lkml.org 
[lkml]   [2007]   [Jan]   [17]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    SubjectNFS causing oops when freeing namespace
    From
    The test-case at the bottom causes the following recursive Oopsing on
    2.6.20-rc5:

    BUG: unable to handle kernel NULL pointer dereference at virtual address
    00000504
    printing eip:
    c02292d4
    *pde = 00000000
    Oops: 0002 [#1]
    PREEMPT SMP
    Modules linked in:
    CPU: 0
    EIP: 0060:[<c02292d4>] Not tainted VLI
    EFLAGS: 00010046 (2.6.20-rc5 #11)
    EIP is at _raw_spin_trylock+0x4/0x30
    eax: 00000000 ebx: 00000213 ecx: 00000001 edx: 00000504
    esi: 00000504 edi: c1493da0 ebp: d5b5ff3c esp: d5b5fee0
    ds: 007b es: 007b ss: 0068
    Process mount (pid: 2618, ti=d5b5e000 task=c17fdaa0 task.ti=d5b5e000)
    Stack: c03be6f0 00000000 00000000 c01f6115 c04240dc c17fdaa0 c17fdc2c
    00000000
    00000000 d555ebe0 c04734a0 c01d26bd c01d8e9c d553b800 c0161c5d
    d707443c
    d54cedc0 c0175e0e d779c9a0 d779cd60 c1493f20 d7f1caa0 c0175e86
    d54cee40
    Call Trace:
    [<c03be6f0>] _spin_lock_irqsave+0x20/0x90
    [<c01f6115>] lockd_down+0x125/0x190
    [<c01d26bd>] nfs_free_server+0x6d/0xd0
    [<c01d8e9c>] nfs_kill_super+0xc/0x20
    [<c0161c5d>] deactivate_super+0x7d/0xa0
    [<c0175e0e>] release_mounts+0x6e/0x80
    [<c0175e86>] __put_mnt_ns+0x66/0x80
    [<c0132b3e>] free_nsproxy+0x5e/0x60
    [<c011f021>] do_exit+0x791/0x810
    [<c011f0c6>] do_group_exit+0x26/0x70
    [<c0103142>] sysenter_past_esp+0x5f/0x85
    [<c03b0033>] rpc_wake_up+0x3/0x70
    =======================
    Code: ff ff c3 8d 74 26 00 c7 00 00 00 00 01 c7 40 08 ed 1e af de c7 40 10
    ff ff ff ff c7 40 0c ff ff ff ff c3 8d 74 26 00 89 c2 31 c0 <86> 02 31 c9
    84 c0 0f 9f c1 85 c9 74 12 65 a1 04 00 00 00 89 42
    EIP: [<c02292d4>] _raw_spin_trylock+0x4/0x30 SS:ESP 0068:d5b5fee0
    <1>BUG: unable to handle kernel NULL pointer dereference at virtual
    address 00000024
    printing eip:
    c011e8dd
    *pde = 00000000
    Oops: 0000 [#2]
    PREEMPT SMP
    Modules linked in:
    CPU: 0
    EIP: 0060:[<c011e8dd>] Not tainted VLI
    EFLAGS: 00010006 (2.6.20-rc5 #11)
    EIP is at do_exit+0x4d/0x810
    eax: 00000000 ebx: d5b5fea8 ecx: c17fdaa0 edx: 00000001
    esi: c17fdaa0 edi: 00000a3a ebp: 0000000b esp: d5b5fde4
    ds: 007b es: 007b ss: 0068
    Process mount (pid: 2618, ti=d5b5e000 task=c17fdaa0 task.ti=d5b5e000)
    Stack: 00000a3a d5b5e000 c17fdaa0 d5b5e000 00000003 c046a307 0000000f
    d5b5fee0
    00000068 00000013 c011c3cb c042b321 d5b5fe24 d5b5fea8 d5b5fee0
    00000068
    00000000 c0104816 c041347f 00000068 d5b5fee0 00000001 d5b5fea8
    c0414df5
    Call Trace:
    [<c011c3cb>] printk+0x1b/0x20
    [<c0104816>] die+0x246/0x260
    [<c03c09b0>] do_page_fault+0x2e0/0x630
    [<c011c2cf>] vprintk+0x28f/0x370
    [<c03c06d0>] do_page_fault+0x0/0x630
    [<c03beea4>] error_code+0x7c/0x84
    [<c03b007b>] rpc_wake_up+0x4b/0x70
    [<c02292d4>] _raw_spin_trylock+0x4/0x30
    [<c03be6f0>] _spin_lock_irqsave+0x20/0x90
    [<c01f6115>] lockd_down+0x125/0x190
    [<c01d26bd>] nfs_free_server+0x6d/0xd0
    [<c01d8e9c>] nfs_kill_super+0xc/0x20
    [<c0161c5d>] deactivate_super+0x7d/0xa0
    [<c0175e0e>] release_mounts+0x6e/0x80
    [<c0175e86>] __put_mnt_ns+0x66/0x80
    [<c0132b3e>] free_nsproxy+0x5e/0x60
    [<c011f021>] do_exit+0x791/0x810
    [<c011f0c6>] do_group_exit+0x26/0x70
    [<c0103142>] sysenter_past_esp+0x5f/0x85
    [<c03b0033>] rpc_wake_up+0x3/0x70
    =======================
    Code: 03 00 00 89 e0 25 00 e0 ff ff f7 40 14 00 ff ff 0f 0f 85 69 03 00 00
    8b be a4 00 00 00 85 ff 0f 84 43 03 00 00 8b 86 48 04 00 00 <8b> 50 24 3b
    72 10 0f 84 1c 03 00 00 65 a1 08 00 00 00 f6 40 11
    EIP: [<c011e8dd>] do_exit+0x4d/0x810 SS:ESP 0068:d5b5fde4

    It seems to go on forever. addr2line output follows:
    $ addr2line -e vmlinux c02292d4 c03be6f0 c01f6115 c01d26bd c01d8e9c
    c0161c5d c0175e0e c0175e86 c0132b3e c011f021 c011e8dd
    include/asm/spinlock.h:90
    kernel/spinlock.c:280
    fs/lockd/svc.c:345
    fs/nfs/client.c:782
    fs/nfs/super.c:679
    fs/super.c:184
    include/linux/list.h:299
    fs/namespace.c:1879
    include/linux/mnt_namespace.h:26
    include/linux/nsproxy.h:42
    include/linux/pid_namespace.h:42

    The problem appears to be that fs/lockd/svc.c:lockd_down tries to lock
    current->sighand->siglock, but during the time it's sleeping the process
    is reaped and released, setting sighand to NULL.

    This also affects 2.6.19.2, but since there are no pid spaces there, it's
    "just" a single oops, and doesn't make the machine totally unusable.

    Test-case, execute as ./a.out mount -t nfs ...:
    #include <stdio.h>
    #include <sched.h>
    #include <unistd.h>

    int main(int argc, char *argv[])
    {
    if (unshare(CLONE_NEWNS) == -1) {
    perror("unshare");
    exit(1);
    }
    execv("/bin/mount", argv+1);
    perror("execv(mount)");
    return 1;
    }

    --
    Daniel Hokka Zakrisson
    -
    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to majordomo@vger.kernel.org
    More majordomo info at http://vger.kernel.org/majordomo-info.html
    Please read the FAQ at http://www.tux.org/lkml/

    \
     
     \ /
      Last update: 2007-01-17 12:37    [W:0.027 / U:92.048 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site