On Tue 2018-04-03 14:54:18, Andy Shevchenko wrote: > On Tue, 2018-04-03 at 13:46 +0200, Petr Mladek wrote: > > On Mon 2018-04-02 17:15:23, Andy Shevchenko wrote: > > > On Thu, 2018-03-29 at 16:53 +0200, Petr Mladek wrote: > > > > On Fri 2018-03-16 20:19:35, Andy Shevchenko wrote: > > > > > On Thu, 2018-03-15 at 16:26 +0100, Petr Mladek wrote: > > > > > > On Thu 2018-03-15 15:09:03, Andy Shevchenko wrote: > > > > > > > I still think that printing a hex value of the error code is > > > > > > > much > > > > > > > better > > > > > > > than some odd "(efault)". > > > > > > > > > > > > Do you mean (err:0e)? Google gives rather confusing answers > > > > > > for > > > > > > this. > > > > > > > > > > More like "(0xHHHH)" (we have already more than 512 error code > > > > > numbers. > > > > > > > > Hmm, I have never seen the error code in this form. > > > > > > We have limited space to print it and error numbers currently can be > > > up > > > to 0xfff (4095). So, I have no better idea how to squeeze them while > > > thinking that "(efault)" is much harder to parse in case of error > > > pointer. > > > > But this will not be used instead of address value. It is used in > > situations > > where we print the information that is stored at the address, for > > example, > > string, IP address, dentry name. > > We have a lot of API functions which returns: > -ERR_PTR > NULL > struct foo * > > There is no guarantee that one of that API won't be used as a supplier > for printf().
OK, I think that I have finally understood it. You would like to detect ERR_PTR values and handle them specially? I mean to show the value? But then we would need to distinguish three types of errors, something like: + (null) for pure NULL address + (e:XXXX) for address in IS_ERR_VALUE() range + (efault) for any other invalid address Then people might want to see values also from the first 4096 bytes. This is getting too complicated. I am not sure if it is worth it. > You can't dereference ERR_PTR value, but anything else except the actual > error value is worse than value itself... Yes and no, see below. > > > > > > Also google gives > > > > rather confusing results when searching, for example for > > > > "(0x000E)". > > > > > > It's not primarily for google, though yeah, people would google for > > > error messages... > > > > > > Another question is what the format: decimal versus hex for errors. > > > Maybe just "(-DDDDD)"? > > > > This still looks confusing and google does not help. > > ...then we have a last option just to print a value as a pointer > address. We could not print the real address from security reasons. The hashed pointer value is not much helpful. IMHO, a common error string is easier to spot or search for. Best Regards, Petr
