From: Matt Mackall <mpm@selenic.com>
To: Zwane Mwaikambo <zwane@arm.linux.org.uk>
Cc: Andrew Morton <akpm@osdl.org>,
Linux Kernel <linux-kernel@vger.kernel.org>
Subject: Re: 2.6.11-rc2-mm1 Random related problems
Date: Tue, 25 Jan 2005 12:40:56 -0800 [thread overview]
Message-ID: <20050125204056.GL12076@waste.org> (raw)
In-Reply-To: <Pine.LNX.4.61.0501242134390.3010@montezuma.fsmlabs.com>
On Mon, Jan 24, 2005 at 09:36:37PM -0700, Zwane Mwaikambo wrote:
> I'm having trouble booting here, were those random-* patches tested?
>
> EIP is at __add_entropy_words+0xc5/0x1c0
> eax: 0000002d ebx: 0000000f ecx: 0000007b edx: f5e50000
> esi: c0810980 edi: 0000000f ebp: f5e4fea4 esp: f5e4fe5c
> ds: 007b es: 007b ss: 0068
> Process dd (pid: 2255, threadinfo=f5e4e000 task=ebdd7ac0)
> Stack: 00000010 78000000 c07043e0 00000286 0000007b 0000001f 00000001 00000007
> 0000000e 00000014 0000001a 00000000 0000002d f5e50000 c07043c0 00000080
> c0704340 c07043c0 f5e4ff40 c037a4e0 00000000 00000010 2cda69d0 f7b9f75e
> Call Trace:
> [<c010403a>] show_stack+0x7a/0x90
> [<c01041c6>] show_registers+0x156/0x1c0
> [<c01043e0>] die+0x100/0x190
> [<c0116d59>] do_page_fault+0x349/0x63f
> [<c0103cc7>] error_code+0x2b/0x30
> [<c037a4e0>] xfer_secondary_pool+0xb0/0xe0
This oops is add_entropy_words running off the top of the stack
reading its input. The overrun is harmless until it causes a page
fault. After much staring:
This should fix Zwane's oops. Looks like I introduced this bug in Aug
2003, but it was hard to trigger until the recent changes. But it
ought to make it to mainline soonish.
Signed-off-by: Matt Mackall <mpm@selenic.com>
Index: rc2mm1/drivers/char/random.c
===================================================================
--- rc2mm1.orig/drivers/char/random.c 2005-01-25 12:27:00.000000000 -0800
+++ rc2mm1/drivers/char/random.c 2005-01-25 12:27:36.000000000 -0800
@@ -701,7 +701,7 @@
bytes=extract_entropy(r->pull, tmp, bytes,
random_read_wakeup_thresh / 8, rsvd);
- add_entropy_words(r, tmp, bytes);
+ add_entropy_words(r, tmp, (bytes + 3) / 4);
credit_entropy_store(r, bytes*8);
}
}
--
Mathematics is the supreme nostalgia of our time.
next prev parent reply other threads:[~2005-01-25 20:43 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-01-25 4:36 2.6.11-rc2-mm1 Random related problems Zwane Mwaikambo
2005-01-25 4:45 ` Matt Mackall
2005-01-25 4:49 ` Zwane Mwaikambo
2005-01-25 20:40 ` Matt Mackall [this message]
2005-01-25 21:42 ` Zwane Mwaikambo
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