Re: [PATCH v2 2/4] cxl/memdev: Hold memdev lock during memdev poison injection/clear

Li Ming
2026-03-18T12:00:03Z

在 2026/3/17 23:00, Dave Jiang 写道:
>
> On 3/14/26 12:06 AM, Li Ming wrote:
>> CXL memdev poison injection/clearing debugfs interfaces are visible
>> before the CXL memdev endpoint initialization, If user accesses the
>> interfaces before cxlmd->endpoint updated, it is possible to access an
>> invalid endpoint in cxl_dpa_to_region().
>>
>> Hold CXL memdev lock at the beginning of the interfaces, this blocks the
>> interfaces until CXL memdev probing completed.
>>
>> The following patch will check the given endpoint validity in
>> cxl_dpa_to_region().
>>
>> Suggested-by: Dan Williams <dan.j.williams@intel.com>
>> Reviewed-by: Dave Jiang <dave.jiang@intel.com>
>> Reviewed-by: Alison Schofield <alison.schofield@intel.com>
>> Signed-off-by: Li Ming <ming.li@zohomail.com>
> Hi Ming, I dropped this patch with Dan's comments [1] and updated cxl/next. Please check and make sure everything looks ok to you. Thanks!
>
> [1]: https://lore.kernel.org/linux-cxl/69b8b81621e16_452b100e@dwillia2-mobl4.notmuch/

Hi Dave,

I think there is no change needed in this patch, just need a independent
patch for holding memdev lock in cxl_region_debugfs_poison_inject/clear.

Or you want to review this patch again?

Ming

>
>> ---
>> drivers/cxl/mem.c | 10 ++++++++++
>> 1 file changed, 10 insertions(+)
>>
>> diff --git a/drivers/cxl/mem.c b/drivers/cxl/mem.c
>> index fcffe24dcb42..ab88eaa31d1d 100644
>> --- a/drivers/cxl/mem.c
>> +++ b/drivers/cxl/mem.c
>> @@ -48,6 +48,11 @@ static int cxl_mem_dpa_show(struct seq_file *file, void *data)
>> static int cxl_debugfs_poison_inject(void *data, u64 dpa)
>> {
>> struct cxl_memdev *cxlmd = data;
>> + int rc;
>> +
>> + ACQUIRE(device_intr, devlock)(&cxlmd->dev);
>> + if ((rc = ACQUIRE_ERR(device_intr, &devlock)))
>> + return rc;
>>
>> return cxl_inject_poison(cxlmd, dpa);
>> }
>> @@ -58,6 +63,11 @@ DEFINE_DEBUGFS_ATTRIBUTE(cxl_poison_inject_fops, NULL,
>> static int cxl_debugfs_poison_clear(void *data, u64 dpa)
>> {
>> struct cxl_memdev *cxlmd = data;
>> + int rc;
>> +
>> + ACQUIRE(device_intr, devlock)(&cxlmd->dev);
>> + if ((rc = ACQUIRE_ERR(device_intr, &devlock)))
>> + return rc;
>>
>> return cxl_clear_poison(cxlmd, dpa);
>> }
>>