All of lore.kernel.org
 help / color / mirror / Atom feed
From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	stable@vger.kernel.org, Andrea Righi <andrea.righi@canonical.com>,
	Pavel Machek <pavel@ucw.cz>
Subject: [PATCH 4.19 16/37] leds: trigger: fix potential deadlock with libata
Date: Tue,  2 Feb 2021 14:38:59 +0100	[thread overview]
Message-ID: <20210202132943.578879547@linuxfoundation.org> (raw)
In-Reply-To: <20210202132942.915040339@linuxfoundation.org>

From: Andrea Righi <andrea.righi@canonical.com>

commit 27af8e2c90fba242460b01fa020e6e19ed68c495 upstream.

We have the following potential deadlock condition:

 ========================================================
 WARNING: possible irq lock inversion dependency detected
 5.10.0-rc2+ #25 Not tainted
 --------------------------------------------------------
 swapper/3/0 just changed the state of lock:
 ffff8880063bd618 (&host->lock){-...}-{2:2}, at: ata_bmdma_interrupt+0x27/0x200
 but this lock took another, HARDIRQ-READ-unsafe lock in the past:
  (&trig->leddev_list_lock){.+.?}-{2:2}

 and interrupts could create inverse lock ordering between them.

 other info that might help us debug this:
  Possible interrupt unsafe locking scenario:

        CPU0                    CPU1
        ----                    ----
   lock(&trig->leddev_list_lock);
                                local_irq_disable();
                                lock(&host->lock);
                                lock(&trig->leddev_list_lock);
   <Interrupt>
     lock(&host->lock);

  *** DEADLOCK ***

 no locks held by swapper/3/0.

 the shortest dependencies between 2nd lock and 1st lock:
  -> (&trig->leddev_list_lock){.+.?}-{2:2} ops: 46 {
     HARDIRQ-ON-R at:
                       lock_acquire+0x15f/0x420
                       _raw_read_lock+0x42/0x90
                       led_trigger_event+0x2b/0x70
                       rfkill_global_led_trigger_worker+0x94/0xb0
                       process_one_work+0x240/0x560
                       worker_thread+0x58/0x3d0
                       kthread+0x151/0x170
                       ret_from_fork+0x1f/0x30
     IN-SOFTIRQ-R at:
                       lock_acquire+0x15f/0x420
                       _raw_read_lock+0x42/0x90
                       led_trigger_event+0x2b/0x70
                       kbd_bh+0x9e/0xc0
                       tasklet_action_common.constprop.0+0xe9/0x100
                       tasklet_action+0x22/0x30
                       __do_softirq+0xcc/0x46d
                       run_ksoftirqd+0x3f/0x70
                       smpboot_thread_fn+0x116/0x1f0
                       kthread+0x151/0x170
                       ret_from_fork+0x1f/0x30
     SOFTIRQ-ON-R at:
                       lock_acquire+0x15f/0x420
                       _raw_read_lock+0x42/0x90
                       led_trigger_event+0x2b/0x70
                       rfkill_global_led_trigger_worker+0x94/0xb0
                       process_one_work+0x240/0x560
                       worker_thread+0x58/0x3d0
                       kthread+0x151/0x170
                       ret_from_fork+0x1f/0x30
     INITIAL READ USE at:
                           lock_acquire+0x15f/0x420
                           _raw_read_lock+0x42/0x90
                           led_trigger_event+0x2b/0x70
                           rfkill_global_led_trigger_worker+0x94/0xb0
                           process_one_work+0x240/0x560
                           worker_thread+0x58/0x3d0
                           kthread+0x151/0x170
                           ret_from_fork+0x1f/0x30
   }
   ... key      at: [<ffffffff83da4c00>] __key.0+0x0/0x10
   ... acquired at:
    _raw_read_lock+0x42/0x90
    led_trigger_blink_oneshot+0x3b/0x90
    ledtrig_disk_activity+0x3c/0xa0
    ata_qc_complete+0x26/0x450
    ata_do_link_abort+0xa3/0xe0
    ata_port_freeze+0x2e/0x40
    ata_hsm_qc_complete+0x94/0xa0
    ata_sff_hsm_move+0x177/0x7a0
    ata_sff_pio_task+0xc7/0x1b0
    process_one_work+0x240/0x560
    worker_thread+0x58/0x3d0
    kthread+0x151/0x170
    ret_from_fork+0x1f/0x30

