From: Gerd Knorr <kraxel@bytesex.org>
To: Andrew Morton <akpm@osdl.org>
Cc: caszonyi@rdslink.ro, linux-kernel@vger.kernel.org
Subject: Re: Fw: Slab coruption and oops with 2.6.1-mm4
Date: Mon, 19 Jan 2004 13:15:46 +0100 [thread overview]
Message-ID: <20040119121546.GD5498@bytesex.org> (raw)
In-Reply-To: <20040118220051.3f3d8420.akpm@osdl.org>
> heh, this is the same bug. Last time we were unlocking an unlocked page.
> Now we're freeing a free page.
Yes. Still no idea why that happens through ...
> CONFIG_PREEMPT=y
Bug reproducable with this one turned off?
> Slab corruption: start=c57c2000, len=4096
> 000: 6e 72 6d 71 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b
> bttv0: skipped frame. no signal? high irq latency? [main=b030000,o_vbi=b030018,o_field=5378000,rc=537801c]
> ------------[ cut here ]------------
> kernel BUG at include/linux/mm.h:275!
page_cache_release()
> EIP is at videobuf_dma_free+0xa9/0xc0 [video_buf]
The code calling page_cache_release looks like this ...
if (dma->pages) {
int i;
for (i=0; i < dma->nr_pages; i++)
page_cache_release(dma->pages[i]);
kfree(dma->pages);
dma->pages = NULL;
}
... even with videobuf_dma_free() called twice by mistake that shouldn't
double-free the pages. Maybe videobuf_dma_free() is called from two
places at the same time because one of the call paths misses a lock, but
I can't find any on a quick review. Hmm.
Does transcode use threads? If so, does it call into bttv from
different threads?
> Call Trace:
> [<d08f3a70>] bttv_dma_free+0x60/0xa0 [bttv]
> [<d08ede63>] bttv_do_ioctl+0x403/0x16a0 [bttv]
must be VIDIOCSYNC ioctl.
> [<c0335498>] video_usercopy+0xe8/0x1e0
> [<d08ef13e>] bttv_ioctl+0x3e/0x70 [bttv]
> [<c0168ef3>] sys_ioctl+0xf3/0x280
> [<c042e9b7>] syscall_call+0x7/0xb
Gerd
--
"... und auch das ganze Wochenende oll" -- Wetterbericht auf RadioEins
next parent reply other threads:[~2004-01-19 12:20 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20040118220051.3f3d8420.akpm@osdl.org>
2004-01-19 12:15 ` Gerd Knorr [this message]
2004-01-19 16:05 ` Fw: Slab coruption and oops with 2.6.1-mm4 Gerd Knorr
2004-01-20 0:27 ` caszonyi
2004-01-20 1:22 ` Mike Fedyk
2004-01-20 11:51 ` Fw: " Gerd Knorr
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