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Date:   Tue, 5 Dec 2023 13:13:51 +0200
From:   Vladimir Oltean <olteanv@gmail.com>
To:     Serge Semin <fancer.lancer@gmail.com>
Cc:     Andrew Lunn <andrew@lunn.ch>,
        Heiner Kallweit <hkallweit1@gmail.com>,
        Russell King <linux@armlinux.org.uk>,
        Alexandre Torgue <alexandre.torgue@foss.st.com>,
        Jose Abreu <joabreu@synopsys.com>,
        Jose Abreu <Jose.Abreu@synopsys.com>,
        Maxime Chevallier <maxime.chevallier@bootlin.com>,
        Tomer Maimon <tmaimon77@gmail.com>,
        Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Conor Dooley <conor+dt@kernel.org>,
        "David S. Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>, openbmc@lists.ozlabs.org,
        netdev@vger.kernel.org, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH net-next 10/16] net: pcs: xpcs: Add generic DW XPCS
 MDIO-device support
Message-ID: <20231205111351.xjjuwpbf7kwg3vuh@skbuf>
References: <20231205103559.9605-1-fancer.lancer@gmail.com>
 <20231205103559.9605-11-fancer.lancer@gmail.com>
MIME-Version: 1.0
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In-Reply-To: <20231205103559.9605-11-fancer.lancer@gmail.com>
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On Tue, Dec 05, 2023 at 01:35:31PM +0300, Serge Semin wrote:
> @@ -1436,21 +1480,32 @@ static struct dw_xpcs *xpcs_create(struct mdio_device *mdiodev,
>  	struct dw_xpcs *xpcs;
>  	int ret;
>  
> +	ret = device_attach(&mdiodev->dev);
> +	if (ret < 0 && ret != -ENODEV)
> +		return ERR_PTR(ret);
> +
>  	xpcs = xpcs_create_data(mdiodev);
>  	if (IS_ERR(xpcs))
>  		return xpcs;
>  
> +	ret = xpcs_init_clks(xpcs);
> +	if (ret)
> +		goto out_free_data;
> +
>  	ret = xpcs_init_id(xpcs);
>  	if (ret)
> -		goto out;
> +		goto out_clear_clks;
>  
>  	ret = xpcs_init_iface(xpcs, interface);
>  	if (ret)
> -		goto out;
> +		goto out_clear_clks;
>  
>  	return xpcs;

[    4.083518] Unable to handle kernel NULL pointer dereference at virtual address 00000000000000d0
[    4.092356] Mem abort info:
[    4.095164]   ESR = 0x0000000096000004
[    4.098932]   EC = 0x25: DABT (current EL), IL = 32 bits
[    4.104277]   SET = 0, FnV = 0
[    4.107352]   EA = 0, S1PTW = 0
[    4.110505]   FSC = 0x04: level 0 translation fault
[    4.115408] Data abort info:
[    4.118296]   ISV = 0, ISS = 0x00000004, ISS2 = 0x00000000
[    4.123807]   CM = 0, WnR = 0, TnD = 0, TagAccess = 0
[    4.128877]   GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0
[    4.134214] [00000000000000d0] user address but active_mm is swapper
[    4.140595] Internal error: Oops: 0000000096000004 [#1] PREEMPT SMP
[    4.146882] Modules linked in:
[    4.149944] CPU: 0 PID: 11 Comm: kworker/u4:0 Not tainted 6.7.0-rc3-00719-g75be5ea8e111-dirty #1551
[    4.164524] Workqueue: events_unbound deferred_probe_work_func
[    4.177372] pc : __device_attach+0x3c/0x1bc
[    4.181570] lr : __device_attach+0x38/0x1bc
[    4.185767] sp : ffff8000800f3800
[    4.189087] x29: ffff8000800f3820 x28: 0000000000000001 x27: ffff063781bda150
[    4.196252] x26: ffff063781bda150 x25: ffff063780827480 x24: ffffcb9a08138a40
[    4.203416] x23: ffff063781114080 x22: 0000000000000000 x21: 0000000000000004
[    4.210579] x20: ffff06378123a400 x19: ffff06378123a480 x18: ffffcb9a07c703a0
