Messages in this thread | | | Subject | Re: [PATCH v5 05/11] vsprintf: Consolidate handling of unknown pointer specifiers | From | Andy Shevchenko <> | Date | Wed, 25 Apr 2018 16:08:26 +0300 |
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On Wed, 2018-04-25 at 13:12 +0200, Petr Mladek wrote: > There are few printk formats that make sense only with two or more > specifiers. Also some specifiers make sense only when a kernel feature > is enabled. > > The handling of unknown specifiers is strange, inconsistent, and > even leaking the address. For example, netdev_bits() prints the > non-hashed pointer value or clock() prints "(null)". > > Using WARN() looks like an overkill for this type of error. pr_warn() > is not good either. It would by handled via printk_sage buffer and > it might be hard to match it with the problematic string. > > A reasonable compromise seems to be writing the unknown format > specifier > into the original string with a question mark, for example (%pC?). > It should be self-explaining enough. Note that it is in brackets > to follow the (null) style.
> + return valid_string(buf, end, "(%pG?)", spec);
> > if (!IS_ENABLED(CONFIG_OF)) > - return valid_string(buf, end, "(!OF)", spec); > + return valid_string(buf, end, "(%OF?)", spec);
"(%pOF?)" ?
-- Andy Shevchenko <andriy.shevchenko@linux.intel.com> Intel Finland Oy
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