drivers/cxl/core/mbox.c | 9 +++++++++ drivers/cxl/core/memdev.c | 26 ++++++++++++++++++++++++++ drivers/cxl/mem.c | 18 ++++++++++-------- drivers/cxl/pci.c | 5 ++++- drivers/cxl/pmem.c | 3 +++ 5 files changed, 52 insertions(+), 9 deletions(-)
Using the proposed type-2 cxl-test device[1] the following
splat was observed:
BUG: kernel NULL pointer dereference, address: 0000000000000278
[...]
RIP: 0010:devm_cxl_add_memdev+0x1de/0x2c0 [cxl_core]
[...]
Call Trace:
<TASK>
? __die+0x1f/0x70
? page_fault_oops+0x149/0x420
? fixup_exception+0x22/0x310
? kernelmode_fixup_or_oops+0x84/0x110
? exc_page_fault+0x6d/0x150
? asm_exc_page_fault+0x22/0x30
? devm_cxl_add_memdev+0x1de/0x2c0 [cxl_core]
cxl_mock_mem_probe+0x632/0x870 [cxl_mock_mem]
platform_probe+0x40/0x90
really_probe+0x19e/0x3e0
? __pfx___driver_attach+0x10/0x10
__driver_probe_device+0x78/0x160
driver_probe_device+0x1f/0x90
__driver_attach+0xce/0x1c0
bus_for_each_dev+0x63/0xa0
bus_add_driver+0x112/0x210
driver_register+0x55/0x100
? __pfx_cxl_mock_mem_driver_init+0x10/0x10 [cxl_mock_mem]
[...]
Commit f6b8ab32e3ec made the mailbox functionality optional. However,
some mailbox functionality was merged after that patch. Therefore some
mailbox functionality can be accessed on a device which did not set up
the mailbox.
While no devices currently exist, commit f6b8ab32e3ec is incomplete.
Complete the checks for memdev state to bring the code to a consistent
state for when type-2 devices are introduced.
[1] https://lore.kernel.org/all/168592160379.1948938.12863272903570476312.stgit@dwillia2-xfh.jf.intel.com/
Fixes: f6b8ab32e3ec ("cxl/memdev: Make mailbox functionality optional")
Cc: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Ira Weiny <ira.weiny@intel.com>
---
drivers/cxl/core/mbox.c | 9 +++++++++
drivers/cxl/core/memdev.c | 26 ++++++++++++++++++++++++++
drivers/cxl/mem.c | 18 ++++++++++--------
drivers/cxl/pci.c | 5 ++++-
drivers/cxl/pmem.c | 3 +++
5 files changed, 52 insertions(+), 9 deletions(-)
diff --git a/drivers/cxl/core/mbox.c b/drivers/cxl/core/mbox.c
index d6d067fbee97..eb1758fb8cdf 100644
--- a/drivers/cxl/core/mbox.c
+++ b/drivers/cxl/core/mbox.c
@@ -482,6 +482,9 @@ int cxl_query_cmd(struct cxl_memdev *cxlmd,
dev_dbg(dev, "Query IOCTL\n");
+ if (!mds)
+ return -EIO;
+
if (get_user(n_commands, &q->n_commands))
return -EFAULT;
@@ -586,6 +589,9 @@ int cxl_send_cmd(struct cxl_memdev *cxlmd, struct cxl_send_command __user *s)
dev_dbg(dev, "Send IOCTL\n");
+ if (!mds)
+ return -EIO;
+
if (copy_from_user(&send, s, sizeof(send)))
return -EFAULT;
@@ -1245,6 +1251,9 @@ int cxl_mem_get_poison(struct cxl_memdev *cxlmd, u64 offset, u64 len,
int nr_records = 0;
int rc;
+ if (!mds)
+ return -EIO;
+
rc = mutex_lock_interruptible(&mds->poison.lock);
if (rc)
return rc;
diff --git a/drivers/cxl/core/memdev.c b/drivers/cxl/core/memdev.c
index f99e7ec3cc40..629e479f751b 100644
--- a/drivers/cxl/core/memdev.c
+++ b/drivers/cxl/core/memdev.c
@@ -201,6 +201,19 @@ static ssize_t security_erase_store(struct device *dev,
static struct device_attribute dev_attr_security_erase =
__ATTR(erase, 0200, NULL, security_erase_store);
+static umode_t cxl_memdev_security_visible(struct kobject *kobj,
+ struct attribute *a, int n)
