• Tejun Heo's avatar
    libata: fix oops when LPM is used with PMP · 5f6f12cc
    Tejun Heo authored
    ae01b249 (libata: Implement ATA_FLAG_NO_DIPM and apply it to mcp65)
    added ATA_FLAG_NO_DIPM and made ata_eh_set_lpm() check the flag.
    However, @ap is NULL if @link points to a PMP link and thus the
    unconditional @ap->flags dereference leads to the following oops.
    
      BUG: unable to handle kernel NULL pointer dereference at 0000000000000018
      IP: [<ffffffff813f98e1>] ata_eh_recover+0x9a1/0x1510
      ...
      Pid: 295, comm: scsi_eh_4 Tainted: P            2.6.38.5-core2 #1 System76, Inc. Serval Professional/Serval Professional
      RIP: 0010:[<ffffffff813f98e1>]  [<ffffffff813f98e1>] ata_eh_recover+0x9a1/0x1510
      RSP: 0018:ffff880132defbf0  EFLAGS: 00010246
      RAX: 0000000000000000 RBX: ffff880132f40000 RCX: 0000000000000000
      RDX: ffff88013377c000 RSI: ffff880132f40000 RDI: 0000000000000000
      RBP: ffff880132defce0 R08: ffff88013377dc58 R09: ffff880132defd98
      R10: 0000000000000000 R11: 00000000ffffffff R12: 0000000000000000
      R13: 0000000000000000 R14: ffff88013377c000 R15: 0000000000000000
      FS:  0000000000000000(0000) GS:ffff8800bf700000(0000) knlGS:0000000000000000
      CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
      CR2: 0000000000000018 CR3: 0000000001a03000 CR4: 00000000000406e0
      DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
      DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
      Process scsi_eh_4 (pid: 295, threadinfo ffff880132dee000, task ffff880133b416c0)
      Stack:
       0000000000000000 ffff880132defcc0 0000000000000000 ffff880132f42738
       ffffffff813ee8f0 ffffffff813eefe0 ffff880132defd98 ffff88013377f190
       ffffffffa00b3e30 ffffffff813ef030 0000000032defc60 ffff880100000000
      Call Trace:
       [<ffffffff81400867>] sata_pmp_error_handler+0x607/0xc30
       [<ffffffffa00b273f>] ahci_error_handler+0x1f/0x70 [libahci]
       [<ffffffff813faade>] ata_scsi_error+0x5be/0x900
       [<ffffffff813cf724>] scsi_error_handler+0x124/0x650
       [<ffffffff810834b6>] kthread+0x96/0xa0
       [<ffffffff8100cd64>] kernel_thread_helper+0x4/0x10
      Code: 8b 95 70 ff ff ff b8 00 00 00 00 48 3b 9a 10 2e 00 00 48 0f 44 c2 48 89 85 70 ff ff ff 48 8b 8d 70 ff ff ff f6 83 69 02 00 00 01 <48> 8b 41 18 0f 85 48 01 00 00 48 85 c9 74 12 48 8b 51 08 48 83
      RIP  [<ffffffff813f98e1>] ata_eh_recover+0x9a1/0x1510
       RSP <ffff880132defbf0>
      CR2: 0000000000000018
    
    Fix it by testing @link->ap->flags instead.
    
    stable: ATA_FLAG_NO_DIPM was added during 2.6.39 cycle but was
            backported to 2.6.37 and 38.  This is a fix for that and thus
            also applicable to 2.6.37 and 38.
    Signed-off-by: default avatarTejun Heo <tj@kernel.org>
    Reported-by: default avatar"Nathan A. Mourey II" <nmoureyii@ne.rr.com>
    LKML-Reference: <1304555277.2059.2.camel@localhost.localdomain>
    Cc: Connor H <cmdkhh@gmail.com>
    Cc: stable@kernel.org
    Signed-off-by: default avatarJeff Garzik <jgarzik@pobox.com>
    5f6f12cc
libata-eh.c 106 KB