Commit b8ea2cb5 authored Nov 09, 2005 by Zachary Amsden Committed by Jens Axboe Nov 12, 2005

[BLOCK] elevator init fixes



I got a panic in the elevator code, backtrace :

Unable to handle kernel NULL pointer dereference at virtual address 00000060
..
EIP is at elevator_put+0x0/0x30 (null elevator_type passed)
..
elevator_init+0x38
blk_init_queu_node+0xc9
floppy_init+0xdb
do_initcalls+0x23
init+0x10a
init+0x0

Clearly if the kmalloc here fails, e->elevator_type is not yet set; this
appears to be the correct fix, but I think I probably hit the second case
due to a race condition.  Someone more familiar with the elevator code
should look at this more closely until I can determine if I can reproduce.

Signed-off-by: Zachary Amsden <zach@vmware.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Jens Axboe <axboe@suse.de>

parent cd52d1ee

block/elevator.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -190,14 +190,14 @@ int elevator_init(request_queue_t q, char name)

		eq = kmalloc(sizeof(struct elevator_queue), GFP_KERNEL);
		if (!eq) {
		elevator_put(e->elevator_type);
		elevator_put(e);
		return -ENOMEM;
		}

		ret = elevator_attach(q, e, eq);
		if (ret) {
		kfree(eq);
		elevator_put(e->elevator_type);
		elevator_put(e);
		}

		return ret;

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