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Groups > linux.kernel > #1696353

[PATCH 4.9 035/125] scsi: Add STARGET_CREATED_REMOVE state to scsi_target_state

From Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Newsgroups linux.kernel
Subject [PATCH 4.9 035/125] scsi: Add STARGET_CREATED_REMOVE state to scsi_target_state
Date 2017-07-25 22:40 +0200
Message-ID <u7eMy-7zW-27@gated-at.bofh.it> (permalink)
References <u7dGN-6Sz-9@gated-at.bofh.it>
Organization linux.* mail to news gateway

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4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Ewan D. Milne <emilne@redhat.com>

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>

---
 drivers/scsi/scsi_scan.c   |    5 +++--
 drivers/scsi/scsi_sysfs.c  |    8 ++++++--
 include/scsi/scsi_device.h |    1 +
 3 files changed, 10 insertions(+), 4 deletions(-)

--- a/drivers/scsi/scsi_scan.c
+++ b/drivers/scsi/scsi_scan.c
@@ -384,11 +384,12 @@ static void scsi_target_reap_ref_release
 		= container_of(kref, struct scsi_target, reap_ref);
 
 	/*
-	 * if we get here and the target is still in the CREATED state that
+	 * if we get here and the target is still in a CREATED state that
 	 * means it was allocated but never made visible (because a scan
 	 * turned up no LUNs), so don't call device_del() on it.
 	 */
-	if (starget->state != STARGET_CREATED) {
+	if ((starget->state != STARGET_CREATED) &&
+	    (starget->state != STARGET_CREATED_REMOVE)) {
 		transport_remove_device(&starget->dev);
 		device_del(&starget->dev);
 	}
--- a/drivers/scsi/scsi_sysfs.c
+++ b/drivers/scsi/scsi_sysfs.c
@@ -1370,11 +1370,15 @@ restart:
 	spin_lock_irqsave(shost->host_lock, flags);
 	list_for_each_entry(starget, &shost->__targets, siblings) {
 		if (starget->state == STARGET_DEL ||
-		    starget->state == STARGET_REMOVE)
+		    starget->state == STARGET_REMOVE ||
+		    starget->state == STARGET_CREATED_REMOVE)
 			continue;
 		if (starget->dev.parent == dev || &starget->dev == dev) {
 			kref_get(&starget->reap_ref);
-			starget->state = STARGET_REMOVE;
+			if (starget->state == STARGET_CREATED)
+				starget->state = STARGET_CREATED_REMOVE;
+			else
+				starget->state = STARGET_REMOVE;
 			spin_unlock_irqrestore(shost->host_lock, flags);
 			__scsi_remove_target(starget);
 			scsi_target_reap(starget);
--- a/include/scsi/scsi_device.h
+++ b/include/scsi/scsi_device.h
@@ -248,6 +248,7 @@ enum scsi_target_state {
 	STARGET_CREATED = 1,
 	STARGET_RUNNING,
 	STARGET_REMOVE,
+	STARGET_CREATED_REMOVE,
 	STARGET_DEL,
 };
 

