From: Yi Zou Date: Wed, 1 Dec 2010 00:18:07 +0000 (-0800) Subject: [SCSI] libfc: fix NULL pointer dereference bug in fc_fcp_pkt_release X-Git-Url: http://git.lede-project.org./?a=commitdiff_plain;h=80e736f8a37bebeb5bff18f2aec31caab4104b8b;p=openwrt%2Fstaging%2Fblogic.git [SCSI] libfc: fix NULL pointer dereference bug in fc_fcp_pkt_release This happens when then tearing down the fcoe interface with active I/O. The back trace shows dead000000200200 in RAX, i.e., LIST_POISON2, indicating that the fsp is already being dequeued, which is probably why no complaining was seen in fc_fcp_destroy() about outstanding fsp not freed, since we dequeue it in the end of fc_io_compl() before releasing it. The bug is due to the fact that we have already destroyed lport's scsi_pkt_pool while on-going i/o is still accessing it through fc_fcp_pkt_release(), like this trace or the similar code path from scsi-ml to fc_eh_abort, etc. This is fixed by moving the fc_fcp_destroy() after lport is detached from scsi-ml since fc_fcp_destroy is supposed to called only once where no lport lock is taken, otherwise the fc_fcp_pkt_release() would have to grab the lport lock. BUG: unable to handle kernel NULL pointer dereference at (null) ....... RIP: 0010:[<0000000000000000>] [<(null)>] (null) RSP: 0018:ffff8803270f7b88 EFLAGS: 00010282 RAX: dead000000200200 RBX: ffff880197d2fbc0 RCX: 0000000000005908 RDX: ffff880195ea6d08 RSI: 0000000000000282 RDI: ffff880180f4fec0 RBP: ffff8803270f7bc0 R08: ffff880197d2fbe0 R09: 0000000000000000 R10: ffff88032867f090 R11: 0000000000000000 R12: ffff880195ea6d08 R13: 0000000000000282 R14: ffff880180f4fec0 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8801b5820000(0000) knlGS:0000000000000000 CS: 0010 DS: 0018 ES: 0018 CR0: 000000008005003b CR2: 0000000000000000 CR3: 00000001a6eae000 CR4: 00000000000006e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Process fc_rport_eq (pid: 5278, threadinfo ffff8803270f6000, task ffff880326254ab0) Stack: ffffffffa02c39ca ffff8803270f7ba0 ffff88019331cbc0 ffff880197d2fbc0 0000000000000000 ffff8801a8c895e0 ffff8801a8c895e0 ffff8803270f7c10 ffffffffa02c4962 ffff8803270f7be0 ffffffff814c94ab ffff8803270f7c10 Call Trace: [] ? fc_io_compl+0x10a/0x530 [libfc] [] fc_fcp_complete_locked+0x72/0x150 [libfc] [] ? _spin_unlock_bh+0x1b/0x20 [] ? fc_exch_done+0x3f/0x60 [libfc] [] fc_fcp_retry_cmd+0x4f/0x60 [libfc] [] fc_fcp_recv+0x9b0/0xc30 [libfc] [] ? _call_console_drivers+0x4a/0x80 [] ? lock_timer_base+0x3c/0x70 [] ? try_to_del_timer_sync+0x7b/0xe0 [] fc_exch_mgr_reset+0x1df/0x250 [libfc] [] ? fc_fcp_recv+0x0/0xc30 [libfc] [] fc_rport_work+0xf2/0x4e0 [libfc] [] ? prepare_to_wait+0x4e/0x80 [] ? fc_rport_work+0x0/0x4e0 [libfc] [] worker_thread+0x170/0x2a0 [] ? autoremove_wake_function+0x0/0x40 [] ? worker_thread+0x0/0x2a0 [] kthread+0x96/0xa0 [] child_rip+0xa/0x20 [] ? kthread+0x0/0xa0 [] ? child_rip+0x0/0x20 Code: Bad RIP value. RIP [<(null)>] (null) RSP CR2: 0000000000000000 Signed-off-by: Yi Zou Signed-off-by: Robert Love Signed-off-by: James Bottomley --- diff --git a/drivers/scsi/fcoe/fcoe.c b/drivers/scsi/fcoe/fcoe.c index d23a538a9dfc..9f9600b67001 100644 --- a/drivers/scsi/fcoe/fcoe.c +++ b/drivers/scsi/fcoe/fcoe.c @@ -854,7 +854,6 @@ static void fcoe_if_destroy(struct fc_lport *lport) /* Cleanup the fc_lport */ fc_lport_destroy(lport); - fc_fcp_destroy(lport); /* Stop the transmit retry timer */ del_timer_sync(&port->timer); @@ -876,6 +875,9 @@ static void fcoe_if_destroy(struct fc_lport *lport) fc_remove_host(lport->host); scsi_remove_host(lport->host); + /* Destroy lport scsi_priv */ + fc_fcp_destroy(lport); + /* There are no more rports or I/O, free the EM */ fc_exch_mgr_free(lport);