mirror of
https://gitlab.isc.org/isc-projects/bind9
synced 2025-08-29 13:38:26 +00:00
Convert rwlock in isc_log_t to RCU
The isc_log_t contains a isc_logconfig_t that is swapped, dereferenced or accessed its fields through a mutex. Instead of protecting it with a rwlock, use RCU.
This commit is contained in:
Aydın Mercan
parent
0a7b0c3896
commit
a911949ebc
102
lib/isc/log.c
102
lib/isc/log.c
@ -30,11 +30,11 @@
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#include <isc/log.h>
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#include <isc/magic.h>
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#include <isc/mem.h>
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#include <isc/rwlock.h>
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#include <isc/stdio.h>
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#include <isc/string.h>
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#include <isc/thread.h>
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#include <isc/time.h>
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#include <isc/urcu.h>
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#include <isc/util.h>
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#define LCTX_MAGIC ISC_MAGIC('L', 'c', 't', 'x')
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@ -143,8 +143,7 @@ struct isc_log {
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isc_logmodule_t *modules;
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unsigned int module_count;
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atomic_int_fast32_t debug_level;
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isc_rwlock_t lcfg_rwl;
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/* Locked by isc_log lcfg_rwl */
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/* RCU-protected pointer */
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isc_logconfig_t *logconfig;
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isc_mutex_t lock;
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/* Locked by isc_log lock. */
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@ -254,19 +253,6 @@ isc_log_create(isc_mem_t *mctx, isc_log_t **lctxp, isc_logconfig_t **lcfgp) {
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REQUIRE(lcfgp == NULL || *lcfgp == NULL);
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lctx = isc_mem_get(mctx, sizeof(*lctx));
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lctx->mctx = NULL;
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isc_mem_attach(mctx, &lctx->mctx);
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lctx->categories = NULL;
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lctx->category_count = 0;
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lctx->modules = NULL;
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lctx->module_count = 0;
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atomic_init(&lctx->debug_level, 0);
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ISC_LIST_INIT(lctx->messages);
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isc_mutex_init(&lctx->lock);
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isc_rwlock_init(&lctx->lcfg_rwl);
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/*
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* Normally setting the magic number is the last step done
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* in a creation function, but a valid log context is needed
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@ -274,12 +260,16 @@ isc_log_create(isc_mem_t *mctx, isc_log_t **lctxp, isc_logconfig_t **lcfgp) {
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* If either fails, the lctx is destroyed and not returned
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* to the caller.
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*/
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lctx->magic = LCTX_MAGIC;
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*lctx = (isc_log_t){
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.magic = LCTX_MAGIC,
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.messages = ISC_LIST_INITIALIZER,
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};
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isc_mem_attach(mctx, &lctx->mctx);
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isc_mutex_init(&lctx->lock);
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isc_log_registercategories(lctx, isc_categories);
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isc_log_registermodules(lctx, isc_modules);
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isc_logconfig_create(lctx, &lcfg);
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sync_channellist(lcfg);
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lctx->logconfig = lcfg;
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@ -302,15 +292,12 @@ isc_logconfig_create(isc_log_t *lctx, isc_logconfig_t **lcfgp) {
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lcfg = isc_mem_get(lctx->mctx, sizeof(*lcfg));
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lcfg->lctx = lctx;
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lcfg->channellists = NULL;
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lcfg->channellist_count = 0;
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lcfg->duplicate_interval = 0;
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lcfg->highest_level = level;
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lcfg->tag = NULL;
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lcfg->dynamic = false;
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ISC_LIST_INIT(lcfg->channels);
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lcfg->magic = LCFG_MAGIC;
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*lcfg = (isc_logconfig_t){
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.magic = LCFG_MAGIC,
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.lctx = lctx,
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.channels = ISC_LIST_INITIALIZER,
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.highest_level = level,
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};
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/*
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* Create the default channels:
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@ -320,11 +307,11 @@ isc_logconfig_create(isc_log_t *lctx, isc_logconfig_t **lcfgp) {
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isc_log_createchannel(lcfg, "default_syslog", ISC_LOG_TOSYSLOG, level,
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&destination, 0);
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destination.file.stream = stderr;
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destination.file.name = NULL;
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destination.file.versions = ISC_LOG_ROLLNEVER;
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destination.file.suffix = isc_log_rollsuffix_increment;
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destination.file.maximum_size = 0;
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destination.file = (isc_logfile_t){
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.stream = stderr,
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.versions = ISC_LOG_ROLLNEVER,
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.suffix = isc_log_rollsuffix_increment,
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};
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isc_log_createchannel(lcfg, "default_stderr", ISC_LOG_TOFILEDESC, level,
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&destination, ISC_LOG_PRINTTIME);
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@ -335,11 +322,11 @@ isc_logconfig_create(isc_log_t *lctx, isc_logconfig_t **lcfgp) {
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*/
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default_channel.channel = ISC_LIST_HEAD(lcfg->channels);
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destination.file.stream = stderr;
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destination.file.name = NULL;
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destination.file.versions = ISC_LOG_ROLLNEVER;
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destination.file.suffix = isc_log_rollsuffix_increment;
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destination.file.maximum_size = 0;
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destination.file = (isc_logfile_t){
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.stream = stderr,
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.versions = ISC_LOG_ROLLNEVER,
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.suffix = isc_log_rollsuffix_increment,
