diff options
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/Kconfig.debug | 40 | ||||
| -rw-r--r-- | lib/Makefile | 2 | ||||
| -rw-r--r-- | lib/debugobjects.c | 58 | ||||
| -rw-r--r-- | lib/halfmd4.c | 67 | ||||
| -rw-r--r-- | lib/sbitmap.c | 139 | ||||
| -rw-r--r-- | lib/timerqueue.c | 3 |
6 files changed, 205 insertions, 104 deletions
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index eb9e9a7870fa..acedbe626d47 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -716,6 +716,19 @@ source "lib/Kconfig.kmemcheck" source "lib/Kconfig.kasan" +config DEBUG_REFCOUNT + bool "Verbose refcount checks" + help + Say Y here if you want reference counters (refcount_t and kref) to + generate WARNs on dubious usage. Without this refcount_t will still + be a saturating counter and avoid Use-After-Free by turning it into + a resource leak Denial-Of-Service. + + Use of this option will increase kernel text size but will alert the + admin of potential abuse. + + If in doubt, say "N". + endmenu # "Memory Debugging" config ARCH_HAS_KCOV @@ -980,20 +993,6 @@ config DEBUG_TIMEKEEPING If unsure, say N. -config TIMER_STATS - bool "Collect kernel timers statistics" - depends on DEBUG_KERNEL && PROC_FS - help - If you say Y here, additional code will be inserted into the - timer routines to collect statistics about kernel timers being - reprogrammed. The statistics can be read from /proc/timer_stats. - The statistics collection is started by writing 1 to /proc/timer_stats, - writing 0 stops it. This feature is useful to collect information - about timer usage patterns in kernel and userspace. This feature - is lightweight if enabled in the kernel config but not activated - (it defaults to deactivated on bootup and will only be activated - if some application like powertop activates it explicitly). - config DEBUG_PREEMPT bool "Debug preemptible kernel" depends on DEBUG_KERNEL && PREEMPT && TRACE_IRQFLAGS_SUPPORT @@ -1180,6 +1179,18 @@ config LOCK_TORTURE_TEST Say M if you want these torture tests to build as a module. Say N if you are unsure. +config WW_MUTEX_SELFTEST + tristate "Wait/wound mutex selftests" + help + This option provides a kernel module that runs tests on the + on the struct ww_mutex locking API. + + It is recommended to enable DEBUG_WW_MUTEX_SLOWPATH in conjunction + with this test harness. + + Say M if you want these self tests to build as a module. + Say N if you are unsure. + endmenu # lock debugging config TRACE_IRQFLAGS @@ -1450,6 +1461,7 @@ config RCU_CPU_STALL_TIMEOUT config RCU_TRACE bool "Enable tracing for RCU" depends on DEBUG_KERNEL + default y if TREE_RCU select TRACE_CLOCK help This option provides tracing in RCU which presents stats diff --git a/lib/Makefile b/lib/Makefile index bc4073a8cd08..19ea76149a37 100644 --- a/lib/Makefile +++ b/lib/Makefile @@ -31,7 +31,7 @@ lib-$(CONFIG_HAS_DMA) += dma-noop.o lib-y += kobject.o klist.o obj-y += lockref.o -obj-y += bcd.o div64.o sort.o parser.o halfmd4.o debug_locks.o random32.o \ +obj-y += bcd.o div64.o sort.o parser.o debug_locks.o random32.o \ bust_spinlocks.o kasprintf.o bitmap.o scatterlist.o \ gcd.o lcm.o list_sort.o uuid.o flex_array.o iov_iter.o clz_ctz.o \ bsearch.o find_bit.o llist.o memweight.o kfifo.o \ diff --git a/lib/debugobjects.c b/lib/debugobjects.c index 04c1ef717fe0..8c28cbd7e104 100644 --- a/lib/debugobjects.c +++ b/lib/debugobjects.c @@ -52,9 +52,18 @@ static int debug_objects_fixups __read_mostly; static int debug_objects_warnings __read_mostly; static int debug_objects_enabled __read_mostly = CONFIG_DEBUG_OBJECTS_ENABLE_DEFAULT; - +static int debug_objects_pool_size __read_mostly + = ODEBUG_POOL_SIZE; +static int debug_objects_pool_min_level __read_mostly + = ODEBUG_POOL_MIN_LEVEL; static struct debug_obj_descr *descr_test __read_mostly; +/* + * Track numbers of kmem_cache_alloc()/free() calls done. + */ +static int debug_objects_allocated; +static int debug_objects_freed; + static void free_obj_work(struct work_struct *work); static DECLARE_WORK(debug_obj_work, free_obj_work); @@ -88,13 +97,13 @@ static void fill_pool(void) struct debug_obj *new; unsigned long flags; - if (likely(obj_pool_free >= ODEBUG_POOL_MIN_LEVEL)) + if (likely(obj_pool_free >= debug_objects_pool_min_level)) return; if (unlikely(!obj_cache)) return; - while (obj_pool_free < ODEBUG_POOL_MIN_LEVEL) { + while (obj_pool_free < debug_objects_pool_min_level) { new = kmem_cache_zalloc(obj_cache, gfp); if (!new) @@ -102,6 +111,7 @@ static void fill_pool(void) raw_spin_lock_irqsave(&pool_lock, flags); hlist_add_head(&new->node, &obj_pool); + debug_objects_allocated++; obj_pool_free++; raw_spin_unlock_irqrestore(&pool_lock, flags); } @@ -162,24 +172,39 @@ alloc_object(void *addr, struct debug_bucket *b, struct debug_obj_descr *descr) /* * workqueue function to free objects. + * + * To reduce contention on the global pool_lock, the actual freeing of + * debug objects will be delayed if the pool_lock is busy. We also free + * the objects in a batch of 4 for each lock/unlock cycle. */ +#define ODEBUG_FREE_BATCH 4 + static void free_obj_work(struct work_struct *work) { - struct debug_obj *obj; + struct debug_obj *objs[ODEBUG_FREE_BATCH]; unsigned long flags; + int i; - raw_spin_lock_irqsave(&pool_lock, flags); - while (obj_pool_free > ODEBUG_POOL_SIZE) { - obj = hlist_entry(obj_pool.first, typeof(*obj), node); - hlist_del(&obj->node); - obj_pool_free--; + if (!raw_spin_trylock_irqsave(&pool_lock, flags)) + return; + while (obj_pool_free >= debug_objects_pool_size + ODEBUG_FREE_BATCH) { + for (i = 0; i < ODEBUG_FREE_BATCH; i++) { + objs[i] = hlist_entry(obj_pool.first, + typeof(*objs[0]), node); + hlist_del(&objs[i]->node); + } + + obj_pool_free -= ODEBUG_FREE_BATCH; + debug_objects_freed += ODEBUG_FREE_BATCH; /* * We release pool_lock across kmem_cache_free() to * avoid contention on pool_lock. */ raw_spin_unlock_irqrestore(&pool_lock, flags); - kmem_cache_free(obj_cache, obj); - raw_spin_lock_irqsave(&pool_lock, flags); + for (i = 0; i < ODEBUG_FREE_BATCH; i++) + kmem_cache_free(obj_cache, objs[i]); + if (!raw_spin_trylock_irqsave(&pool_lock, flags)) + return; } raw_spin_unlock_irqrestore(&pool_lock, flags); } @@ -198,7 +223,7 @@ static void free_object(struct debug_obj *obj) * schedule work when the pool is filled and the cache is * initialized: */ - if (obj_pool_free > ODEBUG_POOL_SIZE && obj_cache) + if (obj_pool_free > debug_objects_pool_size && obj_cache) sched = 1; hlist_add_head(&obj->node, &obj_pool); obj_pool_free++; @@ -758,6 +783,8 @@ static int debug_stats_show(struct seq_file *m, void *v) seq_printf(m, "pool_min_free :%d\n", obj_pool_min_free); seq_printf(m, "pool_used :%d\n", obj_pool_used); seq_printf(m, "pool_max_used :%d\n", obj_pool_max_used); + seq_printf(m, "objs_allocated:%d\n", debug_objects_allocated); + seq_printf(m, "objs_freed :%d\n", debug_objects_freed); return 0; } @@ -1116,4 +1143,11 @@ void __init debug_objects_mem_init(void) pr_warn("out of memory.\n"); } else debug_objects_selftest(); + + /* + * Increase the thresholds for allocating and freeing objects + * according to the number of possible CPUs available in the system. + */ + debug_objects_pool_size += num_possible_cpus() * 32; + debug_objects_pool_min_level += num_possible_cpus() * 4; } diff --git a/lib/halfmd4.c b/lib/halfmd4.c deleted file mode 100644 index 137e861d9690..000000000000 --- a/lib/halfmd4.c +++ /dev/null @@ -1,67 +0,0 @@ -#include <linux/compiler.h> -#include <linux/export.h> -#include <linux/cryptohash.h> -#include <linux/bitops.h> - -/* F, G and H are basic MD4 functions: selection, majority, parity */ -#define F(x, y, z) ((z) ^ ((x) & ((y) ^ (z)))) -#define G(x, y, z) (((x) & (y)) + (((x) ^ (y)) & (z))) -#define H(x, y, z) ((x) ^ (y) ^ (z)) - -/* - * The generic round function. The application is so specific that - * we don't bother protecting all the arguments with parens, as is generally - * good macro practice, in favor of extra legibility. - * Rotation is separate from addition to prevent recomputation - */ -#define ROUND(f, a, b, c, d, x, s) \ - (a += f(b, c, d) + x, a = rol32(a, s)) -#define K1 0 -#define K2 013240474631UL -#define K3 015666365641UL - -/* - * Basic cut-down MD4 transform. Returns only 32 bits of result. - */ -__u32 half_md4_transform(__u32 buf[4], __u32 const in[8]) -{ - __u32 a = buf[0], b = buf[1], c = buf[2], d = buf[3]; - - /* Round 1 */ - ROUND(F, a, b, c, d, in[0] + K1, 3); - ROUND(F, d, a, b, c, in[1] + K1, 7); - ROUND(F, c, d, a, b, in[2] + K1, 11); - ROUND(F, b, c, d, a, in[3] + K1, 19); - ROUND(F, a, b, c, d, in[4] + K1, 3); - ROUND(F, d, a, b, c, in[5] + K1, 7); - ROUND(F, c, d, a, b, in[6] + K1, 11); - ROUND(F, b, c, d, a, in[7] + K1, 19); - - /* Round 2 */ - ROUND(G, a, b, c, d, in[1] + K2, 3); - ROUND(G, d, a, b, c, in[3] + K2, 5); - ROUND(G, c, d, a, b, in[5] + K2, 9); - ROUND(G, b, c, d, a, in[7] + K2, 13); - ROUND(G, a, b, c, d, in[0] + K2, 3); - ROUND(G, d, a, b, c, in[2] + K2, 5); - ROUND(G, c, d, a, b, in[4] + K2, 9); - ROUND(G, b, c, d, a, in[6] + K2, 13); - - /* Round 3 */ - ROUND(H, a, b, c, d, in[3] + K3, 3); - ROUND(H, d, a, b, c, in[7] + K3, 9); - ROUND(H, c, d, a, b, in[2] + K3, 11); - ROUND(H, b, c, d, a, in[6] + K3, 