• Pravin B Shelar's avatar
    vxlan: Fix kernel crash on rmmod. · f89e57c4
    Pravin B Shelar authored
    vxlan exit module unregisters vxlan net and then it unregisters
    rtnl ops which triggers vxlan_dellink() from __rtnl_kill_links().
    vxlan_dellink() deletes vxlan-dev from vxlan_list which has
    list-head in vxlan-net-struct but that is already gone due to
    net-unregister. That is how we are getting following crash.
    
    Following commit fixes the crash by fixing module exit path.
    
    BUG: unable to handle kernel paging request at ffff8804102c8000
    IP: [<ffffffff812cc5e9>] __list_del_entry+0x29/0xd0
    PGD 2972067 PUD 83e019067 PMD 83df97067 PTE 80000004102c8060
    Oops: 0000 [#1] SMP DEBUG_PAGEALLOC
    Modules linked in: ---
    CPU: 19 PID: 6712 Comm: rmmod Tainted: GF            3.10.0+ #95
    Hardware name: Dell Inc. PowerEdge R620/0KCKR5, BIOS 1.4.8 10/25/2012
    task: ffff88080c47c580 ti: ffff88080ac50000 task.ti: ffff88080ac50000
    RIP: 0010:[<ffffffff812cc5e9>]  [<ffffffff812cc5e9>]
    __list_del_entry+0x29/0xd0
    RSP: 0018:ffff88080ac51e08  EFLAGS: 00010206
    RAX: ffff8804102c8000 RBX: ffff88040f0d4b10 RCX: dead000000200200
    RDX: ffff8804102c8000 RSI: ffff88080ac51e58 RDI: ffff88040f0d4b10
    RBP: ffff88080ac51e08 R08: 0000000000000001 R09: 2222222222222222
    R10: 2222222222222222 R11: 2222222222222222 R12: ffff88080ac51e58
    R13: ffffffffa07b8840 R14: ffffffff81ae48c0 R15: ffff88080ac51e58
    FS:  00007f9ef105c700(0000) GS:ffff88082a800000(0000)
    knlGS:0000000000000000
    CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
    CR2: ffff8804102c8000 CR3: 00000008227e5000 CR4: 00000000000407e0
    DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
    DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
    Stack:
     ffff88080ac51e28 ffffffff812cc6a1 2222222222222222 ffff88040f0d4000
     ffff88080ac51e48 ffffffffa07b3311 ffff88040f0d4000 ffffffff81ae49c8
     ffff88080ac51e98 ffffffff81492fc2 ffff88080ac51e58 ffff88080ac51e58
    Call Trace:
     [<ffffffff812cc6a1>] list_del+0x11/0x40
     [<ffffffffa07b3311>] vxlan_dellink+0x51/0x70 [vxlan]
     [<ffffffff81492fc2>] __rtnl_link_unregister+0xa2/0xb0
     [<ffffffff8149448e>] rtnl_link_unregister+0x1e/0x30
     [<ffffffffa07b7b7c>] vxlan_cleanup_module+0x1c/0x2f [vxlan]
     [<ffffffff810c9b31>] SyS_delete_module+0x1d1/0x2c0
     [<ffffffff812b8a0e>] ? trace_hardirqs_on_thunk+0x3a/0x3f
     [<ffffffff81582f42>] system_call_fastpath+0x16/0x1b
    Code: eb 9f 55 48 8b 17 48 b9 00 01 10 00 00 00 ad de 48 8b 47 08 48 89
    e5 48 39 ca 74 29 48 b9 00 02 20 00 00 00 ad de 48 39 c8 74 7a <4c> 8b
    00 4c 39 c7 75 53 4c 8b 42 08 4c 39 c7 75 2b 48 89 42 08
    RIP  [<ffffffff812cc5e9>] __list_del_entry+0x29/0xd0
     RSP <ffff88080ac51e08>
    CR2: ffff8804102c8000
    Signed-off-by: default avatarPravin B Shelar <pshelar@nicira.com>
    Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
    f89e57c4
vxlan.c 47 KB