When inserting a wrong value to /sys/devices/system/memory/memoryX/state file,
following messages are shown. And device_hotplug_lock is never released.
================================================
[ BUG: lock held when returning to user space! ]
3.12.0-rc4-debug+ #3 Tainted: G W
------------------------------------------------
bash/6442 is leaving the kernel with locks still held!
1 lock held by bash/6442:
#0: (device_hotplug_lock){+.+.+.}, at: [<ffffffff8146cbb5>] lock_device_hotplug_sysfs+0x15/0x50
This issue was introdued by commit fa2be40 (drivers: base: use standard
device online/offline for state change).
This patch releases device_hotplug_lcok when store_mem_state returns EINVAL.
Signed-off-by: Yasuaki Ishimatsu <[email protected]>
CC: Toshi Kani <[email protected]>
CC: Seth Jennings <[email protected]>
CC: Greg Kroah-Hartman <[email protected]>
---
drivers/base/memory.c | 7 +++++--
1 files changed, 5 insertions(+), 2 deletions(-)
diff --git a/drivers/base/memory.c b/drivers/base/memory.c
index 9e59f65..bece691 100644
--- a/drivers/base/memory.c
+++ b/drivers/base/memory.c
@@ -333,8 +333,10 @@ store_mem_state(struct device *dev,
online_type = ONLINE_KEEP;
else if (!strncmp(buf, "offline", min_t(int, count, 7)))
online_type = -1;
- else
- return -EINVAL;
+ else {
+ ret = -EINVAL;
+ goto err;
+ }
switch (online_type) {
case ONLINE_KERNEL:
@@ -357,6 +359,7 @@ store_mem_state(struct device *dev,
ret = -EINVAL; /* should never happen */
}
+err:
unlock_device_hotplug();
if (ret)
On Fri, Oct 11, 2013 at 03:36:25PM +0900, Yasuaki Ishimatsu wrote:
> When inserting a wrong value to /sys/devices/system/memory/memoryX/state file,
> following messages are shown. And device_hotplug_lock is never released.
>
> ================================================
> [ BUG: lock held when returning to user space! ]
> 3.12.0-rc4-debug+ #3 Tainted: G W
> ------------------------------------------------
> bash/6442 is leaving the kernel with locks still held!
> 1 lock held by bash/6442:
> #0: (device_hotplug_lock){+.+.+.}, at: [<ffffffff8146cbb5>] lock_device_hotplug_sysfs+0x15/0x50
>
> This issue was introdued by commit fa2be40 (drivers: base: use standard
> device online/offline for state change).
>
> This patch releases device_hotplug_lcok when store_mem_state returns EINVAL.
>
> Signed-off-by: Yasuaki Ishimatsu <[email protected]>
> CC: Toshi Kani <[email protected]>
> CC: Seth Jennings <[email protected]>
> CC: Greg Kroah-Hartman <[email protected]>
Is this needed in 3.12-final, and possibly older kernel releases as well
(3.10, 3.11, etc.)? Or is it ok for 3.13?
thanks,
greg k-h
On Fri, 2013-10-11 at 15:36 +0900, Yasuaki Ishimatsu wrote:
> When inserting a wrong value to /sys/devices/system/memory/memoryX/state file,
> following messages are shown. And device_hotplug_lock is never released.
>
> ================================================
> [ BUG: lock held when returning to user space! ]
> 3.12.0-rc4-debug+ #3 Tainted: G W
> ------------------------------------------------
> bash/6442 is leaving the kernel with locks still held!
> 1 lock held by bash/6442:
> #0: (device_hotplug_lock){+.+.+.}, at: [<ffffffff8146cbb5>] lock_device_hotplug_sysfs+0x15/0x50
>
> This issue was introdued by commit fa2be40 (drivers: base: use standard
> device online/offline for state change).
>
> This patch releases device_hotplug_lcok when store_mem_state returns EINVAL.
>
> Signed-off-by: Yasuaki Ishimatsu <[email protected]>
> CC: Toshi Kani <[email protected]>
> CC: Seth Jennings <[email protected]>
> CC: Greg Kroah-Hartman <[email protected]>
Good catch!
Reviewed-by: Toshi Kani <[email protected]>
Thanks,
-Toshi
Hi Greg,
(2013/10/12 0:54), Greg KH wrote:
> On Fri, Oct 11, 2013 at 03:36:25PM +0900, Yasuaki Ishimatsu wrote:
>> When inserting a wrong value to /sys/devices/system/memory/memoryX/state file,
>> following messages are shown. And device_hotplug_lock is never released.
>>
>> ================================================
>> [ BUG: lock held when returning to user space! ]
>> 3.12.0-rc4-debug+ #3 Tainted: G W
>> ------------------------------------------------
>> bash/6442 is leaving the kernel with locks still held!
>> 1 lock held by bash/6442:
>> #0: (device_hotplug_lock){+.+.+.}, at: [<ffffffff8146cbb5>] lock_device_hotplug_sysfs+0x15/0x50
>>
>> This issue was introdued by commit fa2be40 (drivers: base: use standard
>> device online/offline for state change).
>>
>> This patch releases device_hotplug_lcok when store_mem_state returns EINVAL.
>>
>> Signed-off-by: Yasuaki Ishimatsu <[email protected]>
>> CC: Toshi Kani <[email protected]>
>> CC: Seth Jennings <[email protected]>
>> CC: Greg Kroah-Hartman <[email protected]>
>
> Is this needed in 3.12-final, and possibly older kernel releases as well
> (3.10, 3.11, etc.)? Or is it ok for 3.13?
The patch is needed in 3.12 because this problem has occurred since 3.12-rc1.
Thanks,
Yasuaki Ishimatsu
>
> thanks,
>
> greg k-h
>
(2013/10/12 1:31), Toshi Kani wrote:
> On Fri, 2013-10-11 at 15:36 +0900, Yasuaki Ishimatsu wrote:
>> When inserting a wrong value to /sys/devices/system/memory/memoryX/state file,
>> following messages are shown. And device_hotplug_lock is never released.
>>
>> ================================================
>> [ BUG: lock held when returning to user space! ]
>> 3.12.0-rc4-debug+ #3 Tainted: G W
>> ------------------------------------------------
>> bash/6442 is leaving the kernel with locks still held!
>> 1 lock held by bash/6442:
>> #0: (device_hotplug_lock){+.+.+.}, at: [<ffffffff8146cbb5>] lock_device_hotplug_sysfs+0x15/0x50
>>
>> This issue was introdued by commit fa2be40 (drivers: base: use standard
>> device online/offline for state change).
>>
>> This patch releases device_hotplug_lcok when store_mem_state returns EINVAL.
>>
>> Signed-off-by: Yasuaki Ishimatsu <[email protected]>
>> CC: Toshi Kani <[email protected]>
>> CC: Seth Jennings <[email protected]>
>> CC: Greg Kroah-Hartman <[email protected]>
>
> Good catch!
>
> Reviewed-by: Toshi Kani <[email protected]>
Thank you for your review.
Thanks,
Yasuaki Ishimatsu
>
> Thanks,
> -Toshi
>