diff options
| -rw-r--r-- | include/linux/uprobes.h | 10 | ||||
| -rw-r--r-- | kernel/events/uprobes.c | 72 |
2 files changed, 45 insertions, 37 deletions
diff --git a/include/linux/uprobes.h b/include/linux/uprobes.h index e0a4c2082245..1d449978558d 100644 --- a/include/linux/uprobes.h +++ b/include/linux/uprobes.h @@ -154,12 +154,18 @@ struct return_instance { unsigned long stack; /* stack pointer */ unsigned long orig_ret_vaddr; /* original return address */ bool chained; /* true, if instance is nested */ - int consumers_cnt; + int cons_cnt; /* total number of session consumers */ struct return_instance *next; /* keep as stack */ struct rcu_head rcu; - struct return_consumer consumers[] __counted_by(consumers_cnt); + /* singular pre-allocated return_consumer instance for common case */ + struct return_consumer consumer; + /* + * extra return_consumer instances for rare cases of multiple session consumers, + * contains (cons_cnt - 1) elements + */ + struct return_consumer *extra_consumers; } ____cacheline_aligned; enum rp_check { diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c index daf4314961ab..6beac52239be 100644 --- a/kernel/events/uprobes.c +++ b/kernel/events/uprobes.c @@ -1899,6 +1899,7 @@ static struct return_instance *free_ret_instance(struct return_instance *ri, boo hprobe_finalize(&ri->hprobe, hstate); } + kfree(ri->extra_consumers); kfree_rcu(ri, rcu); return next; } @@ -1974,32 +1975,34 @@ static struct uprobe_task *get_utask(void) return current->utask; } -static size_t ri_size(int consumers_cnt) -{ - struct return_instance *ri; - - return sizeof(*ri) + sizeof(ri->consumers[0]) * consumers_cnt; -} - -#define DEF_CNT 4 - static struct return_instance *alloc_return_instance(void) { struct return_instance *ri; - ri = kzalloc(ri_size(DEF_CNT), GFP_KERNEL); + ri = kzalloc(sizeof(*ri), GFP_KERNEL); if (!ri) return ZERO_SIZE_PTR; - ri->consumers_cnt = DEF_CNT; return ri; } static struct return_instance *dup_return_instance(struct return_instance *old) { - size_t size = ri_size(old->consumers_cnt); + struct return_instance *ri; + + ri = kmemdup(old, sizeof(*ri), GFP_KERNEL); + + if (unlikely(old->cons_cnt > 1)) { + ri->extra_consumers = kmemdup(old->extra_consumers, + sizeof(ri->extra_consumers[0]) * (old->cons_cnt - 1), + GFP_KERNEL); + if (!ri->extra_consumers) { + kfree(ri); + return NULL; + } + } - return kmemdup(old, size, GFP_KERNEL); + return ri; } static int dup_utask(struct task_struct *t, struct uprobe_task *o_utask) @@ -2369,25 +2372,28 @@ static struct uprobe *find_active_uprobe_rcu(unsigned long bp_vaddr, int *is_swb return uprobe; } -static struct return_instance* -push_consumer(struct return_instance *ri, int idx, __u64 id, __u64 cookie) +static struct return_instance *push_consumer(struct return_instance *ri, __u64 id, __u64 cookie) { + struct return_consumer *ric; + if (unlikely(ri == ZERO_SIZE_PTR)) return ri; - if (unlikely(idx >= ri->consumers_cnt)) { - struct return_instance *old_ri = ri; - - ri->consumers_cnt += DEF_CNT; - ri = krealloc(old_ri, ri_size(old_ri->consumers_cnt), GFP_KERNEL); - if (!ri) { - kfree(old_ri); + if (unlikely(ri->cons_cnt > 0)) { + ric = krealloc(ri->extra_consumers, sizeof(*ric) * ri->cons_cnt, GFP_KERNEL); + if (!ric) { + kfree(ri->extra_consumers); + kfree_rcu(ri, rcu); return ZERO_SIZE_PTR; } + ri->extra_consumers = ric; } - ri->consumers[idx].id = id; - ri->consumers[idx].cookie = cookie; + ric = likely(ri->cons_cnt == 0) ? &ri->consumer : &ri->extra_consumers[ri->cons_cnt - 1]; + ric->id = id; + ric->cookie = cookie; + + ri->cons_cnt++; return ri; } @@ -2395,14 +2401,17 @@ static struct return_consumer * return_consumer_find(struct return_instance *ri, int *iter, int id) { struct return_consumer *ric; - int idx = *iter; + int idx; - for (ric = &ri->consumers[idx]; idx < ri->consumers_cnt; idx++, ric++) { + for (idx = *iter; idx < ri->cons_cnt; idx++) + { + ric = likely(idx == 0) ? &ri->consumer : &ri->extra_consumers[idx - 1]; if (ric->id == id) { *iter = idx + 1; return ric; } } + return NULL; } @@ -2416,7 +2425,6 @@ static void handler_chain(struct uprobe *uprobe, struct pt_regs *regs) struct uprobe_consumer *uc; bool has_consumers = false, remove = true; struct return_instance *ri = NULL; - int push_idx = 0; current->utask->auprobe = &uprobe->arch; @@ -2441,18 +2449,12 @@ static void handler_chain(struct uprobe *uprobe, struct pt_regs *regs) ri = alloc_return_instance(); if (session) - ri = push_consumer(ri, push_idx++, uc->id, cookie); + ri = push_consumer(ri, uc->id, cookie); } current->utask->auprobe = NULL; - if (!ZERO_OR_NULL_PTR(ri)) { - /* - * The push_idx value has the final number of return consumers, - * and ri->consumers_cnt has number of allocated consumers. - */ - ri->consumers_cnt = push_idx; + if (!ZERO_OR_NULL_PTR(ri)) prepare_uretprobe(uprobe, regs, ri); - } if (remove && has_consumers) { down_read(&uprobe->register_rwsem); |