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Groups > linux.kernel > #1252262

[PATCH 3.13.y-ckt 60/85] scsi: fix scsi_error_handler vs. scsi_host_dev_release race

From Kamal Mostafa <kamal@canonical.com>
Newsgroups linux.kernel
Subject [PATCH 3.13.y-ckt 60/85] scsi: fix scsi_error_handler vs. scsi_host_dev_release race
Date 2015-10-21 00:40 +0200
Message-ID <qlNJx-Ca-31@gated-at.bofh.it> (permalink)
References <qlMNr-7E9-5@gated-at.bofh.it>
Organization linux.* mail to news gateway

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3.13.11-ckt28 -stable review patch.  If anyone has any objections, please let me know.

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

From: Michal Hocko <mhocko@suse.com>

commit 537b604c8b3aa8b96fe35f87dd085816552e294c upstream.

b9d5c6b7ef57 ("[SCSI] cleanup setting task state in
scsi_error_handler()") has introduced a race between scsi_error_handler
and scsi_host_dev_release resulting in the hang when the device goes
away because scsi_error_handler might miss a wake up:

CPU0					CPU1
scsi_error_handler			scsi_host_dev_release
  					  kthread_stop()
  kthread_should_stop()
    test_bit(KTHREAD_SHOULD_STOP)
					    set_bit(KTHREAD_SHOULD_STOP)
					    wake_up_process()
					    wait_for_completion()

  set_current_state(TASK_INTERRUPTIBLE)
  schedule()

The most straightforward solution seems to be to invert the ordering of
the set_current_state and kthread_should_stop.

The issue has been noticed during reboot test on a 3.0 based kernel but
the current code seems to be affected in the same way.

[jejb: additional comment added]
Reported-and-debugged-by: Mike Mayer <Mike.Meyer@teradata.com>
Signed-off-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: James Bottomley <JBottomley@Odin.com>

Signed-off-by: Kamal Mostafa <kamal@canonical.com>
---
 drivers/scsi/scsi_error.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c
index c6dcbe6..790f716 100644
--- a/drivers/scsi/scsi_error.c
+++ b/drivers/scsi/scsi_error.c
@@ -2025,8 +2025,17 @@ int scsi_error_handler(void *data)
 	 * We never actually get interrupted because kthread_run
 	 * disables signal delivery for the created thread.
 	 */
-	while (!kthread_should_stop()) {
+	while (true) {
+		/*
+		 * The sequence in kthread_stop() sets the stop flag first
+		 * then wakes the process.  To avoid missed wakeups, the task
+		 * should always be in a non running state before the stop
+		 * flag is checked
+		 */
 		set_current_state(TASK_INTERRUPTIBLE);
+		if (kthread_should_stop())
+			break;
+
 		if ((shost->host_failed == 0 && shost->host_eh_scheduled == 0) ||
 		    shost->host_failed != shost->host_busy) {
 			SCSI_LOG_ERROR_RECOVERY(1,
-- 
1.9.1

