CVE-2023-53234 – watchdog: Fix kmemleak in watchdog_cdev_register

CVE ID : CVE-2023-53234

Published : Sept. 15, 2025, 2:22 p.m. | 32 minutes ago

Description : In the Linux kernel, the following vulnerability has been resolved:

watchdog: Fix kmemleak in watchdog_cdev_register

kmemleak reports memory leaks in watchdog_dev_register, as follows:
unreferenced object 0xffff888116233000 (size 2048):
comm “”modprobe””, pid 28147, jiffies 4353426116 (age 61.741s)
hex dump (first 32 bytes):
80 fa b9 05 81 88 ff ff 08 30 23 16 81 88 ff ff ………0#…..
08 30 23 16 81 88 ff ff 00 00 00 00 00 00 00 00 .0#………….
backtrace:
[] __kmem_cache_alloc_node+0x157/0x220
[] kmalloc_trace+0x21/0x110
[] watchdog_dev_register+0x4e/0x780 [watchdog] [] __watchdog_register_device+0x4f0/0x680 [watchdog] [] watchdog_register_device+0xd2/0x110 [watchdog] [] 0xffffffffc10880ae
[] do_one_initcall+0xcb/0x4d0
[] do_init_module+0x1ca/0x5f0
[] load_module+0x6133/0x70f0
…

unreferenced object 0xffff888105b9fa80 (size 16):
comm “”modprobe””, pid 28147, jiffies 4353426116 (age 61.741s)
hex dump (first 16 bytes):
77 61 74 63 68 64 6f 67 31 00 b9 05 81 88 ff ff watchdog1…….
backtrace:
[] __kmem_cache_alloc_node+0x157/0x220
[] __kmalloc_node_track_caller+0x44/0x1b0
[] kvasprintf+0xb5/0x140
[] kvasprintf_const+0x55/0x180
[] kobject_set_name_vargs+0x56/0x150
[] dev_set_name+0xab/0xe0
[] watchdog_dev_register+0x285/0x780 [watchdog] [] __watchdog_register_device+0x4f0/0x680 [watchdog] [] watchdog_register_device+0xd2/0x110 [watchdog] [] 0xffffffffc10880ae
[] do_one_initcall+0xcb/0x4d0
[] do_init_module+0x1ca/0x5f0
[] load_module+0x6133/0x70f0
…

The reason is that put_device is not be called if cdev_device_add fails
and wdd->id != 0.

watchdog_cdev_register
wd_data = kzalloc [1] err = dev_set_name [2] ..
err = cdev_device_add
if (err) {
if (wdd->id == 0) { // wdd->id != 0
..
}
return err; // [1],[2] would be leaked

To fix it, call put_device in all wdd->id cases.

Severity: 0.0 | NA

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