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From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	stable@vger.kernel.org, Josef Bacik <josef@toxicpanda.com>,
	Filipe Manana <fdmanana@suse.com>,
	David Sterba <dsterba@suse.com>, Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.4 99/99] Btrfs: fix race setting up and completing qgroup rescan workers
Date: Thu,  3 Oct 2019 17:54:02 +0200	[thread overview]
Message-ID: <20191003154345.478874796@linuxfoundation.org> (raw)
In-Reply-To: <20191003154252.297991283@linuxfoundation.org>

From: Filipe Manana <fdmanana@suse.com>

[ Upstream commit 13fc1d271a2e3ab8a02071e711add01fab9271f6 ]

There is a race between setting up a qgroup rescan worker and completing
a qgroup rescan worker that can lead to callers of the qgroup rescan wait
ioctl to either not wait for the rescan worker to complete or to hang
forever due to missing wake ups. The following diagram shows a sequence
of steps that illustrates the race.

        CPU 1                                                         CPU 2                                  CPU 3

 btrfs_ioctl_quota_rescan()
  btrfs_qgroup_rescan()
   qgroup_rescan_init()
    mutex_lock(&fs_info->qgroup_rescan_lock)
    spin_lock(&fs_info->qgroup_lock)

    fs_info->qgroup_flags |=
      BTRFS_QGROUP_STATUS_FLAG_RESCAN

    init_completion(
      &fs_info->qgroup_rescan_completion)

    fs_info->qgroup_rescan_running = true

    mutex_unlock(&fs_info->qgroup_rescan_lock)
    spin_unlock(&fs_info->qgroup_lock)

    btrfs_init_work()
     --> starts the worker

                                                        btrfs_qgroup_rescan_worker()
                                                         mutex_lock(&fs_info->qgroup_rescan_lock)

                                                         fs_info->qgroup_flags &=
                                                           ~BTRFS_QGROUP_STATUS_FLAG_RESCAN

                                                         mutex_unlock(&fs_info->qgroup_rescan_lock)

                                                         starts transaction, updates qgroup status
                                                         item, etc

                                                                                                           btrfs_ioctl_quota_rescan()
                                                                                                            btrfs_qgroup_rescan()
                                                                                                             qgroup_rescan_init()
                                                                                                              mutex_lock(&fs_info->qgroup_rescan_lock)
                                                                                                              spin_lock(&fs_info->qgroup_lock)

                                                                                                              fs_info->qgroup_flags |=
                                                                                                                BTRFS_QGROUP_STATUS_FLAG_RESCAN

                                                                                                              init_completion(
                                                                                                                &fs_info->qgroup_rescan_completion)

                                                                                                              fs_info->qgroup_rescan_running = true

                                                                                                              mutex_unlock(&fs_info->qgroup_rescan_lock)
                                                                                                              spin_unlock(&fs_info->qgroup_lock)

                                                                                                              btrfs_init_work()
                                                                                                               --> starts another worker

                                                         mutex_lock(&fs_info->qgroup_rescan_lock)

                                                         fs_info->qgroup_rescan_running = false

                                                         mutex_unlock(&fs_info->qgroup_rescan_lock)

							 complete_all(&fs_info->qgroup_rescan_completion)

Before the rescan worker started by the task at CPU 3 completes, if
another task calls btrfs_ioctl_quota_rescan(), it will get -EINPROGRESS
because the flag BTRFS_QGROUP_STATUS_FLAG_RESCAN is set at
fs_info->qgroup_flags, which is expected and correct behaviour.

However if other task calls btrfs_ioctl_quota_rescan_wait() before the
rescan worker started by the task at CPU 3 completes, it will return
immediately without waiting for the new rescan worker to complete,
because fs_info->qgroup_rescan_running is set to false by CPU 2.

