From mboxrd@z Thu Jan  1 00:00:00 1970
Message-ID: <4752D59B.1020907@rtr.ca>
Date: Sun, 02 Dec 2007 10:56:11 -0500
From: Mark Lord <lkml@rtr.ca>
MIME-Version: 1.0
Subject: Re: [BUG 2.6.24-rc3-git6] SLUB's ksize() fails for size > 2048.
References: <200712021939.HHH18792.FLQSOOtFOFJVHM@I-love.SAKURA.ne.jp>
In-Reply-To: <200712021939.HHH18792.FLQSOOtFOFJVHM@I-love.SAKURA.ne.jp>
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Sender: owner-linux-mm@kvack.org
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To: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org
List-ID: <linux-mm.kvack.org>

Tetsuo Handa wrote:
> Hello.
> 
> I can't pass memory allocated by kmalloc() to ksize()
> if it is allocated by SLUB allocator and
> size is larger than (I guess) PAGE_SIZE / 2.
> 
> Regards.
> 
> ---------- Kernel config (grep CONFIG_SLUB .config) ----------
> CONFIG_SLUB_DEBUG=y
> CONFIG_SLUB=y
> # CONFIG_SLUB_DEBUG_ON is not set
> 
> ---------- Testing program (ksize_test.c) ----------
> #include <linux/module.h>
> #include <linux/slab.h>
> 
> static int __init init_ksize_test(void)
> {
>         void *p = kmalloc(2049, GFP_KERNEL);
>         printk("ksize(%p) = %d\n", p, ksize(p));
>         kfree(p);
>         return -ENOMEM;
> }
> 
> module_init(init_ksize_test)
> 
> MODULE_LICENSE("GPL");
> 
> ------------[ cut here ]------------
> kernel BUG at mm/slub.c:2562!
> invalid opcode: 0000 [#1] SMP
> Modules linked in: ksize_test
> 
> Pid: 8473, comm: modprobe Not tainted (2.6.24-rc3-git6 #4)
> EIP: 0060:[<c01714a2>] EFLAGS: 00010246 CPU: 1
> EIP is at ksize+0x1b/0x4a
> EAX: 00000000 EBX: dd776000 ECX: c16721d0 EDX: 00000000
> ESI: e081b280 EDI: df3a396c EBP: dd595ea0 ESP: dd595ea0
>  DS: 007b ES: 007b FS: 00d8 GS: 0033 SS: 0068
> Process modprobe (pid: 8473, ti=dd595000 task=d347cd60 task.ti=dd595000)
> Stack: dd595eb8 e081e01a dd595eb8 c014010c ffffffff e08193e0 dd595fb0 c0150b18
>        00000000 00000000 00001866 00000000 dd4dac00 d347cd60 c14366ac 00000230
>        0000135c 0000000e dd4dac00 e081b280 00000000 00000000 00000000 00000000
> Call Trace:
>  [<c0106008>] show_trace_log_lvl+0x1a/0x2f
>  [<c01060b8>] show_stack_log_lvl+0x9b/0xa3
>  [<c0106167>] show_registers+0xa7/0x178
>  [<c010634c>] die+0x114/0x1f5
>  [<c0417018>] do_trap+0x8a/0xa3
>  [<c01066ec>] do_invalid_op+0x88/0x92
>  [<c0416dea>] error_code+0x72/0x78
>  [<e081e01a>] init_ksize_test+0x1a/0x40 [ksize_test]
>  [<c0150b18>] sys_init_module+0x13d3/0x14ff
>  [<c0104f7e>] sysenter_past_esp+0x5f/0xa5
>  =======================
> Code: 8b 02 5d 84 c0 b8 00 00 00 00 0f 49 d0 89 d0 c3 55 85 c0 89 e5 75 04 0f 0b eb fe 31 d2 83 f8 10 74 34 e8 b4 ff ff ff 85 c0 75 04 <0f> 0b eb fe 8b 40 0c 85 c0 75 04 0f 0b eb fe 8b 10 f6 c6 0c 74
> EIP: [<c01714a2>] ksize+0x1b/0x4a SS:ESP 0068:dd595ea0
..

Is "p" NULL ?   Where'd your printk() output go to?

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