Re: [perf] lockdep warning between cpu_add_remove_lock and &dev->mutex.

From: Tetsuo Handa
Date: Mon Jan 23 2023 - 09:11:19 EST

On 2023/01/23 20:41, Peter Zijlstra wrote:
> On Mon, Jan 23, 2023 at 07:39:24PM +0900, Tetsuo Handa wrote:
>> Hello.
>>
>> I tried to apply below patch, and hit lockdep warning during boot.
>> Can you break this dependency?
>
> cpu_add_remove_lock
> cpu_hotplug_lock
> pmus_lock
> dev->mutex (pmu_dev_alloc)
>
> vs
>
> dev->mutex
> cpu_add_remove_lock (pci_device_probe)
>
>
> Possibly something like this might do -- I'm not entirely sure it's
> fully correct, needs a bit of auditing.
>

After applying your diff, lockdep message changed like below. Is this
the reason commit 1704f47b50b5 ("lockdep: Add novalidate class for
dev->mutex conversion") was applied?

----------
[ 2.276394][ T9] Trying to unpack rootfs image as initramfs...
[ 2.276394][ T1] software IO TLB: mapped [mem 0x00000000bbed0000-0x00000000bfed0000] (64MB)
[ 2.276394][ T1] workingset: timestamp_bits=46 max_order=21 bucket_order=0
[ 2.276394][ T1] SGI XFS with ACLs, security attributes, verbose warnings, quota, no debug enabled
[ 2.276394][ T1] Block layer SCSI generic (bsg) driver version 0.4 loaded (major 252)
[ 2.837244][ T1]
[ 2.837244][ T1] ============================================
[ 2.837244][ T1] WARNING: possible recursive locking detected
[ 2.837244][ T1] 6.2.0-rc5+ #10 Not tainted
[ 2.837244][ T1] --------------------------------------------
[ 2.837244][ T1] swapper/0/1 is trying to acquire lock:
[ 2.837244][ T1] ffff984dc3d50108 (&dev->mutex){+.+.}-{3:3}, at: __device_attach+0x35/0x1a0
[ 2.837244][ T1]
[ 2.837244][ T1] but task is already holding lock:
[ 2.837244][ T1] ffff984dc1b5e1b8 (&dev->mutex){+.+.}-{3:3}, at: __device_driver_lock+0x28/0x40
[ 2.837244][ T1]
[ 2.837244][ T1] other info that might help us debug this:
[ 2.837244][ T1] Possible unsafe locking scenario:
[ 2.837244][ T1]
[ 2.837244][ T1] CPU0
[ 2.837244][ T1] ----
[ 2.837244][ T1] lock(&dev->mutex);
[ 2.837244][ T1] lock(&dev->mutex);
[ 2.837244][ T1]
[ 2.837244][ T1] *** DEADLOCK ***
[ 2.837244][ T1]
[ 2.837244][ T1] May be due to missing lock nesting notation
[ 2.837244][ T1]
[ 2.837244][ T1] 1 lock held by swapper/0/1:
[ 2.837244][ T1] #0: ffff984dc1b5e1b8 (&dev->mutex){+.+.}-{3:3}, at: __device_driver_lock+0x28/0x40
[ 2.837244][ T1]
[ 2.837244][ T1] stack backtrace:
[ 2.837244][ T1] CPU: 7 PID: 1 Comm: swapper/0 Not tainted 6.2.0-rc5+ #10
[ 2.837244][ T1] Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 11/12/2020
[ 2.837244][ T1] Call Trace:
[ 2.837244][ T1] <TASK>
[ 2.837244][ T1] dump_stack_lvl+0x49/0x5e
[ 2.837244][ T1] dump_stack+0x10/0x12
[ 2.837244][ T1] __lock_acquire.cold.73+0x12e/0x2c7
[ 2.837244][ T1] lock_acquire+0xc7/0x2e0
[ 2.837244][ T1] ? __device_attach+0x35/0x1a0
[ 2.837244][ T1] __mutex_lock+0x99/0xf00
[ 2.837244][ T1] ? __device_attach+0x35/0x1a0
[ 2.837244][ T1] ? __this_cpu_preempt_check+0x13/0x20
[ 2.837244][ T1] ? __device_attach+0x35/0x1a0
[ 2.837244][ T1] ? kobject_uevent_env+0x12f/0x770
[ 2.837244][ T1] mutex_lock_nested+0x16/0x20
[ 2.837244][ T1] ? mutex_lock_nested+0x16/0x20
[ 2.837244][ T1] __device_attach+0x35/0x1a0
[ 2.837244][ T1] device_initial_probe+0xe/0x10
[ 2.837244][ T1] bus_probe_device+0x9b/0xb0
[ 2.837244][ T1] device_add+0x3e1/0x900
[ 2.837244][ T1] ? __init_waitqueue_head+0x4a/0x70
[ 2.837244][ T1] device_register+0x15/0x20
[ 2.837244][ T1] pcie_portdrv_probe+0x3e3/0x670
[ 2.837244][ T1] ? trace_hardirqs_on+0x3b/0x100
[ 2.837244][ T1] pci_device_probe+0xa8/0x150
[ 2.837244][ T1] really_probe+0xd9/0x340
[ 2.837244][ T1] ? pm_runtime_barrier+0x52/0xb0
[ 2.837244][ T1] __driver_probe_device+0x78/0x170
[ 2.837244][ T1] driver_probe_device+0x1f/0x90
[ 2.837244][ T1] __driver_attach+0xaa/0x160
[ 2.837244][ T1] ? __device_attach_driver+0x100/0x100
[ 2.837244][ T1] bus_for_each_dev+0x75/0xb0
[ 2.837244][ T1] driver_attach+0x19/0x20
[ 2.837244][ T1] bus_add_driver+0x1be/0x210
[ 2.837244][ T1] ? dmi_pcie_pme_disable_msi+0x1f/0x1f
[ 2.837244][ T1] ? dmi_pcie_pme_disable_msi+0x1f/0x1f
[ 2.837244][ T1] ? rdinit_setup+0x27/0x27
[ 2.837244][ T1] driver_register+0x6b/0xc0
[ 2.837244][ T1] ? dmi_pcie_pme_disable_msi+0x1f/0x1f
[ 2.837244][ T1] __pci_register_driver+0x7c/0x80
[ 2.837244][ T1] pcie_portdrv_init+0x3d/0x45
[ 2.837244][ T1] do_one_initcall+0x58/0x300
[ 2.837244][ T1] ? rdinit_setup+0x27/0x27
[ 2.837244][ T1] ? rcu_read_lock_sched_held+0x4a/0x70
[ 2.837244][ T1] kernel_init_freeable+0x181/0x1d2
[ 2.837244][ T1] ? rest_init+0x190/0x190
[ 2.837244][ T1] kernel_init+0x15/0x120
[ 2.837244][ T1] ret_from_fork+0x1f/0x30
[ 2.837244][ T1] </TASK>
[ 4.126397][ T1] pcieport 0000:00:15.0: PME: Signaling with IRQ 24
[ 4.126397][ T1] pcieport 0000:00:15.0: pciehp: Slot #160 AttnBtn+ PwrCtrl+ MRL- AttnInd- PwrInd- HotPlug+ Surprise- Interlock- NoCompl+ IbPresDis- LLActRep+
[ 4.126397][ T1] pcieport 0000:00:15.1: PME: Signaling with IRQ 25
----------

