Because gcc doesn't realize that rcu_num_lvls must be strictly greater
than zero, some versions give a spurious warning about levelcnt[0] being
uninitialized in rcu_init_one(). This commit updates the condition on
the pre-existing panic() in order to educate gcc on this point.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Currently, the larger the gp_init_delay boot parameter, the slower
rcutorture will sequence through grace periods. This commit avoids this
issue by decreasing the probability of slowing initialization of a given
grace period as the degree of slowness increases.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
We removed __cpuinit support (leaving no-op stubs) quite some time ago.
However a new instance was added in commit 00df35f991
("cpu: Defer smpboot kthread unparking until CPU known to scheduler")
Since we want to clobber the stubs soon, get this removed now.
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Commit 00df35f991 (cpu: Defer smpboot kthread unparking until CPU known
to scheduler) put the online path's call to smpboot_unpark_threads()
into a CPU-hotplug notifier. This commit places the offline-failure
paths call into the same notifier for the sake of uniformity.
Note that it is not currently possible to place the offline path's call to
smpboot_park_threads() into an existing notifier because the CPU_DYING
notifiers run in a restricted environment, and the CPU_UP_PREPARE
notifiers run too soon.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
The rcu_data structure's ->rcu_qs_ctr_snap field is initialized at
CPU-online time from the current CPU's element of the per-CPU rcu_qs_ctr
variable. Unfortunately, this is at CPU_UP_PREPARE time, so has nothing
to do with the CPU being onlined. This commit therefore initializes
this variable from the incoming CPU's element of rcu_qs_ctr.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Because offline CPUs are propagated up the rcu_node tree's ->qsmaskinit
bits just before each grace period starts, the ->qsmaskinit bit cannot
be clear when the corresponding ->qsmask bit is set. Furthermore, this
condition used to correspond to a CPU that was on its way offline, and
making RCU's notion of an offline CPU more precise has eliminated this
situation. This commit therefore removes the now-redundant offline
check from force_qs_rnp().
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Because force_qs_rnp() is invoked only from the force-quiescent-state
code which runs only in the context of the grace-period kthread, a grace
period must always be in progress throughout force_qs_rnp()'s execution.
This commit therefore removes the rcu_gp_in_progress() check and the
associated dead code.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Tasks are no longer migrated away from a given rcu_node structure
when all CPUs corresponding to that rcu_node structure have gone offline.
This means that rcu_read_unlock_special() no longer needs to loop
retrying rcu_node ->lock acquisition because the current task is
guaranteed to stay put.
This commit takes a small and paranoid step towards relying on this
guarantee by placing a WARN_ON_ONCE() just after the early exit from
the lock-acquisition loop.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
This commit removes a HOTPLUG_CPU #ifdef, replacing it with
IS_ENABLED()-protected return statements. This relies on the
optimizer to remove any resulting dead code.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
This fixes the following sparse warnings:
make C=1 CF=-D__CHECK_ENDIAN__ net/tipc/name_table.o
net/tipc/name_table.c:977:17: error: incompatible types in comparison expression (different address spaces)
net/tipc/name_table.c:977:17: error: incompatible types in comparison expression (different address spaces)
To silence these spare complaints, an RCU annotation should be added to
"next" pointer of hlist_node structure through hlist_next_rcu() macro
when iterating over a hlist with hlist_for_each_entry_from_rcu().
Signed-off-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
rcu_cpu_has_callbacks() is declared int. The current declaration was introduced
in commit c0f4dfd4f9 (rcu: Make RCU_FAST_NO_HZ take advantage of numbered
callbacks). But it is actually returning bool and as the function description
states " * Return true if the specified CPU has any callback....", this probably
should be a bool as all (3) call-sites currently treat it as bool.
Type-checking coccinelle spatches are being used to locate type mismatches
between function signatures and return values in this case this produced:
./kernel/rcu/tree.c:3538 WARNING: return of wrong type
int != bool,
Patch was compile tested with x86_64_defconfig (implies CONFIG_TREE_RCU=y)
Patch is against 4.1-rc3 (localversion-next is -next-20150511) and fixes
Signed-off-by: Nicholas Mc Guire <hofrat@osadl.org>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
rcu_bh_data, rcu_sched_data and rcu_preempt_data are never used outside
kernel/rcu/tree.c and thus can be made static.
Doing so fixes a section mismatch warning reported by clang when
building LLVMLinux with -Wsection, because these variables were declared
in .data..percpu and defined in .data..percpu..shared_aligned since
commit 11bbb235c2 ("rcu: Use DEFINE_PER_CPU_SHARED_ALIGNED for
rcu_data").
