Stable Archive on lore.kernel.org
 help / color / Atom feed
From: Daniel Jordan <daniel.m.jordan@oracle.com>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Sasha Levin <sashal@kernel.org>
Cc: Steffen Klassert <steffen.klassert@secunet.com>,
	linux-kernel@vger.kernel.org,
	Herbert Xu <herbert@gondor.apana.org.au>,
	stable@vger.kernel.org,
	Daniel Jordan <daniel.m.jordan@oracle.com>
Subject: [PATCH v2 4.4] padata: Remove broken queue flushing
Date: Fri, 14 Feb 2020 20:30:01 -0500
Message-ID: <20200215013001.892060-1-daniel.m.jordan@oracle.com> (raw)
In-Reply-To: <20200213151832.123934030@linuxfoundation.org>

From: Herbert Xu <herbert@gondor.apana.org.au>

[ Upstream commit 07928d9bfc81640bab36f5190e8725894d93b659 ]

The function padata_flush_queues is fundamentally broken because
it cannot force padata users to complete the request that is
underway.  IOW padata has to passively wait for the completion
of any outstanding work.

As it stands flushing is used in two places.  Its use in padata_stop
is simply unnecessary because nothing depends on the queues to
be flushed afterwards.

The other use in padata_replace is more substantial as we depend
on it to free the old pd structure.  This patch instead uses the
pd->refcnt to dynamically free the pd structure once all requests
are complete.

Fixes: 2b73b07ab8a4 ("padata: Flush the padata queues actively")
Cc: <stable@vger.kernel.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
[dj: leave "pd->pinst = pinst" assignment in padata_alloc_pd()]
Signed-off-by: Daniel Jordan <daniel.m.jordan@oracle.com>
---
 kernel/padata.c | 45 ++++++++++++---------------------------------
 1 file changed, 12 insertions(+), 33 deletions(-)

diff --git a/kernel/padata.c b/kernel/padata.c
index 282b489a286d..0d7ec5fd520b 100644
--- a/kernel/padata.c
+++ b/kernel/padata.c
@@ -33,6 +33,8 @@
 
 #define MAX_OBJ_NUM 1000
 
+static void padata_free_pd(struct parallel_data *pd);
+
 static int padata_index_to_cpu(struct parallel_data *pd, int cpu_index)
 {
 	int cpu, target_cpu;
@@ -300,6 +302,7 @@ static void padata_serial_worker(struct work_struct *serial_work)
 	struct padata_serial_queue *squeue;
 	struct parallel_data *pd;
 	LIST_HEAD(local_list);
+	int cnt;
 
 	local_bh_disable();
 	squeue = container_of(serial_work, struct padata_serial_queue, work);
@@ -309,6 +312,8 @@ static void padata_serial_worker(struct work_struct *serial_work)
 	list_replace_init(&squeue->serial.list, &local_list);
 	spin_unlock(&squeue->serial.lock);
 
+	cnt = 0;
+
 	while (!list_empty(&local_list)) {
 		struct padata_priv *padata;
 
@@ -318,9 +323,12 @@ static void padata_serial_worker(struct work_struct *serial_work)
 		list_del_init(&padata->list);
 
 		padata->serial(padata);
-		atomic_dec(&pd->refcnt);
+		cnt++;
 	}
 	local_bh_enable();
+
+	if (atomic_sub_and_test(cnt, &pd->refcnt))
+		padata_free_pd(pd);
 }
 
 /**
@@ -443,7 +451,7 @@ static struct parallel_data *padata_alloc_pd(struct padata_instance *pinst,
 	setup_timer(&pd->timer, padata_reorder_timer, (unsigned long)pd);
 	atomic_set(&pd->seq_nr, -1);
 	atomic_set(&pd->reorder_objects, 0);
-	atomic_set(&pd->refcnt, 0);
+	atomic_set(&pd->refcnt, 1);
 	pd->pinst = pinst;
 	spin_lock_init(&pd->lock);
 
@@ -468,31 +476,6 @@ static void padata_free_pd(struct parallel_data *pd)
 	kfree(pd);
 }
 