15); - ROUND(H, a, b, c, d, in[1] + K3, 3); - ROUND(H, d, a, b, c, in[5] + K3, 9); - ROUND(H, c, d, a, b, in[0] + K3, 11); - ROUND(H, b, c, d, a, in[4] + K3, 15); - - buf[0] += a; - buf[1] += b; - buf[2] += c; - buf[3] += d; - - return buf[1]; /* "most hashed" word */ -} -EXPORT_SYMBOL(half_md4_transform); diff --git a/lib/sbitmap.c b/lib/sbitmap.c index 2cecf05c82fd..55e11c4b2f3b 100644 --- a/lib/sbitmap.c +++ b/lib/sbitmap.c @@ -17,6 +17,7 @@ #include <linux/random.h> #include <linux/sbitmap.h> +#include <linux/seq_file.h> int sbitmap_init_node(struct sbitmap *sb, unsigned int depth, int shift, gfp_t flags, int node) @@ -180,6 +181,62 @@ unsigned int sbitmap_weight(const struct sbitmap *sb) } EXPORT_SYMBOL_GPL(sbitmap_weight); +void sbitmap_show(struct sbitmap *sb, struct seq_file *m) +{ + seq_printf(m, "depth=%u\n", sb->depth); + seq_printf(m, "busy=%u\n", sbitmap_weight(sb)); + seq_printf(m, "bits_per_word=%u\n", 1U << sb->shift); + seq_printf(m, "map_nr=%u\n", sb->map_nr); +} +EXPORT_SYMBOL_GPL(sbitmap_show); + +static inline void emit_byte(struct seq_file *m, unsigned int offset, u8 byte) +{ + if ((offset & 0xf) == 0) { + if (offset != 0) + seq_putc(m, '\n'); + seq_printf(m, "%08x:", offset); + } + if ((offset & 0x1) == 0) + seq_putc(m, ' '); + seq_printf(m, "%02x", byte); +} + +void sbitmap_bitmap_show(struct sbitmap *sb, struct seq_file *m) +{ + u8 byte = 0; + unsigned int byte_bits = 0; + unsigned int offset = 0; + int i; + + for (i = 0; i < sb->map_nr; i++) { + unsigned long word = READ_ONCE(sb->map[i].word); + unsigned int word_bits = READ_ONCE(sb->map[i].depth); + + while (word_bits > 0) { + unsigned int bits = min(8 - byte_bits, word_bits); + + byte |= (word & (BIT(bits) - 1)) << byte_bits; + byte_bits += bits; + if (byte_bits == 8) { + emit_byte(m, offset, byte); + byte = 0; + byte_bits = 0; + offset++; + } + word >>= bits; + word_bits -= bits; + } + } + if (byte_bits) { + emit_byte(m, offset, byte); + offset++; + } + if (offset) + seq_putc(m, '\n'); +} +EXPORT_SYMBOL_GPL(sbitmap_bitmap_show); + static unsigned int sbq_calc_wake_batch(unsigned int depth) { unsigned int wake_batch; @@ -239,7 +296,19 @@ EXPORT_SYMBOL_GPL(sbitmap_queue_init_node); void sbitmap_queue_resize(struct sbitmap_queue *sbq, unsigned int depth) { - sbq->wake_batch = sbq_calc_wake_batch(depth); + unsigned int wake_batch = sbq_calc_wake_batch(depth); + int i; + + if (sbq->wake_batch != wake_batch) { + WRITE_ONCE(sbq->wake_batch, wake_batch); + /* + * Pairs with the memory barrier in sbq_wake_up() to ensure that + * the batch size is updated before the wait counts. + */ + smp_mb__before_atomic(); + for (i = 0; i < SBQ_WAIT_QUEUES; i++) + atomic_set(&sbq->ws[i].wait_cnt, 1); + } sbitmap_resize(&sbq->sb, depth); } EXPORT_SYMBOL_GPL(sbitmap_queue_resize); @@ -297,20 +366,39 @@ static struct sbq_wait_state *sbq_wake_ptr(struct sbitmap_queue *sbq) static void sbq_wake_up(struct sbitmap_queue *sbq) { struct sbq_wait_state *ws; + unsigned int wake_batch; int wait_cnt; - /* Ensure that the wait list checks occur