Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
Merge tag 'printk-for-6.1' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux
Pull printk updates from Petr Mladek:
- Initialize pointer hashing using the system workqueue. It avoids
taking locks in printk()/vsprintf() code path
- Misc code clean up
* tag 'printk-for-6.1' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux:
printk: Mark __printk percpu data ready __ro_after_init
printk: Remove bogus comment vs. boot consoles
printk: Remove write only variable nr_ext_console_drivers
printk: Declare log_wait properly
printk: Make pr_flush() static
lib/vsprintf: Initialize vsprintf's pointer hash once the random core is ready.
lib/vsprintf: Remove static_branch_likely() from __ptr_to_hashval().
lib/vnsprintf: add const modifier for param 'bitmap'
+35
-47
-2
fs/proc/kmsg.c
-2
fs/proc/kmsg.c
-7
include/linux/printk.h
-7
include/linux/printk.h
···
169
169
#define printk_deferred_enter __printk_safe_enter
170
170
#define printk_deferred_exit __printk_safe_exit
171
171
172
-
extern bool pr_flush(int timeout_ms, bool reset_on_progress);
173
-
174
172
/*
175
173
* Please don't use printk_ratelimit(), because it shares ratelimiting state
176
174
* with all other unrelated printk_ratelimit() callsites. Instead use
···
217
219
218
220
static inline void printk_deferred_exit(void)
219
221
{
220
-
}
221
-
222
-
static inline bool pr_flush(int timeout_ms, bool reset_on_progress)
223
-
{
224
-
return true;
225
222
}
226
223
227
224
static inline int printk_ratelimit(void)
+3
include/linux/syslog.h
+3
include/linux/syslog.h
···
8
8
#ifndef _LINUX_SYSLOG_H
9
9
#define _LINUX_SYSLOG_H
10
10
11
+
#include <linux/wait.h>
12
+
11
13
/* Close the log. Currently a NOP. */
12
14
#define SYSLOG_ACTION_CLOSE 0
13
15
/* Open the log. Currently a NOP. */
···
37
35
#define SYSLOG_FROM_PROC 1
38
36
39
37
int do_syslog(int type, char __user *buf, int count, int source);
38
+
extern wait_queue_head_t log_wait;
40
39
41
40
#endif /* _LINUX_SYSLOG_H */
+4
-15
kernel/printk/printk.c
+4
-15
kernel/printk/printk.c
···
220
220
}
221
221
#endif /* CONFIG_PRINTK && CONFIG_SYSCTL */
222
222
223
-
/* Number of registered extended console drivers. */
224
-
static int nr_ext_console_drivers;
225
-
226
223
/*
227
224
* Helper macros to handle lockdep when locking/unlocking console_sem. We use
228
225
* macros instead of functions so that _RET_IP_ contains useful information.
···
430
433
* per_cpu_areas are initialised. This variable is set to true when
431
434
* it's safe to access per-CPU data.
432
435
*/
433
-
static bool __printk_percpu_data_ready __read_mostly;
436
+
static bool __printk_percpu_data_ready __ro_after_init;
434
437
435
438
bool printk_percpu_data_ready(void)
436
439
{
···
2293
2296
}
2294
2297
EXPORT_SYMBOL(_printk);
2295
2298
2299
+
static bool pr_flush(int timeout_ms, bool reset_on_progress);
2296
2300
static bool __pr_flush(struct console *con, int timeout_ms, bool reset_on_progress);
2297
2301
2298
2302
#else /* CONFIG_PRINTK */
···
2328
2330
{
2329
2331
}
2330
2332
static bool suppress_message_printing(int level) { return false; }
2333
+
static bool pr_flush(int timeout_ms, bool reset_on_progress) { return true; }
2331
2334
static bool __pr_flush(struct console *con, int timeout_ms, bool reset_on_progress) { return true; }
2332
2335
2333
2336
#endif /* CONFIG_PRINTK */
···
3185
3186
console_drivers->next = newcon;
3186
3187
}
3187
3188
3188
-
if (newcon->flags & CON_EXTENDED)
3189
-
nr_ext_console_drivers++;
3190
-
3191
3189
newcon->dropped = 0;
3192
3190
if (newcon->flags & CON_PRINTBUFFER) {
3193
3191
/* Get a consistent copy of @syslog_seq. */
···
3209
3213
if (bootcon_enabled &&
3210
3214
((newcon->flags & (CON_CONSDEV | CON_BOOT)) == CON_CONSDEV) &&
3211
3215
!keep_bootcon) {
3212
-
/* We need to iterate through all boot consoles, to make
3213
-
* sure we print everything out, before we unregister them.
