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authorEwan D. Milne <emilne@redhat.com>2017-06-27 18:55:58 (GMT)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2017-07-27 22:07:59 (GMT)
commitfc866b296a463661f90ea734c40b1049c4834eaa (patch)
tree6c281d14d5184aa0f9335e8cc704dd9e2908ae6f /fs/fuse
parent542c097f1cb61f57ad42ffd8431371d69e76aa03 (diff)
downloadlinux-fc866b296a463661f90ea734c40b1049c4834eaa.tar.xz
scsi: Add STARGET_CREATED_REMOVE state to scsi_target_state
commit f9279c968c257ee39b0d7bd2571a4d231a67bcc1 upstream. The addition of the STARGET_REMOVE state had the side effect of introducing a race condition that can cause a crash. scsi_target_reap_ref_release() checks the starget->state to see if it still in STARGET_CREATED, and if so, skips calling transport_remove_device() and device_del(), because the starget->state is only set to STARGET_RUNNING after scsi_target_add() has called device_add() and transport_add_device(). However, if an rport loss occurs while a target is being scanned, it can happen that scsi_remove_target() will be called while the starget is still in the STARGET_CREATED state. In this case, the starget->state will be set to STARGET_REMOVE, and as a result, scsi_target_reap_ref_release() will take the wrong path. The end result is a panic: [ 1255.356653] Oops: 0000 [#1] SMP [ 1255.360154] Modules linked in: x86_pkg_temp_thermal kvm_intel kvm irqbypass crc32c_intel ghash_clmulni_i [ 1255.393234] CPU: 5 PID: 149 Comm: kworker/u96:4 Tainted: G W 4.11.0+ #8 [ 1255.401879] Hardware name: Dell Inc. PowerEdge R320/08VT7V, BIOS 2.0.22 11/19/2013 [ 1255.410327] Workqueue: scsi_wq_6 fc_scsi_scan_rport [scsi_transport_fc] [ 1255.417720] task: ffff88060ca8c8c0 task.stack: ffffc900048a8000 [ 1255.424331] RIP: 0010:kernfs_find_ns+0x13/0xc0 [ 1255.429287] RSP: 0018:ffffc900048abbf0 EFLAGS: 00010246 [ 1255.435123] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 [ 1255.443083] RDX: 0000000000000000 RSI: ffffffff8188d659 RDI: 0000000000000000 [ 1255.451043] RBP: ffffc900048abc10 R08: 0000000000000000 R09: 0000012433fe0025 [ 1255.459005] R10: 0000000025e5a4b5 R11: 0000000025e5a4b5 R12: ffffffff8188d659 [ 1255.466972] R13: 0000000000000000 R14: ffff8805f55e5088 R15: 0000000000000000 [ 1255.474931] FS: 0000000000000000(0000) GS:ffff880616b40000(0000) knlGS:0000000000000000 [ 1255.483959] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 1255.490370] CR2: 0000000000000068 CR3: 0000000001c09000 CR4: 00000000000406e0 [ 1255.498332] Call Trace: [ 1255.501058] kernfs_find_and_get_ns+0x31/0x60 [ 1255.505916] sysfs_unmerge_group+0x1d/0x60 [ 1255.510498] dpm_sysfs_remove+0x22/0x60 [ 1255.514783] device_del+0xf4/0x2e0 [ 1255.518577] ? device_remove_file+0x19/0x20 [ 1255.523241] attribute_container_class_device_del+0x1a/0x20 [ 1255.529457] transport_remove_classdev+0x4e/0x60 [ 1255.534607] ? transport_add_class_device+0x40/0x40 [ 1255.540046] attribute_container_device_trigger+0xb0/0xc0 [ 1255.546069] transport_remove_device+0x15/0x20 [ 1255.551025] scsi_target_reap_ref_release+0x25/0x40 [ 1255.556467] scsi_target_reap+0x2e/0x40 [ 1255.560744] __scsi_scan_target+0xaa/0x5b0 [ 1255.565312] scsi_scan_target+0xec/0x100 [ 1255.569689] fc_scsi_scan_rport+0xb1/0xc0 [scsi_transport_fc] [ 1255.576099] process_one_work+0x14b/0x390 [ 1255.580569] worker_thread+0x4b/0x390 [ 1255.584651] kthread+0x109/0x140 [ 1255.588251] ? rescuer_thread+0x330/0x330 [ 1255.592730] ? kthread_park+0x60/0x60 [ 1255.596815] ret_from_fork+0x29/0x40 [ 1255.600801] Code: 24 08 48 83 42 40 01 5b 41 5c 5d c3 66 66 66 2e 0f 1f 84 00 00 00 00 00 66 66 66 66 90 [ 1255.621876] RIP: kernfs_find_ns+0x13/0xc0 RSP: ffffc900048abbf0 [ 1255.628479] CR2: 0000000000000068 [ 1255.632756] ---[ end trace 34a69ba0477d036f ]--- Fix this by adding another scsi_target state STARGET_CREATED_REMOVE to distinguish this case. Fixes: f05795d3d771 ("scsi: Add intermediate STARGET_REMOVE state to scsi_target_state") Reported-by: David Jeffery <djeffery@redhat.com> Signed-off-by: Ewan D. Milne <emilne@redhat.com> Reviewed-by: Laurence Oberman <loberman@redhat.com> Tested-by: Laurence Oberman <loberman@redhat.com> Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'fs/fuse')
0 files changed, 0 insertions, 0 deletions