kernel.git/drivers/scsi/scsi_sysfs.c, branch linux-4.4.y

scsi: core: Put LLD module refcnt after SCSI device is released

2021-11-12T12:17:07Z

commit f2b85040acec9a928b4eb1b57a989324e8e38d3f upstream. SCSI host release is triggered when SCSI device is freed. We have to make sure that the low-level device driver module won't be unloaded before SCSI host instance is released because shost->hostt is required in the release handler. Make sure to put LLD module refcnt after SCSI device is released. Fixes a kernel panic of 'BUG: unable to handle page fault for address' reported by Changhui and Yi. Link: https://lore.kernel.org/r/20211008050118.1440686-1-ming.lei@redhat.com Cc: Greg Kroah-Hartman Reported-by: Changhui Zhong Reported-by: Yi Zhang Tested-by: Yi Zhang Signed-off-by: Ming Lei Signed-off-by: Martin K. Petersen Signed-off-by: Greg Kroah-Hartman

scsi: core: try to get module before removing device

2019-10-29T08:13:26Z

commit 77c301287ebae86cc71d03eb3806f271cb14da79 upstream. We have a test case like block/001 in blktests, which will create a scsi device by loading scsi_debug module and then try to delete the device by sysfs interface. At the same time, it may remove the scsi_debug module. And getting a invalid paging request BUG_ON as following: [ 34.625854] BUG: unable to handle page fault for address: ffffffffa0016bb8 [ 34.629189] Oops: 0000 [#1] SMP PTI [ 34.629618] CPU: 1 PID: 450 Comm: bash Tainted: G W 5.4.0-rc3+ #473 [ 34.632524] RIP: 0010:scsi_proc_hostdir_rm+0x5/0xa0 [ 34.643555] CR2: ffffffffa0016bb8 CR3: 000000012cd88000 CR4: 00000000000006e0 [ 34.644545] Call Trace: [ 34.644907] scsi_host_dev_release+0x6b/0x1f0 [ 34.645511] device_release+0x74/0x110 [ 34.646046] kobject_put+0x116/0x390 [ 34.646559] put_device+0x17/0x30 [ 34.647041] scsi_target_dev_release+0x2b/0x40 [ 34.647652] device_release+0x74/0x110 [ 34.648186] kobject_put+0x116/0x390 [ 34.648691] put_device+0x17/0x30 [ 34.649157] scsi_device_dev_release_usercontext+0x2e8/0x360 [ 34.649953] execute_in_process_context+0x29/0x80 [ 34.650603] scsi_device_dev_release+0x20/0x30 [ 34.651221] device_release+0x74/0x110 [ 34.651732] kobject_put+0x116/0x390 [ 34.652230] sysfs_unbreak_active_protection+0x3f/0x50 [ 34.652935] sdev_store_delete.cold.4+0x71/0x8f [ 34.653579] dev_attr_store+0x1b/0x40 [ 34.654103] sysfs_kf_write+0x3d/0x60 [ 34.654603] kernfs_fop_write+0x174/0x250 [ 34.655165] __vfs_write+0x1f/0x60 [ 34.655639] vfs_write+0xc7/0x280 [ 34.656117] ksys_write+0x6d/0x140 [ 34.656591] __x64_sys_write+0x1e/0x30 [ 34.657114] do_syscall_64+0xb1/0x400 [ 34.657627] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [ 34.658335] RIP: 0033:0x7f156f337130 During deleting scsi target, the scsi_debug module have been removed. Then, sdebug_driver_template belonged to the module cannot be accessd, resulting in scsi_proc_hostdir_rm() BUG_ON. To fix the bug, we add scsi_device_get() in sdev_store_delete() to try to increase refcount of module, avoiding the module been removed. Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20191015130556.18061-1-yuyufen@huawei.com Signed-off-by: Yufen Yu Reviewed-by: Bart Van Assche Signed-off-by: Martin K. Petersen Signed-off-by: Greg Kroah-Hartman

scsi: Add STARGET_CREATED_REMOVE state to scsi_target_state

2018-11-10T15:41:37Z

[ Upstream commit f9279c968c257ee39b0d7bd2571a4d231a67bcc1 ] 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 Signed-off-by: Ewan D. Milne Cc: Reviewed-by: Laurence Oberman Tested-by: Laurence Oberman Reviewed-by: Johannes Thumshirn Signed-off-by: Martin K. Petersen Signed-off-by: Sasha Levin