-/* Flush all objects out of the padata queues. */
-static void padata_flush_queues(struct parallel_data *pd)
-{
-	int cpu;
-	struct padata_parallel_queue *pqueue;
-	struct padata_serial_queue *squeue;
-
-	for_each_cpu(cpu, pd->cpumask.pcpu) {
-		pqueue = per_cpu_ptr(pd->pqueue, cpu);
-		flush_work(&pqueue->work);
-	}
-
-	del_timer_sync(&pd->timer);
-
-	if (atomic_read(&pd->reorder_objects))
-		padata_reorder(pd);
-
-	for_each_cpu(cpu, pd->cpumask.cbcpu) {
-		squeue = per_cpu_ptr(pd->squeue, cpu);
-		flush_work(&squeue->work);
-	}
-
-	BUG_ON(atomic_read(&pd->refcnt) != 0);
-}
-
 static void __padata_start(struct padata_instance *pinst)
 {
 	pinst->flags |= PADATA_INIT;
@@ -506,10 +489,6 @@ static void __padata_stop(struct padata_instance *pinst)
 	pinst->flags &= ~PADATA_INIT;
 
 	synchronize_rcu();
-
-	get_online_cpus();
-	padata_flush_queues(pinst->pd);
-	put_online_cpus();
 }
 
 /* Replace the internal control structure with a new one. */
@@ -530,8 +509,8 @@ static void padata_replace(struct padata_instance *pinst,
 	if (!cpumask_equal(pd_old->cpumask.cbcpu, pd_new->cpumask.cbcpu))
 		notification_mask |= PADATA_CPU_SERIAL;
 
-	padata_flush_queues(pd_old);
-	padata_free_pd(pd_old);
+	if (atomic_dec_and_test(&pd_old->refcnt))
+		padata_free_pd(pd_old);
 
 	if (notification_mask)
 		blocking_notifier_call_chain(&pinst->cpumask_change_notifier,
-- 
2.25.0


