Messages in this thread | | | Subject | Re: [PATCH] megaraid driver fix for 2.5.70 | From | Mark Haverkamp <> | Date | 05 Jun 2003 07:33:13 -0700 |
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On Thu, 2003-06-05 at 07:07, James Bottomley wrote: > On Tue, 2003-06-03 at 10:29, Mark Haverkamp wrote: > > A recent change to the megaraid driver to fix some memset calls resulted > > in overflowing the arrays being cleared and causing a system panic. > > This patch fixes the problem by making sure that the arrays being > > cleared are dimensioned to the correct size. The patch has been tested > > on osdl's stp machines that have megaraid controllers. > > This patch doesn't quite look like a fix to me: The megaraid mailboxes > are always >16 bytes *but* none of the setting commands is supposed to > touch any of the status parts (which begin at byte 15), so I don't see > how your patch would prevent a panic.
In the memset cases, what fixed the panic was that the size of the raw_mbox automatic was set to 16 and the memset was using sizeof(mbox_t). I just increased the size of the raw_mbox so it wouldn't be overflowed. It sounds like, from what you are saying, that the size of raw_mbox should have been left at 16 and the memset changed to fill 16 bytes and not the sizeof(mbox_t).
> > It also looks like the first fifteen (not sixteen) bytes are user data > and the remaining 51 are for data from the card. > > It thus looks like this memcpy in both issue_scb() and issue_scb_block() > may be wrong > > memcpy((char *)mbox, (char *)scb->raw_mbox, 16); > > because it's overwriting the mbox->busy return.
This doesn't seem like it would hurt since issue_scb sets mbox->busy just after the memcpy. and in issue_scb_block, the raw_mbox busy location is set before the memcpy.
> > Logically, it looks like the mbox_t should be split up into an mbox_out > (which is what all the routines want to set values in) and an mbox_in > which is where the status is returned. > > James -- Mark Haverkamp <markh@osdl.org>
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