scsi: core: Avoid that SCSI device removal through sysfs triggers a deadlock

2018-09-05T07:18:40Z

commit 0ee223b2e1f67cb2de9c0e3247c510d846e74d63 upstream. A long time ago the unfortunate decision was taken to add a self-deletion attribute to the sysfs SCSI device directory. That decision was unfortunate because self-deletion is really tricky. We can't drop that attribute because widely used user space software depends on it, namely the rescan-scsi-bus.sh script. Hence this patch that avoids that writing into that attribute triggers a deadlock. See also commit 7973cbd9fbd9 ("[PATCH] add sysfs attributes to scan and delete scsi_devices"). This patch avoids that self-removal triggers the following deadlock: ====================================================== WARNING: possible circular locking dependency detected 4.18.0-rc2-dbg+ #5 Not tainted ------------------------------------------------------ modprobe/6539 is trying to acquire lock: 000000008323c4cd (kn->count#202){++++}, at: kernfs_remove_by_name_ns+0x45/0x90 but task is already holding lock: 00000000a6ec2c69 (&shost->scan_mutex){+.+.}, at: scsi_remove_host+0x21/0x150 [scsi_mod] which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&shost->scan_mutex){+.+.}: __mutex_lock+0xfe/0xc70 mutex_lock_nested+0x1b/0x20 scsi_remove_device+0x26/0x40 [scsi_mod] sdev_store_delete+0x27/0x30 [scsi_mod] dev_attr_store+0x3e/0x50 sysfs_kf_write+0x87/0xa0 kernfs_fop_write+0x190/0x230 __vfs_write+0xd2/0x3b0 vfs_write+0x101/0x270 ksys_write+0xab/0x120 __x64_sys_write+0x43/0x50 do_syscall_64+0x77/0x230 entry_SYSCALL_64_after_hwframe+0x49/0xbe -> #0 (kn->count#202){++++}: lock_acquire+0xd2/0x260 __kernfs_remove+0x424/0x4a0 kernfs_remove_by_name_ns+0x45/0x90 remove_files.isra.1+0x3a/0x90 sysfs_remove_group+0x5c/0xc0 sysfs_remove_groups+0x39/0x60 device_remove_attrs+0x82/0xb0 device_del+0x251/0x580 __scsi_remove_device+0x19f/0x1d0 [scsi_mod] scsi_forget_host+0x37/0xb0 [scsi_mod] scsi_remove_host+0x9b/0x150 [scsi_mod] sdebug_driver_remove+0x4b/0x150 [scsi_debug] device_release_driver_internal+0x241/0x360 device_release_driver+0x12/0x20 bus_remove_device+0x1bc/0x290 device_del+0x259/0x580 device_unregister+0x1a/0x70 sdebug_remove_adapter+0x8b/0xf0 [scsi_debug] scsi_debug_exit+0x76/0xe8 [scsi_debug] __x64_sys_delete_module+0x1c1/0x280 do_syscall_64+0x77/0x230 entry_SYSCALL_64_after_hwframe+0x49/0xbe other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&shost->scan_mutex); lock(kn->count#202); lock(&shost->scan_mutex); lock(kn->count#202); *** DEADLOCK *** 2 locks held by modprobe/6539: #0: 00000000efaf9298 (&dev->mutex){....}, at: device_release_driver_internal+0x68/0x360 #1: 00000000a6ec2c69 (&shost->scan_mutex){+.+.}, at: scsi_remove_host+0x21/0x150 [scsi_mod] stack backtrace: CPU: 10 PID: 6539 Comm: modprobe Not tainted 4.18.0-rc2-dbg+ #5 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.0.0-prebuilt.qemu-project.org 04/01/2014 Call Trace: dump_stack+0xa4/0xf5 print_circular_bug.isra.34+0x213/0x221 __lock_acquire+0x1a7e/0x1b50 lock_acquire+0xd2/0x260 __kernfs_remove+0x424/0x4a0 kernfs_remove_by_name_ns+0x45/0x90 remove_files.isra.1+0x3a/0x90 sysfs_remove_group+0x5c/0xc0 sysfs_remove_groups+0x39/0x60 device_remove_attrs+0x82/0xb0 device_del+0x251/0x580 __scsi_remove_device+0x19f/0x1d0 [scsi_mod] scsi_forget_host+0x37/0xb0 [scsi_mod] scsi_remove_host+0x9b/0x150 [scsi_mod] sdebug_driver_remove+0x4b/0x150 [scsi_debug] device_release_driver_internal+0x241/0x360 device_release_driver+0x12/0x20 bus_remove_device+0x1bc/0x290 device_del+0x259/0x580 device_unregister+0x1a/0x70 sdebug_remove_adapter+0x8b/0xf0 [scsi_debug] scsi_debug_exit+0x76/0xe8 [scsi_debug] __x64_sys_delete_module+0x1c1/0x280 do_syscall_64+0x77/0x230 entry_SYSCALL_64_after_hwframe+0x49/0xbe See also https://www.mail-archive.com/linux-scsi@vger.kernel.org/msg54525.html. Fixes: ac0ece9174ac ("scsi: use device_remove_file_self() instead of device_schedule_callback()") Signed-off-by: Bart Van Assche Cc: Greg Kroah-Hartman Acked-by: Tejun Heo Cc: Johannes Thumshirn Cc: Signed-off-by: Greg Kroah-Hartman Signed-off-by: Martin K. Petersen

