From: "alpha @ steudten Engineering" <alpha@steudten.com>
To: Andrew Morton <akpm@osdl.org>
Cc: Ingo Oeser <netdev@axxeo.de>,
Ivan Kokshaysky <ink@jurassic.park.msu.ru>,
Richard Henderson <rth@twiddle.net>,
shemminger@osdl.org, p_gortmaker@yahoo.com,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
ioe-lkml@rameria.de
Subject: Re: Fw: [Bug 6421] New: kernel 2.6.10-2.6.16 on alpha: arch/alpha/kernel/io.c, iowrite16_rep() BUG_ON((unsigned long)src & 0x1) triggered
Date: Sat, 22 Apr 2006 09:56:07 +0200 [thread overview]
Message-ID: <4449E197.1020102@steudten.org> (raw)
In-Reply-To: <20060421161227.00d688d6.akpm@osdl.org>
Running this on my alpha gives (gcc 4.0.2):
3000
0123456A01234567
Andrew Morton wrote:
>> Because networking does read/write "short" fields in various packet
>> header structures. Results are illustrated in a following example:
>>
>> char foo[] __attribute__((aligned(8))) = "0123456701234567";
>>
>> int main()
>> {
>> short *bar = (short *)&foo[7];
>> printf("%04x\n", *bar); /* 3037 */
>> *bar = 0x4241; /* "AB" */
>> printf("%s\n", foo);
>> return 0;
>> }
>> --------
>> 0037
>> ^^
>> 0123456A01234567
>> ^
>> Misalignment by two bytes for ints and longs is often unavoidable in
>> networking and we can cope with it, but there is no excuse of 1-byte
>> misalignment.
next prev parent reply other threads:[~2006-04-22 18:11 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-04-21 17:27 Fw: [Bug 6421] New: kernel 2.6.10-2.6.16 on alpha: arch/alpha/kernel/io.c, iowrite16_rep() BUG_ON((unsigned long)src & 0x1) triggered Stephen Hemminger
2006-04-21 17:45 ` Ingo Oeser
2006-04-21 23:12 ` Andrew Morton
2006-04-22 7:56 ` alpha @ steudten Engineering [this message]
2006-04-23 5:43 ` Herbert Xu
2006-04-23 5:49 ` Herbert Xu
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