  reply index

Thread overview: 99+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-13 15:19 [PATCH 4.4 00/91] 4.4.214-stable review Greg Kroah-Hartman
2020-02-13 15:19 ` [PATCH 4.4 01/91] media: iguanair: fix endpoint sanity check Greg Kroah-Hartman
2020-02-13 15:19 ` [PATCH 4.4 02/91] x86/cpu: Update cached HLE state on write to TSX_CTRL_CPUID_CLEAR Greg Kroah-Hartman
2020-02-13 15:19 ` [PATCH 4.4 03/91] sparc32: fix struct ipc64_perm type definition Greg Kroah-Hartman
2020-02-13 15:19 ` [PATCH 4.4 04/91] ASoC: qcom: Fix of-node refcount unbalance to link->codec_of_node Greg Kroah-Hartman
2020-02-13 15:19 ` [PATCH 4.4 05/91] cls_rsvp: fix rsvp_policy Greg Kroah-Hartman
2020-02-13 15:19 ` [PATCH 4.4 06/91] net: hsr: fix possible NULL deref in hsr_handle_frame() Greg Kroah-Hartman
2020-02-13 15:19 ` [PATCH 4.4 07/91] net_sched: fix an OOB access in cls_tcindex Greg Kroah-Hartman
2020-02-13 15:19 ` [PATCH 4.4 08/91] tcp: clear tp->total_retrans in tcp_disconnect() Greg Kroah-Hartman
2020-02-13 15:19 ` [PATCH 4.4 09/91] tcp: clear tp->segs_{in|out} " Greg Kroah-Hartman
2020-02-13 15:19 ` [PATCH 4.4 10/91] media: uvcvideo: Avoid cyclic entity chains due to malformed USB descriptors Greg Kroah-Hartman
2020-02-13 15:19 ` [PATCH 4.4 11/91] mfd: dln2: More sanity checking for endpoints Greg Kroah-Hartman
2020-02-13 15:19 ` [PATCH 4.4 12/91] brcmfmac: Fix memory leak in brcmf_usbdev_qinit Greg Kroah-Hartman
2020-02-13 15:19 ` [PATCH 4.4 13/91] usb: gadget: legacy: set max_speed to super-speed Greg Kroah-Hartman
2020-02-13 15:19 ` [PATCH 4.4 14/91] usb: gadget: f_ncm: Use atomic_t to track in-flight request Greg Kroah-Hartman
2020-02-13 15:19 ` [PATCH 4.4 15/91] usb: gadget: f_ecm: " Greg Kroah-Hartman
2020-02-13 15:19 ` [PATCH 4.4 16/91] ALSA: dummy: Fix PCM format loop in proc output Greg Kroah-Hartman
2020-02-13 15:19 ` [PATCH 4.4 17/91] lib/test_kasan.c: fix memory leak in kmalloc_oob_krealloc_more() Greg Kroah-Hartman
2020-02-13 15:19 ` [PATCH 4.4 18/91] powerpc/pseries: Advance pfn if section is not present in lmb_is_removable() Greg Kroah-Hartman
2020-02-13 15:19 ` [PATCH 4.4 19/91] mmc: spi: Toggle SPI polarity, do not hardcode it Greg Kroah-Hartman
2020-02-13 15:19 ` [PATCH 4.4 20/91] PCI: keystone: Fix link training retries initiation Greg Kroah-Hartman
2020-02-13 15:19 ` [PATCH 4.4 21/91] crypto: api - Check spawn->alg under lock in crypto_drop_spawn Greg Kroah-Hartman
2020-02-13 15:19 ` [PATCH 4.4 22/91] scsi: qla2xxx: Fix mtcp dump collection failure Greg Kroah-Hartman
2020-02-13 15:19 ` [PATCH 4.4 23/91] power: supply: ltc2941-battery-gauge: fix use-after-free Greg Kroah-Hartman
2020-02-13 15:19 ` [PATCH 4.4 24/91] Revert "ovl: modify ovl_permission() to do checks on two inodes" Greg Kroah-Hartman
2020-02-13 15:19 ` [PATCH 4.4 25/91] of: Add OF_DMA_DEFAULT_COHERENT & select it on powerpc Greg Kroah-Hartman
2020-02-13 15:19 ` [PATCH 4.4 26/91] dm space map common: fix to ensure new block isnt already in use Greg Kroah-Hartman
2020-02-13 15:19 ` [PATCH 4.4 27/91] padata: Remove broken queue flushing Greg Kroah-Hartman
2020-02-15  1:30   ` Daniel Jordan [this message]
2020-02-13 15:19 ` [PATCH 4.4 28/91] crypto: pcrypt - Do not clear MAY_SLEEP flag in original request Greg Kroah-Hartman
2020-02-13 15:19 ` [PATCH 4.4 29/91] crypto: api - Fix race condition in crypto_spawn_alg Greg Kroah-Hartman
2020-02-13 15:19 ` [PATCH 4.4 30/91] crypto: picoxcell - adjust the position of tasklet_init and fix missed tasklet_kill Greg Kroah-Hartman
2020-02-13 15:19 ` [PATCH 4.4 31/91] btrfs: set trans->drity in btrfs_commit_transaction Greg Kroah-Hartman
2020-02-13 15:19 ` [PATCH 4.4 32/91] ARM: tegra: Enable PLLP bypass during Tegra124 LP1 Greg Kroah-Hartman
2020-02-13 15:19 ` [PATCH 4.4 33/91] mwifiex: fix unbalanced locking in mwifiex_process_country_ie() Greg Kroah-Hartman
