On 09/29/2013 02:55 PM, vaughan wrote:
On 09/23/2013 10:56 PM, Jeff Moyer wrote:
Vaughan Cao<vaughan....@oracle.com> writes:
register_blkdev(0, NULL) can result kernel Oops by copying from NULL
in strlcpy(). Fix it by checking NULL pointer at the beginning and
WARN when encountered in unregister_blkdev.
Uhh, so yeah, this is an exported function, so I could see maybe wanting
to do the argument checking. But honestly, if your driver can't even
get this right, is there any hope of it actually working?
This seems like a pointless patch to me, but ultimately it's up to Jens.
Cheers,
Jeff
p.s. the kerneldoc tells you what to put there:
* @name: the name of the new block device as a zero terminated string
Thanks for your comment, Jeff. I have the same feeling as you, however,
shouldn't kernel do its best to provide the maximum stable working ability?
And it's test case 7 of block driver in ltp project -
http://sourceforge.net/p/ltp/git/ci/master/tree/testcases/kernel/device-drivers/block/kernel_space/test_block.c.
It seems their attitude is we should check this.
I checked most of the callers of this function in current code tree.
Indeed, mostly they pass a static string as a parameter.
As jeff has said if a driver wants to get things right, it should able to
give right parameters.
But as an acknowledge of kernel code protocol, I have a query/question of
the similar situation. if a function is a public one and called rather
commonly.
In what cases should we have a parameter checking in it?
I think if the parameter is a rather obvious one that even a look at it
in the caller telling OK or not.
These parameters may not need checking.
thanks
chai wen
Vaughan
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