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Message-ID: <DM6PR11MB465736A99FADB61391D5AC4A9B682@DM6PR11MB4657.namprd11.prod.outlook.com>
Date: Thu, 11 Jan 2024 09:07:13 +0000
From: "Kubalewski, Arkadiusz" <arkadiusz.kubalewski@...el.com>
To: Jiri Pirko <jiri@...nulli.us>
CC: "netdev@...r.kernel.org" <netdev@...r.kernel.org>,
"vadim.fedorenko@...ux.dev" <vadim.fedorenko@...ux.dev>, "Olech, Milena"
<milena.olech@...el.com>, "pabeni@...hat.com" <pabeni@...hat.com>,
"kuba@...nel.org" <kuba@...nel.org>, "Glaza, Jan" <jan.glaza@...el.com>,
"Kitszel, Przemyslaw" <przemyslaw.kitszel@...el.com>
Subject: RE: [PATCH net v2 2/4] dpll: fix pin dump crash for rebound module
>From: Jiri Pirko <jiri@...nulli.us>
>Sent: Thursday, January 4, 2024 4:41 PM
>
>Thu, Jan 04, 2024 at 12:11:30PM CET, arkadiusz.kubalewski@...el.com wrote:
>>When a kernel module is unbound but the pin resources were not entirely
>>freed (other kernel module instance have had kept the reference to that
>
>Wait, you talk about module, yet you mean pci instance of the same
>module, don't you?
>
Well, the kernel module can have multiple instances. I.e. for multiple PCI
devices, or one each Physical Function available on a single PCI device. Our case
is a kernel module instance of different PF but still a single PCI device.
In general, all the PCI devices controlled by given kernel module which use the
same dpll device would see this behavior.
But sure, can mention that those belong to single PCI device in the commit
message.
>
>>pin), and kernel module is again bound, the pin properties would not be
>>updated (the properties are only assigned when memory for the pin is
>>allocated), prop pointer still points to the kernel module memory of
>>the kernel module which was deallocated on the unbind.
>>
>>If the pin dump is invoked in this state, the result is a kernel crash.
>>Prevent the crash by storing persistent pin properties in dpll subsystem,
>>copy the content from the kernel module when pin is allocated, instead of
>>using memory of the kernel module.
>>
>>Fixes: 9431063ad323 ("dpll: core: Add DPLL framework base functions")
>>Fixes: 9d71b54b65b1 ("dpll: netlink: Add DPLL framework base functions")
>>Reviewed-by: Jan Glaza <jan.glaza@...el.com>
>>Reviewed-by: Przemek Kitszel <przemyslaw.kitszel@...el.com>
>>Signed-off-by: Arkadiusz Kubalewski <arkadiusz.kubalewski@...el.com>
>>---
>> drivers/dpll/dpll_core.c | 29 ++++++++++++++++++++++++++---
>> drivers/dpll/dpll_core.h | 4 ++--
>> drivers/dpll/dpll_netlink.c | 28 ++++++++++++++--------------
>> 3 files changed, 42 insertions(+), 19 deletions(-)
>>
>>diff --git a/drivers/dpll/dpll_core.c b/drivers/dpll/dpll_core.c
>>index 3568149b9562..0b469096ef79 100644
>>--- a/drivers/dpll/dpll_core.c
>>+++ b/drivers/dpll/dpll_core.c
>>@@ -429,6 +429,7 @@ dpll_pin_alloc(u64 clock_id, u32 pin_idx, struct
>>module *module,
>> const struct dpll_pin_properties *prop)
>> {
>> struct dpll_pin *pin;
>>+ size_t freq_size;
>> int ret;
>>
>> pin = kzalloc(sizeof(*pin), GFP_KERNEL);
>>@@ -440,9 +441,22 @@ dpll_pin_alloc(u64 clock_id, u32 pin_idx, struct
>>module *module,
>> if (WARN_ON(prop->type < DPLL_PIN_TYPE_MUX ||
>> prop->type > DPLL_PIN_TYPE_MAX)) {
>> ret = -EINVAL;
>>- goto err;
>>+ goto pin_free;
>> }
>>- pin->prop = prop;
>>+ memcpy(&pin->prop, prop, sizeof(pin->prop));
>>+ if (prop->freq_supported && prop->freq_supported_num) {
>>+ freq_size = prop->freq_supported_num *
>>+ sizeof(*pin->prop.freq_supported);
>>+ pin->prop.freq_supported = kmemdup(prop->freq_supported,
>>+ freq_size, GFP_KERNEL);
>>+ if (!pin->prop.freq_supported) {
>>+ ret = -ENOMEM;
>>+ goto pin_free;
>>+ }
>>+ }
>>+ pin->prop.board_label = kstrdup(prop->board_label, GFP_KERNEL);
>>+ pin->prop.panel_label = kstrdup(prop->panel_label, GFP_KERNEL);
>>+ pin->prop.package_label = kstrdup(prop->package_label, GFP_KERNEL);
>
>Care to check the return values? Also don't kstrdup null pointers, does
>not make much sense.
