This reverts commit 80e846398c695dc3d0d2eac6da91772ff2aade65. Let's see what CI says about reverting this 4 ~ 5 years old commit. We shouldn't be in the business of changing perf/core in our "for CI" drm branch.
Signed-off-by: Lucas De Marchi <[email protected]> --- kernel/events/core.c | 49 ++++++++++++++++++++++---------------------- 1 file changed, 24 insertions(+), 25 deletions(-) diff --git a/kernel/events/core.c b/kernel/events/core.c index bf5b8fc8979e..ac5e7c683526 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -5729,16 +5729,20 @@ static int __perf_read_group_add(struct perf_event *leader, } static int perf_read_group(struct perf_event *event, - u64 read_format, char __user *buf, - u64 *values) + u64 read_format, char __user *buf) { struct perf_event *leader = event->group_leader, *child; struct perf_event_context *ctx = leader->ctx; int ret; + u64 *values; lockdep_assert_held(&ctx->mutex); - *values = 1 + leader->nr_siblings; + values = kzalloc(event->read_size, GFP_KERNEL); + if (!values) + return -ENOMEM; + + values[0] = 1 + leader->nr_siblings; mutex_lock(&leader->child_mutex); @@ -5752,17 +5756,25 @@ static int perf_read_group(struct perf_event *event, goto unlock; } + mutex_unlock(&leader->child_mutex); + ret = event->read_size; + if (copy_to_user(buf, values, event->read_size)) + ret = -EFAULT; + goto out; + unlock: mutex_unlock(&leader->child_mutex); +out: + kfree(values); return ret; } static int perf_read_one(struct perf_event *event, - u64 read_format, char __user *buf, - u64 *values) + u64 read_format, char __user *buf) { u64 enabled, running; + u64 values[5]; int n = 0; values[n++] = __perf_event_read_value(event, &enabled, &running); @@ -5775,6 +5787,9 @@ static int perf_read_one(struct perf_event *event, if (read_format & PERF_FORMAT_LOST) values[n++] = atomic64_read(&event->lost_samples); + if (copy_to_user(buf, values, n * sizeof(u64))) + return -EFAULT; + return n * sizeof(u64); } @@ -5795,8 +5810,7 @@ static bool is_event_hup(struct perf_event *event) * Read the performance event - simple non blocking version for now */ static ssize_t -__perf_read(struct perf_event *event, char __user *buf, - size_t count, u64 *values) +__perf_read(struct perf_event *event, char __user *buf, size_t count) { u64 read_format = event->attr.read_format; int ret; @@ -5814,9 +5828,9 @@ __perf_read(struct perf_event *event, char __user *buf, WARN_ON_ONCE(event->ctx->parent_ctx); if (read_format & PERF_FORMAT_GROUP) - ret = perf_read_group(event, read_format, buf, values); + ret = perf_read_group(event, read_format, buf); else - ret = perf_read_one(event, read_format, buf, values); + ret = perf_read_one(event, read_format, buf); return ret; } @@ -5826,31 +5840,16 @@ perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) { struct perf_event *event = file->private_data; struct perf_event_context *ctx; - u64 stack_values[8]; - u64 *values; int ret; ret = security_perf_event_read(event); if (ret) return ret; - if (event->read_size <= sizeof(stack_values)) - values = memset(stack_values, 0, event->read_size); - else - values = kzalloc(event->read_size, GFP_KERNEL); - if (!values) - return -ENOMEM; - ctx = perf_event_ctx_lock(event); - ret = __perf_read(event, buf, count, values); + ret = __perf_read(event, buf, count); perf_event_ctx_unlock(event, ctx); - if (ret > 0 && copy_to_user(buf, values, ret)) - ret = -EFAULT; - - if (values != stack_values) - kfree(values); - return ret; } -- 2.47.0