scsi: avoid a permanent stop of the scsi device's request queue

2017-01-09T07:07:48Z

commit d2a145252c52792bc59e4767b486b26c430af4bb upstream. A race between scanning and fc_remote_port_delete() may result in a permanent stop if the device gets blocked before scsi_sysfs_add_sdev() and unblocked after. The reason is that blocking a device sets both the SDEV_BLOCKED state and the QUEUE_FLAG_STOPPED. However, scsi_sysfs_add_sdev() unconditionally sets SDEV_RUNNING which causes the device to be ignored by scsi_target_unblock() and thus never have its QUEUE_FLAG_STOPPED cleared leading to a device which is apparently running but has a stopped queue. We actually have two places where SDEV_RUNNING is set: once in scsi_add_lun() which respects the blocked flag and once in scsi_sysfs_add_sdev() which doesn't. Since the second set is entirely spurious, simply remove it to fix the problem. Reported-by: Zengxi Chen Signed-off-by: Wei Fang Reviewed-by: Ewan D. Milne Signed-off-by: Martin K. Petersen Signed-off-by: Greg Kroah-Hartman

scsi: ignore errors from scsi_dh_add_device()

2016-08-16T07:30:48Z

commit 221255aee67ec1c752001080aafec0c4e9390d95 upstream. device handler initialisation might fail due to a number of reasons. But as device_handlers are optional this shouldn't cause us to disable the device entirely. So just ignore errors from scsi_dh_add_device(). Reviewed-by: Johannes Thumshirn Reviewed-by: Christoph Hellwig Signed-off-by: Hannes Reinecke Signed-off-by: Martin K. Petersen Cc: Laura Abbott Signed-off-by: Greg Kroah-Hartman

Revert "scsi: fix soft lockup in scsi_remove_target() on module removal"

2016-06-01T19:15:54Z

commit 305c2e71b3d733ec065cb716c76af7d554bd5571 upstream. Now that we've done a more comprehensive fix with the intermediate target state we can remove the previous hack introduced with commit 90a88d6ef88e ("scsi: fix soft lockup in scsi_remove_target() on module removal"). Signed-off-by: Johannes Thumshirn Reviewed-by: Ewan D. Milne Reviewed-by: Hannes Reinecke Signed-off-by: Martin K. Petersen Signed-off-by: Greg Kroah-Hartman

scsi: Add intermediate STARGET_REMOVE state to scsi_target_state

2016-06-01T19:15:54Z

commit f05795d3d771f30a7bdc3a138bf714b06d42aa95 upstream. Add intermediate STARGET_REMOVE state to scsi_target_state to avoid running into the BUG_ON() in scsi_target_reap(). The STARGET_REMOVE state is only valid in the path from scsi_remove_target() to scsi_target_destroy() indicating this target is going to be removed. This re-fixes the problem introduced in commits bc3f02a795d3 ("[SCSI] scsi_remove_target: fix softlockup regression on hot remove") and 40998193560d ("scsi: restart list search after unlock in scsi_remove_target") in a more comprehensive way. [mkp: Included James' fix for scsi_target_destroy()] Signed-off-by: Johannes Thumshirn Fixes: 40998193560dab6c3ce8d25f4fa58a23e252ef38 Reported-by: Sergey Senozhatsky Tested-by: Sergey Senozhatsky Reviewed-by: Ewan D. Milne Reviewed-by: Hannes Reinecke Reviewed-by: James Bottomley Signed-off-by: Martin K. Petersen Signed-off-by: Greg Kroah-Hartman