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[PATCH 4.9 000/125] 4.9.40-stable review Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-25 22:40 +0200
  [PATCH 4.9 068/125] ipmi: use rcu lock around call to intf->handlers->sender() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-25 22:40 +0200
  [PATCH 4.9 046/125] PCI: rockchip: Use normal register bank for config accessors Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-25 22:40 +0200
  [PATCH 4.9 042/125] powerpc/asm: Mark cr0 as clobbered in mftb() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-25 22:40 +0200
  [PATCH 4.9 035/125] scsi: Add STARGET_CREATED_REMOVE state to scsi_target_state Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-25 22:40 +0200
  [PATCH 4.9 044/125] af_key: Fix sadb_x_ipsecrequest parsing Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-25 22:40 +0200
  [PATCH 4.9 037/125] xen/scsiback: Fix a TMR related use-after-free Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-25 22:40 +0200
  [PATCH 4.9 053/125] usb: storage: return on error to avoid a null pointer dereference Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-25 22:40 +0200
  [PATCH 4.9 030/125] ASoC: compress: Derive substream from stream based on direction Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-25 22:40 +0200
  [PATCH 4.9 008/125] ath9k: fix tx99 bus error Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-25 22:40 +0200
  [PATCH 4.9 027/125] wlcore: fix 64K page support Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-25 22:40 +0200
  [PATCH 4.9 056/125] usb: renesas_usbhs: gadget: disable all eps when the driver stops Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-25 22:40 +0200
  [PATCH 4.9 047/125] PCI/PM: Restore the status of PCI devices across hibernation Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-25 22:40 +0200
  [PATCH 4.9 049/125] xhci: fix 20000ms port resume timeout Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-25 22:40 +0200
  [PATCH 4.9 028/125] btrfs: Dont clear SGID when inheriting ACLs Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-25 22:40 +0200
  [PATCH 4.9 033/125] PM / Domains: Fix unsafe iteration over modified list of domains Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-25 22:40 +0200
  [PATCH 4.9 052/125] [media] mxl111sf: Fix driver to use heap allocate buffers for USB messages Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-25 22:40 +0200
  [PATCH 4.9 009/125] ath9k: fix an invalid pointer dereference in ath9k_rng_stop() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-25 22:40 +0200
  [PATCH 4.9 041/125] powerpc: Fix emulation of mfocrf in emulate_step() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-25 22:40 +0200
  [PATCH 4.9 043/125] powerpc/mm/radix: Properly clear process table entry Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-25 22:40 +0200
  [PATCH 4.9 039/125] powerpc/64: Fix atomic64_inc_not_zero() to return an int Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-25 22:40 +0200
  [PATCH 4.9 034/125] scsi: ses: do not add a device to an enclosure if enclosure_add_links() fails. Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-25 22:40 +0200
  [PATCH 4.9 029/125] igb: Explicitly select page 0 at initialization Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-25 22:40 +0200
  [PATCH 4.9 032/125] PM / Domains: Fix unsafe iteration over modified list of domain providers Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-25 22:40 +0200
  [PATCH 4.9 036/125] iscsi-target: Add login_keys_workaround attribute for non RFC initiators Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-25 22:40 +0200
  [PATCH 4.9 054/125] USB: cdc-acm: add device-id for quirky printer Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-25 22:40 +0200
  [PATCH 4.9 071/125] f2fs: sanity check size of nat and sit cache Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-25 22:40 +0200
  [PATCH 4.9 050/125] xhci: Fix NULL pointer dereference when cleaning up streams for removed host Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-25 22:40 +0200
  [PATCH 4.9 069/125] ipmi:ssif: Add missing unlock in error branch Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-25 22:40 +0200
  [PATCH 4.9 026/125] Bluetooth: use constant time memory comparison for secret values Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-25 22:40 +0200
  [PATCH 4.9 031/125] PM / Domains: Fix unsafe iteration over modified list of device links Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-25 22:40 +0200
  [PATCH 4.9 040/125] powerpc: Fix emulation of mcrf in emulate_step() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-25 22:40 +0200
  [PATCH 4.9 023/125] perf intel-pt: Ensure never to set last_ip when packet count is zero Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-25 22:50 +0200
  [PATCH 4.9 003/125] dm mpath: cleanup -Wbool-operation warning in choose_pgpath() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-25 22:50 +0200
  [PATCH 4.9 017/125] NFC: Add sockaddr length checks before accessing sa_family in bind handlers Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-25 22:50 +0200
  [PATCH 4.9 018/125] perf intel-pt: Move decoder error setting into one condition Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-25 22:50 +0200
  [PATCH 4.9 005/125] thermal: max77620: fix device-node reference imbalance Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-25 22:50 +0200
  [PATCH 4.9 006/125] thermal: cpu_cooling: Avoid accessing potentially freed structures Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-25 22:50 +0200
  [PATCH 4.9 004/125] [media] s5p-jpeg: dont return a random width/height Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-25 22:50 +0200
  [PATCH 4.9 001/125] disable new gcc-7.1.1 warnings for now Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-25 22:50 +0200
  [PATCH 4.9 015/125] nfc: Ensure presence of required attributes in the activate_target handler Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-25 22:50 +0200
  [PATCH 4.9 020/125] perf intel-pt: Fix missing stack clear Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-25 22:50 +0200
  [PATCH 4.9 002/125] [media] ir-core: fix gcc-7 warning on bool arithmetic Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-25 22:50 +0200
  [PATCH 4.9 012/125] NFC: nfcmrvl: do not use device-managed resources Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-25 22:50 +0200
  [PATCH 4.9 007/125] ath9k: fix tx99 use after free Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-25 22:50 +0200
  [PATCH 4.9 021/125] perf intel-pt: Ensure IP is zero when state is INTEL_PT_STATE_NO_IP Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-25 22:50 +0200
  [PATCH 4.9 011/125] NFC: nfcmrvl_uart: add missing tty-device sanity check Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-25 22:50 +0200
  [PATCH 4.9 014/125] NFC: nfcmrvl: fix firmware-management initialisation Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-25 22:50 +0200
  [PATCH 4.9 016/125] nfc: Fix the sockaddr length sanitization in llcp_sock_connect Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-25 22:50 +0200
  [PATCH 4.9 019/125] perf intel-pt: Improve sample timestamp Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-25 22:50 +0200
  [PATCH 4.9 010/125] NFC: fix broken device allocation Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-25 22:50 +0200
  [PATCH 4.9 013/125] NFC: nfcmrvl: use nfc-device for firmware download Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-25 22:50 +0200
  Re: [PATCH 4.9 000/125] 4.9.40-stable review Guenter Roeck <linux@roeck-us.net> - 2017-07-26 05:00 +0200
  Re: [PATCH 4.9 000/125] 4.9.40-stable review Sumit Semwal <sumit.semwal@linaro.org> - 2017-07-26 16:20 +0200
    Re: [PATCH 4.9 000/125] 4.9.40-stable review Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-26 22:00 +0200
  Re: [PATCH 4.9 000/125] 4.9.40-stable review Shuah Khan <shuahkh@osg.samsung.com> - 2017-07-26 16:30 +0200

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