+{
+ struct device *dev = kobj_to_dev(kobj);
+ struct cxl_memdev *cxlmd = to_cxl_memdev(dev);
+ struct cxl_memdev_state *mds = to_cxl_memdev_state(cxlmd->cxlds);
+
+ if (!mds)
+ return 0;
+
+ return a->mode;
+}
+
static int cxl_get_poison_by_memdev(struct cxl_memdev *cxlmd)
{
struct cxl_dev_state *cxlds = cxlmd->cxlds;
@@ -332,6 +345,9 @@ int cxl_inject_poison(struct cxl_memdev *cxlmd, u64 dpa)
struct cxl_region *cxlr;
int rc;
+ if (!mds)
+ return -EIO;
+
if (!IS_ENABLED(CONFIG_DEBUG_FS))
return 0;
@@ -380,6 +396,9 @@ int cxl_clear_poison(struct cxl_memdev *cxlmd, u64 dpa)
struct cxl_region *cxlr;
int rc;
+ if (!mds)
+ return -EIO;
+
if (!IS_ENABLED(CONFIG_DEBUG_FS))
return 0;
@@ -480,6 +499,7 @@ static struct attribute_group cxl_memdev_pmem_attribute_group = {
static struct attribute_group cxl_memdev_security_attribute_group = {
.name = "security",
.attrs = cxl_memdev_security_attributes,
+ .is_visible = cxl_memdev_security_visible,
};
static const struct attribute_group *cxl_memdev_attribute_groups[] = {
@@ -542,6 +562,9 @@ static void cxl_memdev_security_shutdown(struct device *dev)
struct cxl_memdev *cxlmd = to_cxl_memdev(dev);
struct cxl_memdev_state *mds = to_cxl_memdev_state(cxlmd->cxlds);
+ if (!mds)
+ return;
+
if (mds->security.poll)
cancel_delayed_work_sync(&mds->security.poll_dwork);
}
@@ -997,6 +1020,9 @@ static int cxl_memdev_security_init(struct cxl_memdev *cxlmd)
struct device *dev = &cxlmd->dev;
struct kernfs_node *sec;
+ if (!mds)
+ return 0;
+
sec = sysfs_get_dirent(dev->kobj.sd, "security");
if (!sec) {
dev_err(dev, "sysfs_get_dirent 'security' failed\n");
diff --git a/drivers/cxl/mem.c b/drivers/cxl/mem.c
index 317c7548e4e9..4755a890018d 100644
--- a/drivers/cxl/mem.c
+++ b/drivers/cxl/mem.c
@@ -132,12 +132,14 @@ static int cxl_mem_probe(struct device *dev)
dentry = cxl_debugfs_create_dir(dev_name(dev));
debugfs_create_devm_seqfile(dev, "dpamem", dentry, cxl_mem_dpa_show);
- if (test_bit(CXL_POISON_ENABLED_INJECT, mds->poison.enabled_cmds))
- debugfs_create_file("inject_poison", 0200, dentry, cxlmd,
- &cxl_poison_inject_fops);
- if (test_bit(CXL_POISON_ENABLED_CLEAR, mds->poison.enabled_cmds))
- debugfs_create_file("clear_poison", 0200, dentry, cxlmd,
- &cxl_poison_clear_fops);
+ if (mds) {
+ if (test_bit(CXL_POISON_ENABLED_INJECT, mds->poison.enabled_cmds))
+ debugfs_create_file("inject_poison", 0200, dentry, cxlmd,
+ &cxl_poison_inject_fops);
+ if (test_bit(CXL_POISON_ENABLED_CLEAR, mds->poison.enabled_cmds))
+ debugfs_create_file("clear_poison", 0200, dentry, cxlmd,
+ &cxl_poison_clear_fops);
+ }
rc = devm_add_action_or_reset(dev, remove_debugfs, dentry);
if (rc)
@@ -222,8 +224,8 @@ static umode_t cxl_mem_visible(struct kobject *kobj, struct attribute *a, int n)
struct cxl_memdev_state *mds =
to_cxl_memdev_state(cxlmd->cxlds);
- if (!test_bit(CXL_POISON_ENABLED_LIST,
- mds->poison.enabled_cmds))
+ if (!mds || !test_bit(CXL_POISON_ENABLED_LIST,
+ mds->poison.enabled_cmds))
return 0;
}
return a->mode;
diff --git a/drivers/cxl/pci.c b/drivers/cxl/pci.c
index 1cb1494c28fe..93f6140432cd 100644
--- a/drivers/cxl/pci.c
+++ b/drivers/cxl/pci.c
@@ -122,7 +122,7 @@ static irqreturn_t cxl_pci_mbox_irq(int irq, void *id)