 -> (&host->lock){-...}-{2:2} ops: 69 {
    IN-HARDIRQ-W at:
                     lock_acquire+0x15f/0x420
                     _raw_spin_lock_irqsave+0x52/0xa0
                     ata_bmdma_interrupt+0x27/0x200
                     __handle_irq_event_percpu+0xd5/0x2b0
                     handle_irq_event+0x57/0xb0
                     handle_edge_irq+0x8c/0x230
                     asm_call_irq_on_stack+0xf/0x20
                     common_interrupt+0x100/0x1c0
                     asm_common_interrupt+0x1e/0x40
                     native_safe_halt+0xe/0x10
                     arch_cpu_idle+0x15/0x20
                     default_idle_call+0x59/0x1c0
                     do_idle+0x22c/0x2c0
                     cpu_startup_entry+0x20/0x30
                     start_secondary+0x11d/0x150
                     secondary_startup_64_no_verify+0xa6/0xab
    INITIAL USE at:
                    lock_acquire+0x15f/0x420
                    _raw_spin_lock_irqsave+0x52/0xa0
                    ata_dev_init+0x54/0xe0
                    ata_link_init+0x8b/0xd0
                    ata_port_alloc+0x1f1/0x210
                    ata_host_alloc+0xf1/0x130
                    ata_host_alloc_pinfo+0x14/0xb0
                    ata_pci_sff_prepare_host+0x41/0xa0
                    ata_pci_bmdma_prepare_host+0x14/0x30
                    piix_init_one+0x21f/0x600
                    local_pci_probe+0x48/0x80
                    pci_device_probe+0x105/0x1c0
                    really_probe+0x221/0x490
                    driver_probe_device+0xe9/0x160
                    device_driver_attach+0xb2/0xc0
                    __driver_attach+0x91/0x150
                    bus_for_each_dev+0x81/0xc0
                    driver_attach+0x1e/0x20
                    bus_add_driver+0x138/0x1f0
                    driver_register+0x91/0xf0
                    __pci_register_driver+0x73/0x80
                    piix_init+0x1e/0x2e
                    do_one_initcall+0x5f/0x2d0
                    kernel_init_freeable+0x26f/0x2cf
                    kernel_init+0xe/0x113
                    ret_from_fork+0x1f/0x30
  }
  ... key      at: [<ffffffff83d9fdc0>] __key.6+0x0/0x10
  ... acquired at:
    __lock_acquire+0x9da/0x2370
    lock_acquire+0x15f/0x420
    _raw_spin_lock_irqsave+0x52/0xa0
    ata_bmdma_interrupt+0x27/0x200
    __handle_irq_event_percpu+0xd5/0x2b0
    handle_irq_event+0x57/0xb0
    handle_edge_irq+0x8c/0x230
    asm_call_irq_on_stack+0xf/0x20
    common_interrupt+0x100/0x1c0
    asm_common_interrupt+0x1e/0x40
    native_safe_halt+0xe/0x10
    arch_cpu_idle+0x15/0x20
    default_idle_call+0x59/0x1c0
    do_idle+0x22c/0x2c0
    cpu_startup_entry+0x20/0x30
    start_secondary+0x11d/0x150
    secondary_startup_64_no_verify+0xa6/0xab

This lockdep splat is reported after:
commit e918188611f0 ("locking: More accurate annotations for read_lock()")

To clarify:
 - read-locks are recursive only in interrupt context (when
   in_interrupt() returns true)
 - after acquiring host->lock in CPU1, another cpu (i.e. CPU2) may call
   write_lock(&trig->leddev_list_lock) that would be blocked by CPU0
   that holds trig->leddev_list_lock in read-mode
 - when CPU1 (ata_ac_complete()) tries to read-lock
   trig->leddev_list_lock, it would be blocked by the write-lock waiter
   on CPU2 (because we are not in interrupt context, so the read-lock is
   not recursive)
 - at this point if an interrupt happens on CPU0 and
   ata_bmdma_interrupt() is executed it will try to acquire host->lock,
   that is held by CPU1, that is currently blocked by CPU2, so:

   * CPU0 blocked by CPU1
   * CPU1 blocked by CPU2
   * CPU2 blocked by CPU0

     *** DEADLOCK ***

The deadlock scenario is better represented by the following schema
(thanks to Boqun Feng <boqun.feng@gmail.com> for the schema and the
detailed explanation of the deadlock condition):

 CPU 0:                          CPU 1:                        CPU 2:
 -----                           -----                         -----
 led_trigger_event():
   read_lock(&trig->leddev_list_lock);
 				<workqueue>
 				ata_hsm_qc_complete():
 				  spin_lock_irqsave(&host->lock);
 								write_lock(&trig->leddev_list_lock);
 				  ata_port_freeze():
 				    ata_do_link_abort():
 				      ata_qc_complete():
 					ledtrig_disk_activity():
 					  led_trigger_blink_oneshot():
 					    read_lock(&trig->leddev_list_lock);
 					    // ^ not in in_interrupt() context, so could get blocked by CPU 2
 <interrupt>
   ata_bmdma_interrupt():
     spin_lock_irqsave(&host->lock);

Fix by using read_lock_irqsave/irqrestore() in led_trigger_event(), so
that no interrupt can happen in between, preventing the deadlock
condition.