Signed-off-by: Nicolas Iooss <nicolas.iooss_linux@m4x.org>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Currently, synchronize_sched_expedited() will call synchronize_sched()
if there is danger of counter wrap. But if configuration says to
always do expedited grace periods, synchronize_sched() will just
call synchronize_sched_expedited() right back again. In theory,
the old expedited operations will complete, the counters will
get back in synch, and the recursion will end. But we could
easily run out of stack long before that time. This commit
therefore makes synchronize_sched_expedited() invoke the underlying
wait_rcu_gp(call_rcu_sched) instead of synchronize_sched(), the same as
all the other calls out from synchronize_sched_expedited().
This bug was introduced by commit 1924bcb025 (Avoid counter wrap in
synchronize_sched_expedited()).
Reported-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
The current formulation of control dependencies fails on DEC Alpha,
which does not respect dependencies of any kind unless an explicit
memory barrier is provided. This means that the current fomulation of
control dependencies fails on Alpha. This commit therefore creates a
READ_ONCE_CTRL() that has the same overhead on non-Alpha systems, but
causes Alpha to produce the needed ordering. This commit also applies
READ_ONCE_CTRL() to the one known use of control dependencies.
Use of READ_ONCE_CTRL() also has the beneficial effect of adding a bit
of self-documentation to control dependencies.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
This commit adds grace number and command-flags information to the
"kthread starved" message that is sometimes printed out as part of
RCU CPU stall warnings. This message is caused by the corresponding
RCU grace-period kthread not having run for at least two seconds, and
this added information can be helpful when debugging.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
The first item list_for_each_entry_continue(alist) iterates over is
alist->next, rather than alist itself. Consequently,
rcu_print_detail_task_stall_rnp() skips the task referenced by gp_tasks.
Use gp_tasks->prev as the argument to list_for_each_entry_continue()
instead.
Signed-off-by: Patrick Daly <pdaly@codeaurora.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Currently, smp_mb__before_spinlock() is defined to be smp_wmb()
in core code, but this is not sufficient on PowerPC. This patch
therefore supplies an override for the generic definition to
strengthen smp_mb__before_spinlock() to smp_mb(), as is needed
on PowerPC.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: <linuxppc-dev@lists.ozlabs.org>
Use the normal return values for bool functions
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
The rcu_gp_kthread_wake() refuses to do a wakeup unless at least
one of the ->gp_flags bits are set, which normally will not be the
case when the last quiescent state is reported. This results in
up to a 3-jiffy delay given default Kconfig settings. This commit
therefore has rcu_report_qs_rsp() set RCU_GP_FLAG_FQS before invoking
rcu_gp_kthread_wake() in order to force a more immediate wakeup at
grace-period end, thus reducing grace-period latencies.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
This commit converts several CONFIG_RCU_NOCB_CPU_ALL #ifdefs to
instead use IS_ENABLED(). This change should help avoid hiding
code from compiler diagnostics.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
This commit creates an immutable rcu_data_p pointer that references
rcu_preempt_data for TREE_PREEMPT_RCU builds and that references
rcu_sched_data for TREE_RCU builds. This rcu_data_p pointer will enable
more code to move from #ifdef to IS_ENABLED().
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
This commit adds a "const" tag to the declarations of rcu_state_p,
which should allow the compiler to generate better code and also to
catch erroneous assignments to this variable.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
This commit removes a few RCU_BOOST #ifdefs, replacing them with
IS_ENABLED()-protected return statements. This relies on the
optimizer to remove any resulting dead code. There are several other
RCU_BOOST #ifdefs, however these rely on some per-CPU variables that
are available only under RCU_BOOST. These might be converted later,
if the simplification proves to outweigh the increase in memory footprint.
One hoped-for advantage is more easily locating compiler errors in
obscure combinations of Kconfig parameters.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: <linux-rt-users@vger.kernel.org>
It would be good to move more code from #ifdef to IS_ENABLED(), but
that does not work if the body of the IS_ENABLED() "if" statement
references a variable (such as rcu_preempt_state) that does not
exist if the IS_ENABLED() Kconfig variable is not set. This commit
therefore substitutes *rcu_state_p for all uses of rcu_preempt_state
in kernel/rcu/tree_preempt.h, which should enable elimination of
a few #ifdefs.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Make a note stating that repeated calls of rcu_dereference() may not
return the same pointer if update happens while in critical section.