struct cxl_dev_state *cxlds = dev_id->cxlds;
struct cxl_memdev_state *mds = to_cxl_memdev_state(cxlds);
- if (!cxl_mbox_background_complete(cxlds))
+ if (!mds || !cxl_mbox_background_complete(cxlds))
return IRQ_NONE;
reg = readq(cxlds->regs.mbox + CXLDEV_MBOX_BG_CMD_STATUS_OFFSET);
@@ -624,6 +624,9 @@ static irqreturn_t cxl_event_thread(int irq, void *id)
struct cxl_memdev_state *mds = to_cxl_memdev_state(cxlds);
u32 status;
+ if (!mds)
+ return IRQ_HANDLED;
+
do {
/*
* CXL 3.0 8.2.8.3.1: The lower 32 bits are the status;
diff --git a/drivers/cxl/pmem.c b/drivers/cxl/pmem.c
index 7cb8994f8809..f1adfdd1a2b3 100644
--- a/drivers/cxl/pmem.c
+++ b/drivers/cxl/pmem.c
@@ -70,6 +70,9 @@ static int cxl_nvdimm_probe(struct device *dev)
struct nvdimm *nvdimm;
int rc;
+ if (WARN_ON_ONCE(!mds))
+ return -EIO;
+
set_exclusive_cxl_commands(mds, exclusive_cmds);
rc = devm_add_action_or_reset(dev, clear_exclusive, mds);
if (rc)
---
base-commit: 20ea1e7d13c1b544fe67c4a8dc3943bb1ab33e6f
change-id: 20230728-cxl-fix-devmemdev-5003ce927f68
Best regards,
--
Ira Weiny <ira.weiny@intel.com>Ira Weiny wrote: > Using the proposed type-2 cxl-test device[1] the following > splat was observed: > > BUG: kernel NULL pointer dereference, address: 0000000000000278 > [...] > RIP: 0010:devm_cxl_add_memdev+0x1de/0x2c0 [cxl_core] It would be useful to decode this to a line number, the rest of this call trace is not adding much. > [...] > Call Trace: > <TASK> > ? __die+0x1f/0x70 > ? page_fault_oops+0x149/0x420 > ? fixup_exception+0x22/0x310 > ? kernelmode_fixup_or_oops+0x84/0x110 > ? exc_page_fault+0x6d/0x150 > ? asm_exc_page_fault+0x22/0x30 > ? devm_cxl_add_memdev+0x1de/0x2c0 [cxl_core] > cxl_mock_mem_probe+0x632/0x870 [cxl_mock_mem] > platform_probe+0x40/0x90 > really_probe+0x19e/0x3e0 > ? __pfx___driver_attach+0x10/0x10 > __driver_probe_device+0x78/0x160 > driver_probe_device+0x1f/0x90 > __driver_attach+0xce/0x1c0 > bus_for_each_dev+0x63/0xa0 > bus_add_driver+0x112/0x210 > driver_register+0x55/0x100 > ? __pfx_cxl_mock_mem_driver_init+0x10/0x10 [cxl_mock_mem] > [...] > > Commit f6b8ab32e3ec made the mailbox functionality optional. However, > some mailbox functionality was merged after that patch. Therefore some > mailbox functionality can be accessed on a device which did not set up > the mailbox. cxl_memdev_security_init() definitely needs to move out of devm_cxl_add_memdev() and after that I do not think @mds NULL checks need to be sprinkled everywhere. In other words something is wrong at a higher level if we get into some of these helper functions without the memory device state. So definitely this uncovered a problem where cxl_memdev_security_init() needs to move, but the rest of the mds NULL checks need clear reproduction scenarios and expect most of them are precluded higher in the call stack.
On Fri, 28 Jul 2023, Dan Williams wrote:
>Ira Weiny wrote:
>> Using the proposed type-2 cxl-test device[1] the following
>> splat was observed:
>>
>> BUG: kernel NULL pointer dereference, address: 0000000000000278
>> [...]
>> RIP: 0010:devm_cxl_add_memdev+0x1de/0x2c0 [cxl_core]
>
>It would be useful to decode this to a line number, the rest of this
>call trace is not adding much.
>
>> [...]