>
>Could you perhaps move the prop dup/free to separate functions?
>
Sure, will do in v3.
Thank you!
Arkadiusz
>
>> refcount_set(&pin->refcount, 1);
>> xa_init_flags(&pin->dpll_refs, XA_FLAGS_ALLOC);
>> xa_init_flags(&pin->parent_refs, XA_FLAGS_ALLOC);
>>@@ -451,8 +465,13 @@ dpll_pin_alloc(u64 clock_id, u32 pin_idx, struct
>>module *module,
>> goto err;
>> return pin;
>> err:
>>+ kfree(pin->prop.package_label);
>>+ kfree(pin->prop.panel_label);
>>+ kfree(pin->prop.board_label);
>>+ kfree(pin->prop.freq_supported);
>> xa_destroy(&pin->dpll_refs);
>> xa_destroy(&pin->parent_refs);
>>+pin_free:
>> kfree(pin);
>> return ERR_PTR(ret);
>> }
>>@@ -512,6 +531,10 @@ void dpll_pin_put(struct dpll_pin *pin)
>> xa_destroy(&pin->dpll_refs);
>> xa_destroy(&pin->parent_refs);
>> xa_erase(&dpll_pin_xa, pin->id);
>>+ kfree(pin->prop.board_label);
>>+ kfree(pin->prop.panel_label);
>>+ kfree(pin->prop.package_label);
>>+ kfree(pin->prop.freq_supported);
>> kfree(pin);
>> }
>> mutex_unlock(&dpll_lock);
>>@@ -634,7 +657,7 @@ int dpll_pin_on_pin_register(struct dpll_pin *parent,
>>struct dpll_pin *pin,
>> unsigned long i, stop;
>> int ret;
>>
>>- if (WARN_ON(parent->prop->type != DPLL_PIN_TYPE_MUX))
>>+ if (WARN_ON(parent->prop.type != DPLL_PIN_TYPE_MUX))
>> return -EINVAL;
>>
>> if (WARN_ON(!ops) ||
>>diff --git a/drivers/dpll/dpll_core.h b/drivers/dpll/dpll_core.h
>>index 5585873c5c1b..717f715015c7 100644
>>--- a/drivers/dpll/dpll_core.h
>>+++ b/drivers/dpll/dpll_core.h
>>@@ -44,7 +44,7 @@ struct dpll_device {
>> * @module: module of creator
>> * @dpll_refs: hold referencees to dplls pin was registered with
>> * @parent_refs: hold references to parent pins pin was registered
>>with
>>- * @prop: pointer to pin properties given by registerer
>>+ * @prop: pin properties copied from the registerer
>> * @rclk_dev_name: holds name of device when pin can recover clock
>>from it
>> * @refcount: refcount
>> **/
>>@@ -55,7 +55,7 @@ struct dpll_pin {
>> struct module *module;
>> struct xarray dpll_refs;
>> struct xarray parent_refs;
>>- const struct dpll_pin_properties *prop;
>>+ struct dpll_pin_properties prop;
>> refcount_t refcount;
>> };
>>
>>diff --git a/drivers/dpll/dpll_netlink.c b/drivers/dpll/dpll_netlink.c
>>index b53478374a38..3ce9995013f1 100644
>>--- a/drivers/dpll/dpll_netlink.c
>>+++ b/drivers/dpll/dpll_netlink.c
>>@@ -278,17 +278,17 @@ dpll_msg_add_pin_freq(struct sk_buff *msg, struct
>>dpll_pin *pin,
>> if (nla_put_64bit(msg, DPLL_A_PIN_FREQUENCY, sizeof(freq), &freq,
>> DPLL_A_PIN_PAD))
>> return -EMSGSIZE;
>>- for (fs = 0; fs < pin->prop->freq_supported_num; fs++) {
>>+ for (fs = 0; fs < pin->prop.freq_supported_num; fs++) {
>> nest = nla_nest_start(msg, DPLL_A_PIN_FREQUENCY_SUPPORTED);
>> if (!nest)
>> return -EMSGSIZE;
>>- freq = pin->prop->freq_supported[fs].min;
>>+ freq = pin->prop.freq_supported[fs].min;
>> if (nla_put_64bit(msg, DPLL_A_PIN_FREQUENCY_MIN, sizeof(freq),
>> &freq, DPLL_A_PIN_PAD)) {
>> nla_nest_cancel(msg, nest);
>> return -EMSGSIZE;
>> }
>>- freq = pin->prop->freq_supported[fs].max;
