| From | Ben Hutchings <> | Date | Sun, 03 Feb 2019 14:45:08 +0100 | Subject | [PATCH 3.16 186/305] uio: Fix an Oops on load |
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3.16.63-rc1 review patch. If anyone has any objections, please let me know.
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From: Dan Carpenter <dan.carpenter@oracle.com>
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 <Mathias.Thore@infinera.com> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Tested-by: Mathias Thore <Mathias.Thore@infinera.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> [bwh: Backported to 3.16: adjust context] Signed-off-by: Ben Hutchings <ben@decadent.org.uk> --- drivers/uio/uio.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-)
--- a/drivers/uio/uio.c +++ b/drivers/uio/uio.c @@ -852,14 +852,17 @@ int __uio_register_device(struct module if (ret) goto err_uio_dev_add_attributes; + info->uio_dev = idev; + if (info->irq && (info->irq != UIO_IRQ_CUSTOM)) { ret = devm_request_irq(idev->dev, 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:
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