On Fri, Oct 28, 2022 at 07:41:54PM +0530, Deepak R Varma wrote: > On Fri, Oct 28, 2022 at 05:03:25PM +0300, Pavel Skripkin wrote: > > Hi Deepak R, > > > > Deepak R Varma <drv@xxxxxxxxx> says: > > > Flexible-array member should be used instead of one or zero member to > > > meet the need for having a dynamically sized trailing elements in a > > > structure. Refer to links [1] and [2] for detailed guidance on this > > > suggestion. > > > > > > [1] https://en.wikipedia.org/wiki/Flexible_array_member > > > [2] https://www.kernel.org/doc/html/v5.16/process/deprecated.html#zero-length-and-one-element-arrays > > > > > > Issue identified using coccicheck. > > > > > > Signed-off-by: Deepak R Varma <drv@xxxxxxxxx> > > > --- > > > drivers/staging/r8188eu/include/odm.h | 2 +- > > > drivers/staging/r8188eu/include/wlan_bssdef.h | 6 +++--- > > > 2 files changed, 4 insertions(+), 4 deletions(-) > > > > > > diff --git a/drivers/staging/r8188eu/include/odm.h b/drivers/staging/r8188eu/include/odm.h > > > index 89b01dd614ba..e2a9de5b9323 100644 > > > --- a/drivers/staging/r8188eu/include/odm.h > > > +++ b/drivers/staging/r8188eu/include/odm.h > > > @@ -166,7 +166,7 @@ struct odm_ra_info { > > > > > > struct ijk_matrix_regs_set { > > > bool bIQKDone; > > > - s32 Value[1][IQK_Matrix_REG_NUM]; > > > + s32 Value[][IQK_Matrix_REG_NUM]; > > > }; > > > > > > > you are changing the actual size of the struct. Wondering if you have tested > > this patch somehow > > Hello Pavel, > Thank you for reviewing the patch. I build the module post making the changes an > ensured that the build is successful. However, I am not sure how to check the > changes I am proposing. Could you please direct me to some information on how to > test patches? Is there some documentation generic/driver-specific that I can > refer to? You just have to look at every place where it is used and especially look at where it is allocated. It is only used in one place: struct ijk_matrix_regs_set IQKMatrixRegSetting; But that is in the middle of a struct and generally it doesn't make sense to have a flex array in the middle of a struct. So investigating further, we see that it really is a one element array: Do a grep: pDM_Odm->RFCalibrateInfo.IQKMatrixRegSetting[ChannelMappedIndex].Value[0][1]); The first element is always zero. So this patch introduces memory corruption. The code is messy and should be cleaned up, of course. regards, dan carpenter
