Messages in this thread Patch in this message | | | From | Ira Weiny <> | Date | Fri, 28 Jul 2023 16:00:12 -0700 | Subject | [PATCH] cxl/memdev: Avoid mailbox functionality on device memory CXL devices |
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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>
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