From 53ed2ac8fc1de6658aadae5714627ac99b9dddb0 Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Tue, 30 Jan 2024 11:34:49 -0800 Subject: soc: apple: mailbox: error pointers are negative integers In an entirely unrelated discussion where I pointed out a stupid thinko of mine, Rasmus piped up and noted that that obvious mistake already existed elsewhere in the kernel tree. An "error pointer" is the negative error value encoded as a pointer, making the whole "return error or valid pointer" use-case simple and straightforward. We use it all over the kernel. But the key here is that errors are _negative_ error numbers, not the horrid UNIX user-level model of "-1 and the value of 'errno'". The Apple mailbox driver used the positive error values, and thus just returned invalid normal pointers instead of actual errors. Of course, the reason nobody ever noticed is that the errors presumably never actually happen, so this is fixing a conceptual bug rather than an actual one. Reported-by: Rasmus Villemoes Link: https://lore.kernel.org/all/5c30afe0-f9fb-45d5-9333-dd914a1ea93a@prevas.dk/ Signed-off-by: Linus Torvalds --- drivers/soc/apple/mailbox.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'drivers/soc') diff --git a/drivers/soc/apple/mailbox.c b/drivers/soc/apple/mailbox.c index 780199bf351e..49a0955e82d6 100644 --- a/drivers/soc/apple/mailbox.c +++ b/drivers/soc/apple/mailbox.c @@ -296,14 +296,14 @@ struct apple_mbox *apple_mbox_get(struct device *dev, int index) of_node_put(args.np); if (!pdev) - return ERR_PTR(EPROBE_DEFER); + return ERR_PTR(-EPROBE_DEFER); mbox = platform_get_drvdata(pdev); if (!mbox) - return ERR_PTR(EPROBE_DEFER); + return ERR_PTR(-EPROBE_DEFER); if (!device_link_add(dev, &pdev->dev, DL_FLAG_AUTOREMOVE_CONSUMER)) - return ERR_PTR(ENODEV); + return ERR_PTR(-ENODEV); return mbox; } -- cgit v1.2.3-58-ga151