User can call select/poll system calls with a large number of assigned
file descriptors and force kernel to allocate up to several pages of memory
till end of these sleeping system calls. We have here long-living
unaccounted per-task allocations.

It makes sense to account for these allocations to restrict the host's
memory consumption from inside the memcg-limited container.

Signed-off-by: Vasily Averin <redacted>
---
 fs/select.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/fs/select.c b/fs/select.c
index 945896d..e83e563 100644
--- a/fs/select.c
+++ b/fs/select.c

@@ -655,7 +655,7 @@ int core_sys_select(int n, fd_set __user *inp, fd_set __user *outp,
                        goto out_nofds;

                alloc_size = 6 * size;
-               bits = kvmalloc(alloc_size, GFP_KERNEL);
+               bits = kvmalloc(alloc_size, GFP_KERNEL_ACCOUNT);

                if (!bits)
                        goto out_nofds;
        }

@@ -1000,7 +1000,7 @@ static int do_sys_poll(struct pollfd __user *ufds, unsigned int nfds,

                len = min(todo, POLLFD_PER_PAGE);
                walk = walk->next = kmalloc(struct_size(walk, entries, len),
-                                           GFP_KERNEL);
+                                           GFP_KERNEL_ACCOUNT);
                if (!walk) {
                        err = -ENOMEM;
                        goto out_fds;
--

1.8.3.1