From: Ben Hutchings <ben@decadent.org.uk>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: akpm@linux-foundation.org,
"Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
"Ewan D. Milne" <emilne@redhat.com>,
"James Bottomley" <James.Bottomley@HansenPartnership.com>
Subject: [PATCH 3.2 51/67] klist: fix starting point removed bug in klist iterators
Date: Tue, 23 Feb 2016 21:42:03 +0000 [thread overview]
Message-ID: <lsq.1456263723.589835806@decadent.org.uk> (raw)
In-Reply-To: <lsq.1456263722.390955919@decadent.org.uk>
3.2.78-rc1 review patch. If anyone has any objections, please let me know.
------------------
From: James Bottomley <James.Bottomley@HansenPartnership.com>
commit 00cd29b799e3449f0c68b1cc77cd4a5f95b42d17 upstream.
The starting node for a klist iteration is often passed in from
somewhere way above the klist infrastructure, meaning there's no
guarantee the node is still on the list. We've seen this in SCSI where
we use bus_find_device() to iterate through a list of devices. In the
face of heavy hotplug activity, the last device returned by
bus_find_device() can be removed before the next call. This leads to
Dec 3 13:22:02 localhost kernel: WARNING: CPU: 2 PID: 28073 at include/linux/kref.h:47 klist_iter_init_node+0x3d/0x50()
Dec 3 13:22:02 localhost kernel: Modules linked in: scsi_debug x86_pkg_temp_thermal kvm_intel kvm irqbypass crc32c_intel joydev iTCO_wdt dcdbas ipmi_devintf acpi_power_meter iTCO_vendor_support ipmi_si imsghandler pcspkr wmi acpi_cpufreq tpm_tis tpm shpchp lpc_ich mfd_core nfsd nfs_acl lockd grace sunrpc tg3 ptp pps_core
Dec 3 13:22:02 localhost kernel: CPU: 2 PID: 28073 Comm: cat Not tainted 4.4.0-rc1+ #2
Dec 3 13:22:02 localhost kernel: Hardware name: Dell Inc. PowerEdge R320/08VT7V, BIOS 2.0.22 11/19/2013
Dec 3 13:22:02 localhost kernel: ffffffff81a20e77 ffff880613acfd18 ffffffff81321eef 0000000000000000
Dec 3 13:22:02 localhost kernel: ffff880613acfd50 ffffffff8107ca52 ffff88061176b198 0000000000000000
Dec 3 13:22:02 localhost kernel: ffffffff814542b0 ffff880610cfb100 ffff88061176b198 ffff880613acfd60
Dec 3 13:22:02 localhost kernel: Call Trace:
Dec 3 13:22:02 localhost kernel: [<ffffffff81321eef>] dump_stack+0x44/0x55
Dec 3 13:22:02 localhost kernel: [<ffffffff8107ca52>] warn_slowpath_common+0x82/0xc0
Dec 3 13:22:02 localhost kernel: [<ffffffff814542b0>] ? proc_scsi_show+0x20/0x20
Dec 3 13:22:02 localhost kernel: [<ffffffff8107cb4a>] warn_slowpath_null+0x1a/0x20
Dec 3 13:22:02 localhost kernel: [<ffffffff8167225d>] klist_iter_init_node+0x3d/0x50
Dec 3 13:22:02 localhost kernel: [<ffffffff81421d41>] bus_find_device+0x51/0xb0
Dec 3 13:22:02 localhost kernel: [<ffffffff814545ad>] scsi_seq_next+0x2d/0x40
[...]
And an eventual crash. It can actually occur in any hotplug system
which has a device finder and a starting device.
We can fix this globally by making sure the starting node for
klist_iter_init_node() is actually a member of the list before using it
(and by starting from the beginning if it isn't).