2020-02-13 15:19 ` [PATCH 4.4 34/91] sunrpc: expiry_time should be seconds not timeval Greg Kroah-Hartman
2020-02-13 15:19 ` [PATCH 4.4 35/91] KVM: x86: Refactor prefix decoding to prevent Spectre-v1/L1TF attacks Greg Kroah-Hartman
2020-02-13 15:19 ` [PATCH 4.4 36/91] KVM: x86: Protect DR-based index computations from " Greg Kroah-Hartman
2020-02-13 15:19 ` [PATCH 4.4 37/91] KVM: x86: Protect kvm_hv_msr_[get|set]_crash_data() " Greg Kroah-Hartman
2020-02-13 15:19 ` [PATCH 4.4 38/91] KVM: x86: Protect ioapic_write_indirect() " Greg Kroah-Hartman
2020-02-13 15:19 ` [PATCH 4.4 39/91] KVM: x86: Protect MSR-based index computations in pmu.h " Greg Kroah-Hartman
2020-02-13 15:19 ` [PATCH 4.4 40/91] KVM: x86: Protect ioapic_read_indirect() " Greg Kroah-Hartman
2020-02-13 15:19 ` [PATCH 4.4 41/91] KVM: x86: Protect MSR-based index computations from Spectre-v1/L1TF attacks in x86.c Greg Kroah-Hartman
2020-02-13 15:19 ` [PATCH 4.4 42/91] KVM: x86: Protect x86_decode_insn from Spectre-v1/L1TF attacks Greg Kroah-Hartman
2020-02-13 15:20 ` [PATCH 4.4 43/91] KVM: x86: Protect MSR-based index computations in fixed_msr_to_seg_unit() " Greg Kroah-Hartman
2020-02-13 15:20 ` [PATCH 4.4 44/91] KVM: PPC: Book3S HV: Uninit vCPU if vcore creation fails Greg Kroah-Hartman
2020-02-13 15:20 ` [PATCH 4.4 45/91] KVM: PPC: Book3S PR: Free shared page if mmu initialization fails Greg Kroah-Hartman
2020-02-13 15:20 ` [PATCH 4.4 46/91] KVM: x86: Free wbinvd_dirty_mask if vCPU creation fails Greg Kroah-Hartman
2020-02-13 15:20 ` [PATCH 4.4 47/91] scsi: qla2xxx: Fix the endianness of the qla82xx_get_fw_size() return type Greg Kroah-Hartman
2020-02-13 15:20 ` [PATCH 4.4 48/91] scsi: csiostor: Adjust indentation in csio_device_reset Greg Kroah-Hartman
2020-02-13 15:20 ` [PATCH 4.4 49/91] scsi: qla4xxx: Adjust indentation in qla4xxx_mem_free Greg Kroah-Hartman
2020-02-13 15:20 ` [PATCH 4.4 50/91] ext2: Adjust indentation in ext2_fill_super Greg Kroah-Hartman
2020-02-13 15:20 ` [PATCH 4.4 51/91] powerpc/44x: Adjust indentation in ibm4xx_denali_fixup_memsize Greg Kroah-Hartman
2020-02-13 15:20 ` [PATCH 4.4 52/91] NFC: pn544: Adjust indentation in pn544_hci_check_presence Greg Kroah-Hartman
2020-02-13 15:20 ` [PATCH 4.4 53/91] ppp: Adjust indentation into ppp_async_input Greg Kroah-Hartman
2020-02-13 15:20 ` [PATCH 4.4 54/91] net: smc911x: Adjust indentation in smc911x_phy_configure Greg Kroah-Hartman
2020-02-13 15:20 ` [PATCH 4.4 55/91] net: tulip: Adjust indentation in {dmfe, uli526x}_init_module Greg Kroah-Hartman
2020-02-13 15:20 ` [PATCH 4.4 56/91] mfd: da9062: Fix watchdog compatible string Greg Kroah-Hartman
2020-02-13 15:20 ` [PATCH 4.4 57/91] mfd: rn5t618: Mark ADC control register volatile Greg Kroah-Hartman
2020-02-13 15:20 ` [PATCH 4.4 58/91] net: systemport: Avoid RBUF stuck in Wake-on-LAN mode Greg Kroah-Hartman
2020-02-13 15:20 ` [PATCH 4.4 59/91] bonding/alb: properly access headers in bond_alb_xmit() Greg Kroah-Hartman
2020-02-13 15:20 ` [PATCH 4.4 60/91] NFS: Fix memory leaks and corruption in readdir Greg Kroah-Hartman
2020-02-13 15:20 ` [PATCH 4.4 61/91] NFS: Fix bool initialization/comparison Greg Kroah-Hartman
2020-02-13 15:20 ` [PATCH 4.4 62/91] NFS: Directory page cache pages need to be locked when read Greg Kroah-Hartman
2020-02-13 15:20 ` [PATCH 4.4 63/91] Btrfs: fix assertion failure on fsync with NO_HOLES enabled Greg Kroah-Hartman
2020-02-13 15:20 ` [PATCH 4.4 64/91] btrfs: remove trivial locking wrappers of tree mod log Greg Kroah-Hartman
2020-02-13 15:20 ` [PATCH 4.4 65/91] Btrfs: fix race between adding and putting tree mod seq elements and nodes Greg Kroah-Hartman
2020-02-13 15:20 ` [PATCH 4.4 66/91] drm: atmel-hlcdc: enable clock before configuring timing engine Greg Kroah-Hartman
2020-02-13 15:20 ` [PATCH 4.4 67/91] drm/dp_mst: Remove VCPI while disabling topology mgr Greg Kroah-Hartman