This race is making test case btrfs/171 (from fstests) to fail often:

  btrfs/171 9s ... - output mismatch (see /home/fdmanana/git/hub/xfstests/results//btrfs/171.out.bad)
#      --- tests/btrfs/171.out     2018-09-16 21:30:48.505104287 +0100
#      +++ /home/fdmanana/git/hub/xfstests/results//btrfs/171.out.bad      2019-09-19 02:01:36.938486039 +0100
#      @@ -1,2 +1,3 @@
#       QA output created by 171
#      +ERROR: quota rescan failed: Operation now in progress
#       Silence is golden
#      ...
#      (Run 'diff -u /home/fdmanana/git/hub/xfstests/tests/btrfs/171.out /home/fdmanana/git/hub/xfstests/results//btrfs/171.out.bad'  to see the entire diff)

That is because the test calls the btrfs-progs commands "qgroup quota
rescan -w", "qgroup assign" and "qgroup remove" in a sequence that makes
calls to the rescan start ioctl fail with -EINPROGRESS (note the "btrfs"
commands 'qgroup assign' and 'qgroup remove' often call the rescan start
ioctl after calling the qgroup assign ioctl,
btrfs_ioctl_qgroup_assign()), since previous waits didn't actually wait
for a rescan worker to complete.

Another problem the race can cause is missing wake ups for waiters,
since the call to complete_all() happens outside a critical section and
after clearing the flag BTRFS_QGROUP_STATUS_FLAG_RESCAN. In the sequence
diagram above, if we have a waiter for the first rescan task (executed
by CPU 2), then fs_info->qgroup_rescan_completion.wait is not empty, and
if after the rescan worker clears BTRFS_QGROUP_STATUS_FLAG_RESCAN and
before it calls complete_all() against
fs_info->qgroup_rescan_completion, the task at CPU 3 calls
init_completion() against fs_info->qgroup_rescan_completion which
re-initilizes its wait queue to an empty queue, therefore causing the
rescan worker at CPU 2 to call complete_all() against an empty queue,
never waking up the task waiting for that rescan worker.

Fix this by clearing BTRFS_QGROUP_STATUS_FLAG_RESCAN and setting
fs_info->qgroup_rescan_running to false in the same critical section,
delimited by the mutex fs_info->qgroup_rescan_lock, as well as doing the
call to complete_all() in that same critical section. This gives the
protection needed to avoid rescan wait ioctl callers not waiting for a
running rescan worker and the lost wake ups problem, since setting that
rescan flag and boolean as well as initializing the wait queue is done
already in a critical section delimited by that mutex (at
qgroup_rescan_init()).

Fixes: 57254b6ebce4ce ("Btrfs: add ioctl to wait for qgroup rescan completion")
Fixes: d2c609b834d62f ("btrfs: properly track when rescan worker is running")
CC: stable@vger.kernel.org # 4.4+
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/btrfs/qgroup.c |   33 +++++++++++++++++++--------------
 1 file changed, 19 insertions(+), 14 deletions(-)

--- a/fs/btrfs/qgroup.c
+++ b/fs/btrfs/qgroup.c
@@ -2328,9 +2328,6 @@ out:
 	btrfs_free_path(path);
 
 	mutex_lock(&fs_info->qgroup_rescan_lock);
-	if (!btrfs_fs_closing(fs_info))
-		fs_info->qgroup_flags &= ~BTRFS_QGROUP_STATUS_FLAG_RESCAN;
-
 	if (err > 0 &&
 	    fs_info->qgroup_flags & BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT) {
 		fs_info->qgroup_flags &= ~BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT;
@@ -2346,16 +2343,30 @@ out:
 	trans = btrfs_start_transaction(fs_info->quota_root, 1);
 	if (IS_ERR(trans)) {
 		err = PTR_ERR(trans);
+		trans = NULL;
 		btrfs_err(fs_info,
 			  "fail to start transaction for status update: %d\n",
 			  err);
-		goto done;
 	}
-	ret = update_qgroup_status_item(trans, fs_info, fs_info->quota_root);
-	if (ret < 0) {
-		err = ret;
-		btrfs_err(fs_info, "fail to update qgroup status: %d\n", err);
+
+	mutex_lock(&fs_info->qgroup_rescan_lock);
+	if (!btrfs_fs_closing(fs_info))
+		fs_info->qgroup_flags &= ~BTRFS_QGROUP_STATUS_FLAG_RESCAN;
+	if (trans) {
+		ret = update_qgroup_status_item(trans, fs_info, fs_info->quota_root);
+		if (ret < 0) {
+			err = ret;
+			btrfs_err(fs_info, "fail to update qgroup status: %d",
+				  err);
+		}
 	}
+	fs_info->qgroup_rescan_running = false;
+	complete_all(&fs_info->qgroup_rescan_completion);
+	mutex_unlock(&fs_info->qgroup_rescan_lock);
+
+	if (!trans)
+		return;
+
 	btrfs_end_transaction(trans, fs_info->quota_root);
 
