From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
stable@vger.kernel.org, Eric Dumazet <edumazet@google.com>,
"David S. Miller" <davem@davemloft.net>
Subject: [PATCH 4.11 10/84] Fix an intermittent pr_emerg warning about lo becoming free.
Date: Mon, 3 Jul 2017 15:34:50 +0200 [thread overview]
Message-ID: <20170703133403.641849974@linuxfoundation.org> (raw)
In-Reply-To: <20170703133402.874816941@linuxfoundation.org>
4.11-stable review patch. If anyone has any objections, please let me know.
------------------
From: Krister Johansen <kjlx@templeofstupid.com>
[ Upstream commit f186ce61bb8235d80068c390dc2aad7ca427a4c2 ]
It looks like this:
Message from syslogd@flamingo at Apr 26 00:45:00 ...
kernel:unregister_netdevice: waiting for lo to become free. Usage count = 4
They seem to coincide with net namespace teardown.
The message is emitted by netdev_wait_allrefs().
Forced a kdump in netdev_run_todo, but found that the refcount on the lo
device was already 0 at the time we got to the panic.
Used bcc to check the blocking in netdev_run_todo. The only places
where we're off cpu there are in the rcu_barrier() and msleep() calls.
That behavior is expected. The msleep time coincides with the amount of
time we spend waiting for the refcount to reach zero; the rcu_barrier()
wait times are not excessive.
After looking through the list of callbacks that the netdevice notifiers
invoke in this path, it appears that the dst_dev_event is the most
interesting. The dst_ifdown path places a hold on the loopback_dev as
part of releasing the dev associated with the original dst cache entry.
Most of our notifier callbacks are straight-forward, but this one a)
looks complex, and b) places a hold on the network interface in
question.
I constructed a new bcc script that watches various events in the
liftime of a dst cache entry. Note that dst_ifdown will take a hold on
the loopback device until the invalidated dst entry gets freed.
[ __dst_free] on DST: ffff883ccabb7900 IF tap1008300eth0 invoked at 1282115677036183
__dst_free
rcu_nocb_kthread
kthread
ret_from_fork
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
net/core/dst.c | 14 ++++++++++++++
1 file changed, 14 insertions(+)
--- a/net/core/dst.c
+++ b/net/core/dst.c
@@ -469,6 +469,20 @@ static int dst_dev_event(struct notifier
spin_lock_bh(&dst_garbage.lock);
dst = dst_garbage.list;
dst_garbage.list = NULL;
+ /* The code in dst_ifdown places a hold on the loopback device.
+ * If the gc entry processing is set to expire after a lengthy
+ * interval, this hold can cause netdev_wait_allrefs() to hang
+ * out and wait for a long time -- until the the loopback
+ * interface is released. If we're really unlucky, it'll emit
+ * pr_emerg messages to console too. Reset the interval here,
+ * so dst cleanups occur in a more timely fashion.
+ */
+ if (dst_garbage.timer_inc > DST_GC_INC) {
+ dst_garbage.timer_inc = DST_GC_INC;
+ dst_garbage.timer_expires = DST_GC_MIN;
+ mod_delayed_work(system_wq, &dst_gc_work,
+ dst_garbage.timer_expires);
+ }
spin_unlock_bh(&dst_garbage.lock);
if (last)
