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Message-Id: <20240426110215.3361-1-hdanton@sina.com>
Date: Fri, 26 Apr 2024 19:02:15 +0800
From: Hillf Danton <hdanton@...a.com>
To: syzbot <syzbot+159077b1355b8cd72757@...kaller.appspotmail.com>
Cc: linux-kernel@...r.kernel.org,
syzkaller-bugs@...glegroups.com
Subject: Re: [syzbot] [input?] [ext4?] possible deadlock in uinput_request_submit
On Thu, 25 Apr 2024 21:42:26 -0700
> syzbot found the following issue on:
>
> HEAD commit: 7b4f2bc91c15 Add linux-next specific files for 20240418
> git tree: linux-next
> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=14b59430980000
#syz test https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git 7b4f2bc91c15
--- x/drivers/input/misc/uinput.c
+++ y/drivers/input/misc/uinput.c
@@ -311,8 +311,11 @@ static int uinput_create_device(struct u
struct input_dev *dev = udev->dev;
int error, nslot;
+ lockdep_assert_held(&udev->mutex);
+
if (udev->state != UIST_SETUP_COMPLETE) {
printk(KERN_DEBUG "%s: write device info first\n", UINPUT_NAME);
+ mutex_unlock(&udev->mutex);
return -EINVAL;
}
@@ -362,9 +365,12 @@ static int uinput_create_device(struct u
input_set_drvdata(udev->dev, udev);
+ mutex_unlock(&udev->mutex);
error = input_register_device(udev->dev);
- if (error)
+ if (error) {
+ mutex_lock(&udev->mutex);
goto fail2;
+ }
udev->state = UIST_CREATED;
@@ -372,6 +378,7 @@ static int uinput_create_device(struct u
fail2: input_ff_destroy(dev);
fail1: uinput_destroy_device(udev);
+ mutex_unlock(&udev->mutex);
return error;
}
@@ -901,8 +908,7 @@ static long uinput_ioctl_handler(struct
goto out;
case UI_DEV_CREATE:
- retval = uinput_create_device(udev);
- goto out;
+ return uinput_create_device(udev);
case UI_DEV_DESTROY:
uinput_destroy_device(udev);
--
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