From: Helge Deller > Sent: 14 February 2022 11:05 > > On 2/14/22 10:26, David Laight wrote: > > From: David Laight > >> Sent: 14 February 2022 09:12 > >> > >> From: Helge Deller > >>> Sent: 13 February 2022 22:10 > >>> > >>> The put_user(val,ptr) macro wants a pointer in the second parameter, but in > >>> fat_ioctl_filldir() the d_name field references a whole "array of chars". > >>> Usually the compiler automatically converts it and uses a pointer to that > >>> array, but it's more clean to explicitly give the real pointer to where someting > >>> is put, which is in this case the first character of the d_name[] array. > >> > >> That just isn't true. > >> > >> In C both x->char_array and &x->char_array[0] have the same type > >> 'char *'. > >> > >> The 'bug' is caused by put_user() trying to do: > >> __typeof__(ptr) __ptr = ptr; > >> where __typeof__ is returning char[n] not char *. > >> > >> I've tried a few things but can't get __typeof__ to > >> generate a suitable type for both a simple type and array. > > > > Actually the issue is that put_user() writes a single variable > > and needs a pointer to one. > > So changing to: > > put_user(0, &array[0]); > > is probably fine. > > Ok. > > > But the description is all wrong. > > I agree it can be improved. > Would you mind proposing a better description? put_user() needs a pointer to a simple type. David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales)