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[3.13.y-ckt stable] Linux 3.13.11-ckt28 stable review Kamal Mostafa <kamal@canonical.com> - 2015-10-20 23:40 +0200
  [PATCH 3.13.y-ckt 73/85] perf hists: Update the column width for the "srcline" sort key Kamal Mostafa <kamal@canonical.com> - 2015-10-21 00:30 +0200
  [PATCH 3.13.y-ckt 84/85] task_work: remove fifo ordering guarantee Kamal Mostafa <kamal@canonical.com> - 2015-10-21 00:30 +0200
  [PATCH 3.13.y-ckt 65/85] drm/qxl: validate monitors config modes Kamal Mostafa <kamal@canonical.com> - 2015-10-21 00:30 +0200
  [PATCH 3.13.y-ckt 85/85] scsi_dh: fix randconfig build error Kamal Mostafa <kamal@canonical.com> - 2015-10-21 00:30 +0200
  [PATCH 3.13.y-ckt 82/85] mmc: core: fix race condition in mmc_wait_data_done Kamal Mostafa <kamal@canonical.com> - 2015-10-21 00:30 +0200
  [PATCH 3.13.y-ckt 81/85] IB/uverbs: Fix race between ib_uverbs_open and remove_one Kamal Mostafa <kamal@canonical.com> - 2015-10-21 00:30 +0200
  [PATCH 3.13.y-ckt 79/85] IB/mlx4: Forbid using sysfs to change RoCE pkeys Kamal Mostafa <kamal@canonical.com> - 2015-10-21 00:30 +0200
  [PATCH 3.13.y-ckt 80/85] IB/mlx4: Use correct SL on AH query under RoCE Kamal Mostafa <kamal@canonical.com> - 2015-10-21 00:30 +0200
  [PATCH 3.13.y-ckt 83/85] ipv6: fix exthdrs offload registration in out_rt path Kamal Mostafa <kamal@canonical.com> - 2015-10-21 00:30 +0200
  [PATCH 3.13.y-ckt 77/85] perf stat: Get correct cpu id for print_aggr Kamal Mostafa <kamal@canonical.com> - 2015-10-21 00:30 +0200
  [PATCH 3.13.y-ckt 67/85] x86/mm: Initialize pmd_idx in page_table_range_init_count() Kamal Mostafa <kamal@canonical.com> - 2015-10-21 00:40 +0200
  [PATCH 3.13.y-ckt 55/85] Input: evdev - do not report errors form flush() Kamal Mostafa <kamal@canonical.com> - 2015-10-21 00:40 +0200
  [PATCH 3.13.y-ckt 48/85] xfs: return errors from partial I/O failures to files Kamal Mostafa <kamal@canonical.com> - 2015-10-21 00:40 +0200
  [PATCH 3.13.y-ckt 75/85] batman-adv: Make NC capability changes atomic Kamal Mostafa <kamal@canonical.com> - 2015-10-21 00:40 +0200
  [PATCH 3.13.y-ckt 69/85] jbd2: avoid infinite loop when destroying aborted journal Kamal Mostafa <kamal@canonical.com> - 2015-10-21 00:40 +0200
  [PATCH 3.13.y-ckt 56/85] crypto: ghash-clmulni: specify context size for ghash async algorithm Kamal Mostafa <kamal@canonical.com> - 2015-10-21 00:40 +0200
  [PATCH 3.13.y-ckt 50/85] tg3: Fix temperature reporting Kamal Mostafa <kamal@canonical.com> - 2015-10-21 00:40 +0200
  [PATCH 3.13.y-ckt 60/85] scsi: fix scsi_error_handler vs. scsi_host_dev_release race Kamal Mostafa <kamal@canonical.com> - 2015-10-21 00:40 +0200
  [PATCH 3.13.y-ckt 49/85] IB/qib: Change lkey table allocation to support more MRs Kamal Mostafa <kamal@canonical.com> - 2015-10-21 00:40 +0200
  [PATCH 3.13.y-ckt 70/85] clk: versatile: off by one in clk_sp810_timerclken_of_get() Kamal Mostafa <kamal@canonical.com> - 2015-10-21 00:40 +0200
  [PATCH 3.13.y-ckt 74/85] batman-adv: Make DAT capability changes atomic Kamal Mostafa <kamal@canonical.com> - 2015-10-21 00:40 +0200
  [PATCH 3.13.y-ckt 41/85] Btrfs: check if previous transaction aborted to avoid fs corruption Kamal Mostafa <kamal@canonical.com> - 2015-10-21 00:40 +0200
  [PATCH 3.13.y-ckt 71/85] usb: gadget: m66592-udc: forever loop in set_feature() Kamal Mostafa <kamal@canonical.com> - 2015-10-21 00:40 +0200
  [PATCH 3.13.y-ckt 78/85] IB/mlx4: Fix potential deadlock when sending mad to wire Kamal Mostafa <kamal@canonical.com> - 2015-10-21 00:40 +0200
  [PATCH 3.13.y-ckt 57/85] fs: create and use seq_show_option for escaping Kamal Mostafa <kamal@canonical.com> - 2015-10-21 00:40 +0200
