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git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq
Pull two workqueue fixes from Tejun Heo:
"A lockdep notation update so that nested work_on_cpu() invocations
don't lead to spurious lockdep warnings and fix for an unbound attr
bug which made what's shown in sysfs deviate from the actual ones.
Both patches have pretty limited scope"
* 'for-3.11-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq:
workqueue: copy workqueue_attrs with all fields
workqueue: allow work_on_cpu() to be called recursively
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Some of my configs I test with have CONFIG_A11Y_BRAILLE_CONSOLE set.
When I started testing against v3.11-rc4 my console went bonkers. Using
ktest to bisect the issue, it came down to:
commit bbeddf52a "printk: move braille console support into separate
braille.[ch] files"
Looking into the patch I found the problem. It's with the return of
braille_register_console(). As anything other than NULL is considered a
failure.
But for those of us that have CONFIG_A11Y_BRAILLE_CONSOLE set but do not
define a "brl" or "brl=" on the command line, we still may want a
console that those with sight can still use.
Return NULL (success) if "brl" or "brl=" is not on the console line.
Signed-off-by: Steven Rostedt <[email protected]>
Acked-by: Joe Perches <[email protected]>
Cc: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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This reverts commit fab840fc2d542fabcab903db8e03589a6702ba5f.
This commit even has the test-case to prove that the tracee
can be killed by SIGTRAP if the debugger does not remove the
breakpoints before PTRACE_DETACH.
However, this is exactly what wineserver deliberately does,
set_thread_context() calls PTRACE_ATTACH + PTRACE_DETACH just
for PTRACE_POKEUSER(DR*) in between.
So we should revert this fix and document that PTRACE_DETACH
should keep the breakpoints.
Reported-by: Felipe Contreras <[email protected]>
Signed-off-by: Oleg Nesterov <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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unshare_userns(new_cred) does *new_cred = prepare_creds() before
create_user_ns() which can fail. However, the caller expects that
it doesn't need to take care of new_cred if unshare_userns() fails.
We could change the single caller, sys_unshare(), but I think it
would be more clean to avoid the side effects on failure, so with
this patch unshare_userns() does put_cred() itself and initializes
*new_cred only if create_user_ns() succeeeds.
Cc: [email protected]
Signed-off-by: Oleg Nesterov <[email protected]>
Reviewed-by: Andy Lutomirski <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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This patch guards the console_drivers list to be corrupted. The
for_each_console() macro insist on a strictly forward list ended by NULL:
con0->next->con1->next->NULL
Without this patch it may happen easily to destroy this list for example by
adding 'earlyprintk' twice, especially on embedded devices where the early
console is often a single static instance. This will result in the following
list:
con0->next->con0
This in turn will result in an endless loop in console_unlock() later on by
printing the first __log_buf line endlessly.
Signed-off-by: Andreas Bießmann <[email protected]>
Cc: Kay Sievers <[email protected]>
Cc: Ben Hutchings <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
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Fixed two issues with changing the timestamp clock with trace_clock:
- The global buffer was reset on instance clock changes. Change this to pass
the correct per-instance buffer
- ftrace_now() is used to set buf->time_start in tracing_reset_online_cpus().
This was incorrect because ftrace_now() used the global buffer's clock to
return the current time. Change this to use buffer_ftrace_now() which
returns the current time for the correct per-instance buffer.
Also removed tracing_reset_current() because it is not used anywhere
Link: http://lkml.kernel.org/r/[email protected]
Cc: Vaibhav Nagarnaik <[email protected]>
Cc: David Sharp <[email protected]>
Cc: Alexander Z Lam <[email protected]>
Cc: [email protected] # 3.10
Signed-off-by: Alexander Z Lam <[email protected]>
Signed-off-by: Steven Rostedt <[email protected]>
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Releasing the free_buffer file in an instance causes the global buffer
to be stopped when TRACE_ITER_STOP_ON_FREE is enabled. Operate on the
correct buffer.
Link: http://lkml.kernel.org/r/[email protected]
Cc: Vaibhav Nagarnaik <[email protected]>
Cc: David Sharp <[email protected]>
Cc: Alexander Z Lam <[email protected]>
Cc: [email protected] # 3.10
Signed-off-by: Alexander Z Lam <[email protected]>
Signed-off-by: Steven Rostedt <[email protected]>
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tracing_read_pipe zeros all fields bellow "seq". The declaration contains
a comment about that, but it doesn't help.
The first field is "snapshot", it's true when current open file is
snapshot. Looks obvious, that it should not be zeroed.
The second field is "started". It was converted from cpumask_t to
cpumask_var_t (v2.6.28-4983-g4462344), in other words it was
converted from cpumask to pointer on cpumask.
Currently the reference on "started" memory is lost after the first read
from tracing_read_pipe and a proper object will never be freed.
The "started" is never dereferenced for trace_pipe, because trace_pipe
can't have the TRACE_FILE_ANNOTATE options.
Link: http://lkml.kernel.org/r/[email protected]
Cc: [email protected] # 2.6.30
Signed-off-by: Andrew Vagin <[email protected]>
Signed-off-by: Steven Rostedt <[email protected]>
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for-3.12 branch is about to receive invasive updates which are
dependent on da0a12caff ("cgroup: fix a leak when percpu_ref_init()
fails"). Given the amount of scheduled changes, I think it'd less
painful to pull in for-3.11-fixes as preparation. Pull in
for-3.11-fixes into for-3.12.
Signed-off-by: Tejun Heo <[email protected]>
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git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm
Pull ACPI and power management fixes from Rafael Wysocki:
- Revert two cpuidle commits added during the 3.8 development cycle
that turn out to have introduced a significant performance regression
as requested by Jeremy Eder.
- The recent patches that made the freezer less heavy-weight introduced
a regression causing user-space-driven hibernation using the ioctl()
interface to block indefinitely when the hibernate process executes
try_to_freeze(). Fix from Colin Cross addresses this by adding a
process flag to mark the hibernate/suspend process to inform the
freezer that that process should be ignored.
- One of the recent cpufreq reverts uncovered a problem in the core
causing the cpufreq driver module refcount to become negative after a
system suspend-resume cycle. Fix from Rafael J Wysocki.
- The evaluation of the ACPI battery _BIX method has never worked
correctly, because the commit that added support for it forgot to
take the "Revision" field in the return package into account. As a
result, the reading of battery info doesn't work at all on some
systems, which is addressed by a fix from Lan Tianyu.
* tag 'pm+acpi-3.11-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
freezer: set PF_SUSPEND_TASK flag on tasks that call freeze_processes
ACPI / battery: Fix parsing _BIX return value
cpufreq: Fix cpufreq driver module refcount balance after suspend/resume
Revert "cpuidle: Quickly notice prediction failure for repeat mode"
Revert "cpuidle: Quickly notice prediction failure in general case"
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printk(KERN_ERR) from check_hung_task() likely means we have a bug,
but unlike BUG_ON()/WARN_ON ()it doesn't show the kernel version,
this complicates the bug-reports investigation.
Add the additional pr_err() to print tainted/release/version
like dump_stack_print_info() does, the output becomes:
INFO: task perl:504 blocked for more than 2 seconds.
Not tainted 3.11.0-rc1-10367-g136bb46-dirty #1763
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
...
While at it, turn the old printk's into pr_err().
Signed-off-by: Oleg Nesterov <[email protected]>
Cc: [email protected]
Cc: Christopher Williams <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: Mandeep Singh Baines <[email protected]>
Cc: [email protected]
Cc: Linus Torvalds <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
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Uprobes suffer the same problem that kprobes have. There's a race between
writing to the "enable" file and removing the probe. The probe checks for
it being in use and if it is not, goes about deleting the probe and the
event that represents it. But the problem with that is, after it checks
if it is in use it can be enabled, and the deletion of the event (access
to the probe) will fail, as it is in use. But the uprobe will still be
deleted. This is a problem as the event can reference the uprobe that
was deleted.
The fix is to remove the event first, and check to make sure the event
removal succeeds. Then it is safe to remove the probe.
When the event exists, either ftrace or perf can enable the probe and
prevent the event from being removed.
Link: http://lkml.kernel.org/r/[email protected]
Acked-by: Oleg Nesterov <[email protected]>
Signed-off-by: Steven Rostedt <[email protected]>
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It's a rw_semaphore not a mutex.
Signed-off-by: Li Zefan <[email protected]>
Signed-off-by: Tejun Heo <[email protected]>
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It uses a single label and checks the validity of each pointer. This
is err-prone, and actually we had a bug because one of the check was
insufficient.
Use multi lables as we do in other places.
v2:
- drop initializations of local variables.
Signed-off-by: Li Zefan <[email protected]>
Signed-off-by: Tejun Heo <[email protected]>
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$echo '0' > /sys/bus/workqueue/devices/xxx/numa
$cat /sys/bus/workqueue/devices/xxx/numa
I got 1. It should be 0, the reason is copy_workqueue_attrs() called
in apply_workqueue_attrs() doesn't copy no_numa field.
Fix it by making copy_workqueue_attrs() copy ->no_numa too. This
would also make get_unbound_pool() set a pool's ->no_numa attribute
according to the workqueue attributes used when the pool was created.
While harmelss, as ->no_numa isn't a pool attribute, this is a bit
confusing. Clear it explicitly.
tj: Updated description and comments a bit.
Signed-off-by: Shaohua Li <[email protected]>
Signed-off-by: Tejun Heo <[email protected]>
Cc: [email protected]
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When a probe is being removed, it cleans up the event files that correspond
to the probe. But there is a race between writing to one of these files
and deleting the probe. This is especially true for the "enable" file.
CPU 0 CPU 1
----- -----
fd = open("enable",O_WRONLY);
probes_open()
release_all_trace_probes()
unregister_trace_probe()
if (trace_probe_is_enabled(tp))
return -EBUSY
write(fd, "1", 1)
__ftrace_set_clr_event()
call->class->reg()
(kprobe_register)
enable_trace_probe(tp)
__unregister_trace_probe(tp);
list_del(&tp->list)
unregister_probe_event(tp) <-- fails!
free_trace_probe(tp)
write(fd, "0", 1)
__ftrace_set_clr_event()
call->class->unreg
(kprobe_register)
disable_trace_probe(tp) <-- BOOM!