>> Call Trace:
>> <TASK>
>> ? __die+0x1f/0x70
>> ? page_fault_oops+0x149/0x420
>> ? fixup_exception+0x22/0x310
>> ? kernelmode_fixup_or_oops+0x84/0x110
>> ? exc_page_fault+0x6d/0x150
>> ? asm_exc_page_fault+0x22/0x30
>> ? devm_cxl_add_memdev+0x1de/0x2c0 [cxl_core]
>> cxl_mock_mem_probe+0x632/0x870 [cxl_mock_mem]
>> platform_probe+0x40/0x90
>> really_probe+0x19e/0x3e0
>> ? __pfx___driver_attach+0x10/0x10
>> __driver_probe_device+0x78/0x160
>> driver_probe_device+0x1f/0x90
>> __driver_attach+0xce/0x1c0
>> bus_for_each_dev+0x63/0xa0
>> bus_add_driver+0x112/0x210
>> driver_register+0x55/0x100
>> ? __pfx_cxl_mock_mem_driver_init+0x10/0x10 [cxl_mock_mem]
>> [...]
>>
>> Commit f6b8ab32e3ec made the mailbox functionality optional. However,
>> some mailbox functionality was merged after that patch. Therefore some
>> mailbox functionality can be accessed on a device which did not set up
>> the mailbox.
>
>cxl_memdev_security_init() definitely needs to move out of
>devm_cxl_add_memdev() and after that I do not think @mds NULL checks
>need to be sprinkled everywhere. In other words something is wrong at a
>higher level if we get into some of these helper functions without the
>memory device state.
Right, so we can move it directly into cxl_pci_probe() - just as with other
mbox based functionality. This leaves me wondering, however, what to do about
the cxl_memdev_security_shutdown() counterpart. As with the below diff, leaving
it as is and just adding a mds nil check might still be considering a layering
violation in that it would be asymmetrical wrt to the init; but this is tightly
coupled with cxl_memdev_unregister().
Ira does the below fix the crash?
Thanks,
Davidlohr
----8<-------
diff --git a/drivers/cxl/core/memdev.c b/drivers/cxl/core/memdev.c
index 14b547c07f54..4d1bf80c0e54 100644
--- a/drivers/cxl/core/memdev.c
+++ b/drivers/cxl/core/memdev.c
@@ -561,7 +561,7 @@ static void cxl_memdev_security_shutdown(struct device *dev)
struct cxl_memdev *cxlmd = to_cxl_memdev(dev);
struct cxl_memdev_state *mds = to_cxl_memdev_state(cxlmd->cxlds);
- if (mds->security.poll)
+ if (mds && mds->security.poll)
cancel_delayed_work_sync(&mds->security.poll_dwork);
}
@@ -1009,11 +1009,11 @@ static void put_sanitize(void *data)
sysfs_put(mds->security.sanitize_node);
}
-static int cxl_memdev_security_init(struct cxl_memdev *cxlmd)
+int cxl_memdev_security_state_init(struct cxl_memdev_state *mds)
{
- struct cxl_dev_state *cxlds = cxlmd->cxlds;
- struct cxl_memdev_state *mds = to_cxl_memdev_state(cxlds);
- struct device *dev = &cxlmd->dev;
+
+ struct cxl_dev_state *cxlds = &mds->cxlds;
+ struct device *dev = &cxlds->cxlmd->dev;
struct kernfs_node *sec;
sec = sysfs_get_dirent(dev->kobj.sd, "security");
@@ -1029,7 +1029,8 @@ static int cxl_memdev_security_init(struct cxl_memdev *cxlmd)
}
return devm_add_action_or_reset(cxlds->dev, put_sanitize, mds);
- }
+}
+EXPORT_SYMBOL_NS_GPL(cxl_memdev_security_state_init, CXL);
struct cxl_memdev *devm_cxl_add_memdev(struct cxl_dev_state *cxlds)
{
@@ -1059,10 +1060,6 @@ struct cxl_memdev *devm_cxl_add_memdev(struct cxl_dev_state *cxlds)
if (rc)
goto err;
- rc = cxl_memdev_security_init(cxlmd);
- if (rc)
- goto err;
-
rc = devm_add_action_or_reset(cxlds->dev, cxl_memdev_unregister, cxlmd);
if (rc)
return ERR_PTR(rc);
diff --git a/drivers/cxl/cxlmem.h b/drivers/cxl/cxlmem.h
index f86afef90c91..441270770519 100644
--- a/drivers/cxl/cxlmem.h
+++ b/drivers/cxl/cxlmem.h
@@ -884,6 +884,7 @@ static inline void cxl_mem_active_dec(void)
#endif
int cxl_mem_sanitize(struct cxl_memdev_state *mds, u16 cmd);
+int cxl_memdev_security_state_init(struct cxl_memdev_state *mds);
struct cxl_hdm {
struct cxl_component_regs regs;
diff --git a/drivers/cxl/pci.c b/drivers/cxl/pci.c
index 1cb1494c28fe..5242dbf0044d 100644
--- a/drivers/cxl/pci.c
+++ b/drivers/cxl/pci.c
@@ -887,6 +887,10 @@ static int cxl_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
if (IS_ERR(cxlmd))
return PTR_ERR(cxlmd);
+ rc = cxl_memdev_security_state_init(mds);
+ if (rc)
+ return rc;
+
rc = cxl_memdev_setup_fw_upload(mds);
if (rc)
return rc;
Davidlohr Bueso wrote:
> On Fri, 28 Jul 2023, Dan Williams wrote:
>
> >Ira Weiny wrote:
> >> Using the proposed type-2 cxl-test device[1] the following
> >> splat was observed:
> >>
> >> BUG: kernel NULL pointer dereference, address: 0000000000000278
> >> [...]