Reported-by: Jeff Haran <jeff.haran@citrix.com>
Signed-off-by: Milos Vyletel <milos@redhat.com>
Reviewed-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
This commit provides another caveat for the care and feeding of pointers
returned by rcu_dereference() that was pointed out in discussions within
the C++ standards committee.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Our current documentation claims that, when followed by an ACQUIRE,
smp_mb__before_spinlock() orders prior loads against subsequent loads
and stores, which isn't the intent. This commit therefore fixes the
documentation to state that this sequence orders only prior stores
against subsequent loads and stores.
In addition, the original intent of smp_mb__before_spinlock() was to only
order prior loads against subsequent stores, however, people have started
using it as if it ordered prior loads against subsequent loads and stores.
This commit therefore also updates smp_mb__before_spinlock()'s header
comment to reflect this new reality.
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Now that rcu_access_index() and rcu_dereference_index_check() are no
longer used, the commit removes them from the RCU API. This means that
RCU's data dependencies now involve only pointers, give or take the
occasional cast to and then back from an integer type to do pointer
arithmetic. This in turn eliminates the need for a number of operations
on values carrying RCU data dependencies.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: linux-edac@vger.kernel.org
Cc: Tony Luck <tony.luck@intel.com>
Acked-by: Borislav Petkov <bp@suse.de>
Because mce is arch-specific x86 code, there is little or no
performance benefit of using rcu_dereference_index_check() over using
smp_load_acquire(). It also turns out that mce is the only place that
array-index-based RCU is used, and it would be convenient to drop
this portion of the RCU API.
This patch therefore changes rcu_dereference_index_check() uses to
smp_load_acquire(), but keeping the lockdep diagnostics, and also
changes rcu_access_index() uses to READ_ONCE().
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: linux-edac@vger.kernel.org
Cc: Tony Luck <tony.luck@intel.com>
Acked-by: Borislav Petkov <bp@suse.de>
This commit moves from the old ACCESS_ONCE() API to the new READ_ONCE()
and WRITE_ONCE() APIs.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
[ paulmck: Updated to include kernel/torture.c as suggested by Jason Low. ]
In do_otp_write we must initialize the variable datum before calling
map_word_load_partial. Otherwise the upper bits of datum may be undefined,
which later causes problems in chip_good called by do_write_oneword.
Signed-off-by: Christian Riesch <christian.riesch@omicron.at>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
It's harmless to add 'ofpart' (the only different parser supported in
default mtdpart.c) to plat_nand. That let's us kill off one more custom
partition prober listing.
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
We may disable proc fs only for sound part, to reduce ALSA
memory footprint. So add CONFIG_SND_PROC_FS and replace the
old CONFIG_PROC_FSs in alsa code.
With sound proc fs disabled, we can save about 9KB memory
size on X86_64 platform.
Signed-off-by: Jie Yang <yang.jie@intel.com>
Reviewed-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
For some embedded devices, we need reduce code size and data
footprint as much as possible, e.g. disabling procfs, hw/sw
params refinement, mmap, dpcm, dapm, compressed API...
Here add SND_PROC_FS item for expert, we can unselect it to
disable sound proc FS and reduce memory footprint.
Signed-off-by: Jie Yang <yang.jie@intel.com>
Reviewed-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
We've got a regression report that 4.1-rc causes noises on a Dell
laptop. Similar like Realtek codec, this seems also triggered by the
recent power_save_node feature. As this kind of issue is quite hard
to debug without actual hardware, disable the power_save_node flag for
this codec as a workaround.
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=98971
Signed-off-by: Takashi Iwai <tiwai@suse.de>
After commit 07f4c90062 ("tcp/dccp: try to not exhaust
ip_local_port_range in connect()") it is advised to have an even number
of ports described in /proc/sys/net/ipv4/ip_local_port_range
This means start/end values should have a different parity.
Let's warn sysadmins of this, so that they can update their settings
if they want to.
Suggested-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
__inet_hash_connect() does not use its third argument (port_offset)
if socket was already bound to a source port.
No need to perform useless but expensive md5 computations.
Reported-by: Crestez Dan Leonard <cdleonard@gmail.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Hariprasad Shenai says:
====================
cxgb4/cxgb4vf: Adds FL starvation support and cleanup
This patch series adds the following.
Adds debugfs entry to inject freelist starvation and some function and
argument cleanup
This patch series has been created against net-next tree and includes
patches on cxgb4 and cxgb4vf driver.
We have included all the maintainers of respective drivers. Kindly review
the change and let us know in case of any review comments.
Thanks
V2:
Skipping patch "cxgb4: Add support for loopback between VI of same port".
