chardev: fix error handling in cdev_device_add()

Summary

In the Linux kernel, the following vulnerability has been resolved: chardev: fix error handling in cdev_device_add() While doing fault injection test, I got the following report: ------------[ cut here ]------------ kobject: '(null)' (0000000039956980): is not initialized, yet kobject_put() is being called. WARNING: CPU: 3 PID: 6306 at kobject_put+0x23d/0x4e0 CPU: 3 PID: 6306 Comm: 283 Tainted: G W 6.1.0-rc2-00005-g307c1086d7c9 #1253 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1.1 04/01/2014 RIP: 0010:kobject_put+0x23d/0x4e0 Call Trace: <TASK> cdev_device_add+0x15e/0x1b0 __iio_device_register+0x13b4/0x1af0 [industrialio] __devm_iio_device_register+0x22/0x90 [industrialio] max517_probe+0x3d8/0x6b4 [max517] i2c_device_probe+0xa81/0xc00 When device_add() is injected fault and returns error, if dev->devt is not set, cdev_add() is not called, cdev_del() is not needed. Fix this by checking dev->devt in error path.

Timeline

1. Sep 15, 2025, 2:21 PM UTCCVE published
2. May 23, 2026, 3:24 PM UTCRecord last updated

Affected versions

• Linux Linux

  From 4.9.224 · fixed in 4.9.337; From 3.16.83 · fixed in 3.17; From 4.4.224 · fixed in 4.5

• Linux Linux

  4.12

References 9