From b4de4b603110a3189bb494bc75b7dd4c63638900 Mon Sep 17 00:00:00 2001 From: Dan Carpenter Date: Fri, 26 Oct 2018 10:19:51 +0300 Subject: [PATCH] uio: Fix an Oops on load commit 432798195bbce1f8cd33d1c0284d0538835e25fb upstream. I was trying to solve a double free but I introduced a more serious NULL dereference bug. The problem is that if there is an IRQ which triggers immediately, then we need "info->uio_dev" but it's not set yet. This patch puts the original initialization back to how it was and just sets info->uio_dev to NULL on the error path so it should solve both the Oops and the double free. Fixes: f019f07ecf6a ("uio: potential double frees if __uio_register_device() fails") Reported-by: Mathias Thore Signed-off-by: Dan Carpenter Tested-by: Mathias Thore Signed-off-by: Greg Kroah-Hartman [bwh: Backported to 3.16: adjust context] Signed-off-by: Ben Hutchings --- drivers/uio/uio.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/drivers/uio/uio.c b/drivers/uio/uio.c index fa560419117d..a0c8f32f7a60 100644 --- a/drivers/uio/uio.c +++ b/drivers/uio/uio.c @@ -849,14 +849,17 @@ int __uio_register_device(struct module *owner, if (ret) goto err_uio_dev_add_attributes; + info->uio_dev = idev; + if (info->irq && (info->irq != UIO_IRQ_CUSTOM)) { ret = request_irq(info->irq, uio_interrupt, info->irq_flags, info->name, idev); - if (ret) + if (ret) { + info->uio_dev = NULL; goto err_request_irq; + } } - info->uio_dev = idev; return 0; err_request_irq: