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Date:   Tue, 30 Jul 2019 08:08:05 -0700
Message-ID: <0000000000002cd2b1058ee760fe@google.com>
Subject: memory leak in pty_common_install
From:   syzbot <syzbot+bdebcbf44250d75bdd82@syzkaller.appspotmail.com>
To:     gregkh@linuxfoundation.org, jslaby@suse.com,
        linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com
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Sender: linux-kernel-owner@vger.kernel.org
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Hello,

syzbot found the following crash on:

HEAD commit:    6789f873 Merge tag 'pm-5.3-rc2' of git://git.kernel.org/pu..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1696897c600000
kernel config:  https://syzkaller.appspot.com/x/.config?x=339b6a6b3640d115
dashboard link: https://syzkaller.appspot.com/bug?extid=bdebcbf44250d75bdd82
compiler:       gcc (GCC) 9.0.0 20181231 (experimental)
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=153d7544600000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+bdebcbf44250d75bdd82@syzkaller.appspotmail.com

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


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