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authorDavid S. Miller <davem@davemloft.net>2020-08-21 12:54:50 -0700
committerDavid S. Miller <davem@davemloft.net>2020-08-21 12:54:50 -0700
commit4af7b32f84aa4cd60e39b355bc8a1eab6cd8d8a4 (patch)
tree083be545074f0520c7f69ab01e91707c0b41182a /kernel
parent774d977abfd024e6f73484544b9abe5a5cd62de7 (diff)
parentb16fc097bc283184cde40e5b30d15705e1590410 (diff)
Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf
Alexei Starovoitov says: ==================== pull-request: bpf 2020-08-21 The following pull-request contains BPF updates for your *net* tree. We've added 11 non-merge commits during the last 5 day(s) which contain a total of 12 files changed, 78 insertions(+), 24 deletions(-). The main changes are: 1) three fixes in BPF task iterator logic, from Yonghong. 2) fix for compressed dwarf sections in vmlinux, from Jiri. 3) fix xdp attach regression, from Andrii. ==================== Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/bpf/bpf_iter.c15
-rw-r--r--kernel/bpf/task_iter.c6
2 files changed, 18 insertions, 3 deletions
diff --git a/kernel/bpf/bpf_iter.c b/kernel/bpf/bpf_iter.c
index b6715964b685..8faa2ce89396 100644
--- a/kernel/bpf/bpf_iter.c
+++ b/kernel/bpf/bpf_iter.c
@@ -67,6 +67,9 @@ static void bpf_iter_done_stop(struct seq_file *seq)
iter_priv->done_stop = true;
}
+/* maximum visited objects before bailing out */
+#define MAX_ITER_OBJECTS 1000000
+
/* bpf_seq_read, a customized and simpler version for bpf iterator.
* no_llseek is assumed for this file.
* The following are differences from seq_read():
@@ -79,7 +82,7 @@ static ssize_t bpf_seq_read(struct file *file, char __user *buf, size_t size,
{
struct seq_file *seq = file->private_data;
size_t n, offs, copied = 0;
- int err = 0;
+ int err = 0, num_objs = 0;
void *p;
mutex_lock(&seq->lock);
@@ -135,6 +138,7 @@ static ssize_t bpf_seq_read(struct file *file, char __user *buf, size_t size,
while (1) {
loff_t pos = seq->index;
+ num_objs++;
offs = seq->count;
p = seq->op->next(seq, p, &seq->index);
if (pos == seq->index) {
@@ -153,6 +157,15 @@ static ssize_t bpf_seq_read(struct file *file, char __user *buf, size_t size,
if (seq->count >= size)
break;
+ if (num_objs >= MAX_ITER_OBJECTS) {
+ if (offs == 0) {
+ err = -EAGAIN;
+ seq->op->stop(seq, p);
+ goto done;
+ }
+ break;
+ }
+
err = seq->op->show(seq, p);
if (err > 0) {
bpf_iter_dec_seq_num(seq);
diff --git a/kernel/bpf/task_iter.c b/kernel/bpf/task_iter.c
index 232df29793e9..99af4cea1102 100644
--- a/kernel/bpf/task_iter.c
+++ b/kernel/bpf/task_iter.c
@@ -29,8 +29,9 @@ static struct task_struct *task_seq_get_next(struct pid_namespace *ns,
rcu_read_lock();
retry:
- pid = idr_get_next(&ns->idr, tid);
+ pid = find_ge_pid(*tid, ns);
if (pid) {
+ *tid = pid_nr_ns(pid, ns);
task = get_pid_task(pid, PIDTYPE_PID);
if (!task) {
++*tid;
@@ -178,10 +179,11 @@ again:
f = fcheck_files(curr_files, curr_fd);
if (!f)
continue;
+ if (!get_file_rcu(f))
+ continue;
/* set info->fd */
info->fd = curr_fd;
- get_file(f);
rcu_read_unlock();
return f;
}