[ 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@xxxxxxxxx/ Link: https://lore.kernel.org/netdev/c1cb2ca8-6a14-3980-8672-f3de0bb38dfd@xxxxxxx/ Fixes: c0c77d8fb787 ("xsk: add user memory registration support sockopt") Reported-by: Jiri Slaby <jslaby@xxxxxxx> Signed-off-by: Björn Töpel <bjorn.topel@xxxxxxxxx> Signed-off-by: Daniel Borkmann <daniel@xxxxxxxxxxxxx> Signed-off-by: Sasha Levin (Microsoft) <sashal@xxxxxxxxxx> --- 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 7161856bcf9c..c2c10cc9ffa0 100644 --- a/include/net/xdp_sock.h +++ b/include/net/xdp_sock.h @@ -34,7 +34,6 @@ 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 bfe2dbea480b..a3b037fbfecd 100644 --- a/net/xdp/xdp_umem.c +++ b/net/xdp/xdp_umem.c @@ -152,9 +152,6 @@ 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) { @@ -169,21 +166,10 @@ 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); } @@ -312,7 +298,6 @@ 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->props.chunk_mask = ~((u64)chunk_size - 1); umem->props.size = size; @@ -328,7 +313,7 @@ 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) @@ -347,8 +332,6 @@ 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; } -- 2.19.1
