From b6d7c0eb2dcbd238fa233a3a1737654e380e784a Mon Sep 17 00:00:00 2001 From: Andrzej Hajda Date: Fri, 2 Jun 2023 12:21:34 +0200 Subject: [PATCH] lib/ref_tracker: improve printing stats In case the library is tracking busy subsystem, simply printing stack for every active reference will spam log with long, hard to read, redundant stack traces. To improve readabilty following changes have been made: - reports are printed per stack_handle - log is more compact, - added display name for ref_tracker_dir - it will differentiate multiple subsystems, - stack trace is printed indented, in the same printk call, - info about dropped references is printed as well. Signed-off-by: Andrzej Hajda Reviewed-by: Andi Shyti Reviewed-by: Eric Dumazet Signed-off-by: Jakub Kicinski --- include/linux/ref_tracker.h | 9 +++- lib/ref_tracker.c | 90 ++++++++++++++++++++++++++++++++----- lib/test_ref_tracker.c | 2 +- net/core/dev.c | 2 +- net/core/net_namespace.c | 4 +- 5 files changed, 90 insertions(+), 17 deletions(-) diff --git a/include/linux/ref_tracker.h b/include/linux/ref_tracker.h index 87a92f2bec1b..19a69e7809d6 100644 --- a/include/linux/ref_tracker.h +++ b/include/linux/ref_tracker.h @@ -17,12 +17,15 @@ struct ref_tracker_dir { bool dead; struct list_head list; /* List of active trackers */ struct list_head quarantine; /* List of dead trackers */ + char name[32]; #endif }; #ifdef CONFIG_REF_TRACKER + static inline void ref_tracker_dir_init(struct ref_tracker_dir *dir, - unsigned int quarantine_count) + unsigned int quarantine_count, + const char *name) { INIT_LIST_HEAD(&dir->list); INIT_LIST_HEAD(&dir->quarantine); @@ -31,6 +34,7 @@ static inline void ref_tracker_dir_init(struct ref_tracker_dir *dir, dir->dead = false; refcount_set(&dir->untracked, 1); refcount_set(&dir->no_tracker, 1); + strscpy(dir->name, name, sizeof(dir->name)); stack_depot_init(); } @@ -51,7 +55,8 @@ int ref_tracker_free(struct ref_tracker_dir *dir, #else /* CONFIG_REF_TRACKER */ static inline void ref_tracker_dir_init(struct ref_tracker_dir *dir, - unsigned int quarantine_count) + unsigned int quarantine_count, + const char *name) { } diff --git a/lib/ref_tracker.c b/lib/ref_tracker.c index d4eb0929af8f..2ffe79c90c17 100644 --- a/lib/ref_tracker.c +++ b/lib/ref_tracker.c @@ -1,11 +1,16 @@ // SPDX-License-Identifier: GPL-2.0-or-later + +#define pr_fmt(fmt) "ref_tracker: " fmt + #include +#include #include #include #include #include #define REF_TRACKER_STACK_ENTRIES 16 +#define STACK_BUF_SIZE 1024 struct ref_tracker { struct list_head head; /* anchor into dir->list or dir->quarantine */ @@ -14,24 +19,87 @@ struct ref_tracker { depot_stack_handle_t free_stack_handle; }; +struct ref_tracker_dir_stats { + int total; + int count; + struct { + depot_stack_handle_t stack_handle; + unsigned int count; + } stacks[]; +}; + +static struct ref_tracker_dir_stats * +ref_tracker_get_stats(struct ref_tracker_dir *dir, unsigned int limit) +{ + struct ref_tracker_dir_stats *stats; + struct ref_tracker *tracker; + + stats = kmalloc(struct_size(stats, stacks, limit), + GFP_NOWAIT | __GFP_NOWARN); + if (!stats) + return ERR_PTR(-ENOMEM); + stats->total = 0; + stats->count = 0; + + list_for_each_entry(tracker, &dir->list, head) { + depot_stack_handle_t stack = tracker->alloc_stack_handle; + int i; + + ++stats->total; + for (i = 0; i < stats->count; ++i) + if (stats->stacks[i].stack_handle == stack) + break; + if (i >= limit) + continue; + if (i >= stats->count) { + stats->stacks[i].stack_handle = stack; + stats->stacks[i].count = 0; + ++stats->count; + } + ++stats->stacks[i].count; + } + + return stats; +} + void ref_tracker_dir_print_locked(struct ref_tracker_dir *dir, unsigned int display_limit) { - struct ref_tracker *tracker; - unsigned int i = 0; + struct ref_tracker_dir_stats *stats; + unsigned int i = 0, skipped; + depot_stack_handle_t stack; + char *sbuf; lockdep_assert_held(&dir->lock); - list_for_each_entry(tracker, &dir->list, head) { - if (i < display_limit) { - pr_err("leaked reference.\n"); - if (tracker->alloc_stack_handle) - stack_depot_print(tracker->alloc_stack_handle); - i++; - } else { - break; - } + if (list_empty(&dir->list)) + return; + + stats = ref_tracker_get_stats(dir, display_limit); + if (IS_ERR(stats)) { + pr_err("%s@%pK: couldn't get stats, error %pe\n", + dir->name, dir, stats); + return; } + + sbuf = kmalloc(STACK_BUF_SIZE, GFP_NOWAIT | __GFP_NOWARN); + + for (i = 0, skipped = stats->total; i < stats->count; ++i) { + stack = stats->stacks[i].stack_handle; + if (sbuf && !stack_depot_snprint(stack, sbuf, STACK_BUF_SIZE, 4)) + sbuf[0] = 0; + pr_err("%s@%pK has %d/%d users at\n%s\n", dir->name, dir, + stats->stacks[i].count, stats->total, sbuf); + skipped -= stats->stacks[i].count; + } + + if (skipped) + pr_err("%s@%pK skipped reports about %d/%d users.\n", + dir->name, dir, skipped, stats->total); + + kfree(sbuf); + + kfree(stats); } EXPORT_SYMBOL(ref_tracker_dir_print_locked); diff --git a/lib/test_ref_tracker.c b/lib/test_ref_tracker.c index 19d7dec70cc6..49970a7c96f3 100644 --- a/lib/test_ref_tracker.c +++ b/lib/test_ref_tracker.c @@ -64,7 +64,7 @@ static int __init test_ref_tracker_init(void) { int i; - ref_tracker_dir_init(&ref_dir, 100); + ref_tracker_dir_init(&ref_dir, 100, "selftest"); timer_setup(&test_ref_tracker_timer, test_ref_tracker_timer_func, 0); mod_timer(&test_ref_tracker_timer, jiffies + 1); diff --git a/net/core/dev.c b/net/core/dev.c index b3c13e041935..5ca7a133d3be 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -10630,7 +10630,7 @@ struct net_device *alloc_netdev_mqs(int sizeof_priv, const char *name, dev = PTR_ALIGN(p, NETDEV_ALIGN); dev->padded = (char *)dev - (char *)p; - ref_tracker_dir_init(&dev->refcnt_tracker, 128); + ref_tracker_dir_init(&dev->refcnt_tracker, 128, name); #ifdef CONFIG_PCPU_DEV_REFCNT dev->pcpu_refcnt = alloc_percpu(int); if (!dev->pcpu_refcnt) diff --git a/net/core/net_namespace.c b/net/core/net_namespace.c index 3e3598cd49f2..f4183c4c1ec8 100644 --- a/net/core/net_namespace.c +++ b/net/core/net_namespace.c @@ -308,7 +308,7 @@ EXPORT_SYMBOL_GPL(get_net_ns_by_id); /* init code that must occur even if setup_net() is not called. */ static __net_init void preinit_net(struct net *net) { - ref_tracker_dir_init(&net->notrefcnt_tracker, 128); + ref_tracker_dir_init(&net->notrefcnt_tracker, 128, "net notrefcnt"); } /* @@ -322,7 +322,7 @@ static __net_init int setup_net(struct net *net, struct user_namespace *user_ns) LIST_HEAD(net_exit_list); refcount_set(&net->ns.count, 1); - ref_tracker_dir_init(&net->refcnt_tracker, 128); + ref_tracker_dir_init(&net->refcnt_tracker, 128, "net refcnt"); refcount_set(&net->passive, 1); get_random_bytes(&net->hash_mix, sizeof(u32));