[    4.217743] x17: ffffcb9a07c703a4 x16: 00000000000000d4 x15: ffffcb9a07be70fc
[    4.224906] x14: ffffcb9a08299638 x13: 0000000000000053 x12: ffff003000000200
[    4.232069] x11: 0000000000000000 x10: 0000000000000000 x9 : 0000000000000000
[    4.239233] x8 : 0000000000000000 x7 : 0000000000000000 x6 : 000000000000003a
[    4.246396] x5 : ffff0637809a037b x4 : ffffcb9a087b0d47 x3 : ffff10300000020f
[    4.253560] x2 : ffffcb9a0910c561 x1 : 0000000000000000 x0 : ffff06378123a480
[    4.260724] Call trace:
[    4.263172]  __device_attach+0x3c/0x1bc
[    4.267020]  device_attach+0x14/0x20
[    4.270606]  xpcs_create+0x24/0x384
[    4.274107]  xpcs_create_byaddr+0x74/0xa0
[    4.278129]  sja1105_mdiobus_register+0xf8/0x478
[    4.282763]  sja1105_setup+0xb4/0x1194
[    4.286524]  dsa_register_switch+0xab0/0x11f8
[    4.290895]  sja1105_probe+0x2bc/0x2e4
[    4.294654]  spi_probe+0xa4/0xc4
[    4.297890]  really_probe+0x16c/0x3fc
[    4.301564]  __driver_probe_device+0xa4/0x168
[    4.305935]  driver_probe_device+0x3c/0x220
[    4.310131]  __device_attach_driver+0x128/0x1cc
[    4.314676]  bus_for_each_drv+0xf4/0x14c
[    4.318610]  __device_attach+0xfc/0x1bc
[    4.322457]  device_initial_probe+0x14/0x20
[    4.326654]  bus_probe_device+0x94/0x100
[    4.330587]  deferred_probe_work_func+0xa0/0xfc
[    4.335132]  process_scheduled_works+0x210/0x318
[    4.339764]  worker_thread+0x28c/0x450
[    4.343523]  kthread+0xfc/0x184
[    4.346669]  ret_from_fork+0x10/0x20
[    4.350256] Code: 2a0103f6 f81f83a8 9431ccd8 f9402688 (39434109)
[    4.356366] ---[ end trace 0000000000000000 ]---

I haven't looked at the code at all, but disassembling drivers/base/dd.lst,
I think the NPD is at dev->p->dead (0xa68 + 0x3c = 0xaa4).

0000000000000a68 <__device_attach>:
; {
     a68: d503233f     	paciasp
     a6c: d10143ff     	sub	sp, sp, #0x50
     a70: a9027bfd     	stp	x29, x30, [sp, #0x20]
     a74: a90357f6     	stp	x22, x21, [sp, #0x30]
     a78: a9044ff4     	stp	x20, x19, [sp, #0x40]
     a7c: 910083fd     	add	x29, sp, #0x20
     a80: d5384108     	mrs	x8, SP_EL0
; 	mutex_lock(&dev->mutex);
     a84: 91020013     	add	x19, x0, #0x80
     a88: f9423508     	ldr	x8, [x8, #0x468]
     a8c: aa0003f4     	mov	x20, x0
     a90: aa1303e0     	mov	x0, x19
     a94: 2a0103f6     	mov	w22, w1
     a98: f81f83a8     	stur	x8, [x29, #-0x8]
     a9c: 94000000     	bl	0xa9c <__device_attach+0x34>
		0000000000000a9c:  R_AARCH64_CALL26	mutex_lock
; 	if (dev->p->dead) {
     aa0: f9402688     	ldr	x8, [x20, #0x48]
     aa4: 39434109     	ldrb	w9, [x8, #0xd0]
     aa8: 37000129     	tbnz	w9, #0x0, 0xacc <__device_attach+0x64>
; 	} else if (dev->driver) {
     aac: f9403689     	ldr	x9, [x20, #0x68]
     ab0: b40003e9     	cbz	x9, 0xb2c <__device_attach+0xc4>
; 	return dev->p && klist_node_attached(&dev->p->knode_driver);
     ab4: b40002a8     	cbz	x8, 0xb08 <__device_attach+0xa0>
     ab8: 91012100     	add	x0, x8, #0x48
     abc: 94000000     	bl	0xabc <__device_attach+0x54>
		0000000000000abc:  R_AARCH64_CALL26	klist_node_attached
; 		if (device_is_bound(dev)) {
     ac0: 34000240     	cbz	w0, 0xb08 <__device_attach+0xa0>
     ac4: 52800035     	mov	w21, #0x1
     ac8: 14000002     	b	0xad0 <__device_attach+0x68>
     acc: 2a1f03f5     	mov	w21, wzr
; 	mutex_unlock(&dev->mutex);
     ad0: aa1303e0     	mov	x0, x19