# ./scripts/faddr2line --list vmlinux __device_attach+0x35/0x1a0 __device_driver_lock+0x28/0x40
__device_attach+0x35/0x1a0:

__device_attach at drivers/base/dd.c:984
979 {
980 int ret = 0;
981 bool async = false;
982
983 device_lock(dev);
>984< if (dev->p->dead) {
985 goto out_unlock;
986 } else if (dev->driver) {
987 if (device_is_bound(dev)) {
988 ret = 1;
989 goto out_unlock;

__device_driver_lock+0x28/0x40:

__device_driver_lock at drivers/base/dd.c:1074
1069 static void __device_driver_lock(struct device *dev, struct device *parent)
1070 {
1071 if (parent && dev->bus->need_parent_lock)
1072 device_lock(parent);
1073 device_lock(dev);
>1074< }
1075
1076 /*
1077 * __device_driver_unlock - release locks needed to manipulate dev->drv
1078 * @dev: Device we will update driver info for
1079 * @parent: Parent device. Needed if the bus requires parent lock

# ./scripts/faddr2line vmlinux __device_attach+0x35/0x1a0 device_initial_probe+0xe/0x10 bus_probe_device+0x9b/0xb0 device_add+0x3e1/0x900 device_register+0x15/0x20 pcie_portdrv_probe+0x3e3/0x670 pci_device_probe+0xa8/0x150 really_probe+0xd9/0x340 __driver_probe_device+0x78/0x170 driver_probe_device+0x1f/0x90 __driver_attach+0xaa/0x160 bus_for_each_dev+0x75/0xb0 driver_attach+0x19/0x20 bus_add_driver+0x1be/0x210 driver_register+0x6b/0xc0
__device_attach+0x35/0x1a0:
__device_attach at drivers/base/dd.c:984

device_initial_probe+0xe/0x10:
device_initial_probe at drivers/base/dd.c:1058

bus_probe_device+0x9b/0xb0:
bus_probe_device at drivers/base/bus.c:487

device_add+0x3e1/0x900:
device_add at drivers/base/core.c:3485

device_register+0x15/0x20:
device_register at drivers/base/core.c:3560

pcie_portdrv_probe+0x3e3/0x670:
pcie_device_init at drivers/pci/pcie/portdrv.c:310
(inlined by) pcie_port_device_register at drivers/pci/pcie/portdrv.c:363
(inlined by) pcie_portdrv_probe at drivers/pci/pcie/portdrv.c:696

pci_device_probe+0xa8/0x150:
local_pci_probe at drivers/pci/pci-driver.c:324
(inlined by) pci_call_probe at drivers/pci/pci-driver.c:392
(inlined by) __pci_device_probe at drivers/pci/pci-driver.c:417
(inlined by) pci_device_probe at drivers/pci/pci-driver.c:460

really_probe+0xd9/0x340:
call_driver_probe at drivers/base/dd.c:560
(inlined by) really_probe at drivers/base/dd.c:639

__driver_probe_device+0x78/0x170:
__driver_probe_device at drivers/base/dd.c:778

driver_probe_device+0x1f/0x90:
driver_probe_device at drivers/base/dd.c:808

__driver_attach+0xaa/0x160:
__driver_attach at drivers/base/dd.c:1195

bus_for_each_dev+0x75/0xb0:
bus_for_each_dev at drivers/base/bus.c:300

driver_attach+0x19/0x20:
driver_attach at drivers/base/dd.c:1212

bus_add_driver+0x1be/0x210:
bus_add_driver at drivers/base/bus.c:619

driver_register+0x6b/0xc0:
driver_register at drivers/base/driver.c:246