>>+ freq = pin->prop.freq_supported[fs].max;
>> if (nla_put_64bit(msg, DPLL_A_PIN_FREQUENCY_MAX, sizeof(freq),
>> &freq, DPLL_A_PIN_PAD)) {
>> nla_nest_cancel(msg, nest);
>>@@ -304,9 +304,9 @@ static bool dpll_pin_is_freq_supported(struct dpll_pin
>>*pin, u32 freq)
>> {
>> int fs;
>>
>>- for (fs = 0; fs < pin->prop->freq_supported_num; fs++)
>>- if (freq >= pin->prop->freq_supported[fs].min &&
>>- freq <= pin->prop->freq_supported[fs].max)
>>+ for (fs = 0; fs < pin->prop.freq_supported_num; fs++)
>>+ if (freq >= pin->prop.freq_supported[fs].min &&
>>+ freq <= pin->prop.freq_supported[fs].max)
>> return true;
>> return false;
>> }
>>@@ -398,7 +398,7 @@ static int
>> dpll_cmd_pin_get_one(struct sk_buff *msg, struct dpll_pin *pin,
>> struct netlink_ext_ack *extack)
>> {
>>- const struct dpll_pin_properties *prop = pin->prop;
>>+ const struct dpll_pin_properties *prop = &pin->prop;
>> struct dpll_pin_ref *ref;
>> int ret;
>>
>>@@ -691,7 +691,7 @@ dpll_pin_on_pin_state_set(struct dpll_pin *pin, u32
>>parent_idx,
>> int ret;
>>
>> if (!(DPLL_PIN_CAPABILITIES_STATE_CAN_CHANGE &
>>- pin->prop->capabilities)) {
>>+ pin->prop.capabilities)) {
>> NL_SET_ERR_MSG(extack, "state changing is not allowed");
>> return -EOPNOTSUPP;
>> }
>>@@ -727,7 +727,7 @@ dpll_pin_state_set(struct dpll_device *dpll, struct
>>dpll_pin *pin,
>> int ret;
>>
>> if (!(DPLL_PIN_CAPABILITIES_STATE_CAN_CHANGE &
>>- pin->prop->capabilities)) {
>>+ pin->prop.capabilities)) {
>> NL_SET_ERR_MSG(extack, "state changing is not allowed");
>> return -EOPNOTSUPP;
>> }
>>@@ -754,7 +754,7 @@ dpll_pin_prio_set(struct dpll_device *dpll, struct
>>dpll_pin *pin,
>> int ret;
>>
>> if (!(DPLL_PIN_CAPABILITIES_PRIORITY_CAN_CHANGE &
>>- pin->prop->capabilities)) {
>>+ pin->prop.capabilities)) {
>> NL_SET_ERR_MSG(extack, "prio changing is not allowed");
>> return -EOPNOTSUPP;
>> }
>>@@ -782,7 +782,7 @@ dpll_pin_direction_set(struct dpll_pin *pin, struct
>>dpll_device *dpll,
>> int ret;
>>
>> if (!(DPLL_PIN_CAPABILITIES_DIRECTION_CAN_CHANGE &
>>- pin->prop->capabilities)) {
>>+ pin->prop.capabilities)) {
>> NL_SET_ERR_MSG(extack, "direction changing is not allowed");
>> return -EOPNOTSUPP;
>> }
>>@@ -812,8 +812,8 @@ dpll_pin_phase_adj_set(struct dpll_pin *pin, struct
>>nlattr *phase_adj_attr,
>> int ret;
>>
>> phase_adj = nla_get_s32(phase_adj_attr);
>>- if (phase_adj > pin->prop->phase_range.max ||
>>- phase_adj < pin->prop->phase_range.min) {
>>+ if (phase_adj > pin->prop.phase_range.max ||
>>+ phase_adj < pin->prop.phase_range.min) {
>> NL_SET_ERR_MSG_ATTR(extack, phase_adj_attr,
>> "phase adjust value not supported");
>> return -EINVAL;
>>@@ -997,7 +997,7 @@ dpll_pin_find(u64 clock_id, struct nlattr
>>*mod_name_attr,
>> unsigned long i;
>>
>> xa_for_each_marked(&dpll_pin_xa, i, pin, DPLL_REGISTERED) {
>>- prop = pin->prop;
>>+ prop = &pin->prop;
>> cid_match = clock_id ? pin->clock_id == clock_id : true;
>> mod_match = mod_name_attr && module_name(pin->module) ?
>> !nla_strcmp(mod_name_attr,
>>--
>>2.38.1
>>
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