Re: kobject: delayed kobject release: help find buggy drivers

[Dave Jones]

On Tue, Sep 03, 2013 at 06:59:24PM +0000, Linux Kernel wrote:
 > Gitweb:     http://git.kernel.org/linus/;a=commit;h=c817a67ecba7c3c2aaa104796d78f160af60920d
 > Commit:     c817a67ecba7c3c2aaa104796d78f160af60920d
 > Parent:     7c42721fe0c58a848849b43ff558cf2fb86aa35a
 > Author:     Russell King <rmk+kernel@xxxxxxxxxxxxxxxx>
 > AuthorDate: Thu Jun 27 15:06:14 2013 +0100
 > Committer:  Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
 > CommitDate: Thu Jul 25 15:39:04 2013 -0700
 > 
 >     kobject: delayed kobject release: help find buggy drivers
 >     
 >     Implement debugging for kobject release functions.  kobjects are
 >     reference counted, so the drop of the last reference to them is not
 >     predictable. However, the common case is for the last reference to be
 >     the kobject's removal from a subsystem, which results in the release
 >     function being immediately called.
 >     
 >     This can hide subtle bugs, which can occur when another thread holds a
 >     reference to the kobject at the same time that a kobject is removed.
 >     This results in the release method being delayed.
 >     
 >     In order to make these kinds of problems more visible, the following
 >     patch implements a delayed release; this has the effect that the
 >     release function will be out of order with respect to the removal of
 >     the kobject in the same manner that it would be if a reference was
 >     being held.
 >     
 >     This provides us with an easy way to allow driver writers to debug
 >     their drivers and fix otherwise hidden problems.
 >     
 >     Signed-off-by: Russell King <rmk+kernel@xxxxxxxxxxxxxxxx>
 >     Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

With this enabled, I get a bunch of scrolling oopses immediately after
exiting the bootloader. It happens so early I can't even capture them
over usb-serial, or earlyprintk=dbgp.

And for whatever reason, the printk path while oopsing ignores boot_delay parameter,
so I can't even use that.

any ideas ?

	Dave

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