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Subject: [RFC] kmemleak: Is DMI supported ?
From: Eric Dumazet <eric.dumazet@gmail.com>
To: Catalin Marinas <catalin.marinas@arm.com>
Cc: linux-kernel <linux-kernel@vger.kernel.org>
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Date: Thu, 11 Mar 2010 18:34:28 +0100
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Hi Catalin

On my i686 machine, I have
CONFIG_DMI=y

and 12 entries in /sys/firmware/memmap/ like first one named "0" :

$ grep . /sys/firmware/memmap/0/*
/sys/firmware/memmap/0/end:0x9f3ff
/sys/firmware/memmap/0/start:0x0
/sys/firmware/memmap/0/type:System RAM


All 12 kobjects are allocated in DMI zone between
c1001000 b .brk.dmi_alloc
c1011000 B __brk_limit)

see arch/x86/kernel/setup.c:124

#ifdef CONFIG_DMI
RESERVE_BRK(dmi_alloc, 65536);
#endif

Still kmemleak seems to thing their names are unreferenced objects.


unreferenced object 0xf6a4bcd8 (size 8):
  comm "swapper", pid 1, jiffies 4294669233 (age 2454.223s)
  hex dump (first 8 bytes):
    31 31 00 f6 00 00 00 00                          11......
  backtrace:
    [<c05a5bc5>] kmemleak_alloc+0x45/0x60
    [<c02dcfa2>] __kmalloc+0x122/0x1f0
    [<c039fe00>] kvasprintf+0x30/0x50
    [<c0397469>] kobject_set_name_vargs+0x49/0xa0
    [<c03974e1>] kobject_add_varg+0x21/0x50
    [<c039756c>] kobject_add+0x2c/0x60
    [<c04bed4c>] add_sysfs_fw_map_entry+0x4c/0x90
    [<c07ec523>] memmap_init+0x13/0x2d
    [<c0201038>] do_one_initcall+0x28/0x180
    [<c07c539d>] kernel_init+0x140/0x1df
    [<c02030fa>] kernel_thread_helper+0x6/0x10
    [<ffffffff>] 0xffffffff


Any idea how to include dmi_alloc zone in kmemleak logic ?

Thanks