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};
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isc_log_createchannel(lcfg, "default_debug", ISC_LOG_TOFILEDESC,
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ISC_LOG_DYNAMIC, &destination, ISC_LOG_PRINTTIME);
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@ -364,11 +351,9 @@ isc_logconfig_use(isc_log_t *lctx, isc_logconfig_t *lcfg) {
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*/
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sync_channellist(lcfg);
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WRLOCK(&lctx->lcfg_rwl);
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old_cfg = lctx->logconfig;
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lctx->logconfig = lcfg;
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old_cfg = rcu_xchg_pointer(&lctx->logconfig, lcfg);
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sync_highest_level(lctx, lcfg);
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WRUNLOCK(&lctx->lcfg_rwl);
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synchronize_rcu();
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isc_logconfig_destroy(&old_cfg);
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}
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@ -391,16 +376,13 @@ isc_log_destroy(isc_log_t **lctxp) {
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atomic_store_release(&lctx->highest_level, 0);
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atomic_store_release(&lctx->dynamic, false);
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WRLOCK(&lctx->lcfg_rwl);
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lcfg = lctx->logconfig;
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lctx->logconfig = NULL;
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WRUNLOCK(&lctx->lcfg_rwl);
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lcfg = rcu_xchg_pointer(&lctx->logconfig, NULL);
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synchronize_rcu();
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if (lcfg != NULL) {
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isc_logconfig_destroy(&lcfg);
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}
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isc_rwlock_destroy(&lctx->lcfg_rwl);
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isc_mutex_destroy(&lctx->lock);
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while ((message = ISC_LIST_HEAD(lctx->messages)) != NULL) {
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@ -440,9 +422,9 @@ isc_logconfig_destroy(isc_logconfig_t **lcfgp) {
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*/
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REQUIRE(lcfg->lctx != NULL);
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RDLOCK(&lcfg->lctx->lcfg_rwl);
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REQUIRE(lcfg->lctx->logconfig != lcfg);
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RDUNLOCK(&lcfg->lctx->lcfg_rwl);
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rcu_read_lock();
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REQUIRE(rcu_dereference(lcfg->lctx->logconfig) != lcfg);
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rcu_read_unlock();
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mctx = lcfg->lctx->mctx;
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@ -756,9 +738,11 @@ isc_log_usechannel(isc_logconfig_t *lcfg, const char *name,
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/*
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* Update the highest logging level, if the current lcfg is in use.
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*/
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if (lcfg->lctx->logconfig == lcfg) {
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rcu_read_lock();
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if (rcu_dereference(lcfg->lctx->logconfig) == lcfg) {
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sync_highest_level(lctx, lcfg);
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}
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rcu_read_unlock();
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return (ISC_R_SUCCESS);
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}
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@ -825,8 +809,8 @@ isc_log_setdebuglevel(isc_log_t *lctx, unsigned int level) {
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* Close ISC_LOG_DEBUGONLY channels if level is zero.
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*/
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if (level == 0) {
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RDLOCK(&lctx->lcfg_rwl);
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isc_logconfig_t *lcfg = lctx->logconfig;
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rcu_read_lock();
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isc_logconfig_t *lcfg = rcu_dereference(lctx->logconfig);
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if (lcfg != NULL) {
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LOCK(&lctx->lock);
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for (isc_logchannel_t *channel =
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@ -844,7 +828,7 @@ isc_log_setdebuglevel(isc_log_t *lctx, unsigned int level) {
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}
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UNLOCK(&lctx->lock);
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}
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RDUNLOCK(&lctx->lcfg_rwl);
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rcu_read_unlock();
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}
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}
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@ -903,8 +887,8 @@ void
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isc_log_closefilelogs(isc_log_t *lctx) {
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REQUIRE(VALID_CONTEXT(lctx));
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RDLOCK(&lctx->lcfg_rwl);
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isc_logconfig_t *lcfg = lctx->logconfig;
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rcu_read_lock();
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isc_logconfig_t *lcfg = rcu_dereference(lctx->logconfig);
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if (lcfg != NULL) {
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LOCK(&lctx->lock);
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for (isc_logchannel_t *channel = ISC_LIST_HEAD(lcfg->channels);
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@ -919,7 +903,7 @@ isc_log_closefilelogs(isc_log_t *lctx) {
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}
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UNLOCK(&lctx->lock);
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}
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RDUNLOCK(&lctx->lcfg_rwl);
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rcu_read_unlock();
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}
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/****
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@ -1521,12 +1505,12 @@ isc_log_doit(isc_log_t *lctx, isc_logcategory_t *category,
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iso8601l_string[0] = '\0';
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iso8601z_string[0] = '\0';
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RDLOCK(&lctx->lcfg_rwl);
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rcu_read_lock();
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LOCK(&lctx->lock);
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lctx->buffer[0] = '\0';
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isc_logconfig_t *lcfg = lctx->logconfig;
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isc_logconfig_t *lcfg = rcu_dereference(lctx->logconfig);
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category_channels = ISC_LIST_HEAD(lcfg->channellists[category->id]);
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@ -1877,7 +1861,7 @@ isc_log_doit(isc_log_t *lctx, isc_logcategory_t *category,
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unlock:
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UNLOCK(&lctx->lock);
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RDUNLOCK(&lctx->lcfg_rwl);
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rcu_read_unlock();
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}
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void
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