> >> RIP: 0010:devm_cxl_add_memdev+0x1de/0x2c0 [cxl_core]
> >
> >It would be useful to decode this to a line number, the rest of this
> >call trace is not adding much.
> >
> >> [...]
> >> Call Trace:
> >> <TASK>
> >> ? __die+0x1f/0x70
> >> ? page_fault_oops+0x149/0x420
> >> ? fixup_exception+0x22/0x310
> >> ? kernelmode_fixup_or_oops+0x84/0x110
> >> ? exc_page_fault+0x6d/0x150
> >> ? asm_exc_page_fault+0x22/0x30
> >> ? devm_cxl_add_memdev+0x1de/0x2c0 [cxl_core]
> >> cxl_mock_mem_probe+0x632/0x870 [cxl_mock_mem]
> >> platform_probe+0x40/0x90
> >> really_probe+0x19e/0x3e0
> >> ? __pfx___driver_attach+0x10/0x10
> >> __driver_probe_device+0x78/0x160
> >> driver_probe_device+0x1f/0x90
> >> __driver_attach+0xce/0x1c0
> >> bus_for_each_dev+0x63/0xa0
> >> bus_add_driver+0x112/0x210
> >> driver_register+0x55/0x100
> >> ? __pfx_cxl_mock_mem_driver_init+0x10/0x10 [cxl_mock_mem]
> >> [...]
> >>
> >> Commit f6b8ab32e3ec made the mailbox functionality optional. However,
> >> some mailbox functionality was merged after that patch. Therefore some
> >> mailbox functionality can be accessed on a device which did not set up
> >> the mailbox.
> >
> >cxl_memdev_security_init() definitely needs to move out of
> >devm_cxl_add_memdev() and after that I do not think @mds NULL checks
> >need to be sprinkled everywhere. In other words something is wrong at a
> >higher level if we get into some of these helper functions without the
> >memory device state.
>
> Right, so we can move it directly into cxl_pci_probe() - just as with other
> mbox based functionality. This leaves me wondering, however, what to do about
> the cxl_memdev_security_shutdown() counterpart. As with the below diff, leaving
> it as is and just adding a mds nil check might still be considering a layering
> violation in that it would be asymmetrical wrt to the init; but this is tightly
> coupled with cxl_memdev_unregister().
>
> Ira does the below fix the crash?
I had to apply it by hand but yea it fixes the immediate crash.
Did you want to submit that as part of other work?
