On 2019-01-18 17:12, Jens Axboe wrote:
[...]
+
+static int io_uring_create(unsigned entries, struct io_uring_params
*p,
+ bool compat)
+{
+ struct user_struct *user = NULL;
+ struct io_ring_ctx *ctx;
+ int ret;
+
+ if (entries > IORING_MAX_ENTRIES)
+ return -EINVAL;
+
+ /*
+ * Use twice as many entries for the CQ ring. It's possible for the
+ * application to drive a higher depth than the size of the SQ ring,
+ * since the sqes are only used at submission time. This allows for
+ * some flexibility in overcommitting a bit.
+ */
+ p->sq_entries = roundup_pow_of_two(entries);
+ p->cq_entries = 2 * p->sq_entries;
+
+ if (!capable(CAP_IPC_LOCK)) {
+ user = get_uid(current_user());
+ ret = __io_account_mem(user, ring_pages(p->sq_entries,
+ p->cq_entries));
+ if (ret) {
+ free_uid(user);
+ return ret;
+ }
+ }
+
+ ctx = io_ring_ctx_alloc(p);
+ if (!ctx)
+ return -ENOMEM;
Hi Jens,
It seems pages should be "unaccounted" back here and uid freed if path
with "if (!capable(CAP_IPC_LOCK))" above was taken.
But really, could please someone explain me what is wrong with
allocating
all urings in mmap() without touching RLIMIT_MEMLOCK at all? Thus all
memory will be accounted to the caller app and if app is greedy it will
be killed by oom. What I'm missing?
--
Roman