Reported-by: Ewan D. Milne <emilne@redhat.com>
Tested-by: Ewan D. Milne <emilne@redhat.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
lib/klist.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
--- a/lib/klist.c
+++ b/lib/klist.c
@@ -282,9 +282,9 @@ void klist_iter_init_node(struct klist *
struct klist_node *n)
{
i->i_klist = k;
- i->i_cur = n;
- if (n)
- kref_get(&n->n_ref);
+ i->i_cur = NULL;
+ if (n && kref_get_unless_zero(&n->n_ref))
+ i->i_cur = n;
}
EXPORT_SYMBOL_GPL(klist_iter_init_node);
next prev parent reply other threads:[~2016-02-23 21:55 UTC|newest]
Thread overview: 74+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-02-23 21:42 [PATCH 3.2 00/67] 3.2.78-rc1 review Ben Hutchings
2016-02-23 21:42 ` Ben Hutchings [this message]
2016-02-23 21:42 ` [PATCH 3.2 06/67] usb: cdc-acm: send zero packet for intel 7260 modem Ben Hutchings
2016-02-23 21:42 ` [PATCH 3.2 61/67] ALSA: usb-audio: avoid freeing umidi object twice Ben Hutchings
2016-02-23 21:42 ` [PATCH 3.2 11/67] USB: cp210x: add ID for IAI USB to RS485 adaptor Ben Hutchings
2016-02-23 21:42 ` [PATCH 3.2 58/67] ahci: Intel DNV device IDs SATA Ben Hutchings
2016-02-23 21:42 ` [PATCH 3.2 60/67] btrfs: properly set the termination value of ctx->pos in readdir Ben Hutchings
2016-02-23 21:42 ` [PATCH 3.2 33/67] ALSA: pcm: Fix potential deadlock in OSS emulation Ben Hutchings
2016-02-23 21:42 ` [PATCH 3.2 04/67] posix-timers: Handle relative timers with CONFIG_TIME_LOW_RES proper Ben Hutchings
2016-02-23 21:42 ` [PATCH 3.2 56/67] ALSA: timer: Fix race between stop and interrupt Ben Hutchings
2016-02-23 21:42 ` [PATCH 3.2 57/67] ALSA: timer: Fix race at concurrent reads Ben Hutchings
2016-02-23 21:42 ` [PATCH 3.2 42/67] xhci: Fix list corruption in urb dequeue at host removal Ben Hutchings
2016-02-23 21:42 ` [PATCH 3.2 36/67] libata: fix sff host state machine locking while polling Ben Hutchings
2016-02-23 21:42 ` [PATCH 3.2 26/67] ALSA: dummy: Disable switching timer backend via sysfs Ben Hutchings
2016-02-23 21:42 ` [PATCH 3.2 19/67] libata: disable forced PORTS_IMPL for >= AHCI 1.3 Ben Hutchings
2016-02-23 21:42 ` [PATCH 3.2 16/67] ALSA: seq: Degrade the error message for too many opens Ben Hutchings
2016-02-23 21:42 ` [PATCH 3.2 09/67] pptp: fix illegal memory access caused by multiple bind()s Ben Hutchings
2016-02-23 21:42 ` [PATCH 3.2 27/67] drm/vmwgfx: respect 'nomodeset' Ben Hutchings
2016-02-23 21:42 ` [PATCH 3.2 38/67] ALSA: rawmidi: Fix race at copying & updating the position Ben Hutchings
2016-02-23 21:42 ` [PATCH 3.2 02/67] hrtimer: Handle remaining time proper for TIME_LOW_RES Ben Hutchings
2016-02-23 21:42 ` [PATCH 3.2 25/67] crypto: shash - Fix has_key setting Ben Hutchings
2016-02-23 21:42 ` [PATCH 3.2 10/67] sctp: allow setting SCTP_SACK_IMMEDIATELY by the application Ben Hutchings
2016-02-23 21:42 ` [PATCH 3.2 43/67] [media] tda1004x: only update the frontend properties if locked Ben Hutchings
2016-02-23 21:42 ` [PATCH 3.2 44/67] ALSA: timer: Fix leftover link at closing Ben Hutchings
2016-02-23 21:42 ` [PATCH 3.2 50/67] crypto: algif_skcipher - Do not dereference ctx without socket lock Ben Hutchings
2016-02-23 21:42 ` [PATCH 3.2 67/67] sched: fix __sched_setscheduler() vs load balancing race Ben Hutchings
2016-02-23 21:42 ` [PATCH 3.2 23/67] SCSI: fix crashes in sd and sr runtime PM Ben Hutchings
2016-02-23 21:42 ` [PATCH 3.2 34/67] ALSA: seq: Fix yet another races among ALSA timer accesses Ben Hutchings
2016-02-23 21:42 ` [PATCH 3.2 45/67] [media] saa7134-alsa: Only frees registered sound cards Ben Hutchings
2016-02-23 21:42 ` [PATCH 3.2 15/67] ALSA: seq: Fix incorrect sanity check at snd_seq_oss_synth_cleanup() Ben Hutchings
2016-02-23 21:42 ` [PATCH 3.2 21/67] rfkill: fix rfkill_fop_read wait_event usage Ben Hutchings
2016-02-23 21:42 ` [PATCH 3.2 31/67] ALSA: seq: Fix race at closing in virmidi driver Ben Hutchings
2016-02-23 21:42 ` [PATCH 3.2 01/67] KVM: vmx: fix MPX detection Ben Hutchings
2016-02-23 21:42 ` [PATCH 3.2 65/67] iw_cxgb3: Fix incorrectly returning error on success Ben Hutchings