3214
-
*/
3215
3216
for_each_console(con)
3216
3217
if (con->flags & CON_BOOT)
3217
3218
unregister_console(con);
···
3246
3253
3247
3254
if (res)
3248
3255
goto out_disable_unlock;
3249
-
3250
-
if (console->flags & CON_EXTENDED)
3251
-
nr_ext_console_drivers--;
3252
3256
3253
3257
/*
3254
3258
* If this isn't the last console and it has CON_CONSDEV set, we
···
3428
3438
* Context: Process context. May sleep while acquiring console lock.
3429
3439
* Return: true if all enabled printers are caught up.
3430
3440
*/
3431
-
bool pr_flush(int timeout_ms, bool reset_on_progress)
3441
+
static bool pr_flush(int timeout_ms, bool reset_on_progress)
3432
3442
{
3433
3443
return __pr_flush(NULL, timeout_ms, reset_on_progress);
3434
3444
}
3435
-
EXPORT_SYMBOL(pr_flush);
3436
3445
3437
3446
/*
3438
3447
* Delayed printk version, for scheduler-internal messages:
+28
-23
lib/vsprintf.c
+28
-23
lib/vsprintf.c
···
750
750
}
751
751
early_param("debug_boot_weak_hash", debug_boot_weak_hash_enable);
752
752
753
-
static DEFINE_STATIC_KEY_FALSE(filled_random_ptr_key);
753
+
static bool filled_random_ptr_key __read_mostly;
754
+
static siphash_key_t ptr_key __read_mostly;
755
+
static void fill_ptr_key_workfn(struct work_struct *work);
756
+
static DECLARE_DELAYED_WORK(fill_ptr_key_work, fill_ptr_key_workfn);
754
757
755
-
static void enable_ptr_key_workfn(struct work_struct *work)
758
+
static void fill_ptr_key_workfn(struct work_struct *work)
756
759
{
757
-
static_branch_enable(&filled_random_ptr_key);
760
+
if (!rng_is_initialized()) {
761
+
queue_delayed_work(system_unbound_wq, &fill_ptr_key_work, HZ * 2);
762
+
return;
763
+
}
764
+
765
+
get_random_bytes(&ptr_key, sizeof(ptr_key));
766
+
767
+
/* Pairs with smp_rmb() before reading ptr_key. */
768
+
smp_wmb();
769
+
WRITE_ONCE(filled_random_ptr_key, true);
758
770
}
771
+
772
+
static int __init vsprintf_init_hashval(void)
773
+
{
774
+
fill_ptr_key_workfn(NULL);
775
+
return 0;
776
+
}
777
+
subsys_initcall(vsprintf_init_hashval)
759
778
760
779
/* Maps a pointer to a 32 bit unique identifier. */
761
780
static inline int __ptr_to_hashval(const void *ptr, unsigned long *hashval_out)
762
781
{
763
-
static siphash_key_t ptr_key __read_mostly;
764
782
unsigned long hashval;
765
783
766
-
if (!static_branch_likely(&filled_random_ptr_key)) {
767
-
static bool filled = false;
768
-
static DEFINE_SPINLOCK(filling);
769
-
static DECLARE_WORK(enable_ptr_key_work, enable_ptr_key_workfn);
770
-
unsigned long flags;
784
+
if (!READ_ONCE(filled_random_ptr_key))
785
+
return -EBUSY;
771
786
772
-
if (!system_unbound_wq || !rng_is_initialized() ||
773
-
!spin_trylock_irqsave(&filling, flags))
774
-
return -EAGAIN;
775
-
776
-
if (!filled) {
777
-
get_random_bytes(&ptr_key, sizeof(ptr_key));
778
-
queue_work(system_unbound_wq, &enable_ptr_key_work);
779
-
filled = true;
780
-
}
781
-
spin_unlock_irqrestore(&filling, flags);
782
-
}
783
-
787
+
/* Pairs with smp_wmb() after writing ptr_key. */
788
+
smp_rmb();
784
789
785
790
#ifdef CONFIG_64BIT
786
791
hashval = (unsigned long)siphash_1u64((u64)ptr, &ptr_key);
···
1194
1189
}
1195
1190
1196
1191
static noinline_for_stack
1197
-
char *bitmap_string(char *buf, char *end, unsigned long *bitmap,
1192
+
char *bitmap_string(char *buf, char *end, const unsigned long *bitmap,
1198
1193
struct printf_spec spec, const char *fmt)
1199
1194
{
1200
1195
const int CHUNKSZ = 32;
···
1238
1233
}
1239
1234
1240
1235
static noinline_for_stack
1241
-
char *bitmap_list_string(char *buf, char *end, unsigned long *bitmap,
1236
+
char *bitmap_list_string(char *buf, char *end, const unsigned long *bitmap,
1242
1237
struct printf_spec spec, const char *fmt)
1243
1238
{
1244
1239
int nr_bits = max_t(int, spec.field_width, 0);