Apply the same change to led_trigger_blink_setup() as well, since the
same deadlock scenario can also happen in power_supply_update_bat_leds()
-> led_trigger_blink() -> led_trigger_blink_setup() (workqueue context),
and potentially prevent other similar usages.

Link: https://lore.kernel.org/lkml/20201101092614.GB3989@xps-13-7390/
Fixes: eb25cb9956cc ("leds: convert IDE trigger to common disk trigger")
Signed-off-by: Andrea Righi <andrea.righi@canonical.com>
Signed-off-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/leds/led-triggers.c |   10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

--- a/drivers/leds/led-triggers.c
+++ b/drivers/leds/led-triggers.c
@@ -317,14 +317,15 @@ void led_trigger_event(struct led_trigge
 			enum led_brightness brightness)
 {
 	struct led_classdev *led_cdev;
+	unsigned long flags;
 
 	if (!trig)
 		return;
 
-	read_lock(&trig->leddev_list_lock);
+	read_lock_irqsave(&trig->leddev_list_lock, flags);
 	list_for_each_entry(led_cdev, &trig->led_cdevs, trig_list)
 		led_set_brightness(led_cdev, brightness);
-	read_unlock(&trig->leddev_list_lock);
+	read_unlock_irqrestore(&trig->leddev_list_lock, flags);
 }
 EXPORT_SYMBOL_GPL(led_trigger_event);
 
@@ -335,11 +336,12 @@ static void led_trigger_blink_setup(stru
 			     int invert)
 {
 	struct led_classdev *led_cdev;
+	unsigned long flags;
 
 	if (!trig)
 		return;
 
-	read_lock(&trig->leddev_list_lock);
+	read_lock_irqsave(&trig->leddev_list_lock, flags);
 	list_for_each_entry(led_cdev, &trig->led_cdevs, trig_list) {
 		if (oneshot)
 			led_blink_set_oneshot(led_cdev, delay_on, delay_off,
@@ -347,7 +349,7 @@ static void led_trigger_blink_setup(stru
 		else
 			led_blink_set(led_cdev, delay_on, delay_off);
 	}
-	read_unlock(&trig->leddev_list_lock);
+	read_unlock_irqrestore(&trig->leddev_list_lock, flags);
 }
 
 void led_trigger_blink(struct led_trigger *trig,



  parent reply	other threads:[~2021-02-02 14:49 UTC|newest]

