[SCSI] iscsi: don't hang in endless loop if no targets present
iscsi_if_send_reply() may return -ESRCH if there were no targets to send data to. Currently we're ignoring this value and looping in attempt to do it over and over, which will usually lead in a hung task like this one: [ 4920.817298] INFO: task trinity:9074 blocked for more than 120 seconds. [ 4920.818527] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [ 4920.819982] trinity D 0000000000000000 5504 9074 2756 0x00000004 [ 4920.825374] ffff880003961a98 0000000000000086 ffff8800001aa000 ffff8800001aa000 [ 4920.826791] 00000000001d4340 ffff880003961fd8 ffff880003960000 00000000001d4340 [ 4920.828241] 00000000001d4340 00000000001d4340 ffff880003961fd8 00000000001d4340 [ 4920.833231] [ 4920.833519] Call Trace: [ 4920.834010] [<ffffffff826363fa>] schedule+0x3a/0x50 [ 4920.834953] [<ffffffff82634ac9>] __mutex_lock_common+0x209/0x5b0 [ 4920.836226] [<ffffffff81af805d>] ? iscsi_if_rx+0x2d/0x990 [ 4920.837281] [<ffffffff81053943>] ? sched_clock+0x13/0x20 [ 4920.838305] [<ffffffff81af805d>] ? iscsi_if_rx+0x2d/0x990 [ 4920.839336] [<ffffffff82634eb0>] mutex_lock_nested+0x40/0x50 [ 4920.840423] [<ffffffff81af805d>] iscsi_if_rx+0x2d/0x990 [ 4920.841434] [<ffffffff810dffed>] ? sub_preempt_count+0x9d/0xd0 [ 4920.842548] [<ffffffff82637bb0>] ? _raw_read_unlock+0x30/0x60 [ 4920.843666] [<ffffffff821f71de>] netlink_unicast+0x1ae/0x1f0 [ 4920.844751] [<ffffffff821f7997>] netlink_sendmsg+0x227/0x350 [ 4920.845850] [<ffffffff821857bd>] ? sock_update_netprioidx+0xdd/0x1b0 [ 4920.847060] [<ffffffff82185732>] ? sock_update_netprioidx+0x52/0x1b0 [ 4920.848276] [<ffffffff8217f226>] sock_aio_write+0x166/0x180 [ 4920.849348] [<ffffffff810dfe41>] ? get_parent_ip+0x11/0x50 [ 4920.850428] [<ffffffff811d0d9a>] do_sync_write+0xda/0x120 [ 4920.851465] [<ffffffff810dffed>] ? sub_preempt_count+0x9d/0xd0 [ 4920.852579] [<ffffffff810dfe41>] ? get_parent_ip+0x11/0x50 [ 4920.853608] [<ffffffff81791887>] ? security_file_permission+0x27/0xb0 [ 4920.854821] [<ffffffff811d0f4c>] vfs_write+0x16c/0x180 [ 4920.855781] [<ffffffff811d104f>] sys_write+0x4f/0xa0 [ 4920.856798] [<ffffffff82638e79>] system_call_fastpath+0x16/0x1b [ 4920.877487] 1 lock held by trinity/9074: [ 4920.878239] #0: (rx_queue_mutex){+.+...}, at: [<ffffffff81af805d>] iscsi_if_rx+0x2d/0x990 [ 4920.880005] Kernel panic - not syncing: hung_task: blocked tasks Signed-off-by: NSasha Levin <levinsasha928@gmail.com> Acked-by: NMike Christie <michaelc@cs.wisc.edu> Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>
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