WARNING: kmalloc bug in input_mt_init_slots

From: syzbot <syzbot+87829a10073277282ad1@syzkaller.appspotmail.com>
To: dmitry.torokhov@gmail.com, linux-input@vger.kernel.org,
	linux-kernel@vger.kernel.org, rydberg@bitmath.org,
	syzkaller-bugs@googlegroups.com
Subject: WARNING: kmalloc bug in input_mt_init_slots
Date: Fri, 21 Sep 2018 10:24:02 -0700	[thread overview]
Message-ID: <000000000000e5f76c057664e73d@google.com> (raw)

Hello,

syzbot found the following crash on:

HEAD commit:    234b69e3e089 ocfs2: fix ocfs2 read block panic
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=131f761a400000
kernel config:  https://syzkaller.appspot.com/x/.config?x=5fa12be50bca08d8
dashboard link: https://syzkaller.appspot.com/bug?extid=87829a10073277282ad1
compiler:       gcc (GCC) 8.0.1 20180413 (experimental)
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=126ca61a400000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=119d6511400000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+87829a10073277282ad1@syzkaller.appspotmail.com

input: syz0 as /devices/virtual/input/input25382
WARNING: CPU: 0 PID: 11238 at mm/slab_common.c:1031 kmalloc_slab+0x56/0x70  
mm/slab_common.c:1031
Kernel panic - not syncing: panic_on_warn set ...

CPU: 0 PID: 11238 Comm: syz-executor124 Not tainted 4.19.0-rc4+ #25
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS  
Google 01/01/2011
Call Trace:
  __dump_stack lib/dump_stack.c:77 [inline]
  dump_stack+0x1c4/0x2b4 lib/dump_stack.c:113
  panic+0x238/0x4e7 kernel/panic.c:184
  __warn.cold.8+0x163/0x1ba kernel/panic.c:536
  report_bug+0x254/0x2d0 lib/bug.c:186
  fixup_bug arch/x86/kernel/traps.c:178 [inline]
  do_error_trap+0x1fc/0x4d0 arch/x86/kernel/traps.c:296
  do_invalid_op+0x1b/0x20 arch/x86/kernel/traps.c:316
  invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:993
RIP: 0010:kmalloc_slab+0x56/0x70 mm/slab_common.c:1031
kobject: 'input25395' (00000000663cc863): kobject_cleanup, parent            
(null)
Code: c5 40 2b 17 89 5d c3 48 85 ff b8 10 00 00 00 74 f4 83 ef 01 c1 ef 03  
0f b6 87 60 2a 17 89 eb d8 31 c0 81 e6 00 02 00 00 75 db <0f> 0b 5d c3 48  
8b 04 c5 80 2a 17 89 5d c3 66 90 66 2e 0f 1f 84 00
kobject: 'input25395' (00000000663cc863): calling ktype release
RSP: 0018:ffff8801c477f978 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 00000000fffffffd RCX: ffffffff8534b947
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000003fffffff60
RBP: ffff8801c477f978 R08: ffff8801d2eee000 R09: ffffed003731ee41
R10: ffff8801c477fa48 R11: ffff8801b98f720f R12: 0000000000000000
R13: 0000000000000000 R14: ffff8801b92ac9c0 R15: 00000000006080c0
  __do_kmalloc mm/slab.c:3713 [inline]
  __kmalloc+0x25/0x760 mm/slab.c:3727
kobject: 'input25395': free name
  kmalloc include/linux/slab.h:518 [inline]
  kzalloc include/linux/slab.h:707 [inline]
  input_mt_init_slots+0xe5/0x4a0 drivers/input/input-mt.c:52
  uinput_create_device drivers/input/misc/uinput.c:335 [inline]
  uinput_ioctl_handler.isra.10+0x2049/0x2540 drivers/input/misc/uinput.c:876
  uinput_ioctl+0x4c/0x60 drivers/input/misc/uinput.c:1047
  vfs_ioctl fs/ioctl.c:46 [inline]
  file_ioctl fs/ioctl.c:501 [inline]
  do_vfs_ioctl+0x1de/0x1720 fs/ioctl.c:685
  ksys_ioctl+0xa9/0xd0 fs/ioctl.c:702
  __do_sys_ioctl fs/ioctl.c:709 [inline]
  __se_sys_ioctl fs/ioctl.c:707 [inline]
  __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:707
  do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
  entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x446ec9
Code: e8 2c b3 02 00 48 83 c4 18 c3 0f 1f 80 00 00 00 00 48 89 f8 48 89 f7  
48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff  
ff 0f 83 2b 09 fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fa83f4b1da8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00000000006dbc28 RCX: 0000000000446ec9
RDX: 0000000000446ec9 RSI: 0000000000005501 RDI: 0000000000000004
RBP: 00000000006dbc20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000006dbc2c
R13: 6e69752f7665642f R14: 00007fa83f4b29c0 R15: 00000000006dbd2c
Kernel Offset: disabled
Rebooting in 86400 seconds..

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