A test program was written that used two threads to simulate the
above scenario adding a nanosleep() interval to change the timings
and after several thousand runs, it was able to trigger this bug
and crash:
BUG: unable to handle kernel paging request at 00000005000000f9
IP: [<ffffffff810dee70>] probes_open+0x3b/0xa7
PGD 7808a067 PUD 0
Oops: 0000 [#1] PREEMPT SMP
Dumping ftrace buffer:
---------------------------------
Modules linked in: ipt_MASQUERADE sunrpc ip6t_REJECT nf_conntrack_ipv6
CPU: 1 PID: 2070 Comm: test-kprobe-rem Not tainted 3.11.0-rc3-test+ #47
Hardware name: To Be Filled By O.E.M. To Be Filled By O.E.M./To be filled by O.E.M., BIOS SDBLI944.86P 05/08/2007
task: ffff880077756440 ti: ffff880076e52000 task.ti: ffff880076e52000
RIP: 0010:[<ffffffff810dee70>] [<ffffffff810dee70>] probes_open+0x3b/0xa7
RSP: 0018:ffff880076e53c38 EFLAGS: 00010203
RAX: 0000000500000001 RBX: ffff88007844f440 RCX: 0000000000000003
RDX: 0000000000000003 RSI: 0000000000000003 RDI: ffff880076e52000
RBP: ffff880076e53c58 R08: ffff880076e53bd8 R09: 0000000000000000
R10: ffff880077756440 R11: 0000000000000006 R12: ffffffff810dee35
R13: ffff880079250418 R14: 0000000000000000 R15: ffff88007844f450
FS: 00007f87a276f700(0000) GS:ffff88007d480000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b
CR2: 00000005000000f9 CR3: 0000000077262000 CR4: 00000000000007e0
Stack:
ffff880076e53c58 ffffffff81219ea0 ffff88007844f440 ffffffff810dee35
ffff880076e53ca8 ffffffff81130f78 ffff8800772986c0 ffff8800796f93a0
ffffffff81d1b5d8 ffff880076e53e04 0000000000000000 ffff88007844f440
Call Trace:
[<ffffffff81219ea0>] ? security_file_open+0x2c/0x30
[<ffffffff810dee35>] ? unregister_trace_probe+0x4b/0x4b
[<ffffffff81130f78>] do_dentry_open+0x162/0x226
[<ffffffff81131186>] finish_open+0x46/0x54
[<ffffffff8113f30b>] do_last+0x7f6/0x996
[<ffffffff8113cc6f>] ? inode_permission+0x42/0x44
[<ffffffff8113f6dd>] path_openat+0x232/0x496
[<ffffffff8113fc30>] do_filp_open+0x3a/0x8a
[<ffffffff8114ab32>] ? __alloc_fd+0x168/0x17a
[<ffffffff81131f4e>] do_sys_open+0x70/0x102
[<ffffffff8108f06e>] ? trace_hardirqs_on_caller+0x160/0x197
[<ffffffff81131ffe>] SyS_open+0x1e/0x20
[<ffffffff81522742>] system_call_fastpath+0x16/0x1b
Code: e5 41 54 53 48 89 f3 48 83 ec 10 48 23 56 78 48 39 c2 75 6c 31 f6 48 c7
RIP [<ffffffff810dee70>] probes_open+0x3b/0xa7
RSP <ffff880076e53c38>
CR2: 00000005000000f9
---[ end trace 35f17d68fc569897 ]---
The unregister_trace_probe() must be done first, and if it fails it must
fail the removal of the kprobe.
Several changes have already been made by Oleg Nesterov and Masami Hiramatsu
to allow moving the unregister_probe_event() before the removal of
the probe and exit the function if it fails. This prevents the tp
structure from being used after it is freed.
Link: http://lkml.kernel.org/r/[email protected]
Acked-by: Masami Hiramatsu <[email protected]>
Signed-off-by: Steven Rostedt <[email protected]>
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Merge more patches from Andrew Morton:
"A bunch of fixes.
Plus Joe's printk move and rework. It's not a -rc3 thing but now
would be a nice time to offload it, while things are quiet. I've been
sitting on it all for a couple of weeks, no issues"
* emailed patches from Andrew Morton <[email protected]>:
vmpressure: make sure there are no events queued after memcg is offlined
vmpressure: do not check for pending work to prevent from new work
vmpressure: change vmpressure::sr_lock to spinlock
printk: rename struct log to struct printk_log
printk: use pointer for console_cmdline indexing
printk: move braille console support into separate braille.[ch] files
printk: add console_cmdline.h
printk: move to separate directory for easier modification
drivers/rtc/rtc-twl.c: fix: rtcX/wakealarm attribute isn't created
mm: zbud: fix condition check on allocation size
thp, mm: avoid PageUnevictable on active/inactive lru lists
mm/swap.c: clear PageActive before adding pages onto unevictable list
arch/x86/platform/ce4100/ce4100.c: include reboot.h
mm: sched: numa: fix NUMA balancing when !SCHED_DEBUG
rapidio: fix use after free in rio_unregister_scan()
.gitignore: ignore *.lz4 files
MAINTAINERS: dynamic debug: Jason's not there...
dmi_scan: add comments on dmi_present() and the loop in dmi_scan_machine()
ocfs2/refcounttree: add the missing NULL check of the return value of find_or_create_page()
mm: mempolicy: fix mbind_range() && vma_adjust() interaction
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Rename the struct to enable moving portions of
printk.c to separate files.