Ira
>
> Thanks,
> Davidlohr
>
> ----8<-------
> diff --git a/drivers/cxl/core/memdev.c b/drivers/cxl/core/memdev.c
> index 14b547c07f54..4d1bf80c0e54 100644
> --- a/drivers/cxl/core/memdev.c
> +++ b/drivers/cxl/core/memdev.c
> @@ -561,7 +561,7 @@ static void cxl_memdev_security_shutdown(struct device *dev)
> struct cxl_memdev *cxlmd = to_cxl_memdev(dev);
> struct cxl_memdev_state *mds = to_cxl_memdev_state(cxlmd->cxlds);
>
> - if (mds->security.poll)
> + if (mds && mds->security.poll)
> cancel_delayed_work_sync(&mds->security.poll_dwork);
> }
>
> @@ -1009,11 +1009,11 @@ static void put_sanitize(void *data)
> sysfs_put(mds->security.sanitize_node);
> }
>
> -static int cxl_memdev_security_init(struct cxl_memdev *cxlmd)
> +int cxl_memdev_security_state_init(struct cxl_memdev_state *mds)
> {
> - struct cxl_dev_state *cxlds = cxlmd->cxlds;
> - struct cxl_memdev_state *mds = to_cxl_memdev_state(cxlds);
> - struct device *dev = &cxlmd->dev;
> +
> + struct cxl_dev_state *cxlds = &mds->cxlds;
> + struct device *dev = &cxlds->cxlmd->dev;
> struct kernfs_node *sec;
>
> sec = sysfs_get_dirent(dev->kobj.sd, "security");
> @@ -1029,7 +1029,8 @@ static int cxl_memdev_security_init(struct cxl_memdev *cxlmd)
> }
>
> return devm_add_action_or_reset(cxlds->dev, put_sanitize, mds);
> - }
> +}
> +EXPORT_SYMBOL_NS_GPL(cxl_memdev_security_state_init, CXL);
>
> struct cxl_memdev *devm_cxl_add_memdev(struct cxl_dev_state *cxlds)
> {
> @@ -1059,10 +1060,6 @@ struct cxl_memdev *devm_cxl_add_memdev(struct cxl_dev_state *cxlds)
> if (rc)
> goto err;
>
> - rc = cxl_memdev_security_init(cxlmd);
> - if (rc)
> - goto err;
> -
> rc = devm_add_action_or_reset(cxlds->dev, cxl_memdev_unregister, cxlmd);
> if (rc)
> return ERR_PTR(rc);
> diff --git a/drivers/cxl/cxlmem.h b/drivers/cxl/cxlmem.h
> index f86afef90c91..441270770519 100644
> --- a/drivers/cxl/cxlmem.h
> +++ b/drivers/cxl/cxlmem.h
> @@ -884,6 +884,7 @@ static inline void cxl_mem_active_dec(void)
> #endif
>
> int cxl_mem_sanitize(struct cxl_memdev_state *mds, u16 cmd);
> +int cxl_memdev_security_state_init(struct cxl_memdev_state *mds);
>
> struct cxl_hdm {
> struct cxl_component_regs regs;
> diff --git a/drivers/cxl/pci.c b/drivers/cxl/pci.c
> index 1cb1494c28fe..5242dbf0044d 100644
> --- a/drivers/cxl/pci.c
> +++ b/drivers/cxl/pci.c
> @@ -887,6 +887,10 @@ static int cxl_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
> if (IS_ERR(cxlmd))
> return PTR_ERR(cxlmd);
>
> + rc = cxl_memdev_security_state_init(mds);
> + if (rc)
> + return rc;
> +
> rc = cxl_memdev_setup_fw_upload(mds);
> if (rc)
> return rc;
On 7/28/23 16:00, Ira Weiny wrote:
> Using the proposed type-2 cxl-test device[1] the following
> splat was observed:
>
> BUG: kernel NULL pointer dereference, address: 0000000000000278
> [...]
> RIP: 0010:devm_cxl_add_memdev+0x1de/0x2c0 [cxl_core]
> [...]
> Call Trace:
> <TASK>
> ? __die+0x1f/0x70
> ? page_fault_oops+0x149/0x420
> ? fixup_exception+0x22/0x310
> ? kernelmode_fixup_or_oops+0x84/0x110
> ? exc_page_fault+0x6d/0x150
> ? asm_exc_page_fault+0x22/0x30
> ? devm_cxl_add_memdev+0x1de/0x2c0 [cxl_core]
> cxl_mock_mem_probe+0x632/0x870 [cxl_mock_mem]
> platform_probe+0x40/0x90
> really_probe+0x19e/0x3e0
> ? __pfx___driver_attach+0x10/0x10
> __driver_probe_device+0x78/0x160
> driver_probe_device+0x1f/0x90
> __driver_attach+0xce/0x1c0
> bus_for_each_dev+0x63/0xa0
> bus_add_driver+0x112/0x210
> driver_register+0x55/0x100
> ? __pfx_cxl_mock_mem_driver_init+0x10/0x10 [cxl_mock_mem]
> [...]
>
> Commit f6b8ab32e3ec made the mailbox functionality optional. However,
> some mailbox functionality was merged after that patch. Therefore some
> mailbox functionality can be accessed on a device which did not set up
> the mailbox.
>
> While no devices currently exist, commit f6b8ab32e3ec is incomplete.
> Complete the checks for memdev state to bring the code to a consistent
> state for when type-2 devices are introduced.
