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Date:   Sat, 09 Jun 2018 15:47:03 -0700
Message-ID: <00000000000092de58056e3d4b96@google.com>
Subject: WARNING: kmalloc bug in xdp_umem_create
From:   syzbot <syzbot+4abadc5d69117b346506@syzkaller.appspotmail.com>
To:     bjorn.topel@intel.com, davem@davemloft.net,
        linux-kernel@vger.kernel.org, magnus.karlsson@intel.com,
        netdev@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:    7d3bf613e99a Merge tag 'libnvdimm-for-4.18' of git://git.k..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1073f68f800000
kernel config:  https://syzkaller.appspot.com/x/.config?x=f04d8d0a2afb789a
dashboard link: https://syzkaller.appspot.com/bug?extid=4abadc5d69117b346506
compiler:       gcc (GCC) 8.0.1 20180413 (experimental)
syzkaller repro:https://syzkaller.appspot.com/x/repro.syz?x=13c9756f800000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=16366f9f800000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+4abadc5d69117b346506@syzkaller.appspotmail.com

random: sshd: uninitialized urandom read (32 bytes read)
random: sshd: uninitialized urandom read (32 bytes read)
random: sshd: uninitialized urandom read (32 bytes read)
random: sshd: uninitialized urandom read (32 bytes read)
random: sshd: uninitialized urandom read (32 bytes read)
WARNING: CPU: 1 PID: 4537 at mm/slab_common.c:996 kmalloc_slab+0x56/0x70  
mm/slab_common.c:996
Kernel panic - not syncing: panic_on_warn set ...

CPU: 1 PID: 4537 Comm: syz-executor849 Not tainted 4.17.0+ #92
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+0x1b9/0x294 lib/dump_stack.c:113
  panic+0x22f/0x4de kernel/panic.c:184
  __warn.cold.8+0x163/0x1b3 kernel/panic.c:536
  report_bug+0x252/0x2d0 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:992
RIP: 0010:kmalloc_slab+0x56/0x70 mm/slab_common.c:996
Code: c5 c0 ca d0 88 5d c3 b8 10 00 00 00 48 85 ff 74 f4 83 ef 01 c1 ef 03  
0f b6 87 e0 c9 d0 88 eb d8 31 c0 81 e6 00 02 00 00 75 db <0f> 0b 5d c3 48  
8b 04 c5 00 ca d0 88 5d c3 66 90 66 2e 0f 1f 84 00
RSP: 0018:ffff8801acc67998 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 0000000000000001 RCX: ffffffff877abea2
RDX: 1ffff10035e17ce3 RSI: 0000000000000000 RDI: 0000000001000010
RBP: ffff8801acc67998 R08: ffff8801d91d82c0 R09: ffffed0035e17cd9
R10: ffffed0035e17cd9 R11: ffff8801af0be6cb R12: dffffc0000000000
R13: 0000000020000000 R14: ffff8801af0be6b0 R15: 00000000006080c0
  __do_kmalloc mm/slab.c:3713 [inline]
  __kmalloc+0x25/0x760 mm/slab.c:3727
  kmalloc_array include/linux/slab.h:634 [inline]
  kcalloc include/linux/slab.h:645 [inline]
  xdp_umem_pin_pages net/xdp/xdp_umem.c:205 [inline]
  xdp_umem_reg net/xdp/xdp_umem.c:318 [inline]
  xdp_umem_create+0x5c9/0x10f0 net/xdp/xdp_umem.c:349
  xsk_setsockopt+0x443/0x550 net/xdp/xsk.c:531
  __sys_setsockopt+0x1bd/0x390 net/socket.c:1935
  __do_sys_setsockopt net/socket.c:1946 [inline]
  __se_sys_setsockopt net/socket.c:1943 [inline]
  __x64_sys_setsockopt+0xbe/0x150 net/socket.c:1943
  do_syscall_64+0x1b1/0x800 arch/x86/entry/common.c:287
  entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x43fce9
Code: 18 89 d0 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 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 6b 45 00 00 c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007ffedcafaac8 EFLAGS: 00000213 ORIG_RAX: 0000000000000036
RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 000000000043fce9
RDX: 0000000000000004 RSI: 000000000000011b RDI: 0000000000000003
RBP: 00000000006ca018 R08: 0000000000000018 R09: 00000000004002c8
R10: 0000000020000040 R11: 0000000000000213 R12: 0000000000401610
R13: 00000000004016a0 R14: 0000000000000000 R15: 0000000000000000
Dumping ftrace buffer:
    (ftrace buffer empty)
Kernel Offset: disabled
Rebooting in 86400 seconds..


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