The rename changes output of /proc/vmcoreinfo.
Signed-off-by: Joe Perches <[email protected]>
Cc: Samuel Thibault <[email protected]>
Cc: Ming Lei <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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Make the code a bit more compact by always using a pointer for the active
console_cmdline.
Move overly indented code to correct indent level.
Signed-off-by: Joe Perches <[email protected]>
Cc: Samuel Thibault <[email protected]>
Cc: Ming Lei <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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Create files with prototypes and static inlines for braille support. Make
braille_console functions return 1 on success.
Corrected CONFIG_A11Y_BRAILLE_CONSOLE=n _braille_console_setup
return value to NULL.
Signed-off-by: Joe Perches <[email protected]>
Reviewed-by: Samuel Thibault <[email protected]>
Cc: Ming Lei <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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Add an include file for the console_cmdline struct so that the braille
console driver can be separated.
Signed-off-by: Joe Perches <[email protected]>
Cc: Samuel Thibault <[email protected]>
Cc: Ming Lei <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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Make it easier to break up printk into bite-sized chunks.
Remove printk path/filename from comment.
Signed-off-by: Joe Perches <[email protected]>
Cc: Samuel Thibault <[email protected]>
Cc: Ming Lei <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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Commit 3105b86a9fee ("mm: sched: numa: Control enabling and disabling of
NUMA balancing if !SCHED_DEBUG") defined numabalancing_enabled to
control the enabling and disabling of automatic NUMA balancing, but it
is never used.
I believe the intention was to use this in place of sched_feat_numa(NUMA).
Currently, if SCHED_DEBUG is not defined, sched_feat_numa(NUMA) will
never be changed from the initial "false".
Signed-off-by: Dave Kleikamp <[email protected]>
Acked-by: Mel Gorman <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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Pull networking fixes from David Miller:
1) Fix association failures not triggering a connect-failure event in
cfg80211, from Johannes Berg.
2) Eliminate a potential NULL deref with older iptables tools when
configuring xt_socket rules, from Eric Dumazet.
3) Missing RTNL locking in wireless regulatory code, from Johannes
Berg.
4) Fix OOPS caused by firmware loading races in ath9k_htc, from Alexey
Khoroshilov.
5) Fix usb URB leak in usb_8dev CAN driver, also from Alexey
Khoroshilov.
6) VXLAN namespace teardown fails to unregister devices, from Stephen
Hemminger.
7) Fix multicast settings getting dropped by firmware in qlcnic driver,
from Sucheta Chakraborty.
8) Add sysctl range enforcement for tcp_syn_retries, from Michal Tesar.
9) Fix a nasty bug in bridging where an active timer would get
reinitialized with a setup_timer() call. From Eric Dumazet.
10) Fix use after free in new mlx5 driver, from Dan Carpenter.
11) Fix freed pointer reference in ipv6 multicast routing on namespace
cleanup, from Hannes Frederic Sowa.
12) Some usbnet drivers report TSO and SG in their feature set, but the
usbnet layer doesn't really support them. From Eric Dumazet.
13) Fix crash on EEH errors in tg3 driver, from Gavin Shan.
14) Drop cb_lock when requesting modules in genetlink, from Stanislaw
Gruszka.
15) Kernel stack leaks in cbq scheduler and af_key pfkey messages, from
Dan Carpenter.
16) FEC driver erroneously signals NETDEV_TX_BUSY on transmit leading to
endless loops, from Uwe Kleine-König.
17) Fix hangs from loading mvneta driver, from Arnaud Patard.
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (84 commits)
mlx5: fix error return code in mlx5_alloc_uuars()
mvneta: Try to fix mvneta when compiled as module
mvneta: Fix hang when loading the mvneta driver
atl1c: Fix misuse of netdev_alloc_skb in refilling rx ring
genetlink: fix usage of NLM_F_EXCL or NLM_F_REPLACE
af_key: more info leaks in pfkey messages
net/fec: Don't let ndo_start_xmit return NETDEV_TX_BUSY without link
net_sched: Fix stack info leak in cbq_dump_wrr().
igb: fix vlan filtering in promisc mode when not in VT mode
ixgbe: Fix Tx Hang issue with lldpad on 82598EB
genetlink: release cb_lock before requesting additional module
net: fec: workaround stop tx during errata ERR006358
qlcnic: Fix diagnostic interrupt test for 83xx adapters.
qlcnic: Fix setting Guest VLAN
qlcnic: Fix operation type and command type.
qlcnic: Fix initialization of work function.
Revert "atl1c: Fix misuse of netdev_alloc_skb in refilling rx ring"
atl1c: Fix misuse of netdev_alloc_skb in refilling rx ring
net/tg3: Fix warning from pci_disable_device()
net/tg3: Fix kernel crash
...