next prev parent reply other threads:[~2017-07-03 13:47 UTC|newest]
Thread overview: 81+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-07-03 13:34 [PATCH 4.11 00/84] 4.11.9-stable review Greg Kroah-Hartman
2017-07-03 13:34 ` [PATCH 4.11 01/84] net: dont call strlen on non-terminated string in dev_set_alias() Greg Kroah-Hartman
2017-07-03 13:34 ` [PATCH 4.11 02/84] net: Fix inconsistent teardown and release of private netdev state Greg Kroah-Hartman
2017-07-03 13:34 ` [PATCH 4.11 03/84] net: s390: fix up for "Fix inconsistent teardown and release of private netdev state" Greg Kroah-Hartman
2017-07-03 13:34 ` [PATCH 4.11 04/84] mac80211: free netdev on dev_alloc_name() error Greg Kroah-Hartman
2017-07-03 13:34 ` [PATCH 4.11 05/84] decnet: dn_rtmsg: Improve input length sanitization in dnrmg_receive_user_skb Greg Kroah-Hartman
2017-07-03 13:34 ` [PATCH 4.11 06/84] net: Zero ifla_vf_info in rtnl_fill_vfinfo() Greg Kroah-Hartman
2017-07-03 13:34 ` [PATCH 4.11 07/84] net: ipv6: Release route when device is unregistering Greg Kroah-Hartman
2017-07-03 13:34 ` [PATCH 4.11 08/84] net: vrf: Make add_fib_rules per network namespace flag Greg Kroah-Hartman
2017-07-03 13:34 ` [PATCH 4.11 09/84] af_unix: Add sockaddr length checks before accessing sa_family in bind and connect handlers Greg Kroah-Hartman
2017-07-03 13:34 ` Greg Kroah-Hartman [this message]
2017-07-03 13:34 ` [PATCH 4.11 11/84] sctp: disable BH in sctp_for_each_endpoint Greg Kroah-Hartman
2017-07-03 13:34 ` [PATCH 4.11 12/84] net: caif: Fix a sleep-in-atomic bug in cfpkt_create_pfx Greg Kroah-Hartman
2017-07-03 13:34 ` [PATCH 4.11 13/84] net: tipc: Fix a sleep-in-atomic bug in tipc_msg_reverse Greg Kroah-Hartman
2017-07-03 13:34 ` [PATCH 4.11 14/84] net/mlx5: Remove several module events out of ethtool stats Greg Kroah-Hartman
2017-07-03 13:34 ` [PATCH 4.11 15/84] net/mlx5e: Added BW check for DIM decision mechanism Greg Kroah-Hartman
2017-07-03 13:34 ` [PATCH 4.11 16/84] net/mlx5e: Fix wrong indications in DIM due to counter wraparound Greg Kroah-Hartman
2017-07-03 13:34 ` [PATCH 4.11 17/84] net/mlx5: Enable 4K UAR only when page size is bigger than 4K Greg Kroah-Hartman
2017-07-03 13:34 ` [PATCH 4.11 18/84] proc: snmp6: Use correct type in memset Greg Kroah-Hartman
2017-07-03 13:34 ` [PATCH 4.11 19/84] igmp: acquire pmc lock for ip_mc_clear_src() Greg Kroah-Hartman
2017-07-03 13:35 ` [PATCH 4.11 20/84] igmp: add a missing spin_lock_init() Greg Kroah-Hartman
2017-07-03 13:35 ` [PATCH 4.11 22/84] net: dont global ICMP rate limit packets originating from loopback Greg Kroah-Hartman
2017-07-03 13:35 ` [PATCH 4.11 23/84] ipv6: fix calling in6_ifa_hold incorrectly for dad work Greg Kroah-Hartman
2017-07-03 13:35 ` [PATCH 4.11 24/84] sctp: return next obj by passing pos + 1 into sctp_transport_get_idx Greg Kroah-Hartman
2017-07-03 13:35 ` [PATCH 4.11 25/84] net/mlx5e: Fix min inline value for VF rep SQs Greg Kroah-Hartman
2017-07-03 13:35 ` [PATCH 4.11 26/84] net/mlx5e: Avoid doing a cleanup call if the profile doesnt have it Greg Kroah-Hartman
