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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2021-02-22 11:04:36 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2021-02-22 11:04:36 -0800 |
| commit | b2bec7d8a42a3885d525e821d9354b6b08fd6adf (patch) | |
| tree | 8198d77e5b2fb8fc645ae42662b93a575910a032 /Documentation/admin-guide | |
| parent | 783955f03de770e94a1200b8f719975f8768e76c (diff) | |
| parent | 16182ac1f02c8a5fc9753f9b8b5f3ef8c01707d8 (diff) | |
Merge tag 'printk-for-5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux
Pull printk updates from Petr Mladek:
- New "no_hash_pointers" kernel parameter causes that %p shows raw
pointer values instead of hashed ones. It is intended only for
debugging purposes. Misuse is prevented by a fat warning message that
is inspired by trace_printk().
- Prevent a possible deadlock when flushing printk_safe buffers during
panic().
- Fix performance regression caused by the lockless printk ringbuffer.
It was visible with huge log buffer and long messages.
- Documentation fix-up.
* tag 'printk-for-5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux:
lib/vsprintf: no_hash_pointers prints all addresses as unhashed
kselftest: add support for skipped tests
lib: use KSTM_MODULE_GLOBALS macro in kselftest drivers
printk: avoid prb_first_valid_seq() where possible
printk: fix deadlock when kernel panic
printk: rectify kernel-doc for prb_rec_init_wr()
Diffstat (limited to 'Documentation/admin-guide')
| -rw-r--r-- | Documentation/admin-guide/kernel-parameters.txt | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 52f8233f8bb8..8b5f717b8c8c 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -3293,6 +3293,21 @@ in certain environments such as networked servers or real-time systems. + no_hash_pointers + Force pointers printed to the console or buffers to be + unhashed. By default, when a pointer is printed via %p + format string, that pointer is "hashed", i.e. obscured + by hashing the pointer value. This is a security feature + that hides actual kernel addresses from unprivileged + users, but it also makes debugging the kernel more + difficult since unequal pointers can no longer be + compared. However, if this command-line option is + specified, then all normal pointers will have their true + value printed. Pointers printed via %pK may still be + hashed. This option should only be specified when + debugging the kernel. Please do not use on production + kernels. + nohibernate [HIBERNATION] Disable hibernation and resume. nohz= [KNL] Boottime enable/disable dynamic ticks |