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Message-ID: <ZZbRhsldnlKQfoDb@nanopsycho>
Date: Thu, 4 Jan 2024 16:40:54 +0100
From: Jiri Pirko <jiri@...nulli.us>
To: Arkadiusz Kubalewski <arkadiusz.kubalewski@...el.com>
Cc: netdev@...r.kernel.org, vadim.fedorenko@...ux.dev,
michal.michalik@...el.com, milena.olech@...el.com,
pabeni@...hat.com, kuba@...nel.org, Jan Glaza <jan.glaza@...el.com>,
Przemek Kitszel <przemyslaw.kitszel@...el.com>
Subject: Re: [PATCH net v2 2/4] dpll: fix pin dump crash for rebound module
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?
>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?
> 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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