[ Upstream commit 044175a06706d516aa42874bb44dbbfc3c4d20eb ]
When the umem is cleaned up, the task that created it might already be gone. If the task was gone, the xdp_umem_release function did not free the pages member of struct xdp_umem.
It turned out that the task lookup was not needed at all; The code was a left-over when we moved from task accounting to user accounting [1].
This patch fixes the memory leak by removing the task lookup logic completely.
[1] https://lore.kernel.org/netdev/20180131135356.19134-3-bjorn.topel@gmail.com/
Link: https://lore.kernel.org/netdev/c1cb2ca8-6a14-3980-8672-f3de0bb38dfd@suse.cz/ Fixes: c0c77d8fb787 ("xsk: add user memory registration support sockopt") Reported-by: Jiri Slaby jslaby@suse.cz Signed-off-by: Björn Töpel bjorn.topel@intel.com Signed-off-by: Daniel Borkmann daniel@iogearbox.net Signed-off-by: Sasha Levin (Microsoft) sashal@kernel.org --- include/net/xdp_sock.h | 1 - net/xdp/xdp_umem.c | 19 +------------------ 2 files changed, 1 insertion(+), 19 deletions(-)
diff --git a/include/net/xdp_sock.h b/include/net/xdp_sock.h index 13acb9803a6d..05d39e579953 100644 --- a/include/net/xdp_sock.h +++ b/include/net/xdp_sock.h @@ -36,7 +36,6 @@ struct xdp_umem { u32 headroom; u32 chunk_size_nohr; struct user_struct *user; - struct pid *pid; unsigned long address; refcount_t users; struct work_struct work; diff --git a/net/xdp/xdp_umem.c b/net/xdp/xdp_umem.c index 37e1fe180769..9c767c68ed3a 100644 --- a/net/xdp/xdp_umem.c +++ b/net/xdp/xdp_umem.c @@ -189,9 +189,6 @@ static void xdp_umem_unaccount_pages(struct xdp_umem *umem)
static void xdp_umem_release(struct xdp_umem *umem) { - struct task_struct *task; - struct mm_struct *mm; - xdp_umem_clear_dev(umem);
if (umem->fq) { @@ -208,21 +205,10 @@ static void xdp_umem_release(struct xdp_umem *umem)
xdp_umem_unpin_pages(umem);
- task = get_pid_task(umem->pid, PIDTYPE_PID); - put_pid(umem->pid); - if (!task) - goto out; - mm = get_task_mm(task); - put_task_struct(task); - if (!mm) - goto out; - - mmput(mm); kfree(umem->pages); umem->pages = NULL;
xdp_umem_unaccount_pages(umem); -out: kfree(umem); }
@@ -351,7 +337,6 @@ static int xdp_umem_reg(struct xdp_umem *umem, struct xdp_umem_reg *mr) if (size_chk < 0) return -EINVAL;
- umem->pid = get_task_pid(current, PIDTYPE_PID); umem->address = (unsigned long)addr; umem->chunk_mask = ~((u64)chunk_size - 1); umem->size = size; @@ -367,7 +352,7 @@ static int xdp_umem_reg(struct xdp_umem *umem, struct xdp_umem_reg *mr)
err = xdp_umem_account_pages(umem); if (err) - goto out; + return err;
err = xdp_umem_pin_pages(umem); if (err) @@ -386,8 +371,6 @@ static int xdp_umem_reg(struct xdp_umem *umem, struct xdp_umem_reg *mr)
out_account: xdp_umem_unaccount_pages(umem); -out: - put_pid(umem->pid); return err; }