 	if (btrfs_fs_closing(fs_info)) {
@@ -2366,12 +2377,6 @@ out:
 	} else {
 		btrfs_err(fs_info, "qgroup scan failed with %d", err);
 	}
-
-done:
-	mutex_lock(&fs_info->qgroup_rescan_lock);
-	fs_info->qgroup_rescan_running = false;
-	mutex_unlock(&fs_info->qgroup_rescan_lock);
-	complete_all(&fs_info->qgroup_rescan_completion);
 }
 
 /*



  parent reply	other threads:[~2019-10-03 16:00 UTC|newest]

Thread overview: 107+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-03 15:52 [PATCH 4.4 00/99] 4.4.195-stable review Greg Kroah-Hartman
2019-10-03 15:52 ` [PATCH 4.4 01/99] Revert "Bluetooth: validate BLE connection interval updates" Greg Kroah-Hartman
2019-10-03 15:52 ` [PATCH 4.4 02/99] HID: prodikeys: Fix general protection fault during probe Greg Kroah-Hartman
2019-10-03 15:52 ` [PATCH 4.4 03/99] HID: lg: make transfer buffers DMA capable Greg Kroah-Hartman
2019-10-03 15:52 ` [PATCH 4.4 04/99] HID: logitech: Fix general protection fault caused by Logitech driver Greg Kroah-Hartman
2019-10-03 15:52 ` [PATCH 4.4 05/99] HID: hidraw: Fix invalid read in hidraw_ioctl Greg Kroah-Hartman
2019-10-03 15:52 ` [PATCH 4.4 06/99] mtd: cfi_cmdset_0002: Use chip_good() to retry in do_write_oneword() Greg Kroah-Hartman
2019-10-03 15:52   ` Greg Kroah-Hartman
2019-10-03 15:52 ` [PATCH 4.4 07/99] crypto: talitos - fix missing break in switch statement Greg Kroah-Hartman
2019-10-03 15:52 ` [PATCH 4.4 08/99] [PATCH stable 4.4 net] net: rds: Fix NULL ptr use in rds_tcp_kill_sock Greg Kroah-Hartman
2019-10-03 15:52 ` [PATCH 4.4 09/99] ASoC: fsl: Fix of-node refcount unbalance in fsl_ssi_probe_from_dt() Greg Kroah-Hartman
2019-10-03 15:52 ` [PATCH 4.4 10/99] ALSA: hda - Add laptop imic fixup for ASUS M9V laptop Greg Kroah-Hartman
2019-10-03 15:52 ` [PATCH 4.4 11/99] mac80211: Print text for disassociation reason Greg Kroah-Hartman
2019-10-03 15:52 ` [PATCH 4.4 12/99] mac80211: handle deauthentication/disassociation from TDLS peer Greg Kroah-Hartman
2019-10-03 15:52 ` [PATCH 4.4 13/99] locking/lockdep: Add debug_locks check in __lock_downgrade() Greg Kroah-Hartman
2019-10-03 15:52 ` [PATCH 4.4 14/99] irqchip/gic-v3-its: Fix LPI release for Multi-MSI devices Greg Kroah-Hartman
2019-10-03 15:52 ` [PATCH 4.4 15/99] f2fs: check all the data segments against all node ones Greg Kroah-Hartman
2019-10-03 15:52 ` [PATCH 4.4 16/99] Revert "f2fs: avoid out-of-range memory access" Greg Kroah-Hartman
2019-10-03 15:52 ` [PATCH 4.4 17/99] f2fs: fix to do sanity check on segment bitmap of LFS curseg Greg Kroah-Hartman
2019-10-03 15:52 ` [PATCH 4.4 18/99] drm: Flush output polling on shutdown Greg Kroah-Hartman
2019-10-03 15:52 ` [PATCH 4.4 19/99] Bluetooth: btrtl: Additional Realtek 8822CE Bluetooth devices Greg Kroah-Hartman
2019-10-03 15:52 ` [PATCH 4.4 20/99] arcnet: provide a buffer big enough to actually receive packets Greg Kroah-Hartman