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The "break" used in the do_for_each_event_file() is used as an optimization
as the loop is really a double loop. The loop searches all event files
for each trace_array. There's only one matching event file per trace_array
and after we find the event file for the trace_array, the break is used
to jump to the next trace_array and start the search there.
As this is not a standard way of using "break" in C code, it requires
a comment right before the break to let people know what is going on.
Signed-off-by: Steven Rostedt <[email protected]>
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Change trace_remove_event_call(call) to return the error if this
call is active. This is what the callers assume but can't verify
outside of the tracing locks. Both trace_kprobe.c/trace_uprobe.c
need the additional changes, unregister_trace_probe() should abort
if trace_remove_event_call() fails.
The caller is going to free this call/file so we must ensure that
nobody can use them after trace_remove_event_call() succeeds.
debugfs should be fine after the previous changes and event_remove()
does TRACE_REG_UNREGISTER, but still there are 2 reasons why we need
the additional checks:
- There could be a perf_event(s) attached to this tp_event, so the
patch checks ->perf_refcount.
- TRACE_REG_UNREGISTER can be suppressed by FTRACE_EVENT_FL_SOFT_MODE,
so we simply check FTRACE_EVENT_FL_ENABLED protected by event_mutex.
Link: http://lkml.kernel.org/r/[email protected]
Reviewed-by: Masami Hiramatsu <[email protected]>
Signed-off-by: Oleg Nesterov <[email protected]>
Signed-off-by: Steven Rostedt <[email protected]>
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This enables us to lookup a cgroup by its id.
v4:
- add a comment for idr_remove() in cgroup_offline_fn().
v3:
- on success, idr_alloc() returns the id but not 0, so fix the BUG_ON()
in cgroup_init().
- pass the right value to idr_alloc() so that the id for dummy cgroup is 0.
Signed-off-by: Li Zefan <[email protected]>
Reviewed-by: Michal Hocko <[email protected]>
Signed-off-by: Tejun Heo <[email protected]>
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Constantly use @cset for css_set variables and use @cgrp as cgroup
variables.
Signed-off-by: Li Zefan <[email protected]>
Signed-off-by: Tejun Heo <[email protected]>
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We can use struct cfent instead.
v2:
- remove cgroup_seqfile_release().
Signed-off-by: Li Zefan <[email protected]>
Signed-off-by: Tejun Heo <[email protected]>
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This should have been removed in commit d7eeac1913ff
("cgroup: hold cgroup_mutex before calling css_offline").
While at it, update the comments.
Signed-off-by: Li Zefan <[email protected]>
Signed-off-by: Tejun Heo <[email protected]>
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ss->css_free() is not called when perfcpu_ref_init() fails.
Signed-off-by: Li Zefan <[email protected]>
Signed-off-by: Tejun Heo <[email protected]>
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There's been a nasty bug that would show up and not give much info.
The bug displayed the following warning:
WARNING: at kernel/trace/ftrace.c:1529 __ftrace_hash_rec_update+0x1e3/0x230()
Pid: 20903, comm: bash Tainted: G O 3.6.11+ #38405.trunk
Call Trace:
[<ffffffff8103e5ff>] warn_slowpath_common+0x7f/0xc0
[<ffffffff8103e65a>] warn_slowpath_null+0x1a/0x20
[<ffffffff810c2ee3>] __ftrace_hash_rec_update+0x1e3/0x230
[<ffffffff810c4f28>] ftrace_hash_move+0x28/0x1d0
[<ffffffff811401cc>] ? kfree+0x2c/0x110
[<ffffffff810c68ee>] ftrace_regex_release+0x8e/0x150
[<ffffffff81149f1e>] __fput+0xae/0x220
[<ffffffff8114a09e>] ____fput+0xe/0x10
[<ffffffff8105fa22>] task_work_run+0x72/0x90
[<ffffffff810028ec>] do_notify_resume+0x6c/0xc0
[<ffffffff8126596e>] ? trace_hardirqs_on_thunk+0x3a/0x3c
[<ffffffff815c0f88>] int_signal+0x12/0x17
---[ end trace 793179526ee09b2c ]---
It was finally narrowed down to unloading a module that was being traced.
It was actually more than that. When functions are being traced, there's
a table of all functions that have a ref count of the number of active
tracers attached to that function. When a function trace callback is
registered to a function, the function's record ref count is incremented.
When it is unregistered, the function's record ref count is decremented.
If an inconsistency is detected (ref count goes below zero) the above
warning is shown and the function tracing is permanently disabled until
reboot.
The ftrace callback ops holds a hash of functions that it filters on
(and/or filters off). If the hash is empty, the default means to filter
all functions (for the filter_hash) or to disable no functions (for the
notrace_hash).
When a module is unloaded, it frees the function records that represent
the module functions. These records exist on their own pages, that is
function records for one module will not exist on the same page as
function records for other modules or even the core kernel.
Now when a module unloads, the records that represents its functions are
freed. When the module is loaded again, the records are recreated with
a default ref count of zero (unless there's a callback that traces all
functions, then they will also be traced, and the ref count will be
incremented).
