATCH AUTOSEL 6.1 16/20] PCI: vmd: Make vmd_dev::cfg_lock a raw_spinlock_t type
From: Ryo Takakura <ryotkkr98@...il.com>
[ Upstream commit 18056a48669a040bef491e63b25896561ee14d90 ]
The access to the PCI config space via pci_ops::read and pci_ops::write is
a low-level hardware access. The functions can be accessed with disabled
interrupts even on PREEMPT_RT. The pci_lock is a raw_spinlock_t for this
purpose.
A spinlock_t becomes a sleeping lock on PREEMPT_RT, so it cannot be
acquired with disabled interrupts. The vmd_dev::cfg_lock is accessed in
the same context as the pci_lock.
Make vmd_dev::cfg_lock a raw_spinlock_t type so it can be used with
interrupts disabled.
This was reported as:
BUG: sleeping function called from invalid context at kernel/locking/spinlock_rt.c:48
Call Trace:
rt_spin_lock+0x4e/0x130
vmd_pci_read+0x8d/0x100 [vmd]
pci_user_read_config_byte+0x6f/0xe0
pci_read_config+0xfe/0x290
sysfs_kf_bin_read+0x68/0x90
Signed-off-by: Ryo Takakura <ryotkkr98@...il.com>
Tested-by: Luis Claudio R. Goncalves <lgoncalv@...hat.com>
Acked-by: Luis Claudio R. Goncalves <lgoncalv@...hat.com>
[bigeasy: reword commit message]
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@...utronix.de>
Tested-off-by: Luis Claudio R. Goncalves <lgoncalv@...hat.com>
Link: https://lore.kernel.org/r/20250218080830.ufw3IgyX@linutronix.de
[kwilczynski: commit log]
Signed-off-by: Krzysztof Wilczyński <kwilczynski@...nel.org>
[bhelgaas: add back report info from
https://lore.kernel.org/lkml/20241218115951.83062-1-ryotkkr98@gmail.com/]
Signed-off-by: Bjorn Helgaas <bhelgaas@...gle.com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
drivers/pci/controller/vmd.c | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)
diff --git a/drivers/pci/controller/vmd.c b/drivers/pci/controller/vmd.c
index a1dd614bdc324..09995b6e73bcc 100644
--- a/drivers/pci/controller/vmd.c
+++ b/drivers/pci/controller/vmd.c
@@ -110,7 +110,7 @@ struct vmd_irq_list {
struct vmd_dev {
struct pci_dev *dev;
- spinlock_t cfg_lock;
+ raw_spinlock_t cfg_lock;
void __iomem *cfgbar;
int msix_count;
@@ -387,7 +387,7 @@ static int vmd_pci_read(struct pci_bus *bus, unsigned int devfn, int reg,
if (!addr)
return -EFAULT;
- spin_lock_irqsave(&vmd->cfg_lock, flags);
+ raw_spin_lock_irqsave(&vmd->cfg_lock, flags);
switch (len) {
case 1:
*value = readb(addr);
@@ -402,7 +402,7 @@ static int vmd_pci_read(struct pci_bus *bus, unsigned int devfn, int reg,
ret = -EINVAL;
break;
}
- spin_unlock_irqrestore(&vmd->cfg_lock, flags);
+ raw_spin_unlock_irqrestore(&vmd->cfg_lock, flags);
return ret;
}
@@ -422,7 +422,7 @@ static int vmd_pci_write(struct pci_bus *bus, unsigned int devfn, int reg,
if (!addr)
return -EFAULT;
- spin_lock_irqsave(&vmd->cfg_lock, flags);
+ raw_spin_lock_irqsave(&vmd->cfg_lock, flags);
switch (len) {
case 1:
writeb(value, addr);
@@ -440,7 +440,7 @@ static int vmd_pci_write(struct pci_bus *bus, unsigned int devfn, int reg,
ret = -EINVAL;
break;
}
- spin_unlock_irqrestore(&vmd->cfg_lock, flags);
+ raw_spin_unlock_irqrestore(&vmd->cfg_lock, flags);
return ret;
}
@@ -958,7 +958,7 @@ static int vmd_probe(struct pci_dev *dev, const struct pci_device_id *id)
if (features & VMD_FEAT_OFFSET_FIRST_VECTOR)
vmd->first_vec = 1;
- spin_lock_init(&vmd->cfg_lock);
+ raw_spin_lock_init(&vmd->cfg_lock);
pci_set_drvdata(dev, vmd);
err = vmd_enable_domain(vmd, features);
if (err)
--
2.39.5
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