Should I do anything about this warning?

2014-10-08 Thread Sagar Padhye 
Hi,
I am new at kernel programming. I have written a driver for a custom device, 
running on arm board. It works well (for last few months).
I happen to look at kernel logs and I seen,

[231250.894334] [ cut here ]
[231250.899146] WARNING: at kernel/workqueue.c:1953 
process_one_work+0x398/0x52c()
[231250.906491] Modules linked in: bcmdhd cfg80211 XYZ
[231250.911885] [c0016450] (unwind_backtrace+0x0/0x144) from [c05c04f0] 
(dump_stack+0x20/0x24)
[231250.920672] [c05c04f0] (dump_stack+0x20/0x24) from [c006c330] 
(warn_slowpath_common+0x5c/0x74)
[231250.929757] [c006c330] (warn_slowpath_common+0x5c/0x74) from [c006c374] 
(warn_slowpath_null+0x2c/0x34)
[231250.939581] [c006c374] (warn_slowpath_null+0x2c/0x34) from [c0088f08] 
(process_one_work+0x398/0x52c)
[231250.949232] [c0088f08] (process_one_work+0x398/0x52c) from [c00895c8] 
(rescuer_thread+0x184/0x230)
[231250.958708] [c00895c8] (rescuer_thread+0x184/0x230) from [c008dd60] 
(kthread+0xac/0xb4)
[231250.967236] [c008dd60] (kthread+0xac/0xb4) from [c000fd4c] 
(kernel_thread_exit+0x0/0x8)
[231250.975755] ---[ end trace 9f9c2187c0bee21b ]---

The device is still working after this. No issues in operation. I am just 
sceptical about analyzing this issue? Do I need to check more? If yes how? with 
this trace?

Thanks,
Sagar

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Re: Should I do anything about this warning?

2014-10-08 Thread Sagar Padhye 
On Wed, Oct 08, 2014 at 11:33:57AM +0200, Kristof Provost wrote:
 On 2014-10-08 12:43:58 (+0530), Sagar Padhye sgr.m@gmail.com wrote:
  I am new at kernel programming. I have written a driver for a custom
  device, running on arm board. It works well (for last few months).  I
  happen to look at kernel logs and I seen,
  
  [231250.899146] WARNING: at kernel/workqueue.c:1953 
  process_one_work+0x398/0x52c()
  
 You triggered a warning in the code.
Yes, I got that

  The device is still working after this. No issues in operation. I am
  just sceptical about analyzing this issue? Do I need to check more? If
  yes how? with this trace?
  
 Yes, this indicates a potential problem.
The issue is not reproducible. Haven't seen in over 6 months. And the module is 
working just fine after the log.
Is there a way I can get more info on this e.g. more stacktrace that will end 
up in module's work function (if this occurs again)?
 You start my looking at line 1953 in kernel/workqueue.c, where you'll
 see which specific warning you're triggering.
 
 It's probably this one:
/* ensure we're on the correct CPU */
 WARN_ON_ONCE(!(pool-flags  POOL_DISASSOCIATED) 
  raw_smp_processor_id() != pool-cpu);
They are,
1952 WARN_ON_ONCE(!(worker-flags  (WORKER_UNBOUND | WORKER_REBIND)) 
1953  raw_smp_processor_id() != gcwq-cpu);
But I am not sure what they signify :(

Thanks,
Sagar

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Re: [PATCH] FIXED sparse warning : drivers/cpuidle/cpuidle.c:27:1: warning: symbol 'cpuidle_dev' was not declared. Should it be static?

2013-10-03 Thread Sagar Padhye 
  I checked that cpuidle_devices is only being used in cpuidle.c - hence
  thought that it can be made static and be removed from header.
 
 cpuidle_devices is actually used in drivers/cpuidle/coupled.c as well
 so this breaks the build.

Darn! I forgot 'clean build' part. sorry.
 
 Even for cpuidle_dev the patch isn't right.  It doesn't fix the
 warning, for me.  The DEFINE_PER_CPU() macro defines several variables
 actually.  Per CPU variables are a bit complicated and they have to have
 globally unique names.  So just ignore the Sparse warning for per CPU
 variables.
 

Ok, let me look at my sparse log once again, will pick some other problem (any 
suggestions?)

 There are several other process problems with the patch submission.
 
 1) Incorrect subject.  It should be:
   [PATCH] cpuidle: make a variable static
 
This is based on `git log --oneline drivers/cpuidle/cpuidle.c`
output.
 
 2) No blank line between subject and body of commit message.
 3) Line wrap the body of the email at 72 characters.
 4) No Signed-off-by line.
 

Ok, will keep this in mind

Thanks and Regards,
Sagar 

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[PATCH] FIXED sparse warning : drivers/cpuidle/cpuidle.c:27:1: warning: symbol 'cpuidle_dev' was not declared. Should it be static?

2013-10-02 Thread Sagar Padhye 
---
This is the first (and minor) patch I am sending out, hope this is ok. I 
checked that cpuidle_devices is only being used in cpuidle.c - hence thought 
that it can be made static and be removed from header.

 drivers/cpuidle/cpuidle.c | 4 ++--
 include/linux/cpuidle.h   | 1 -
 2 files changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c
index d75040d..4826506 100644
--- a/drivers/cpuidle/cpuidle.c
+++ b/drivers/cpuidle/cpuidle.c
@@ -23,8 +23,8 @@
 
 #include cpuidle.h
 
-DEFINE_PER_CPU(struct cpuidle_device *, cpuidle_devices);
-DEFINE_PER_CPU(struct cpuidle_device, cpuidle_dev);
+static DEFINE_PER_CPU(struct cpuidle_device *, cpuidle_devices);
+static DEFINE_PER_CPU(struct cpuidle_device, cpuidle_dev);
 
 DEFINE_MUTEX(cpuidle_lock);
 LIST_HEAD(cpuidle_detected_devices);
diff --git a/include/linux/cpuidle.h b/include/linux/cpuidle.h
index 781addc..96c8ed8 100644
--- a/include/linux/cpuidle.h
+++ b/include/linux/cpuidle.h
@@ -83,7 +83,6 @@ struct cpuidle_device {
 #endif
 };
 
-DECLARE_PER_CPU(struct cpuidle_device *, cpuidle_devices);
 
 /**
  * cpuidle_get_last_residency - retrieves the last state's residency time
-- 
1.8.1.2


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