memory leak in tty_init

memory leak in tty_init_dev
Status: upstream: reported C repro on 2019/08/29 21:28
Reported-by: syzbot+f303e045423e617d2cad@syzkaller.appspotmail.com
First crash: 559d, last: 48d

Patch testing requests:
Created	Duration	User	Patch	Repo	Result
2020/09/23 10:40	3m	anant.thazhemadam@gmail.com		upstream	error

Sample crash report:

BUG: memory leak
unreferenced object 0xffff88810b6a1c00 (size 1024):
  comm "syz-executor275", pid 8485, jiffies 4294949277 (age 13.800s)
  hex dump (first 32 bytes):
    01 54 00 00 01 00 00 00 00 cc 9c 42 81 88 ff ff  .T.........B....
    80 24 8c 42 81 88 ff ff a0 1a a3 84 ff ff ff ff  .$.B............
  backtrace:
    [<00000000b792389d>] kmalloc include/linux/slab.h:552 [inline]
    [<00000000b792389d>] kzalloc include/linux/slab.h:682 [inline]
    [<00000000b792389d>] alloc_tty_struct+0x3c/0x2e0 drivers/tty/tty_io.c:2987
    [<000000000483200f>] tty_init_dev.part.0+0x20/0x250 drivers/tty/tty_io.c:1335
    [<00000000c124343d>] tty_init_dev drivers/tty/tty_io.c:1979 [inline]
    [<00000000c124343d>] tty_open_by_driver drivers/tty/tty_io.c:1987 [inline]
    [<00000000c124343d>] tty_open+0x882/0xa20 drivers/tty/tty_io.c:2035
    [<00000000004c360e>] chrdev_open+0x10d/0x340 fs/char_dev.c:414
    [<00000000dcb15ca5>] do_dentry_open+0x1e6/0x620 fs/open.c:817
    [<0000000071c204de>] do_open fs/namei.c:3254 [inline]
    [<0000000071c204de>] path_openat+0x74a/0x1b00 fs/namei.c:3371
    [<0000000003c24a4a>] do_filp_open+0xa0/0x190 fs/namei.c:3398
    [<000000003bc2b77f>] do_sys_openat2+0xed/0x230 fs/open.c:1172
    [<00000000374986fc>] do_sys_open fs/open.c:1188 [inline]
    [<00000000374986fc>] __do_sys_openat fs/open.c:1204 [inline]
    [<00000000374986fc>] __se_sys_openat fs/open.c:1199 [inline]
    [<00000000374986fc>] __x64_sys_openat+0x7f/0xe0 fs/open.c:1199
    [<00000000d3bdaba6>] do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
    [<0000000010c109c7>] entry_SYSCALL_64_after_hwframe+0x44/0xa9

BUG: memory leak
unreferenced object 0xffff88810eff5c00 (size 1024):
  comm "syz-executor275", pid 8489, jiffies 4294949855 (age 8.020s)
  hex dump (first 32 bytes):
    01 54 00 00 01 00 00 00 00 cc 9c 42 81 88 ff ff  .T.........B....
    80 24 8c 42 81 88 ff ff a0 1a a3 84 ff ff ff ff  .$.B............
  backtrace:
    [<00000000b792389d>] kmalloc include/linux/slab.h:552 [inline]
    [<00000000b792389d>] kzalloc include/linux/slab.h:682 [inline]
    [<00000000b792389d>] alloc_tty_struct+0x3c/0x2e0 drivers/tty/tty_io.c:2987
    [<000000000483200f>] tty_init_dev.part.0+0x20/0x250 drivers/tty/tty_io.c:1335
    [<00000000c124343d>] tty_init_dev drivers/tty/tty_io.c:1979 [inline]
    [<00000000c124343d>] tty_open_by_driver drivers/tty/tty_io.c:1987 [inline]
    [<00000000c124343d>] tty_open+0x882/0xa20 drivers/tty/tty_io.c:2035
    [<00000000004c360e>] chrdev_open+0x10d/0x340 fs/char_dev.c:414
    [<00000000dcb15ca5>] do_dentry_open+0x1e6/0x620 fs/open.c:817
    [<0000000071c204de>] do_open fs/namei.c:3254 [inline]
    [<0000000071c204de>] path_openat+0x74a/0x1b00 fs/namei.c:3371
    [<0000000003c24a4a>] do_filp_open+0xa0/0x190 fs/namei.c:3398
    [<000000003bc2b77f>] do_sys_openat2+0xed/0x230 fs/open.c:1172
    [<00000000374986fc>] do_sys_open fs/open.c:1188 [inline]
    [<00000000374986fc>] __do_sys_openat fs/open.c:1204 [inline]
    [<00000000374986fc>] __se_sys_openat fs/open.c:1199 [inline]
    [<00000000374986fc>] __x64_sys_openat+0x7f/0xe0 fs/open.c:1199
    [<00000000d3bdaba6>] do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
    [<0000000010c109c7>] entry_SYSCALL_64_after_hwframe+0x44/0xa9

Crashes (8):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report	Syz repro	C repro	Title
ci-upstream-gce-leak	2021/01/17 17:16	upstream	0da0a8a0	813be542	.config	log	report	syz	C	memory leak in tty_init_dev
ci-upstream-gce-leak	2020/12/19 06:43	upstream	a409ed15	04201c06	.config	log	report	syz	C
ci-upstream-gce-leak	2019/10/31 05:58	upstream	320000e7	a41ca8fa	.config	log	report	syz	C
ci-upstream-gce-leak	2019/08/25 19:38	upstream	e67095fd	d21c5d9d	.config	log	report	syz	C
ci-upstream-gce-leak	2021/01/02 11:10	upstream	eda809ae	79264ae3	.config	log	report	syz
ci-upstream-gce-leak	2020/12/14 01:28	upstream	6bff9bb8	b22a7ec3	.config	log	report	syz
ci-upstream-gce-leak	2020/12/13 14:39	upstream	7b1b868e	bca53db9	.config	log	report	syz
ci-upstream-gce-leak	2019/11/08 14:05	upstream	847120f8	1e35461e	.config	log	report	syz