2019-10-03 15:52 ` [PATCH 4.4 21/99] cdc_ncm: fix divide-by-zero caused by invalid wMaxPacketSize Greg Kroah-Hartman
2019-10-03 15:52 ` [PATCH 4.4 22/99] net/phy: fix DP83865 10 Mbps HDX loopback disable function Greg Kroah-Hartman
2019-10-03 15:52 ` [PATCH 4.4 23/99] openvswitch: change type of UPCALL_PID attribute to NLA_UNSPEC Greg Kroah-Hartman
2019-10-03 15:52 ` [PATCH 4.4 24/99] sch_netem: fix a divide by zero in tabledist() Greg Kroah-Hartman
2019-10-03 15:52 ` [PATCH 4.4 25/99] skge: fix checksum byte order Greg Kroah-Hartman
2019-10-03 15:52 ` [PATCH 4.4 26/99] usbnet: ignore endpoints with invalid wMaxPacketSize Greg Kroah-Hartman
2019-10-03 15:52 ` [PATCH 4.4 27/99] usbnet: sanity checking of packet sizes and device mtu Greg Kroah-Hartman
2019-10-03 15:52 ` [PATCH 4.4 28/99] mISDN: enforce CAP_NET_RAW for raw sockets Greg Kroah-Hartman
2019-10-03 15:52 ` [PATCH 4.4 29/99] appletalk: " Greg Kroah-Hartman
2019-10-03 15:52 ` [PATCH 4.4 30/99] ax25: " Greg Kroah-Hartman
2019-10-03 15:52 ` [PATCH 4.4 31/99] ieee802154: " Greg Kroah-Hartman
2019-10-03 15:52 ` [PATCH 4.4 32/99] nfc: " Greg Kroah-Hartman
2019-10-03 15:52 ` [PATCH 4.4 33/99] ALSA: hda: Flush interrupts on disabling Greg Kroah-Hartman
2019-10-03 15:52 ` [PATCH 4.4 34/99] ASoC: sgtl5000: Fix charge pump source assignment Greg Kroah-Hartman
2019-10-03 15:52 ` [PATCH 4.4 35/99] dmaengine: bcm2835: Print error in case setting DMA mask fails Greg Kroah-Hartman
2019-10-03 15:52 ` [PATCH 4.4 36/99] leds: leds-lp5562 allow firmware files up to the maximum length Greg Kroah-Hartman
2019-10-03 15:53 ` [PATCH 4.4 37/99] media: dib0700: fix link error for dibx000_i2c_set_speed Greg Kroah-Hartman
2019-10-03 15:53 ` [PATCH 4.4 38/99] media: hdpvr: Add device num check and handling Greg Kroah-Hartman
2019-10-03 15:53 ` [PATCH 4.4 39/99] sched/fair: Fix imbalance due to CPU affinity Greg Kroah-Hartman
2019-10-03 15:53 ` [PATCH 4.4 40/99] sched/core: Fix CPU controller for !RT_GROUP_SCHED Greg Kroah-Hartman
2019-10-03 15:53 ` [PATCH 4.4 41/99] x86/reboot: Always use NMI fallback when shutdown via reboot vector IPI fails Greg Kroah-Hartman
2019-10-03 15:53 ` [PATCH 4.4 42/99] x86/apic: Soft disable APIC before initializing it Greg Kroah-Hartman
2019-10-03 15:53 ` [PATCH 4.4 43/99] ALSA: hda - Show the fatal CORB/RIRB error more clearly Greg Kroah-Hartman
2019-10-03 15:53 ` [PATCH 4.4 44/99] ALSA: i2c: ak4xxx-adda: Fix a possible null pointer dereference in build_adc_controls() Greg Kroah-Hartman
2019-10-03 15:53 ` [PATCH 4.4 45/99] media: iguanair: add sanity checks Greg Kroah-Hartman
2019-10-03 15:53 ` [PATCH 4.4 46/99] base: soc: Export soc_device_register/unregister APIs Greg Kroah-Hartman
2019-10-03 15:53 ` [PATCH 4.4 47/99] ALSA: usb-audio: Skip bSynchAddress endpoint check if it is invalid Greg Kroah-Hartman
2019-10-03 15:53 ` [PATCH 4.4 48/99] ia64:unwind: fix double free for mod->arch.init_unw_table Greg Kroah-Hartman