The problem is that if an ftrace callback hash includes functions of the
module being unloaded, those hash entries will not be removed. If the
module is reloaded in the same location, the hash entries still point
to the functions of the module but the module's ref counts do not reflect
that.
With the help of Steve and Joern, we found a reproducer:
Using uinput module and uinput_release function.
cd /sys/kernel/debug/tracing
modprobe uinput
echo uinput_release > set_ftrace_filter
echo function > current_tracer
rmmod uinput
modprobe uinput
# check /proc/modules to see if loaded in same addr, otherwise try again
echo nop > current_tracer
[BOOM]
The above loads the uinput module, which creates a table of functions that
can be traced within the module.
We add uinput_release to the filter_hash to trace just that function.
Enable function tracincg, which increments the ref count of the record
associated to uinput_release.
Remove uinput, which frees the records including the one that represents
uinput_release.
Load the uinput module again (and make sure it's at the same address).
This recreates the function records all with a ref count of zero,
including uinput_release.
Disable function tracing, which will decrement the ref count for uinput_release
which is now zero because of the module removal and reload, and we have
a mismatch (below zero ref count).
The solution is to check all currently tracing ftrace callbacks to see if any
are tracing any of the module's functions when a module is loaded (it already does
that with callbacks that trace all functions). If a callback happens to have
a module function being traced, it increments that records ref count and starts
tracing that function.
There may be a strange side effect with this, where tracing module functions
on unload and then reloading a new module may have that new module's functions
being traced. This may be something that confuses the user, but it's not
a big deal. Another approach is to disable all callback hashes on module unload,
but this leaves some ftrace callbacks that may not be registered, but can
still have hashes tracing the module's function where ftrace doesn't know about
it. That situation can cause the same bug. This solution solves that case too.
Another benefit of this solution, is it is possible to trace a module's
function on unload and load.
Link: http://lkml.kernel.org/r/[email protected]
Reported-by: Jörn Engel <[email protected]>
Reported-by: Dave Jones <[email protected]>
Reported-by: Steve Hodgson <[email protected]>
Tested-by: Steve Hodgson <[email protected]>
Signed-off-by: Steven Rostedt <[email protected]>
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A perf event can be used without forcing the tick to
stay alive if it doesn't use a frequency but a sample
period and if it doesn't throttle (raise storm of events).
Since the lockup detector neither use a perf event frequency
nor should ever throttle due to its high period, it can now
run concurrently with the full dynticks feature.
So remove the hack that disabled the watchdog.
Signed-off-by: Frederic Weisbecker <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Arnaldo Carvalho de Melo <[email protected]>
Cc: Stephane Eranian <[email protected]>
Cc: Don Zickus <[email protected]>
Cc: Srivatsa S. Bhat <[email protected]>
Cc: Anish Singh <[email protected]>
Signed-off-by: Peter Zijlstra <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
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Currently the full dynticks subsystem keep the
tick alive as long as there are perf events running.
This prevents the tick from being stopped as long as features
such that the lockup detectors are running. As a temporary fix,
the lockup detector is disabled by default when full dynticks
is built but this is not a long term viable solution.
To fix this, only keep the tick alive when an event configured
with a frequency rather than a period is running on the CPU,
or when an event throttles on the CPU.
These are the only purposes of the perf tick, especially now that
the rotation of flexible events is handled from a seperate hrtimer.
The tick can be shutdown the rest of the time.
Original-patch-by: Peter Zijlstra <[email protected]>
Signed-off-by: Frederic Weisbecker <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Arnaldo Carvalho de Melo <[email protected]>
Cc: Stephane Eranian <[email protected]>
Signed-off-by: Peter Zijlstra <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
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This is going to be used by the full dynticks subsystem
as a finer-grained information to know when to keep and
when to stop the tick.
Original-patch-by: Peter Zijlstra <[email protected]>
Signed-off-by: Frederic Weisbecker <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Arnaldo Carvalho de Melo <[email protected]>
Cc: Stephane Eranian <[email protected]>
Signed-off-by: Peter Zijlstra <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
|
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When an event is migrated, move the event per-cpu
accounting accordingly so that branch stack and cgroup
events work correctly on the new CPU.
Original-patch-by: Peter Zijlstra <[email protected]>
Signed-off-by: Frederic Weisbecker <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Arnaldo Carvalho de Melo <[email protected]>
Cc: Stephane Eranian <[email protected]>
Signed-off-by: Peter Zijlstra <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
|
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This way we can use the per-cpu handling seperately.
This is going to be used by to fix the event migration
code accounting.
Original-patch-by: Peter Zijlstra <[email protected]>
Signed-off-by: Frederic Weisbecker <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Arnaldo Carvalho de Melo <[email protected]>
Cc: Stephane Eranian <[email protected]>
Signed-off-by: Peter Zijlstra <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
|
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Gather all the event accounting code to a single place,
once all the prerequisites are completed. This simplifies
the refcounting.
Original-patch-by: Peter Zijlstra <[email protected]>
Signed-off-by: Frederic Weisbecker <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Arnaldo Carvalho de Melo <[email protected]>
Cc: Stephane Eranian <[email protected]>
Signed-off-by: Peter Zijlstra <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
|
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In case of allocation failure, get_callchain_buffer() keeps the
refcount incremented for the current event.
