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fix(log): Fix wrap-around of cache generation counter

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Closes https://github.com/espressif/esp-idf/issues/6516
This commit is contained in:
Konstantin Kondrashov 2024-03-28 18:56:19 +02:00
parent 46976bdcb7
commit 1e7830e57b
1 changed files with 29 additions and 16 deletions
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45
components/log/log.c
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@ -21,11 +21,6 @@
* After that, bubble-down operation is performed to fix ordering in the * After that, bubble-down operation is performed to fix ordering in the
* min-heap. * min-heap.
* *
* The potential problem with wrap-around of cache generation counter is
* ignored for now. This will happen if someone happens to output more
* than 4 billion log entries, at which point wrap-around will not be
* the biggest problem.
*
*/ */
#include <stdbool.h> #include <stdbool.h>
@ -49,11 +44,12 @@
// Number of tags to be cached. Must be 2**n - 1, n >= 2. // Number of tags to be cached. Must be 2**n - 1, n >= 2.
#define TAG_CACHE_SIZE 31 #define TAG_CACHE_SIZE 31
#define MAX_GENERATION ((1 << 29) - 1)
typedef struct { typedef struct {
const char *tag; const char *tag;
uint32_t level : 3; uint32_t level : 3;
uint32_t generation : 29; uint32_t generation : 29; // this size should be the same in MAX_GENERATION
} cached_tag_entry_t; } cached_tag_entry_t;
typedef struct uncached_tag_entry_ { typedef struct uncached_tag_entry_ {
@ -81,6 +77,7 @@ static void heap_bubble_down(int index);
static inline void heap_swap(int i, int j); static inline void heap_swap(int i, int j);
static inline bool should_output(esp_log_level_t level_for_message, esp_log_level_t level_for_tag); static inline bool should_output(esp_log_level_t level_for_message, esp_log_level_t level_for_tag);
static inline void clear_log_level_list(void); static inline void clear_log_level_list(void);
static void fix_cache_generation_overflow(void);
vprintf_like_t esp_log_set_vprintf(vprintf_like_t func) vprintf_like_t esp_log_set_vprintf(vprintf_like_t func)
{ {
@ -238,6 +235,10 @@ static inline bool get_cached_log_level(const char *tag, esp_log_level_t *level)
s_log_cache[i].generation = s_log_cache_max_generation++; s_log_cache[i].generation = s_log_cache_max_generation++;
// Restore heap ordering // Restore heap ordering
heap_bubble_down(i); heap_bubble_down(i);
// Check for generation count wrap and fix if necessary
if (s_log_cache_max_generation == MAX_GENERATION) {
fix_cache_generation_overflow();
}
} }
return true; return true;
} }
@ -255,18 +256,30 @@ static inline void add_to_cache(const char *tag, esp_log_level_t level)
.tag = tag .tag = tag
}; };
++s_log_cache_entry_count; ++s_log_cache_entry_count;
return; } else {
// Cache is full, so we replace the oldest entry (which is at index 0
// because this is a min-heap) with the new one, and do bubble-down
// operation to restore min-heap ordering.
s_log_cache[0] = (cached_tag_entry_t) {
.tag = tag,
.level = level,
.generation = generation
};
heap_bubble_down(0);
} }
// Check for generation count wrap and fix if necessary
if (s_log_cache_max_generation == MAX_GENERATION) {
fix_cache_generation_overflow();
}
}
// Cache is full, so we replace the oldest entry (which is at index 0 static void fix_cache_generation_overflow(void)
// because this is a min-heap) with the new one, and do bubble-down {
// operation to restore min-heap ordering. // Fix generation count wrap
s_log_cache[0] = (cached_tag_entry_t) { for (uint32_t i = 0; i < s_log_cache_entry_count; ++i) {
.tag = tag, s_log_cache[i].generation = i;
.level = level, }
.generation = generation s_log_cache_max_generation = s_log_cache_entry_count;
};
heap_bubble_down(0);
} }
static inline bool get_uncached_log_level(const char *tag, esp_log_level_t *level) static inline bool get_uncached_log_level(const char *tag, esp_log_level_t *level)