This needs some major code change, since module param is not recommended.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch changes variable name 'fn' to 'pf' of structure adapter.
A 'fn' usually stands for PCI function which could be a PF or a VF.
However, the use of this particular variable is explicitly limited to PF
only. So, be specific about it in the variable name.
Also corrects arguments passed for fn t4_ofld_eq_free, t4_ctrl_eq_free,
t4_eth_eq_free, t4_iq_free, t4_alloc_vi, t4_fw_hello, t4_wr_mbox and
t4_cfg_pfvf function.
Also renames cxgb4_t4_bar2_sge_qregs to t4_bar2_sge_qregs and renames
the latter function name in cxgb4vf driver to t4vf_bar2_sge_qregs to
avoid conflicts. Also fixes alignment for these function.
Signed-off-by: Hariprasad Shenai <hariprasad@chelsio.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add debugfs entry to inject Freelist starvation, used only for debugging
purpose.
Signed-off-by: Hariprasad Shenai <hariprasad@chelsio.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
vmalloc.h used to be included from include/net/inet_hashtables.h
but it is no longer the case.
Fixes: 095dc8e0c3 ("tcp: fix/cleanup inet_ehash_locks_alloc()")
Reported-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Eric Dumazet <edumzet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Aleksey Makarov says:
====================
Adding support for Cavium ThunderX network controller
This patchset adds support for the Cavium ThunderX network controller.
changes in v6:
* unused preprocessor symbols were removed
* reduce no of atomic operations in SQ maintenance
* support for TCP segmentation at driver level
* reset RBDR if fifo state is FAIL
* fixed an issue with link state mailbox message
changes in v5:
* __packed were removed. now we rely on C language ABI
* nic_dbg() -> netdev_dbg()
* fixes for a typo, constant spelling and using BIT_ULL
* use print_hex_dump()
* unnecessary conditions in a long if() chain were removed
changes in v4:
* the patch "pci: Add Cavium PCI vendor id" was attributed correctly
* a note that Cavium id is used in many drivers was added
* the license comments now match MODULE_LICENSE
* a comment explaining usage of writeq_relaxed()/readq_relaxed() was added
changes in v3:
* code cleanup
* issues discovered by reviewers were addressed
changes in v2:
* non-generic module parameters removed
* ethtool support added (nicvf_set_rxnfc())
v5: https://lkml.kernel.org/g/<1432344498-17131-1-git-send-email-aleksey.makarov@caviumnetworks.com>
v4: https://lkml.kernel.org/g/<1432000757-28700-1-git-send-email-aleksey.makarov@auriga.com>
v3: https://lkml.kernel.org/g/<1431747401-20847-1-git-send-email-aleksey.makarov@auriga.com>
v2: https://lkml.kernel.org/g/<1415596445-10061-1-git-send-email-rric@kernel.org>
v1: https://lkml.kernel.org/g/<20141030165434.GW20170@rric.localhost>
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch adds support for the Cavium ThunderX network controller.
The driver is on the pci bus and thus requires the Thunder PCIe host
controller driver to be enabled.
Signed-off-by: Maciej Czekaj <mjc@semihalf.com>
Signed-off-by: David Daney <david.daney@cavium.com>
Signed-off-by: Sunil Goutham <sgoutham@cavium.com>
Signed-off-by: Ganapatrao Kulkarni <ganapatrao.kulkarni@caviumnetworks.com>
Signed-off-by: Aleksey Makarov <aleksey.makarov@caviumnetworks.com>
Signed-off-by: Tomasz Nowicki <tomasz.nowicki@linaro.org>
Signed-off-by: Robert Richter <rrichter@cavium.com>
Signed-off-by: Kamil Rytarowski <kamil@semihalf.com>
Signed-off-by: Thanneeru Srinivasulu <tsrinivasulu@caviumnetworks.com>
Signed-off-by: Sruthi Vangala <svangala@cavium.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This vendor id will be used by network (vNIC), USB (xHCI),
SATA (AHCI), GPIO, I2C, MMC and maybe other drivers
for ThunderX SoC.
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Sunil Goutham <sgoutham@cavium.com>
Signed-off-by: Aleksey Makarov <aleksey.makarov@caviumnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
sctp_v4_map_v6 was subtly writing and reading from members
of a union in a way the clobbered data it needed to read before
it read it.
Zeroing the v6 flowinfo overwrites the v4 sin_addr with 0, meaning
that every place that calls sctp_v4_map_v6 gets ::ffff:0.0.0.0 as the
result.
Reorder things to guarantee correct behaviour no matter what the
union layout is.