As a result, when get_callchain_buffers() returns an error,
we must cleanup what it did by cancelling its last refcount
with a call to put_callchain_buffers().
This is a hack in order to be able to call free_event()
after that failure.
The original purpose of that was to simplify the failure
path. But this error handling is actually counter intuitive,
ugly and not very easy to follow because one expect to
see the resources used to perform a service to be cleaned
by the callee if case of failure, not by the caller.
So lets clean this up by cancelling the refcount from
get_callchain_buffer() in case of failure. And correctly free
the event accordingly in perf_event_alloc().
Signed-off-by: Frederic Weisbecker <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Arnaldo Carvalho de Melo <[email protected]>
Cc: Stephane Eranian <[email protected]>
Signed-off-by: Peter Zijlstra <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
|
|
On callchain buffers allocation failure, free_event() is
called and all the accounting performed in perf_event_alloc()
for that event is cancelled.
But if the event has branch stack sampling, it is unaccounted
as well from the branch stack sampling events refcounts.
This is a bug because this accounting is performed after the
callchain buffer allocation. As a result, the branch stack sampling
events refcount can become negative.
To fix this, move the branch stack event accounting before the
callchain buffer allocation.
Reported-by: Peter Zijlstra <[email protected]>
Signed-off-by: Frederic Weisbecker <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Arnaldo Carvalho de Melo <[email protected]>
Cc: Stephane Eranian <[email protected]>
Signed-off-by: Peter Zijlstra <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
|
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After commit 8969a5ede0f9e17da4b943712429aef2c9bcd82b
("generic-ipi: remove kmalloc()"), wait = 0 can be guaranteed,
and all callsites of generic_exec_single() do an unconditional
csd_lock() now.
So csd_flags is unnecessary now. Remove it.
Signed-off-by: Xie XiuQi <[email protected]>
Signed-off-by: Peter Zijlstra <[email protected]>
Cc: Oleg Nesterov <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Nick Piggin <[email protected]>
Cc: Jens Axboe <[email protected]>
Cc: "Paul E. McKenney" <[email protected]>
Cc: Rusty Russell <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
|
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The check needs to be for > 1, because ctx->acquired is already incremented.
This will prevent ww_mutex_lock_slow from returning -EDEADLK and not locking
the mutex. It caused a lot of false gpu lockups on radeon with
CONFIG_DEBUG_WW_MUTEX_SLOWPATH=y because a function that shouldn't be able
to return -EDEADLK did.
Signed-off-by: Maarten Lankhorst <[email protected]>
Signed-off-by: Peter Zijlstra <[email protected]>
Cc: Alex Deucher <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
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continuously-running tasks
We typically update a task_group's shares within the dequeue/enqueue
path. However, continuously running tasks sharing a CPU are not
subject to these updates as they are only put/picked. Unfortunately,
when we reverted f269ae046 (in 17bc14b7), we lost the augmenting
periodic update that was supposed to account for this; resulting in a
potential loss of fairness.
To fix this, re-introduce the explicit update in
update_cfs_rq_blocked_load() [called via entity_tick()].
Reported-by: Max Hailperin <[email protected]>
Signed-off-by: Peter Zijlstra <[email protected]>
Reviewed-by: Paul Turner <[email protected]>
Link: http://lkml.kernel.org/n/[email protected]
Cc: <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>
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The ARM architected system counter has at least 56 usable bits.
Add support for counters with more than 32 bits to the generic
sched_clock implementation so we can increase the time between
wakeups due to dealing with wrap-around on these devices while
benefiting from the irqtime accounting and suspend/resume
handling that the generic sched_clock code already has. On my
system using 56 bits over 32 bits changes the wraparound time
from a few minutes to an hour. For faster running counters (GHz
range) this is even more important because we may not be able to
execute the timer in time to deal with the wraparound if only 32
bits are used.
We choose a maxsec value of 3600 seconds because we assume no
system will go idle for more than an hour. In the future we may
need to increase this value.
Note: All users should switch over to the 64-bit read function so
we can remove setup_sched_clock() in favor of sched_clock_register().
Cc: Russell King <[email protected]>
Signed-off-by: Stephen Boyd <[email protected]>
Signed-off-by: John Stultz <[email protected]>
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In the next patch we're going to increase the number of bits that
the generic sched_clock can handle to be greater than 32. With
more than 32 bits the wraparound time can be larger than what can
fit into the units that msecs_to_jiffies takes (unsigned int).
Luckily, the wraparound is initially calculated in nanoseconds
which we can easily use with hrtimers, so switch to using an
hrtimer.
Cc: Russell King <[email protected]>
Signed-off-by: Stephen Boyd <[email protected]>
[jstultz: Fixup hrtimer intitialization order issue]
Signed-off-by: John Stultz <[email protected]>
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We're going to increase the cyc value to 64 bits in the near
future. Doing that is going to break the custom seqcount
implementation in the sched_clock code because 64 bit numbers
aren't guaranteed to be atomic. Replace the cyc_copy with a
seqcount to avoid this problem.