2017-07-03 13:35 ` [PATCH 4.11 27/84] net/mlx5: Wait for FW readiness before initializing command interface Greg Kroah-Hartman
2017-07-03 13:35 ` [PATCH 4.11 28/84] net/mlx5e: Fix timestamping capabilities reporting Greg Kroah-Hartman
2017-07-03 13:35 ` [PATCH 4.11 29/84] decnet: always not take dst->__refcnt when inserting dst into hash table Greg Kroah-Hartman
2017-07-03 13:35 ` [PATCH 4.11 30/84] net: 8021q: Fix one possible panic caused by BUG_ON in free_netdev Greg Kroah-Hartman
2017-07-03 13:35 ` [PATCH 4.11 31/84] ipv6: Do not leak throw route references Greg Kroah-Hartman
2017-07-03 13:35 ` [PATCH 4.11 32/84] rtnetlink: add IFLA_GROUP to ifla_policy Greg Kroah-Hartman
2017-07-03 13:35 ` [PATCH 4.11 33/84] netfilter: synproxy: fix conntrackd interaction Greg Kroah-Hartman
2017-07-03 13:35 ` [PATCH 4.11 34/84] NFSv4.x/callback: Create the callback service through svc_create_pooled Greg Kroah-Hartman
2017-07-03 13:35 ` [PATCH 4.11 36/84] MIPS: head: Reorder instructions missing a delay slot Greg Kroah-Hartman
2017-07-03 13:35 ` [PATCH 4.11 37/84] MIPS: Avoid accidental raw backtrace Greg Kroah-Hartman
2017-07-03 13:35 ` [PATCH 4.11 38/84] MIPS: pm-cps: Drop manual cache-line alignment of ready_count Greg Kroah-Hartman
2017-07-03 13:35 ` [PATCH 4.11 39/84] MIPS: Fix IRQ tracing & lockdep when rescheduling Greg Kroah-Hartman
2017-07-03 13:35 ` [PATCH 4.11 40/84] ALSA: hda - Fix endless loop of codec configure Greg Kroah-Hartman
2017-07-03 13:35 ` [PATCH 4.11 41/84] ALSA: hda - set input_path bitmap to zero after moving it to new place Greg Kroah-Hartman
2017-07-03 13:35 ` [PATCH 4.11 42/84] NFSv4.2: Dont send mode again in post-EXCLUSIVE4_1 SETATTR with umask Greg Kroah-Hartman
2017-07-03 13:35 ` [PATCH 4.11 43/84] NFSv4.1: Fix a race in nfs4_proc_layoutget Greg Kroah-Hartman
2017-07-03 13:35 ` [PATCH 4.11 44/84] Revert "NFS: nfs_rename() handle -ERESTARTSYS dentry left behind" Greg Kroah-Hartman
2017-07-03 13:35 ` [PATCH 4.11 45/84] ovl: copy-up: dont unlock between lookup and link Greg Kroah-Hartman
2017-07-03 13:35 ` [PATCH 4.11 46/84] gpiolib: fix filtering out unwanted events Greg Kroah-Hartman
2017-07-03 13:35 ` [PATCH 4.11 47/84] x86/intel_rdt: Fix memory leak on mount failure Greg Kroah-Hartman
2017-07-03 13:35 ` [PATCH 4.11 48/84] perf/x86/intel/uncore: Fix wrong box pointer check Greg Kroah-Hartman
2017-07-03 13:35 ` [PATCH 4.11 49/84] drm/vmwgfx: Free hash table allocated by cmdbuf managed res mgr Greg Kroah-Hartman
2017-07-03 13:35 ` [PATCH 4.11 50/84] dm thin: do not queue freed thin mapping for next stage processing Greg Kroah-Hartman
2017-07-03 13:35 ` [PATCH 4.11 51/84] x86/mm: Fix boot crash caused by incorrect loop count calculation in sync_global_pgds() Greg Kroah-Hartman
2017-07-03 13:35 ` [PATCH 4.11 52/84] pinctrl/amd: Use regular interrupt instead of chained Greg Kroah-Hartman
2017-07-03 13:35 ` [PATCH 4.11 53/84] mm/vmalloc.c: huge-vmap: fail gracefully on unexpected huge vmap mappings Greg Kroah-Hartman
2017-07-03 13:35 ` [PATCH 4.11 55/84] xfrm6: Fix IPv6 payload_len in xfrm6_transport_finish Greg Kroah-Hartman
