Messages in this thread | | | Date | Thu, 25 Jun 2009 10:56:01 -0400 | From | Dave Jones <> | Subject | Re: kmemleak false positive? |
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On Thu, Jun 25, 2009 at 10:25:17AM +0100, Catalin Marinas wrote:
> > kmemleak: backtrace: > > kmemleak: [<c04fd8b3>] kmemleak_alloc+0x193/0x2b8 > > kmemleak: [<c04f5e73>] kmem_cache_alloc+0x11e/0x174 > > kmemleak: [<c0aae5a7>] debug_objects_mem_init+0x63/0x1d9 > > kmemleak: [<c0a86a62>] start_kernel+0x2da/0x38d > > kmemleak: [<c0a86090>] i386_start_kernel+0x7f/0x98 > > kmemleak: [<ffffffff>] 0xffffffff > > It could be a false positive. Do you get some "kmemleak: referenced" > messages as well at a later time? In this case, it is just transient > "leak", caused maybe by pointers stored on the stack or registers.
Yes, some time later.
> Is the obj_pool in lib/debugobjects.c supposed to be empty at the end of > the test and all objects freed? The obj_pool is a list and the first > elements in this list are from obj_static_pool, which is __initdata. > Objects added to the list may be referred by chaining with the > obj_static_pool objects but kmemleak doesn't scan __initdata as this is > usually freed before kmemleak does its first scan. So, if it is just a > transient "leak", kmemleak should later report "kmemleak: referenced" if > a kmem_cache_free() is called on any of the reported objects.
Hmm, it's pretty noisy, and everything it's found so far looks to be a false positive.
> You can mount debugfs on /sys/kerne/debug and read the kmemleak file in > there (it triggers a new scan as well).
Currently prints the acpi traces I already posted.
> You can also echo stack=on to > the above kmemleak file to enable kernel stack scanning. > > Could you send me your config options for DEBUG_OBJECTS_* and slab > allocator so I can try to reproduce this?
CONFIG_DEBUG_OBJECTS=y # CONFIG_DEBUG_OBJECTS_SELFTEST is not set CONFIG_DEBUG_OBJECTS_FREE=y CONFIG_DEBUG_OBJECTS_TIMERS=y CONFIG_DEBUG_OBJECTS_ENABLE_DEFAULT=1
Dave
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