Thread overview: 44+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-02-02 13:38 [PATCH 4.19 00/37] 4.19.173-rc1 review Greg Kroah-Hartman
2021-02-02 13:38 ` [PATCH 4.19 01/37] nbd: freeze the queue while were adding connections Greg Kroah-Hartman
2021-02-02 13:38 ` [PATCH 4.19 02/37] ACPI: sysfs: Prefer "compatible" modalias Greg Kroah-Hartman
2021-02-02 13:38 ` [PATCH 4.19 03/37] kernel: kexec: remove the lock operation of system_transition_mutex Greg Kroah-Hartman
2021-02-02 13:38 ` [PATCH 4.19 04/37] xen/privcmd: allow fetching resource sizes Greg Kroah-Hartman
2021-02-02 13:38 ` [PATCH 4.19 05/37] ALSA: hda/via: Apply the workaround generically for Clevo machines Greg Kroah-Hartman
2021-02-02 13:38 ` [PATCH 4.19 06/37] media: rc: ensure that uevent can be read directly after rc device register Greg Kroah-Hartman
2021-02-02 13:38 ` [PATCH 4.19 07/37] ARM: dts: imx6qdl-gw52xx: fix duplicate regulator naming Greg Kroah-Hartman
2021-02-02 13:38 ` [PATCH 4.19 08/37] wext: fix NULL-ptr-dereference with cfg80211s lack of commit() Greg Kroah-Hartman
2021-02-02 13:38 ` [PATCH 4.19 09/37] net: usb: qmi_wwan: added support for Thales Cinterion PLSx3 modem family Greg Kroah-Hartman
2021-02-02 13:38 ` [PATCH 4.19 10/37] PM: hibernate: flush swap writer after marking Greg Kroah-Hartman
2021-02-02 13:38 ` [PATCH 4.19 11/37] drivers: soc: atmel: Avoid calling at91_soc_init on non AT91 SoCs Greg Kroah-Hartman
2021-02-02 13:38 ` [PATCH 4.19 12/37] drivers: soc: atmel: add null entry at the end of at91_soc_allowed_list[] Greg Kroah-Hartman
2021-02-02 13:38 ` [PATCH 4.19 13/37] KVM: x86/pmu: Fix HW_REF_CPU_CYCLES event pseudo-encoding in intel_arch_events[] Greg Kroah-Hartman
2021-02-02 13:38 ` [PATCH 4.19 14/37] KVM: x86: get smi pending status correctly Greg Kroah-Hartman
2021-02-02 13:38 ` [PATCH 4.19 15/37] xen: Fix XenStore initialisation for XS_LOCAL Greg Kroah-Hartman
2021-02-02 13:38 ` Greg Kroah-Hartman [this message]
2021-02-02 13:39 ` [PATCH 4.19 17/37] mt7601u: fix kernel crash unplugging the device Greg Kroah-Hartman
2021-02-02 13:39 ` [PATCH 4.19 18/37] mt7601u: fix rx buffer refcounting Greg Kroah-Hartman
2021-02-02 13:39 ` [PATCH 4.19 19/37] xen-blkfront: allow discard-* nodes to be optional Greg Kroah-Hartman
2021-02-02 13:39 ` [PATCH 4.19 20/37] ARM: imx: build suspend-imx6.S with arm instruction set Greg Kroah-Hartman
2021-02-02 13:39 ` [PATCH 4.19 21/37] netfilter: nft_dynset: add timeout extension to template Greg Kroah-Hartman
2021-02-02 13:39 ` [PATCH 4.19 22/37] xfrm: Fix oops in xfrm_replay_advance_bmp Greg Kroah-Hartman
2021-02-02 13:39 ` [PATCH 4.19 23/37] xfrm: fix disable_xfrm sysctl when used on xfrm interfaces Greg Kroah-Hartman
2021-02-02 13:39 ` [PATCH 4.19 24/37] RDMA/cxgb4: Fix the reported max_recv_sge value Greg Kroah-Hartman
2021-02-02 13:39 ` [PATCH 4.19 25/37] pNFS/NFSv4: Fix a layout segment leak in pnfs_layout_process() Greg Kroah-Hartman
2021-02-02 13:39 ` [PATCH 4.19 26/37] iwlwifi: pcie: use jiffies for memory read spin time limit Greg Kroah-Hartman
2021-02-03 20:42   ` Pavel Machek
2021-02-02 13:39 ` [PATCH 4.19 27/37] iwlwifi: pcie: reschedule in long-running memory reads Greg Kroah-Hartman
2021-02-02 13:39 ` [PATCH 4.19 28/37] mac80211: pause TX while changing interface type Greg Kroah-Hartman
2021-02-02 13:39 ` [PATCH 4.19 29/37] net/mlx5: Fix memory leak on flow table creation error flow Greg Kroah-Hartman
2021-02-02 13:39 ` [PATCH 4.19 30/37] can: dev: prevent potential information leak in can_fill_info() Greg Kroah-Hartman
2021-02-02 13:39 ` [PATCH 4.19 31/37] iommu/vt-d: Gracefully handle DMAR units with no supported address widths Greg Kroah-Hartman
2021-02-02 13:39 ` [PATCH 4.19 32/37] iommu/vt-d: Dont dereference iommu_device if IOMMU_API is not built Greg Kroah-Hartman
2021-02-02 13:39 ` [PATCH 4.19 33/37] rxrpc: Fix memory leak in rxrpc_lookup_local Greg Kroah-Hartman
2021-02-02 13:39 ` [PATCH 4.19 34/37] NFC: fix resource leak when target index is invalid Greg Kroah-Hartman
2021-02-02 13:39 ` [PATCH 4.19 35/37] NFC: fix possible resource leak Greg Kroah-Hartman
2021-02-02 13:39 ` [PATCH 4.19 36/37] team: protect features update by RCU to avoid deadlock Greg Kroah-Hartman
2021-02-02 13:39 ` [PATCH 4.19 37/37] tcp: fix TLP timer not set when CA_STATE changes from DISORDER to OPEN Greg Kroah-Hartman
2021-02-02 17:48 ` [PATCH 4.19 00/37] 4.19.173-rc1 review Pavel Machek
2021-02-02 20:21 ` Jon Hunter
2021-02-03  3:22 ` Naresh Kamboju
2021-02-03 15:42 ` Shuah Khan
2021-02-03 20:42 ` Guenter Roeck

Reply instructions:

You may reply publicly 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=20210202132943.578879547@linuxfoundation.org \
    --to=gregkh@linuxfoundation.org \
    --cc=andrea.righi@canonical.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=pavel@ucw.cz \
    --cc=stable@vger.kernel.org \
    /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
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.