scsi: fix soft lockup in scsi_remove_target() on module removal

2016-02-25T20:01:17Z

commit 90a88d6ef88edcfc4f644dddc7eef4ea41bccf8b upstream. This softlockup is currently happening: [ 444.088002] NMI watchdog: BUG: soft lockup - CPU#1 stuck for 22s! [kworker/1:1:29] [ 444.088002] Modules linked in: lpfc(-) qla2x00tgt(O) qla2xxx_scst(O) scst_vdisk(O) scsi_transport_fc libcrc32c scst(O) dlm configfs nfsd lockd grace nfs_acl auth_rpcgss sunrpc ed d snd_pcm_oss snd_mixer_oss snd_seq snd_seq_device dm_mod iTCO_wdt snd_hda_codec_realtek snd_hda_codec_generic gpio_ich iTCO_vendor_support ppdev snd_hda_intel snd_hda_codec snd_hda _core snd_hwdep tg3 snd_pcm snd_timer libphy lpc_ich parport_pc ptp acpi_cpufreq snd pps_core fjes parport i2c_i801 ehci_pci tpm_tis tpm sr_mod cdrom soundcore floppy hwmon sg 8250_ fintek pcspkr i915 drm_kms_helper uhci_hcd ehci_hcd drm fb_sys_fops sysimgblt sysfillrect syscopyarea i2c_algo_bit usbcore button video usb_common fan ata_generic ata_piix libata th ermal [ 444.088002] CPU: 1 PID: 29 Comm: kworker/1:1 Tainted: G O 4.4.0-rc5-2.g1e923a3-default #1 [ 444.088002] Hardware name: FUJITSU SIEMENS ESPRIMO E /D2164-A1, BIOS 5.00 R1.10.2164.A1 05/08/2006 [ 444.088002] Workqueue: fc_wq_4 fc_rport_final_delete [scsi_transport_fc] [ 444.088002] task: f6266ec0 ti: f6268000 task.ti: f6268000 [ 444.088002] EIP: 0060:[] EFLAGS: 00000286 CPU: 1 [ 444.088002] EIP is at _raw_spin_unlock_irqrestore+0x14/0x20 [ 444.088002] EAX: 00000286 EBX: f20d3800 ECX: 00000002 EDX: 00000286 [ 444.088002] ESI: f50ba800 EDI: f2146848 EBP: f6269ec8 ESP: f6269ec8 [ 444.088002] DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068 [ 444.088002] CR0: 8005003b CR2: 08f96600 CR3: 363ae000 CR4: 000006d0 [ 444.088002] Stack: [ 444.088002] f6269eec c066b0f7 00000286 f2146848 f50ba808 f50ba800 f50ba800 f2146a90 [ 444.088002] f2146848 f6269f08 f8f0a4ed f3141000 f2146800 f2146a90 f619fa00 00000040 [ 444.088002] f6269f40 c026cb25 00000001 166c6392 00000061 f6757140 f6136340 00000004 [ 444.088002] Call Trace: [ 444.088002] [] scsi_remove_target+0x167/0x1c0 [ 444.088002] [] fc_rport_final_delete+0x9d/0x1e0 [scsi_transport_fc] [ 444.088002] [] process_one_work+0x155/0x3e0 [ 444.088002] [] worker_thread+0x37/0x490 [ 444.088002] [] kthread+0x9b/0xb0 [ 444.088002] [] ret_from_kernel_thread+0x21/0x40 What appears to be happening is that something has pinned the target so it can't go into STARGET_DEL via final release and the loop in scsi_remove_target spins endlessly until that happens. The fix for this soft lockup is to not keep looping over a device that we've called remove on but which hasn't gone into DEL state. This patch will retain a simplistic memory of the last target and not keep looping over it. Reported-by: Sebastian Herbszt Tested-by: Sebastian Herbszt Fixes: 40998193560dab6c3ce8d25f4fa58a23e252ef38 Signed-off-by: James Bottomley Signed-off-by: Greg Kroah-Hartman

Merge branch 'mkp-fixes' into fixes

2015-12-03T17:32:33Z