diff options
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/printk-formats.txt | 18 |
1 files changed, 17 insertions, 1 deletions
diff --git a/Documentation/printk-formats.txt b/Documentation/printk-formats.txt index b4e668ac4fe33..aa0a776c817a7 100644 --- a/Documentation/printk-formats.txt +++ b/Documentation/printk-formats.txt @@ -49,7 +49,8 @@ Pointer Types Pointers printed without a specifier extension (i.e unadorned %p) are hashed to give a unique identifier without leaking kernel addresses to user -space. On 64 bit machines the first 32 bits are zeroed. +space. On 64 bit machines the first 32 bits are zeroed. If you _really_ +want the address see %px below. :: @@ -106,6 +107,21 @@ For printing kernel pointers which should be hidden from unprivileged users. The behaviour of ``%pK`` depends on the ``kptr_restrict sysctl`` - see Documentation/sysctl/kernel.txt for more details. +Unmodified Addresses +==================== + +:: + + %px 01234567 or 0123456789abcdef + +For printing pointers when you _really_ want to print the address. Please +consider whether or not you are leaking sensitive information about the +Kernel layout in memory before printing pointers with %px. %px is +functionally equivalent to %lx. %px is preferred to %lx because it is more +uniquely grep'able. If, in the future, we need to modify the way the Kernel +handles printing pointers it will be nice to be able to find the call +sites. + Struct Resources ================ |