2020-02-13 15:20 ` [PATCH 4.4 68/91] KVM: x86: drop picdev_in_range() Greg Kroah-Hartman
2020-02-13 15:20 ` [PATCH 4.4 69/91] KVM: x86: Refactor picdev_write() to prevent Spectre-v1/L1TF attacks Greg Kroah-Hartman
2020-02-13 15:20 ` [PATCH 4.4 70/91] KVM: x86: Protect pmu_intel.c from " Greg Kroah-Hartman
2020-02-13 15:20 ` [PATCH 4.4 71/91] KVM: x86: Protect kvm_lapic_reg_write() " Greg Kroah-Hartman
2020-02-13 15:20 ` [PATCH 4.4 72/91] btrfs: flush write bio if we loop in extent_write_cache_pages Greg Kroah-Hartman
2020-02-13 15:20 ` [PATCH 4.4 73/91] KVM: x86/mmu: Apply max PA check for MMIO sptes to 32-bit KVM Greg Kroah-Hartman
2020-02-13 15:20 ` [PATCH 4.4 74/91] KVM: VMX: Add non-canonical check on writes to RTIT address MSRs Greg Kroah-Hartman
2020-02-13 15:20 ` [PATCH 4.4 75/91] KVM: nVMX: vmread should not set rflags to specify success in case of #PF Greg Kroah-Hartman
2020-02-13 15:20 ` [PATCH 4.4 76/91] cifs: fail i/o on soft mounts if sessionsetup errors out Greg Kroah-Hartman
2020-02-13 15:20 ` [PATCH 4.4 77/91] clocksource: Prevent double add_timer_on() for watchdog_timer Greg Kroah-Hartman
2020-02-13 15:20 ` [PATCH 4.4 78/91] perf/core: Fix mlock accounting in perf_mmap() Greg Kroah-Hartman
2020-02-13 15:20 ` [PATCH 4.4 79/91] ASoC: pcm: update FE/BE trigger order based on the command Greg Kroah-Hartman
2020-02-13 15:20 ` [PATCH 4.4 80/91] scsi: ufs: Fix ufshcd_probe_hba() reture value in case ufshcd_scsi_add_wlus() fails Greg Kroah-Hartman
2020-02-13 15:20 ` [PATCH 4.4 81/91] rtc: hym8563: Return -EINVAL if the time is known to be invalid Greg Kroah-Hartman
2020-02-13 15:20 ` [PATCH 4.4 82/91] ARC: [plat-axs10x]: Add missing multicast filter number to GMAC node Greg Kroah-Hartman
2020-02-13 15:20 ` [PATCH 4.4 83/91] ARM: dts: at91: sama5d3: fix maximum peripheral clock rates Greg Kroah-Hartman
2020-02-13 15:20 ` [PATCH 4.4 84/91] ARM: dts: at91: sama5d3: define clock rate range for tcb1 Greg Kroah-Hartman
2020-02-13 15:20 ` [PATCH 4.4 85/91] powerpc/pseries: Allow not having ibm, hypertas-functions::hcall-multi-tce for DDW Greg Kroah-Hartman
2020-02-13 15:20 ` [PATCH 4.4 86/91] pinctrl: sh-pfc: r8a7778: Fix duplicate SDSELF_B and SD1_CLK_B Greg Kroah-Hartman
2020-02-13 15:20 ` [PATCH 4.4 87/91] mwifiex: Fix possible buffer overflows in mwifiex_ret_wmm_get_status() Greg Kroah-Hartman
2020-02-13 15:20 ` [PATCH 4.4 88/91] mwifiex: Fix possible buffer overflows in mwifiex_cmd_append_vsie_tlv() Greg Kroah-Hartman
2020-02-13 15:20 ` [PATCH 4.4 89/91] libertas: dont exit from lbs_ibss_join_existing() with RCU read lock held Greg Kroah-Hartman
2020-02-13 15:20 ` [PATCH 4.4 90/91] libertas: make lbs_ibss_join_existing() return error code on rates overflow Greg Kroah-Hartman
2020-02-13 15:20 ` [PATCH 4.4 91/91] dm: fix potential for q->make_request_fn NULL pointer Greg Kroah-Hartman
2020-02-13 16:57 ` [PATCH 4.4 00/91] 4.4.214-stable review Chris Paterson
2020-02-13 23:17   ` Greg Kroah-Hartman
2020-02-14  1:21 ` shuah
2020-02-14  5:26 ` Guenter Roeck
2020-02-14 10:25 ` Jon Hunter
2020-02-14 10:37 ` Naresh Kamboju

Reply instructions:

You may reply publically to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20200215013001.892060-1-daniel.m.jordan@oracle.com \
    --to=daniel.m.jordan@oracle.com \
    --cc=gregkh@linuxfoundation.org \
    --cc=herbert@gondor.apana.org.au \
    --cc=linux-kernel@vger.kernel.org \
    --cc=sashal@kernel.org \
    --cc=stable@vger.kernel.org \
    --cc=steffen.klassert@secunet.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

Stable Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/stable/0 stable/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 stable stable/ https://lore.kernel.org/stable \
		stable@vger.kernel.org
	public-inbox-index stable

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.stable


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git