Messages in this thread | | | From | Keith Owens <> | Subject | Re: [CHECKER] 120 potential dereference to invalid pointers errors forlinux 2.4.1 | Date | Sun, 18 Mar 2001 23:16:16 +1100 |
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On Sun, 18 Mar 2001 06:29:50 -0500, Jeff Garzik <jgarzik@mandrakesoft.com> wrote: >Junfeng Yang wrote: >> Start ---> >> busy = kmalloc(sizeof(erase_busy_t), GFP_KERNEL); >> Error ---> > >This sizeof() construct may be a special case for your checker, but it's >a common one for the kernel... It definitely doesn't de-reference a >pointer.
IMHO the above line is a bad construct. If the type of the variable changes it is extremely easy to miss the fact that *alloc is now returning the wrong size. I always do
busy = kmalloc(sizeof(*busy), GFP_KERNEL);
and let the compiler insert the correct type.
For the checker, you can also have typeof(). kdb has this line
typeof (*ef) local_ef;
The type definition of ef is kdb_eframe_t which is "pointer to some arch dependent type" and local_ef is in arch independent code, much easier to do this than use multiple #ifdef. Of course it would have been even easier if kdb had separate types for the struct and the pointer to the struct, then I would not need typeof(). OTOH I am sure that somebody will find a use for typeof().
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