• Bruno Prémont's avatar
    sysfs: Prevent crash on unset sysfs group attributes · 5631f2c1
    Bruno Prémont authored
    Do not let the kernel crash when a device is registered with
    sysfs while group attributes are not set (aka NULL).
    
    Warn about the offender with some information about the offending
    device.
    
    This would warn instead of trying NULL pointer deref like:
     BUG: unable to handle kernel NULL pointer dereference at (null)
     IP: [<ffffffff81152673>] internal_create_group+0x83/0x1a0
     PGD 0
     Oops: 0000 [#1] SMP
     CPU 0
     Modules linked in:
    
     Pid: 1, comm: swapper/0 Not tainted 3.4.0-rc1-x86_64 #3 HP ProLiant DL360 G4
     RIP: 0010:[<ffffffff81152673>]  [<ffffffff81152673>] internal_create_group+0x83/0x1a0
     RSP: 0018:ffff88019485fd70  EFLAGS: 00010202
     RAX: 0000000000000001 RBX: 0000000000000000 RCX: 0000000000000001
     RDX: ffff880192e99908 RSI: ffff880192e99630 RDI: ffffffff81a26c60
     RBP: ffff88019485fdc0 R08: 0000000000000000 R09: 0000000000000000
     R10: ffff880192e99908 R11: 0000000000000000 R12: ffffffff81a16a00
     R13: ffff880192e99908 R14: ffffffff81a16900 R15: 0000000000000000
     FS:  0000000000000000(0000) GS:ffff88019bc00000(0000) knlGS:0000000000000000
     CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
     CR2: 0000000000000000 CR3: 0000000001a0c000 CR4: 00000000000007f0
     DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
     DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
     Process swapper/0 (pid: 1, threadinfo ffff88019485e000, task ffff880194878000)
     Stack:
      ffff88019485fdd0 ffff880192da9d60 0000000000000000 ffff880192e99908
      ffff880192e995d8 0000000000000001 ffffffff81a16a00 ffff880192da9d60
      0000000000000000 0000000000000000 ffff88019485fdd0 ffffffff811527be
     Call Trace:
      [<ffffffff811527be>] sysfs_create_group+0xe/0x10
      [<ffffffff81376ca6>] device_add_groups+0x46/0x80
      [<ffffffff81377d3d>] device_add+0x46d/0x6a0
      ...
    Signed-off-by: default avatarBruno Prémont <bonbons@linux-vserver.org>
    Acked-by: default avatarIngo Molnar <mingo@elte.hu>
    Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
    5631f2c1
group.c 5.45 KB