| Message ID | 20221116012714.102066-1-chenjun102@huawei.com |
|---|---|
| State | New |
| Headers | show |
| Series | watchdog: Fix kmemleak in watchdog_cdev_register | expand |
On Wed, Nov 16, 2022 at 01:27:14AM +0000, Chen Jun wrote: > 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: > [<000000007f001ffd>] __kmem_cache_alloc_node+0x157/0x220 > [<000000006a389304>] kmalloc_trace+0x21/0x110 > [<000000008d640eea>] watchdog_dev_register+0x4e/0x780 [watchdog] > [<0000000053c9f248>] __watchdog_register_device+0x4f0/0x680 [watchdog] > [<00000000b2979824>] watchdog_register_device+0xd2/0x110 [watchdog] > [<000000001f730178>] 0xffffffffc10880ae > [<000000007a1a8bcc>] do_one_initcall+0xcb/0x4d0 > [<00000000b98be325>] do_init_module+0x1ca/0x5f0 > [<0000000046d08e7c>] 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: > [<000000007f001ffd>] __kmem_cache_alloc_node+0x157/0x220 > [<00000000486ab89b>] __kmalloc_node_track_caller+0x44/0x1b0 > [<000000005a39aab0>] kvasprintf+0xb5/0x140 > [<0000000024806f85>] kvasprintf_const+0x55/0x180 > [<000000009276cb7f>] kobject_set_name_vargs+0x56/0x150 > [<00000000a92e820b>] dev_set_name+0xab/0xe0 > [<00000000cec812c6>] watchdog_dev_register+0x285/0x780 [watchdog] > [<0000000053c9f248>] __watchdog_register_device+0x4f0/0x680 [watchdog] > [<00000000b2979824>] watchdog_register_device+0xd2/0x110 [watchdog] > [<000000001f730178>] 0xffffffffc10880ae > [<000000007a1a8bcc>] do_one_initcall+0xcb/0x4d0 > [<00000000b98be325>] do_init_module+0x1ca/0x5f0 > [<0000000046d08e7c>] 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. > > Fixes: 72139dfa2464 ("watchdog: Fix the race between the release of watchdog_core_data and cdev") > Signed-off-by: Chen Jun <chenjun102@huawei.com> Reviewed-by: Guenter Roeck <linux@roeck-us.net> > --- > drivers/watchdog/watchdog_dev.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/watchdog/watchdog_dev.c b/drivers/watchdog/watchdog_dev.c > index 55574ed42504..fdffa6859dde 100644 > --- a/drivers/watchdog/watchdog_dev.c > +++ b/drivers/watchdog/watchdog_dev.c > @@ -1061,8 +1061,8 @@ static int watchdog_cdev_register(struct watchdog_device *wdd) > if (wdd->id == 0) { > misc_deregister(&watchdog_miscdev); > old_wd_data = NULL; > - put_device(&wd_data->dev); > } > + put_device(&wd_data->dev); > return err; > } > > -- > 2.17.1 >
diff --git a/drivers/watchdog/watchdog_dev.c b/drivers/watchdog/watchdog_dev.c index 55574ed42504..fdffa6859dde 100644 --- a/drivers/watchdog/watchdog_dev.c +++ b/drivers/watchdog/watchdog_dev.c @@ -1061,8 +1061,8 @@ static int watchdog_cdev_register(struct watchdog_device *wdd) if (wdd->id == 0) { misc_deregister(&watchdog_miscdev); old_wd_data = NULL; - put_device(&wd_data->dev); } + put_device(&wd_data->dev); return err; }
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: [<000000007f001ffd>] __kmem_cache_alloc_node+0x157/0x220 [<000000006a389304>] kmalloc_trace+0x21/0x110 [<000000008d640eea>] watchdog_dev_register+0x4e/0x780 [watchdog] [<0000000053c9f248>] __watchdog_register_device+0x4f0/0x680 [watchdog] [<00000000b2979824>] watchdog_register_device+0xd2/0x110 [watchdog] [<000000001f730178>] 0xffffffffc10880ae [<000000007a1a8bcc>] do_one_initcall+0xcb/0x4d0 [<00000000b98be325>] do_init_module+0x1ca/0x5f0 [<0000000046d08e7c>] 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: [<000000007f001ffd>] __kmem_cache_alloc_node+0x157/0x220 [<00000000486ab89b>] __kmalloc_node_track_caller+0x44/0x1b0 [<000000005a39aab0>] kvasprintf+0xb5/0x140 [<0000000024806f85>] kvasprintf_const+0x55/0x180 [<000000009276cb7f>] kobject_set_name_vargs+0x56/0x150 [<00000000a92e820b>] dev_set_name+0xab/0xe0 [<00000000cec812c6>] watchdog_dev_register+0x285/0x780 [watchdog] [<0000000053c9f248>] __watchdog_register_device+0x4f0/0x680 [watchdog] [<00000000b2979824>] watchdog_register_device+0xd2/0x110 [watchdog] [<000000001f730178>] 0xffffffffc10880ae [<000000007a1a8bcc>] do_one_initcall+0xcb/0x4d0 [<00000000b98be325>] do_init_module+0x1ca/0x5f0 [<0000000046d08e7c>] 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. Fixes: 72139dfa2464 ("watchdog: Fix the race between the release of watchdog_core_data and cdev") Signed-off-by: Chen Jun <chenjun102@huawei.com> --- drivers/watchdog/watchdog_dev.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)