>
> [1] https://lore.kernel.org/all/168592160379.1948938.12863272903570476312.stgit@dwillia2-xfh.jf.intel.com/
>
> Fixes: f6b8ab32e3ec ("cxl/memdev: Make mailbox functionality optional")
> Cc: Dan Williams <dan.j.williams@intel.com>
> Signed-off-by: Ira Weiny <ira.weiny@intel.com>
I think you'll need to coordinate with this patch from Davidlohr?
https://lore.kernel.org/linux-cxl/20230726051940.3570-4-dave@stgolabs.net/
> ---
> drivers/cxl/core/mbox.c | 9 +++++++++
> drivers/cxl/core/memdev.c | 26 ++++++++++++++++++++++++++
> drivers/cxl/mem.c | 18 ++++++++++--------
> drivers/cxl/pci.c | 5 ++++-
> drivers/cxl/pmem.c | 3 +++
> 5 files changed, 52 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/cxl/core/mbox.c b/drivers/cxl/core/mbox.c
> index d6d067fbee97..eb1758fb8cdf 100644
> --- a/drivers/cxl/core/mbox.c
> +++ b/drivers/cxl/core/mbox.c
> @@ -482,6 +482,9 @@ int cxl_query_cmd(struct cxl_memdev *cxlmd,
>
> dev_dbg(dev, "Query IOCTL\n");
>
> + if (!mds)
> + return -EIO;
> +
> if (get_user(n_commands, &q->n_commands))
> return -EFAULT;
>
> @@ -586,6 +589,9 @@ int cxl_send_cmd(struct cxl_memdev *cxlmd, struct cxl_send_command __user *s)
>
> dev_dbg(dev, "Send IOCTL\n");
>
> + if (!mds)
> + return -EIO;
> +
> if (copy_from_user(&send, s, sizeof(send)))
> return -EFAULT;
>
> @@ -1245,6 +1251,9 @@ int cxl_mem_get_poison(struct cxl_memdev *cxlmd, u64 offset, u64 len,
> int nr_records = 0;
> int rc;
>
> + if (!mds)
> + return -EIO;
> +
> rc = mutex_lock_interruptible(&mds->poison.lock);
> if (rc)
> return rc;
> diff --git a/drivers/cxl/core/memdev.c b/drivers/cxl/core/memdev.c
> index f99e7ec3cc40..629e479f751b 100644
> --- a/drivers/cxl/core/memdev.c
> +++ b/drivers/cxl/core/memdev.c
> @@ -201,6 +201,19 @@ static ssize_t security_erase_store(struct device *dev,
> static struct device_attribute dev_attr_security_erase =
> __ATTR(erase, 0200, NULL, security_erase_store);
>
> +static umode_t cxl_memdev_security_visible(struct kobject *kobj,
> + struct attribute *a, int n)
> +{
> + struct device *dev = kobj_to_dev(kobj);
> + struct cxl_memdev *cxlmd = to_cxl_memdev(dev);
> + struct cxl_memdev_state *mds = to_cxl_memdev_state(cxlmd->cxlds);
> +
> + if (!mds)
> + return 0;
> +
> + return a->mode;
> +}
> +
> static int cxl_get_poison_by_memdev(struct cxl_memdev *cxlmd)
> {
> struct cxl_dev_state *cxlds = cxlmd->cxlds;
> @@ -332,6 +345,9 @@ int cxl_inject_poison(struct cxl_memdev *cxlmd, u64 dpa)
> struct cxl_region *cxlr;
> int rc;
>
> + if (!mds)
> + return -EIO;
> +
> if (!IS_ENABLED(CONFIG_DEBUG_FS))
> return 0;
>
> @@ -380,6 +396,9 @@ int cxl_clear_poison(struct cxl_memdev *cxlmd, u64 dpa)
> struct cxl_region *cxlr;
> int rc;
>
> + if (!mds)
> + return -EIO;
> +
> if (!IS_ENABLED(CONFIG_DEBUG_FS))
> return 0;
>
> @@ -480,6 +499,7 @@ static struct attribute_group cxl_memdev_pmem_attribute_group = {
> static struct attribute_group cxl_memdev_security_attribute_group = {
> .name = "security",
> .attrs = cxl_memdev_security_attributes,
> + .is_visible = cxl_memdev_security_visible,
> };
>
> static const struct attribute_group *cxl_memdev_attribute_groups[] = {
> @@ -542,6 +562,9 @@ static void cxl_memdev_security_shutdown(struct device *dev)
> struct cxl_memdev *cxlmd = to_cxl_memdev(dev);
> struct cxl_memdev_state *mds = to_cxl_memdev_state(cxlmd->cxlds);
