Messages in this thread | | | Date | Mon, 31 Oct 2022 13:15:06 -0700 (PDT) | From | matthew.gerlach@linux ... | Subject | Re: [PATCH v4 3/4] fpga: dfl: add basic support DFHv1 |
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On Mon, 31 Oct 2022, Andy Shevchenko wrote:
> On Mon, Oct 31, 2022 at 09:16:19AM +0800, Xu Yilun wrote: >> On 2022-10-31 at 00:06:28 +0200, Andy Shevchenko wrote: >>> On Sat, Oct 29, 2022 at 09:08:44PM +0800, Xu Yilun wrote: >>>> On 2022-10-20 at 14:26:09 -0700, matthew.gerlach@linux.intel.com wrote: >>> >>>>> struct dfl_feature_info { >>>>> u16 fid; >>>>> u8 revision; >>>>> + u8 dfh_version; >>>>> struct resource mmio_res; >>>>> void __iomem *ioaddr; >>>>> struct list_head node; >>>>> unsigned int irq_base; >>>>> unsigned int nr_irqs; >>>>> + unsigned int param_size; >>>>> + u64 params[]; >>>>> }; >>> >>> ... >>> >>>>> + finfo = kzalloc(sizeof(*finfo) + dfh_psize, GFP_KERNEL); >>> >>> >>> This probably may use something from overflow.h. >>> >>>> The u64 flexible array in the structure, but seems dfh_get_psize could >>>> not garantee 64bit aligned size. >>>> >>>> What's the mandatory alignment of param data? If 64bit aligned, bit 33-34 >>>> of PARAM_HDR should be reserved. If 32bit aligned, finfo:params should be >>>> u32[]. >>> >>> Isn't it guaranteed by the C standard / architecture ABI? >> >> I'm referring to the malloc size of the structure. It reserved dfh_psize >> bytes for this u64 array, but there is no garantee dfh_psize should be a >> multiple of 8. So there may be memory leak when accessing the last >> array element? > > Have you looked at macros in the overflow.h? Would the use of it solve your > concern?
By clarifying the definition of the next field in the parameter header as the number of 8-byte words, dfh_get_psize is guaranteed to be a multiple of 8. This is fixed in the next revision of patches.
Matthew Gerlach
> > -- > With Best Regards, > Andy Shevchenko > > >
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