This impacts user space clients that open an IPv6 SCTP socket and
receive IPv4 connections. Prior to 299ee user space would see a
sockaddr with AF_INET and a correct address, after 299ee the sockaddr
is AF_INET6, but the address is wrong.
Fixes: 299ee123e1 (sctp: Fixup v4mapped behaviour to comply with Sock API)
Signed-off-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
For mq qdisc, we add per tx queue qdisc to root qdisc
for display purpose, however, that happens too early,
before the new dev->qdisc is finally set, this causes
q->list points to an old root qdisc which is going to be
freed right before assigning with a new one.
Fix this by moving ->attach() after setting dev->qdisc.
For the record, this fixes the following crash:
------------[ cut here ]------------
WARNING: CPU: 1 PID: 975 at lib/list_debug.c:59 __list_del_entry+0x5a/0x98()
list_del corruption. prev->next should be ffff8800d1998ae8, but was 6b6b6b6b6b6b6b6b
CPU: 1 PID: 975 Comm: tc Not tainted 4.1.0-rc4+ #1019
Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
0000000000000009 ffff8800d73fb928 ffffffff81a44e7f 0000000047574756
ffff8800d73fb978 ffff8800d73fb968 ffffffff810790da ffff8800cfc4cd20
ffffffff814e725b ffff8800d1998ae8 ffffffff82381250 0000000000000000
Call Trace:
[<ffffffff81a44e7f>] dump_stack+0x4c/0x65
[<ffffffff810790da>] warn_slowpath_common+0x9c/0xb6
[<ffffffff814e725b>] ? __list_del_entry+0x5a/0x98
[<ffffffff81079162>] warn_slowpath_fmt+0x46/0x48
[<ffffffff81820eb0>] ? dev_graft_qdisc+0x5e/0x6a
[<ffffffff814e725b>] __list_del_entry+0x5a/0x98
[<ffffffff814e72a7>] list_del+0xe/0x2d
[<ffffffff81822f05>] qdisc_list_del+0x1e/0x20
[<ffffffff81820cd1>] qdisc_destroy+0x30/0xd6
[<ffffffff81822676>] qdisc_graft+0x11d/0x243
[<ffffffff818233c1>] tc_get_qdisc+0x1a6/0x1d4
[<ffffffff810b5eaf>] ? mark_lock+0x2e/0x226
[<ffffffff817ff8f5>] rtnetlink_rcv_msg+0x181/0x194
[<ffffffff817ff72e>] ? rtnl_lock+0x17/0x19
[<ffffffff817ff72e>] ? rtnl_lock+0x17/0x19
[<ffffffff817ff774>] ? __rtnl_unlock+0x17/0x17
[<ffffffff81855dc6>] netlink_rcv_skb+0x4d/0x93
[<ffffffff817ff756>] rtnetlink_rcv+0x26/0x2d
[<ffffffff818544b2>] netlink_unicast+0xcb/0x150
[<ffffffff81161db9>] ? might_fault+0x59/0xa9
[<ffffffff81854f78>] netlink_sendmsg+0x4fa/0x51c
[<ffffffff817d6e09>] sock_sendmsg_nosec+0x12/0x1d
[<ffffffff817d8967>] sock_sendmsg+0x29/0x2e
[<ffffffff817d8cf3>] ___sys_sendmsg+0x1b4/0x23a
[<ffffffff8100a1b8>] ? native_sched_clock+0x35/0x37
[<ffffffff810a1d83>] ? sched_clock_local+0x12/0x72
[<ffffffff810a1fd4>] ? sched_clock_cpu+0x9e/0xb7
[<ffffffff810def2a>] ? current_kernel_time+0xe/0x32
[<ffffffff810b4bc5>] ? lock_release_holdtime.part.29+0x71/0x7f
[<ffffffff810ddebf>] ? read_seqcount_begin.constprop.27+0x5f/0x76
[<ffffffff810b6292>] ? trace_hardirqs_on_caller+0x17d/0x199
[<ffffffff811b14d5>] ? __fget_light+0x50/0x78
[<ffffffff817d9808>] __sys_sendmsg+0x42/0x60
[<ffffffff817d9838>] SyS_sendmsg+0x12/0x1c
[<ffffffff81a50e97>] system_call_fastpath+0x12/0x6f
---[ end trace ef29d3fb28e97ae7 ]---
For long term, we probably need to clean up the qdisc_graft() code
in case it hides other bugs like this.
Fixes: 95dc19299f ("pkt_sched: give visibility to mq slave qdiscs")
Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
