memory leak in pty_common

memory leak in pty_common_install
Status: upstream: reported syz repro on 2019/07/30 15:08
Reported-by: syzbot+bdebcbf44250d75bdd82@syzkaller.appspotmail.com
First crash: 539d, last: 539d

Patch testing requests:
Created	Duration	User	Patch	Repo	Result
2020/09/23 10:42	3m	anant.thazhemadam@gmail.com		upstream	error

Sample crash report:

BUG: memory leak
unreferenced object 0xffff88810d84d400 (size 512):
  comm "syz-executor.5", pid 7522, jiffies 4294954305 (age 14.260s)
  hex dump (first 32 bytes):
    50 d4 84 0d 81 88 ff ff e0 ff ff ff 0f 00 00 00  P...............
    10 d4 84 0d 81 88 ff ff 10 d4 84 0d 81 88 ff ff  ................
  backtrace:
    [<000000003d61da44>] kmemleak_alloc_recursive include/linux/kmemleak.h:43 [inline]
    [<000000003d61da44>] slab_post_alloc_hook mm/slab.h:522 [inline]
    [<000000003d61da44>] slab_alloc mm/slab.c:3319 [inline]
    [<000000003d61da44>] kmem_cache_alloc_trace+0x145/0x2c0 mm/slab.c:3548
    [<00000000a6239e0a>] kmalloc include/linux/slab.h:552 [inline]
    [<00000000a6239e0a>] pty_common_install+0x4e/0x2b0 drivers/tty/pty.c:391
    [<00000000bd8cb19d>] pty_unix98_install+0x20/0x30 drivers/tty/pty.c:740
    [<000000001b46b5e1>] tty_driver_install_tty drivers/tty/tty_io.c:1227 [inline]
    [<000000001b46b5e1>] tty_init_dev drivers/tty/tty_io.c:1340 [inline]
    [<000000001b46b5e1>] tty_init_dev+0x86/0x210 drivers/tty/tty_io.c:1317
    [<00000000845ae712>] ptmx_open drivers/tty/pty.c:845 [inline]
    [<00000000845ae712>] ptmx_open+0xba/0x1c0 drivers/tty/pty.c:811
    [<000000007e87d771>] chrdev_open+0xe3/0x290 fs/char_dev.c:414
    [<00000000bd556826>] do_dentry_open+0x199/0x4f0 fs/open.c:797
    [<000000001ba9145b>] vfs_open+0x35/0x40 fs/open.c:906
    [<00000000c0275eb4>] do_last fs/namei.c:3416 [inline]
    [<00000000c0275eb4>] path_openat+0x854/0x1cd0 fs/namei.c:3533
    [<00000000156ad8b1>] do_filp_open+0xaa/0x130 fs/namei.c:3563
    [<00000000074d96c0>] do_sys_open+0x253/0x330 fs/open.c:1089
    [<000000009f7fc64a>] __do_sys_openat fs/open.c:1116 [inline]
    [<000000009f7fc64a>] __se_sys_openat fs/open.c:1110 [inline]
    [<000000009f7fc64a>] __x64_sys_openat+0x24/0x30 fs/open.c:1110
    [<000000005ca4479f>] do_syscall_64+0x76/0x1a0 arch/x86/entry/common.c:296
    [<00000000e1f64b0f>] entry_SYSCALL_64_after_hwframe+0x44/0xa9

BUG: memory leak
unreferenced object 0xffff88810e639800 (size 1024):
  comm "syz-executor.5", pid 7522, jiffies 4294954305 (age 14.260s)
  hex dump (first 32 bytes):
    01 54 00 00 01 00 00 00 00 00 00 00 00 00 00 00  .T..............
    00 83 fa 19 82 88 ff ff a0 7f 9b 83 ff ff ff ff  ................
  backtrace:
    [<000000003d61da44>] kmemleak_alloc_recursive include/linux/kmemleak.h:43 [inline]
    [<000000003d61da44>] slab_post_alloc_hook mm/slab.h:522 [inline]
    [<000000003d61da44>] slab_alloc mm/slab.c:3319 [inline]
    [<000000003d61da44>] kmem_cache_alloc_trace+0x145/0x2c0 mm/slab.c:3548
    [<000000001cfffc30>] kmalloc include/linux/slab.h:552 [inline]
    [<000000001cfffc30>] kzalloc include/linux/slab.h:748 [inline]
    [<000000001cfffc30>] alloc_tty_struct+0x3f/0x290 drivers/tty/tty_io.c:2981
    [<000000001946a70c>] pty_common_install+0xac/0x2b0 drivers/tty/pty.c:399
    [<00000000bd8cb19d>] pty_unix98_install+0x20/0x30 drivers/tty/pty.c:740
    [<000000001b46b5e1>] tty_driver_install_tty drivers/tty/tty_io.c:1227 [inline]
    [<000000001b46b5e1>] tty_init_dev drivers/tty/tty_io.c:1340 [inline]
    [<000000001b46b5e1>] tty_init_dev+0x86/0x210 drivers/tty/tty_io.c:1317
    [<00000000845ae712>] ptmx_open drivers/tty/pty.c:845 [inline]
    [<00000000845ae712>] ptmx_open+0xba/0x1c0 drivers/tty/pty.c:811
    [<000000007e87d771>] chrdev_open+0xe3/0x290 fs/char_dev.c:414
    [<00000000bd556826>] do_dentry_open+0x199/0x4f0 fs/open.c:797
    [<000000001ba9145b>] vfs_open+0x35/0x40 fs/open.c:906
    [<00000000c0275eb4>] do_last fs/namei.c:3416 [inline]
    [<00000000c0275eb4>] path_openat+0x854/0x1cd0 fs/namei.c:3533
    [<00000000156ad8b1>] do_filp_open+0xaa/0x130 fs/namei.c:3563
    [<00000000074d96c0>] do_sys_open+0x253/0x330 fs/open.c:1089
    [<000000009f7fc64a>] __do_sys_openat fs/open.c:1116 [inline]
    [<000000009f7fc64a>] __se_sys_openat fs/open.c:1110 [inline]
    [<000000009f7fc64a>] __x64_sys_openat+0x24/0x30 fs/open.c:1110
    [<000000005ca4479f>] do_syscall_64+0x76/0x1a0 arch/x86/entry/common.c:296
    [<00000000e1f64b0f>] entry_SYSCALL_64_after_hwframe+0x44/0xa9

Crashes (1):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report	Syz repro	C repro	VM info	Maintainers
ci-upstream-gce-leak	2019/07/26 13:52	upstream	6789f873	3e5d1beb	.config	log	report	syz			gregkh@linuxfoundation.org, jslaby@suse.com, linux-kernel@vger.kernel.org