2016-02-23 21:42 ` [PATCH 3.2 62/67] unix: properly account for FDs passed over unix sockets Ben Hutchings
2016-02-23 21:42 ` [PATCH 3.2 59/67] ARM: 8519/1: ICST: try other dividends than 1 Ben Hutchings
2016-02-23 21:42 ` [PATCH 3.2 47/67] mm, vmstat: fix wrong WQ sleep when memory reclaim doesn't make any progress Ben Hutchings
2016-02-23 21:42 ` [PATCH 3.2 48/67] ocfs2/dlm: clear refmap bit of recovery lock while doing local recovery cleanup Ben Hutchings
2016-02-23 21:42 ` [PATCH 3.2 32/67] ALSA: rawmidi: Remove kernel WARNING for NULL user-space buffer check Ben Hutchings
2016-02-23 21:42 ` [PATCH 3.2 14/67] USB: serial: option: Adding support for Telit LE922 Ben Hutchings
2016-02-23 21:42 ` [PATCH 3.2 46/67] scsi_dh_rdac: always retry MODE SELECT on command lock violation Ben Hutchings
2016-02-23 21:42 ` [PATCH 3.2 39/67] ALSA: seq: Fix lockdep warnings due to double mutex locks Ben Hutchings
2016-02-23 21:42 ` [PATCH 3.2 28/67] x86/mm/pat: Avoid truncation when converting cpa->numpages to address Ben Hutchings
2016-02-23 21:42 ` [PATCH 3.2 18/67] PCI/AER: Flush workqueue on device remove to avoid use-after-free Ben Hutchings
2016-02-23 21:42 ` [PATCH 3.2 08/67] af_unix: fix struct pid memory leak Ben Hutchings
2016-02-23 22:07 ` Rainer Weikusat
2016-02-24 21:24 ` Ben Hutchings
2016-02-25 7:26 ` Willy Tarreau
2016-02-23 21:42 ` [PATCH 3.2 07/67] cdc-acm:exclude Samsung phone 04e8:685d Ben Hutchings
2016-02-23 21:42 ` [PATCH 3.2 49/67] crypto: user - lock crypto_alg_list on alg dump Ben Hutchings
2016-02-23 21:42 ` [PATCH 3.2 63/67] unix: correctly track in-flight fds in sending process user_struct Ben Hutchings
2016-02-23 21:42 ` [PATCH 3.2 12/67] USB: visor: fix null-deref at probe Ben Hutchings
2016-02-23 21:42 ` [PATCH 3.2 40/67] Revert "xhci: don't finish a TD if we get a short-transfer event mid TD" Ben Hutchings
2016-02-23 21:42 ` [PATCH 3.2 41/67] usb: xhci: apply XHCI_PME_STUCK_QUIRK to Intel Broxton-M platforms Ben Hutchings
2016-02-23 21:42 ` [PATCH 3.2 35/67] ALSA: timer: Fix link corruption due to double start or stop Ben Hutchings
2016-02-23 21:42 ` [PATCH 3.2 66/67] pipe: Fix buffer offset after partially failed read Ben Hutchings
2016-02-23 21:42 ` [PATCH 3.2 53/67] ALSA: timer: Fix wrong instance passed to slave callbacks Ben Hutchings
2016-02-23 21:42 ` [PATCH 3.2 37/67] ALSA: rawmidi: Make snd_rawmidi_transmit() race-free Ben Hutchings
2016-02-23 21:42 ` [PATCH 3.2 54/67] ARM: 8517/1: ICST: avoid arithmetic overflow in icst_hz() Ben Hutchings
2016-02-23 21:42 ` [PATCH 3.2 64/67] pipe: limit the per-user amount of pages allocated in pipes Ben Hutchings
2016-02-23 21:42 ` [PATCH 3.2 20/67] virtio_pci: fix use after free on release Ben Hutchings
2016-02-23 21:42 ` [PATCH 3.2 29/67] crypto: algif_hash - wait for crypto_ahash_init() to complete Ben Hutchings
2016-02-23 21:42 ` [PATCH 3.2 13/67] USB: serial: visor: fix crash on detecting device without write_urbs Ben Hutchings
2016-02-23 21:42 ` [PATCH 3.2 05/67] itimers: Handle relative timers with CONFIG_TIME_LOW_RES proper Ben Hutchings
2016-02-23 21:42 ` [PATCH 3.2 52/67] ALSA: dummy: Implement timer backend switching more safely Ben Hutchings
2016-02-23 21:42 ` [PATCH 3.2 03/67] timerfd: Handle relative timers with CONFIG_TIME_LOW_RES proper Ben Hutchings
2016-02-23 21:42 ` [PATCH 3.2 17/67] USB: serial: ftdi_sio: add support for Yaesu SCU-18 cable Ben Hutchings
2016-02-23 21:42 ` [PATCH 3.2 22/67] perf annotate browser: Fix behaviour of Shift-Tab with nothing focussed Ben Hutchings
2016-02-23 21:42 ` [PATCH 3.2 30/67] intel_scu_ipcutil: underflow in scu_reg_access() Ben Hutchings
2016-02-23 21:42 ` [PATCH 3.2 24/67] tty: Fix unsafe ldisc reference via ioctl(TIOCGETD) Ben Hutchings
2016-02-23 21:42 ` [PATCH 3.2 55/67] sctp: translate network order to host order when users get a hmacid Ben Hutchings
2016-02-24 0:48 ` [PATCH 3.2 00/67] 3.2.78-rc1 review Ben Hutchings
2016-02-24 2:48 ` Guenter Roeck
2016-02-24 14:41 ` Ben Hutchings
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