after clear_bit(). */ - smp_mb(); + /* + * Pairs with the memory barrier in set_current_state() to ensure the + * proper ordering of clear_bit()/waitqueue_active() in the waker and + * test_and_set_bit()/prepare_to_wait()/finish_wait() in the waiter. See + * the comment on waitqueue_active(). This is __after_atomic because we + * just did clear_bit() in the caller. + */ + smp_mb__after_atomic(); ws = sbq_wake_ptr(sbq); if (!ws) return; wait_cnt = atomic_dec_return(&ws->wait_cnt); - if (unlikely(wait_cnt < 0)) - wait_cnt = atomic_inc_return(&ws->wait_cnt); - if (wait_cnt == 0) { - atomic_add(sbq->wake_batch, &ws->wait_cnt); + if (wait_cnt <= 0) { + wake_batch = READ_ONCE(sbq->wake_batch); + /* + * Pairs with the memory barrier in sbitmap_queue_resize() to + * ensure that we see the batch size update before the wait + * count is reset. + */ + smp_mb__before_atomic(); + /* + * If there are concurrent callers to sbq_wake_up(), the last + * one to decrement the wait count below zero will bump it back + * up. If there is a concurrent resize, the count reset will + * either cause the cmpxchg to fail or overwrite after the + * cmpxchg. + */ + atomic_cmpxchg(&ws->wait_cnt, wait_cnt, wait_cnt + wake_batch); sbq_index_atomic_inc(&sbq->wake_index); wake_up(&ws->wait); } @@ -331,7 +419,8 @@ void sbitmap_queue_wake_all(struct sbitmap_queue *sbq) int i, wake_index; /* - * Make sure all changes prior to this are visible from other CPUs. + * Pairs with the memory barrier in set_current_state() like in + * sbq_wake_up(). */ smp_mb(); wake_index = atomic_read(&sbq->wake_index); @@ -345,3 +434,37 @@ void sbitmap_queue_wake_all(struct sbitmap_queue *sbq) } } EXPORT_SYMBOL_GPL(sbitmap_queue_wake_all); + +void sbitmap_queue_show(struct sbitmap_queue *sbq, struct seq_file *m) +{ + bool first; + int i; + + sbitmap_show(&sbq->sb, m); + + seq_puts(m, "alloc_hint={"); + first = true; + for_each_possible_cpu(i) { + if (!first) + seq_puts(m, ", "); + first = false; + seq_printf(m, "%u", *per_cpu_ptr(sbq->alloc_hint, i)); + } + seq_puts(m, "}\n"); + + seq_printf(m, "wake_batch=%u\n", sbq->wake_batch); + seq_printf(m, "wake_index=%d\n", atomic_read(&sbq->wake_index)); + + seq_puts(m, "ws={\n"); + for (i = 0; i < SBQ_WAIT_QUEUES; i++) { + struct sbq_wait_state *ws = &sbq->ws[i]; + + seq_printf(m, "\t{.wait_cnt=%d, .wait=%s},\n", + atomic_read(&ws->wait_cnt), + waitqueue_active(&ws->wait) ? "active" : "inactive"); + } + seq_puts(m, "}\n"); + + seq_printf(m, "round_robin=%d\n", sbq->round_robin); +} +EXPORT_SYMBOL_GPL(sbitmap_queue_show); diff --git a/lib/timerqueue.c b/lib/timerqueue.c index adc6ee0a5126..4a720ed4fdaf 100644 --- a/lib/timerqueue.c +++ b/lib/timerqueue.c @@ -80,8 +80,7 @@ bool timerqueue_del(struct timerqueue_head *head, struct timerqueue_node *node) if (head->next == node) { struct rb_node *rbn = rb_next(&node->node); - head->next = rbn ? - rb_entry(rbn, struct timerqueue_node, node) : NULL; + head->next = rb_entry_safe(rbn, struct timerqueue_node, node); } rb_erase(&node->node, &head->head); RB_CLEAR_NODE(&node->node); |