  [PATCH 3.13.y-ckt 58/85] ALSA: hda - Enable headphone jack detect on old Fujitsu laptops Kamal Mostafa <kamal@canonical.com> - 2015-10-21 00:40 +0200
  [PATCH 3.13.y-ckt 53/85] IB/uverbs: reject invalid or unknown opcodes Kamal Mostafa <kamal@canonical.com> - 2015-10-21 00:40 +0200
  [PATCH 3.13.y-ckt 61/85] parisc: Use double word condition in 64bit CAS operation Kamal Mostafa <kamal@canonical.com> - 2015-10-21 00:40 +0200
  [PATCH 3.13.y-ckt 76/85] powerpc/mm: Fix pte_pagesize_index() crash on 4K w/64K hash Kamal Mostafa <kamal@canonical.com> - 2015-10-21 00:40 +0200
  [PATCH 3.13.y-ckt 51/85] drm/i915: Always mark the object as dirty when used by the GPU Kamal Mostafa <kamal@canonical.com> - 2015-10-21 00:40 +0200
  [PATCH 3.13.y-ckt 54/85] hpfs: update ctime and mtime on directory modification Kamal Mostafa <kamal@canonical.com> - 2015-10-21 00:40 +0200
  [PATCH 3.13.y-ckt 46/85] drivercore: Fix unregistration path of platform devices Kamal Mostafa <kamal@canonical.com> - 2015-10-21 00:40 +0200
  [PATCH 3.13.y-ckt 68/85] powerpc/rtas: Introduce rtas_get_sensor_fast() for IRQ handlers Kamal Mostafa <kamal@canonical.com> - 2015-10-21 00:40 +0200
  [PATCH 3.13.y-ckt 47/85] Input: synaptics - fix handling of disabling gesture mode Kamal Mostafa <kamal@canonical.com> - 2015-10-21 00:40 +0200
    Re: [PATCH 3.13.y-ckt 47/85] Input: synaptics - fix handling of  disabling gesture mode Dmitry Torokhov <dmitry.torokhov@gmail.com> - 2015-10-21 00:50 +0200
      Re: [PATCH 3.13.y-ckt 47/85] Input: synaptics - fix handling of  disabling gesture mode Kamal Mostafa <kamal@canonical.com> - 2015-10-21 22:30 +0200
  [PATCH 3.13.y-ckt 43/85] rtlwifi: rtl8192cu: Add new device ID Kamal Mostafa <kamal@canonical.com> - 2015-10-21 00:40 +0200
  [PATCH 3.13.y-ckt 21/85] iio: event: Remove negative error code from iio_event_poll Kamal Mostafa <kamal@canonical.com> - 2015-10-21 00:40 +0200
  [PATCH 3.13.y-ckt 72/85] windfarm: decrement client count when unregistering Kamal Mostafa <kamal@canonical.com> - 2015-10-21 00:40 +0200
  [PATCH 3.13.y-ckt 22/85] NFSv4: don't set SETATTR for O_RDONLY|O_EXCL Kamal Mostafa <kamal@canonical.com> - 2015-10-21 00:40 +0200
  [PATCH 3.13.y-ckt 52/85] Add radeon suspend/resume quirk for HP Compaq dc5750. Kamal Mostafa <kamal@canonical.com> - 2015-10-21 00:40 +0200
  [PATCH 3.13.y-ckt 59/85] ALSA: hda - Use ALC880_FIXUP_FUJITSU for FSC Amilo M1437 Kamal Mostafa <kamal@canonical.com> - 2015-10-21 00:40 +0200
  [PATCH 3.13.y-ckt 35/85] USB: ftdi_sio: Added custom PID for CustomWare products Kamal Mostafa <kamal@canonical.com> - 2015-10-21 00:50 +0200
  [PATCH 3.13.y-ckt 30/85] xtensa: fix kernel register spilling Kamal Mostafa <kamal@canonical.com> - 2015-10-21 00:50 +0200
  [PATCH 3.13.y-ckt 26/85] drivers: usb: fsl: Workaround for USB erratum-A005275 Kamal Mostafa <kamal@canonical.com> - 2015-10-21 00:50 +0200
  [PATCH 3.13.y-ckt 36/85] HID: usbhid: Fix the check for HID_RESET_PENDING in hid_io_error Kamal Mostafa <kamal@canonical.com> - 2015-10-21 00:50 +0200
  [PATCH 3.13.y-ckt 17/85] iio: adis16400: Fix adis16448 gyroscope scale Kamal Mostafa <kamal@canonical.com> - 2015-10-21 00:50 +0200
  [PATCH 3.13.y-ckt 38/85] libxfs: readahead of dir3 data blocks should use the read verifier Kamal Mostafa <kamal@canonical.com> - 2015-10-21 00:50 +0200
  [PATCH 3.13.y-ckt 18/85] iio: Add inverse unit conversion macros Kamal Mostafa <kamal@canonical.com> - 2015-10-21 00:50 +0200
  [PATCH 3.13.y-ckt 37/85] eCryptfs: Invalidate dcache entries when lower i_nlink is zero Kamal Mostafa <kamal@canonical.com> - 2015-10-21 00:50 +0200
  [PATCH 3.13.y-ckt 31/85] NFS: nfs_set_pgio_error sometimes misses errors Kamal Mostafa <kamal@canonical.com> - 2015-10-21 00:50 +0200