2017-07-03 13:35 ` [PATCH 4.11 56/84] xfrm: move xfrm_garbage_collect out of xfrm_policy_flush Greg Kroah-Hartman
2017-07-03 13:35 ` [PATCH 4.11 57/84] xfrm: fix stack access out of bounds with CONFIG_XFRM_SUB_POLICY Greg Kroah-Hartman
2017-07-03 13:35 ` [PATCH 4.11 58/84] xfrm: NULL dereference on allocation failure Greg Kroah-Hartman
2017-07-03 13:35 ` [PATCH 4.11 59/84] xfrm: Oops on error in pfkey_msg2xfrm_state() Greg Kroah-Hartman
2017-07-03 13:35 ` [PATCH 4.11 60/84] watchdog: bcm281xx: Fix use of uninitialized spinlock Greg Kroah-Hartman
2017-07-03 13:35 ` [PATCH 4.11 61/84] ARM64: PCI: Fix struct acpi_pci_root_ops allocation failure path Greg Kroah-Hartman
2017-07-03 13:35 ` [PATCH 4.11 62/84] ARM64/ACPI: Fix BAD_MADT_GICC_ENTRY() macro implementation Greg Kroah-Hartman
2017-07-03 13:35 ` [PATCH 4.11 63/84] ARM: 8685/1: ensure memblock-limit is pmd-aligned Greg Kroah-Hartman
2017-07-03 13:35 ` [PATCH 4.11 64/84] ARM: davinci: PM: Free resources in error handling path in davinci_pm_init Greg Kroah-Hartman
2017-07-03 13:35 ` [PATCH 4.11 65/84] ARM: davinci: PM: Do not free useful resources in normal " Greg Kroah-Hartman
2017-07-03 13:35 ` [PATCH 4.11 66/84] tools arch: Sync arch/x86/lib/memcpy_64.S with the kernel Greg Kroah-Hartman
2017-07-03 13:35 ` [PATCH 4.11 67/84] Revert "x86/entry: Fix the end of the stack for newly forked tasks" Greg Kroah-Hartman
2017-07-03 13:35 ` [PATCH 4.11 68/84] x86/mshyperv: Remove excess #includes from mshyperv.h Greg Kroah-Hartman
2017-07-03 13:35 ` [PATCH 4.11 69/84] x86/boot/KASLR: Fix kexec crash due to virt_addr calculation bug Greg Kroah-Hartman
2017-07-03 13:35 ` [PATCH 4.11 70/84] perf/x86: Fix spurious NMI with PEBS Load Latency event Greg Kroah-Hartman
2017-07-03 13:35 ` [PATCH 4.11 71/84] x86/mpx: Correctly report do_mpx_bt_fault() failures to user-space Greg Kroah-Hartman
2017-07-03 13:35 ` [PATCH 4.11 72/84] x86/mm: Fix flush_tlb_page() on Xen Greg Kroah-Hartman
2017-07-03 13:35 ` [PATCH 4.11 73/84] ocfs2: o2hb: revert hb threshold to keep compatible Greg Kroah-Hartman
2017-07-03 13:35 ` [PATCH 4.11 74/84] ocfs2: fix deadlock caused by recursive locking in xattr Greg Kroah-Hartman
2017-07-03 13:35 ` [PATCH 4.11 75/84] iommu/dma: Dont reserve PCI I/O windows Greg Kroah-Hartman
2017-07-03 13:35 ` [PATCH 4.11 76/84] iommu/amd: Fix incorrect error handling in amd_iommu_bind_pasid() Greg Kroah-Hartman
2017-07-03 13:35 ` [PATCH 4.11 77/84] iommu/amd: Fix interrupt remapping when disable guest_mode Greg Kroah-Hartman
2017-07-03 13:35 ` [PATCH 4.11 78/84] infiniband: hns: avoid gcc-7.0.1 warning for uninitialized data Greg Kroah-Hartman
2017-07-03 13:35 ` [PATCH 4.11 79/84] mtd: nand: brcmnand: Check flash #WP pin status before nand erase/program Greg Kroah-Hartman
2017-07-03 13:36 ` [PATCH 4.11 80/84] mtd: nand: fsmc: fix NAND width handling Greg Kroah-Hartman
2017-07-03 13:36 ` [PATCH 4.11 81/84] KVM: x86: fix emulation of RSM and IRET instructions Greg Kroah-Hartman
2017-07-03 19:55 ` [PATCH 4.11 00/84] 4.11.9-stable review Guenter Roeck
2017-07-04 7:59 ` Greg Kroah-Hartman
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