2019-10-03 15:53 ` [PATCH 4.4 49/99] md: dont call spare_active in md_reap_sync_thread if all member devices cant work Greg Kroah-Hartman
2019-10-03 15:53 ` [PATCH 4.4 50/99] md: dont set In_sync if array is frozen Greg Kroah-Hartman
2019-10-03 15:53 ` [PATCH 4.4 51/99] efi: cper: print AER info of PCIe fatal error Greg Kroah-Hartman
2019-10-03 15:53 ` [PATCH 4.4 52/99] media: gspca: zero usb_buf on error Greg Kroah-Hartman
2019-10-03 15:53 ` [PATCH 4.4 53/99] dmaengine: iop-adma: use correct printk format strings Greg Kroah-Hartman
2019-10-03 15:53 ` [PATCH 4.4 54/99] media: omap3isp: Dont set streaming state on random subdevs Greg Kroah-Hartman
2019-10-03 15:53 ` [PATCH 4.4 55/99] net: lpc-enet: fix printk format strings Greg Kroah-Hartman
2019-10-03 15:53 ` [PATCH 4.4 56/99] media: radio/si470x: kill urb on error Greg Kroah-Hartman
2019-10-03 15:53 ` [PATCH 4.4 57/99] media: hdpvr: add terminating 0 at end of string Greg Kroah-Hartman
2019-10-03 15:53 ` [PATCH 4.4 58/99] media: saa7146: add cleanup in hexium_attach() Greg Kroah-Hartman
2019-10-03 15:53 ` [PATCH 4.4 59/99] media: cpia2_usb: fix memory leaks Greg Kroah-Hartman
2019-10-03 15:53 ` [PATCH 4.4 60/99] media: saa7134: fix terminology around saa7134_i2c_eeprom_md7134_gate() Greg Kroah-Hartman
2019-10-03 15:53 ` [PATCH 4.4 61/99] media: ov9650: add a sanity check Greg Kroah-Hartman
2019-10-03 15:53 ` [PATCH 4.4 62/99] ACPI / CPPC: do not require the _PSD method Greg Kroah-Hartman
2019-10-03 15:53 ` [PATCH 4.4 63/99] libtraceevent: Change users plugin directory Greg Kroah-Hartman
2019-10-03 15:53 ` [PATCH 4.4 64/99] ACPI: custom_method: fix memory leaks Greg Kroah-Hartman
2019-10-03 15:53 ` [PATCH 4.4 65/99] hwmon: (acpi_power_meter) Change log level for unsafe software power cap Greg Kroah-Hartman
2019-10-03 15:53 ` [PATCH 4.4 66/99] md/raid1: fail run raid1 array when active disk less than one Greg Kroah-Hartman
2019-10-03 15:53 ` [PATCH 4.4 67/99] dmaengine: ti: edma: Do not reset reserved paRAM slots Greg Kroah-Hartman
2019-10-03 15:53 ` [PATCH 4.4 68/99] kprobes: Prohibit probing on BUG() and WARN() address Greg Kroah-Hartman
2019-10-03 15:53 ` [PATCH 4.4 69/99] ASoC: dmaengine: Make the pcm->name equal to pcm->id if the name is not set Greg Kroah-Hartman
2019-10-03 15:53 ` [PATCH 4.4 70/99] mmc: sdhci: Fix incorrect switch to HS mode Greg Kroah-Hartman
2019-10-03 15:53 ` [PATCH 4.4 71/99] libertas: Add missing sentinel at end of if_usb.c fw_table Greg Kroah-Hartman
2019-10-03 15:53 ` [PATCH 4.4 72/99] media: ttusb-dec: Fix info-leak in ttusb_dec_send_command() Greg Kroah-Hartman
2019-10-03 15:53 ` [PATCH 4.4 73/99] ALSA: hda/realtek - Blacklist PC beep for Lenovo ThinkCentre M73/93 Greg Kroah-Hartman
2019-10-03 15:53 ` [PATCH 4.4 74/99] btrfs: extent-tree: Make sure we only allocate extents from block groups with the same type Greg Kroah-Hartman
2019-10-03 15:53 ` [PATCH 4.4 75/99] media: omap3isp: Set device on omap3isp subdevs Greg Kroah-Hartman
