Messages in this thread Patch in this message | | | Subject | Re: 2.6.0-test8, DEBUG_SLAB, oops in as_latter_request() | From | Peter Osterlund <> | Date | 20 Oct 2003 21:37:03 +0200 |
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Nick Piggin <piggin@cyberone.com.au> writes:
> Andrew Morton wrote: > > >Peter Osterlund <petero2@telia.com> wrote: > > > >>I was running 2.6.0-test8 compiled with CONFIG_DEBUG_SLAB=y. When > >> testing the CDRW packet writing driver, I got an oops in > >> as_latter_request. (Full oops at the end of this message.) It is > >> repeatable and happens because arq->rb_node.rb_right is uninitialized. > >> > > > >deadline seems to have the same problem. > > > >We may as well squish this with the big hammer? > > > > Thanks for the report, Peter. > > The request is a special request, so either blk_attempt_remerge should > never be called on it, or blk_attempt_remerge (or as_latter_request) should > check for this. Its up to Jens.
I don't think it is a special request. I added this debug hack:
--- linux/drivers/block/as-iosched.c~ 2003-10-19 20:33:45.000000000 +0200 +++ linux/drivers/block/as-iosched.c 2003-10-20 21:14:20.000000000 +0200 @@ -1501,9 +1501,18 @@ static struct request * as_latter_request(request_queue_t *q, struct request *rq) { - struct as_rq *arq = RQ_DATA(rq); - struct rb_node *rbnext = rb_next(&arq->rb_node); - struct request *ret = NULL; + struct as_rq *arq; + struct rb_node *rbnext; + struct request *ret; + + arq = RQ_DATA(rq); + if (arq->rb_node.rb_right == (void*)0x5a5a5a5a) { + printk("flags:%lx sector:%ld cmd:%02x %02x %02x %02x\n", + rq->flags, rq->sector, + rq->cmd[0], rq->cmd[1], rq->cmd[2], rq->cmd[3]); + } + rbnext = rb_next(&arq->rb_node); + ret = NULL; if (rbnext) ret = rb_entry_arq(rbnext)->request; The result was:
flags:50 sector:186920 cmd:28 00 00 00 Unable to handle kernel paging request at virtual address 5a5a5a66 printing eip: ...
Note that:
0x50 == REQ_CMD | REQ_STARTED 0x28 == GPCMD_READ_10 So this looks like a regular read request to me. I'm not sure if this means that something else is wrong.
-- Peter Osterlund - petero2@telia.com http://w1.894.telia.com/~u89404340 - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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