  [PATCH 3.13.y-ckt 44/85] rtlwifi: rtl8192cu: Add new device ID Kamal Mostafa <kamal@canonical.com> - 2015-10-21 00:50 +0200
  [PATCH 3.13.y-ckt 45/85] of/address: Don't loop forever in of_find_matching_node_by_address(). Kamal Mostafa <kamal@canonical.com> - 2015-10-21 00:50 +0200
  [PATCH 3.13.y-ckt 28/85] staging: comedi: adl_pci7x3x: fix digital output on PCI-7230 Kamal Mostafa <kamal@canonical.com> - 2015-10-21 00:50 +0200
  [PATCH 3.13.y-ckt 39/85] xfs: Fix xfs_attr_leafblock definition Kamal Mostafa <kamal@canonical.com> - 2015-10-21 00:50 +0200
  [PATCH 3.13.y-ckt 27/85] serial: 8250: don't bind to SMSC IrCC IR port Kamal Mostafa <kamal@canonical.com> - 2015-10-21 00:50 +0200
  [PATCH 3.13.y-ckt 34/85] USB: symbolserial: Use usb_get_serial_port_data Kamal Mostafa <kamal@canonical.com> - 2015-10-21 00:50 +0200
  [PATCH 3.13.y-ckt 32/85] NFS: Fix a NULL pointer dereference of migration recovery ops for v4.2 client Kamal Mostafa <kamal@canonical.com> - 2015-10-21 00:50 +0200
  [PATCH 3.13.y-ckt 29/85] blk-mq: fix buffer overflow when reading sysfs file of 'pending' Kamal Mostafa <kamal@canonical.com> - 2015-10-21 00:50 +0200
  [PATCH 3.13.y-ckt 42/85] DRM - radeon: Don't link train DisplayPort on HPD until we get the dpcd Kamal Mostafa <kamal@canonical.com> - 2015-10-21 00:50 +0200
  [PATCH 3.13.y-ckt 33/85] usb: host: ehci-sys: delete useless bus_to_hcd conversion Kamal Mostafa <kamal@canonical.com> - 2015-10-21 00:50 +0200
  [PATCH 3.13.y-ckt 40/85] arm64: kconfig: Move LIST_POISON to a safe value Kamal Mostafa <kamal@canonical.com> - 2015-10-21 00:50 +0200
  [PATCH 3.13.y-ckt 02/85] dcache: Handle escaped paths in prepend_path Kamal Mostafa <kamal@canonical.com> - 2015-10-21 00:50 +0200
  [PATCH 3.13.y-ckt 07/85] xtensa: fix threadptr reload on return to userspace Kamal Mostafa <kamal@canonical.com> - 2015-10-21 01:00 +0200
  [PATCH 3.13.y-ckt 03/85] vfs: Test for and handle paths that are unreachable from their mnt_root Kamal Mostafa <kamal@canonical.com> - 2015-10-21 01:00 +0200
  [PATCH 3.13.y-ckt 05/85] [media] v4l: omap3isp: Fix sub-device power management code Kamal Mostafa <kamal@canonical.com> - 2015-10-21 01:00 +0200
  [PATCH 3.13.y-ckt 16/85] devres: fix devres_get() Kamal Mostafa <kamal@canonical.com> - 2015-10-21 01:00 +0200
  [PATCH 3.13.y-ckt 08/85] ARM: OMAP2+: DRA7: clockdomain: change l4per2_7xx_clkdm to SW_WKUP Kamal Mostafa <kamal@canonical.com> - 2015-10-21 01:00 +0200
  [PATCH 3.13.y-ckt 04/85] sctp: fix race on protocol/netns initialization Kamal Mostafa <kamal@canonical.com> - 2015-10-21 01:00 +0200
  [PATCH 3.13.y-ckt 12/85] usb: dwc3: ep0: Fix mem corruption on OUT transfers of more than 512 bytes Kamal Mostafa <kamal@canonical.com> - 2015-10-21 01:00 +0200
  [PATCH 3.13.y-ckt 14/85] KVM: MMU: fix validation of mmio page fault Kamal Mostafa <kamal@canonical.com> - 2015-10-21 01:00 +0200
  [PATCH 3.13.y-ckt 11/85] PCI: Add VPD function 0 quirk for Intel Ethernet devices Kamal Mostafa <kamal@canonical.com> - 2015-10-21 01:00 +0200
  [PATCH 3.13.y-ckt 10/85] PCI: Add dev_flags bit to access VPD through function 0 Kamal Mostafa <kamal@canonical.com> - 2015-10-21 01:00 +0200
  [PATCH 3.13.y-ckt 15/85] auxdisplay: ks0108: fix refcount Kamal Mostafa <kamal@canonical.com> - 2015-10-21 01:00 +0200
  [PATCH 3.13.y-ckt 09/85] mac80211: enable assoc check for mesh interfaces Kamal Mostafa <kamal@canonical.com> - 2015-10-21 01:00 +0200
  [PATCH 3.13.y-ckt 13/85] serial: 8250_pci: Add support for Pericom PI7C9X795[1248] Kamal Mostafa <kamal@canonical.com> - 2015-10-21 01:00 +0200

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