2019-10-03 15:53 ` [PATCH 4.4 76/99] ALSA: firewire-tascam: handle error code when getting current source of clock Greg Kroah-Hartman
2019-10-03 15:53 ` [PATCH 4.4 77/99] ALSA: firewire-tascam: check intermediate state of clock status and retry Greg Kroah-Hartman
2019-10-03 15:53 ` [PATCH 4.4 78/99] printk: Do not lose last line in kmsg buffer dump Greg Kroah-Hartman
2019-10-03 15:53 ` [PATCH 4.4 79/99] fuse: fix missing unlock_page in fuse_writepage() Greg Kroah-Hartman
2019-10-03 15:53 ` [PATCH 4.4 80/99] parisc: Disable HP HSC-PCI Cards to prevent kernel crash Greg Kroah-Hartman
2019-10-03 15:53 ` [PATCH 4.4 81/99] KVM: x86: always stop emulation on page fault Greg Kroah-Hartman
2019-10-03 15:53 ` [PATCH 4.4 82/99] KVM: x86: set ctxt->have_exception in x86_decode_insn() Greg Kroah-Hartman
2019-10-03 15:53 ` [PATCH 4.4 83/99] KVM: x86: Manually calculate reserved bits when loading PDPTRS Greg Kroah-Hartman
2019-10-03 15:53 ` [PATCH 4.4 84/99] media: sn9c20x: Add MSI MS-1039 laptop to flip_dmi_table Greg Kroah-Hartman
2019-10-03 15:53 ` [PATCH 4.4 85/99] ASoC: Intel: Fix use of potentially uninitialized variable Greg Kroah-Hartman
2019-10-03 15:53 ` [PATCH 4.4 86/99] ARM: zynq: Use memcpy_toio instead of memcpy on smp bring-up Greg Kroah-Hartman
2019-10-03 15:53 ` [PATCH 4.4 87/99] alarmtimer: Use EOPNOTSUPP instead of ENOTSUPP Greg Kroah-Hartman
2019-10-03 15:53 ` [PATCH 4.4 88/99] md/raid6: Set R5_ReadError when there is read failure on parity disk Greg Kroah-Hartman
2019-10-03 15:53 ` [PATCH 4.4 89/99] cfg80211: Purge frame registrations on iftype change Greg Kroah-Hartman
2019-10-03 15:53 ` [PATCH 4.4 90/99] /dev/mem: Bail out upon SIGKILL Greg Kroah-Hartman
2019-10-03 15:53 ` [PATCH 4.4 91/99] ext4: fix punch hole for inline_data file systems Greg Kroah-Hartman
2019-10-03 15:53 ` [PATCH 4.4 92/99] quota: fix wrong condition in is_quota_modification() Greg Kroah-Hartman
2019-10-03 15:53 ` [PATCH 4.4 93/99] hwrng: core - dont wait on add_early_randomness() Greg Kroah-Hartman
2019-10-03 15:53 ` [PATCH 4.4 94/99] i2c: riic: Clear NACK in tend isr Greg Kroah-Hartman
2019-10-03 15:53 ` [PATCH 4.4 95/99] CIFS: Fix oplock handling for SMB 2.1+ protocols Greg Kroah-Hartman
2019-10-03 15:53 ` [PATCH 4.4 96/99] ovl: filter of trusted xattr results in audit Greg Kroah-Hartman
2019-10-03 15:54 ` [PATCH 4.4 97/99] Btrfs: fix use-after-free when using the tree modification log Greg Kroah-Hartman
2019-10-03 15:54 ` [PATCH 4.4 98/99] btrfs: Relinquish CPUs in btrfs_compare_trees Greg Kroah-Hartman
2019-10-03 15:54 ` Greg Kroah-Hartman [this message]
2019-10-03 23:53 ` [PATCH 4.4 00/99] 4.4.195-stable review shuah
2019-10-04  6:41 ` kernelci.org bot
2019-10-04  7:36 ` Jon Hunter
2019-10-04  7:36   ` Jon Hunter
2019-10-04 15:02 ` Dan Rue
2019-10-04 22:55 ` Guenter Roeck

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