>
> + if (!mds)
> + return;
> +
> if (mds->security.poll)
> cancel_delayed_work_sync(&mds->security.poll_dwork);
> }
> @@ -997,6 +1020,9 @@ static int cxl_memdev_security_init(struct cxl_memdev *cxlmd)
> struct device *dev = &cxlmd->dev;
> struct kernfs_node *sec;
>
> + if (!mds)
> + return 0;
> +
> sec = sysfs_get_dirent(dev->kobj.sd, "security");
> if (!sec) {
> dev_err(dev, "sysfs_get_dirent 'security' failed\n");
> diff --git a/drivers/cxl/mem.c b/drivers/cxl/mem.c
> index 317c7548e4e9..4755a890018d 100644
> --- a/drivers/cxl/mem.c
> +++ b/drivers/cxl/mem.c
> @@ -132,12 +132,14 @@ static int cxl_mem_probe(struct device *dev)
> dentry = cxl_debugfs_create_dir(dev_name(dev));
> debugfs_create_devm_seqfile(dev, "dpamem", dentry, cxl_mem_dpa_show);
>
> - if (test_bit(CXL_POISON_ENABLED_INJECT, mds->poison.enabled_cmds))
> - debugfs_create_file("inject_poison", 0200, dentry, cxlmd,
> - &cxl_poison_inject_fops);
> - if (test_bit(CXL_POISON_ENABLED_CLEAR, mds->poison.enabled_cmds))
> - debugfs_create_file("clear_poison", 0200, dentry, cxlmd,
> - &cxl_poison_clear_fops);
> + if (mds) {
> + if (test_bit(CXL_POISON_ENABLED_INJECT, mds->poison.enabled_cmds))
> + debugfs_create_file("inject_poison", 0200, dentry, cxlmd,
> + &cxl_poison_inject_fops);
> + if (test_bit(CXL_POISON_ENABLED_CLEAR, mds->poison.enabled_cmds))
> + debugfs_create_file("clear_poison", 0200, dentry, cxlmd,
> + &cxl_poison_clear_fops);
> + }
>
> rc = devm_add_action_or_reset(dev, remove_debugfs, dentry);
> if (rc)
> @@ -222,8 +224,8 @@ static umode_t cxl_mem_visible(struct kobject *kobj, struct attribute *a, int n)
> struct cxl_memdev_state *mds =
> to_cxl_memdev_state(cxlmd->cxlds);
>
> - if (!test_bit(CXL_POISON_ENABLED_LIST,
> - mds->poison.enabled_cmds))
> + if (!mds || !test_bit(CXL_POISON_ENABLED_LIST,
> + mds->poison.enabled_cmds))
> return 0;
> }
> return a->mode;
> diff --git a/drivers/cxl/pci.c b/drivers/cxl/pci.c
> index 1cb1494c28fe..93f6140432cd 100644
> --- a/drivers/cxl/pci.c
> +++ b/drivers/cxl/pci.c
> @@ -122,7 +122,7 @@ static irqreturn_t cxl_pci_mbox_irq(int irq, void *id)
> struct cxl_dev_state *cxlds = dev_id->cxlds;
> struct cxl_memdev_state *mds = to_cxl_memdev_state(cxlds);
>
> - if (!cxl_mbox_background_complete(cxlds))
> + if (!mds || !cxl_mbox_background_complete(cxlds))
> return IRQ_NONE;
>
> reg = readq(cxlds->regs.mbox + CXLDEV_MBOX_BG_CMD_STATUS_OFFSET);
> @@ -624,6 +624,9 @@ static irqreturn_t cxl_event_thread(int irq, void *id)
> struct cxl_memdev_state *mds = to_cxl_memdev_state(cxlds);
> u32 status;
>
> + if (!mds)
> + return IRQ_HANDLED;
> +
> do {
> /*
> * CXL 3.0 8.2.8.3.1: The lower 32 bits are the status;
> diff --git a/drivers/cxl/pmem.c b/drivers/cxl/pmem.c
> index 7cb8994f8809..f1adfdd1a2b3 100644
> --- a/drivers/cxl/pmem.c
> +++ b/drivers/cxl/pmem.c
> @@ -70,6 +70,9 @@ static int cxl_nvdimm_probe(struct device *dev)
> struct nvdimm *nvdimm;
> int rc;
>
> + if (WARN_ON_ONCE(!mds))
> + return -EIO;
> +
> set_exclusive_cxl_commands(mds, exclusive_cmds);
> rc = devm_add_action_or_reset(dev, clear_exclusive, mds);
> if (rc)
>
> ---
> base-commit: 20ea1e7d13c1b544fe67c4a8dc3943bb1ab33e6f
> change-id: 20230728-cxl-fix-devmemdev-5003ce927f68
>
> Best regards,
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