     ad4: 94000000     	bl	0xad4 <__device_attach+0x6c>
		0000000000000ad4:  R_AARCH64_CALL26	mutex_unlock
     ad8: d5384108     	mrs	x8, SP_EL0
     adc: f9423508     	ldr	x8, [x8, #0x468]
     ae0: f85f83a9     	ldur	x9, [x29, #-0x8]
     ae4: eb09011f     	cmp	x8, x9
     ae8: 540008c1     	b.ne	0xc00 <__device_attach+0x198>
; 	return ret;
     aec: 2a1503e0     	mov	w0, w21
     af0: a9444ff4     	ldp	x20, x19, [sp, #0x40]
     af4: a94357f6     	ldp	x22, x21, [sp, #0x30]
     af8: a9427bfd     	ldp	x29, x30, [sp, #0x20]
     afc: 910143ff     	add	sp, sp, #0x50
     b00: d50323bf     	autiasp
     b04: d65f03c0     	ret
; 	ret = driver_sysfs_add(dev);
     b08: aa1403e0     	mov	x0, x20
     b0c: 97ffff21     	bl	0x790 <driver_sysfs_add>
; 	if (!ret) {
     b10: 340006c0     	cbz	w0, 0xbe8 <__device_attach+0x180>
; 		bus_notify(dev, BUS_NOTIFY_DRIVER_NOT_BOUND);
     b14: aa1403e0     	mov	x0, x20
     b18: 528000e1     	mov	w1, #0x7
     b1c: 94000000     	bl	0xb1c <__device_attach+0xb4>
		0000000000000b1c:  R_AARCH64_CALL26	bus_notify
     b20: 2a1f03f5     	mov	w21, wzr
; 			dev->driver = NULL;
     b24: f900369f     	str	xzr, [x20, #0x68]
     b28: 17ffffea     	b	0xad0 <__device_attach+0x68>
     b2c: 120002c8     	and	w8, w22, #0x1
; 		if (dev->parent)
     b30: f9402280     	ldr	x0, [x20, #0x40]
; 		struct device_attach_data data = {
     b34: a900fff4     	stp	x20, xzr, [sp, #0x8]
     b38: 39004bff     	strb	wzr, [sp, #0x12]
     b3c: 390043e8     	strb	w8, [sp, #0x10]
; 		if (dev->parent)
     b40: b4000060     	cbz	x0, 0xb4c <__device_attach+0xe4>
; 	return __pm_runtime_resume(dev, RPM_GET_PUT);
     b44: 52800081     	mov	w1, #0x4
     b48: 94000000     	bl	0xb48 <__device_attach+0xe0>
		0000000000000b48:  R_AARCH64_CALL26	__pm_runtime_resume
; 		ret = bus_for_each_drv(dev->bus, NULL, &data,
     b4c: f9403280     	ldr	x0, [x20, #0x60]
     b50: 90000003     	adrp	x3, 0x0 <driver_deferred_probe_add>
		0000000000000b50:  R_AARCH64_ADR_PREL_PG_HI21	.text+0x17ac
     b54: 91000063     	add	x3, x3, #0x0
		0000000000000b54:  R_AARCH64_ADD_ABS_LO12_NC	.text+0x17ac
     b58: 910023e2     	add	x2, sp, #0x8
     b5c: aa1f03e1     	mov	x1, xzr
     b60: 94000000     	bl	0xb60 <__device_attach+0xf8>
		0000000000000b60:  R_AARCH64_CALL26	bus_for_each_drv
     b64: 39404be8     	ldrb	w8, [sp, #0x12]
; 		if (!ret && allow_async && data.have_async) {
     b68: 7100001f     	cmp	w0, #0x0
     b6c: 1a9f07e9     	cset	w9, ne
; 		ret = bus_for_each_drv(dev->bus, NULL, &data,
     b70: 2a0003f5     	mov	w21, w0
     b74: 7100011f     	cmp	w8, #0x0
; 		if (!ret && allow_async && data.have_async) {
     b78: 520002c8     	eor	w8, w22, #0x1
     b7c: 1a9f17ea     	cset	w10, eq
     b80: 2a0a0108     	orr	w8, w8, w10
     b84: 2a080136     	orr	w22, w9, w8
     b88: 360000f6     	tbz	w22, #0x0, 0xba4 <__device_attach+0x13c>
; 	return __pm_runtime_idle(dev, RPM_ASYNC);
     b8c: aa1403e0     	mov	x0, x20
     b90: 52800021     	mov	w1, #0x1
     b94: 94000000     	bl	0xb94 <__device_attach+0x12c>
		0000000000000b94:  R_AARCH64_CALL26	__pm_runtime_idle
; 		if (dev->parent)
     b98: f9402280     	ldr	x0, [x20, #0x40]
     b9c: b50000e0     	cbnz	x0, 0xbb8 <__device_attach+0x150>
     ba0: 14000008     	b	0xbc0 <__device_attach+0x158>
; 	asm_volatile_goto(
     ba4: d503201f     	nop