Revision 15cf17d26e08ee95c2e392a3a71f55d32e99e971 authored by Konstantin Khlebnikov on 08 March 2013, 20:43:36 UTC, committed by Linus Torvalds on 08 March 2013, 23:05:34 UTC
Fix a warning from lockdep caused by calling cancel_work_sync() for uninitialized struct work. This path has been triggered by destructon kmem-cache hierarchy via destroying its root kmem-cache. cache ffff88003c072d80 obj ffff88003b410000 cache ffff88003c072d80 obj ffff88003b924000 cache ffff88003c20bd40 INFO: trying to register non-static key. the code is fine but needs lockdep annotation. turning off the locking correctness validator. Pid: 2825, comm: insmod Tainted: G O 3.9.0-rc1-next-20130307+ #611 Call Trace: __lock_acquire+0x16a2/0x1cb0 lock_acquire+0x8a/0x120 flush_work+0x38/0x2a0 __cancel_work_timer+0x89/0xf0 cancel_work_sync+0xb/0x10 kmem_cache_destroy_memcg_children+0x81/0xb0 kmem_cache_destroy+0xf/0xe0 init_module+0xcb/0x1000 [kmem_test] do_one_initcall+0x11a/0x170 load_module+0x19b0/0x2320 SyS_init_module+0xc6/0xf0 system_call_fastpath+0x16/0x1b Example module to demonstrate: #include <linux/module.h> #include <linux/slab.h> #include <linux/mm.h> #include <linux/workqueue.h> int __init mod_init(void) { int size = 256; struct kmem_cache *cache; void *obj; struct page *page; cache = kmem_cache_create("kmem_cache_test", size, size, 0, NULL); if (!cache) return -ENOMEM; printk("cache %p\n", cache); obj = kmem_cache_alloc(cache, GFP_KERNEL); if (obj) { page = virt_to_head_page(obj); printk("obj %p cache %p\n", obj, page->slab_cache); kmem_cache_free(cache, obj); } flush_scheduled_work(); obj = kmem_cache_alloc(cache, GFP_KERNEL); if (obj) { page = virt_to_head_page(obj); printk("obj %p cache %p\n", obj, page->slab_cache); kmem_cache_free(cache, obj); } kmem_cache_destroy(cache); return -EBUSY; } module_init(mod_init); MODULE_LICENSE("GPL"); Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org> Cc: Glauber Costa <glommer@parallels.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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REPORTING-BUGS
[Some of this is taken from Frohwalt Egerer's original linux-kernel FAQ]
What follows is a suggested procedure for reporting Linux bugs. You
aren't obliged to use the bug reporting format, it is provided as a guide
to the kind of information that can be useful to developers - no more.
If the failure includes an "OOPS:" type message in your log or on
screen please read "Documentation/oops-tracing.txt" before posting your
bug report. This explains what you should do with the "Oops" information
to make it useful to the recipient.
Send the output to the maintainer of the kernel area that seems to
be involved with the problem, and cc the relevant mailing list. Don't
worry too much about getting the wrong person. If you are unsure send it
to the person responsible for the code relevant to what you were doing.
If it occurs repeatably try and describe how to recreate it. That is
worth even more than the oops itself. The list of maintainers and
mailing lists is in the MAINTAINERS file in this directory. If you
know the file name that causes the problem you can use the following
command in this directory to find some of the maintainers of that file:
perl scripts/get_maintainer.pl -f <filename>
If it is a security bug, please copy the Security Contact listed
in the MAINTAINERS file. They can help coordinate bugfix and disclosure.
See Documentation/SecurityBugs for more information.
If you are totally stumped as to whom to send the report, send it to
linux-kernel@vger.kernel.org. (For more information on the linux-kernel
mailing list see http://www.tux.org/lkml/).
This is a suggested format for a bug report sent to the Linux kernel mailing
list. Having a standardized bug report form makes it easier for you not to
overlook things, and easier for the developers to find the pieces of
information they're really interested in. Don't feel you have to follow it.
First run the ver_linux script included as scripts/ver_linux, which
reports the version of some important subsystems. Run this script with
the command "sh scripts/ver_linux".
Use that information to fill in all fields of the bug report form, and
post it to the mailing list with a subject of "PROBLEM: <one line
summary from [1.]>" for easy identification by the developers.
[1.] One line summary of the problem:
[2.] Full description of the problem/report:
[3.] Keywords (i.e., modules, networking, kernel):
[4.] Kernel information
[4.1.] Kernel version (from /proc/version):
[4.2.] Kernel .config file:
[5.] Most recent kernel version which did not have the bug:
[6.] Output of Oops.. message (if applicable) with symbolic information
resolved (see Documentation/oops-tracing.txt)
[7.] A small shell script or example program which triggers the
problem (if possible)
[8.] Environment
[8.1.] Software (add the output of the ver_linux script here)
[8.2.] Processor information (from /proc/cpuinfo):
[8.3.] Module information (from /proc/modules):
[8.4.] Loaded driver and hardware information (/proc/ioports, /proc/iomem)
[8.5.] PCI information ('lspci -vvv' as root)
[8.6.] SCSI information (from /proc/scsi/scsi)
[8.7.] Other information that might be relevant to the problem
(please look in /proc and include all information that you
think to be relevant):
[X.] Other notes, patches, fixes, workarounds:
Thank you
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