Cc: Russell King <[email protected]>
Acked-by: Will Deacon <[email protected]>
Signed-off-by: Stephen Boyd <[email protected]>
Signed-off-by: John Stultz <[email protected]>
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We need to calculate the same number in the clocksource code and
the sched_clock code, so extract this code into its own function.
We also drop the min_t and just use min() because the two types
are the same.
Signed-off-by: Stephen Boyd <[email protected]>
Signed-off-by: John Stultz <[email protected]>
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|
On Wed, Jun 12, 2013 at 11:14:40AM -0700, Kent Overstreet wrote:
> On Mon, Apr 15, 2013 at 02:40:55PM +0300, Octavian Purdila wrote:
> > When using a large number of threads performing AIO operations the
> > IOCTX list may get a significant number of entries which will cause
> > significant overhead. For example, when running this fio script:
> >
> > rw=randrw; size=256k ;directory=/mnt/fio; ioengine=libaio; iodepth=1
> > blocksize=1024; numjobs=512; thread; loops=100
> >
> > on an EXT2 filesystem mounted on top of a ramdisk we can observe up to
> > 30% CPU time spent by lookup_ioctx:
> >
> > 32.51% [guest.kernel] [g] lookup_ioctx
> > 9.19% [guest.kernel] [g] __lock_acquire.isra.28
> > 4.40% [guest.kernel] [g] lock_release
> > 4.19% [guest.kernel] [g] sched_clock_local
> > 3.86% [guest.kernel] [g] local_clock
> > 3.68% [guest.kernel] [g] native_sched_clock
> > 3.08% [guest.kernel] [g] sched_clock_cpu
> > 2.64% [guest.kernel] [g] lock_release_holdtime.part.11
> > 2.60% [guest.kernel] [g] memcpy
> > 2.33% [guest.kernel] [g] lock_acquired
> > 2.25% [guest.kernel] [g] lock_acquire
> > 1.84% [guest.kernel] [g] do_io_submit
> >
> > This patchs converts the ioctx list to a radix tree. For a performance
> > comparison the above FIO script was run on a 2 sockets 8 core
> > machine. This are the results (average and %rsd of 10 runs) for the
> > original list based implementation and for the radix tree based
> > implementation:
> >
> > cores 1 2 4 8 16 32
> > list 109376 ms 69119 ms 35682 ms 22671 ms 19724 ms 16408 ms
> > %rsd 0.69% 1.15% 1.17% 1.21% 1.71% 1.43%
> > radix 73651 ms 41748 ms 23028 ms 16766 ms 15232 ms 13787 ms
> > %rsd 1.19% 0.98% 0.69% 1.13% 0.72% 0.75%
> > % of radix
> > relative 66.12% 65.59% 66.63% 72.31% 77.26% 83.66%
> > to list
> >
> > To consider the impact of the patch on the typical case of having
> > only one ctx per process the following FIO script was run:
> >
> > rw=randrw; size=100m ;directory=/mnt/fio; ioengine=libaio; iodepth=1
> > blocksize=1024; numjobs=1; thread; loops=100
> >
> > on the same system and the results are the following:
> >
> > list 58892 ms
> > %rsd 0.91%
> > radix 59404 ms
> > %rsd 0.81%
> > % of radix
> > relative 100.87%
> > to list
>
> So, I was just doing some benchmarking/profiling to get ready to send
> out the aio patches I've got for 3.11 - and it looks like your patch is
> causing a ~1.5% throughput regression in my testing :/
... <snip>
I've got an alternate approach for fixing this wart in lookup_ioctx()...
Instead of using an rbtree, just use the reserved id in the ring buffer
header to index an array pointing the ioctx. It's not finished yet, and
it needs to be tidied up, but is most of the way there.
-ben
--
"Thought is the essence of where you are now."
--
kmo> And, a rework of Ben's code, but this was entirely his idea
kmo> -Kent
bcrl> And fix the code to use the right mm_struct in kill_ioctx(), actually
free memory.
Signed-off-by: Benjamin LaHaise <[email protected]>
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Calling freeze_processes sets a global flag that will cause any
process that calls try_to_freeze to enter the refrigerator. It
skips sending a signal to the current task, but if the current
task ever hits try_to_freeze, all threads will be frozen and the
system will deadlock.
Set a new flag, PF_SUSPEND_TASK, on the task that calls
freeze_processes. The flag notifies the freezer that the thread
is involved in suspend and should not be frozen. Also add a
WARN_ON in thaw_processes if the caller does not have the
PF_SUSPEND_TASK flag set to catch if a different task calls
thaw_processes than the one that called freeze_processes, leaving
a task with PF_SUSPEND_TASK permanently set on it.
Threads that spawn off a task with PF_SUSPEND_TASK set (which
swsusp does) will also have PF_SUSPEND_TASK set, preventing them
from freezing while they are helping with suspend, but they need
to be dead by the time suspend is triggered, otherwise they may
run when userspace is expected to be frozen. Add a WARN_ON in
thaw_processes if more than one thread has the PF_SUSPEND_TASK
flag set.
Reported-and-tested-by: Michael Leun <[email protected]>
Signed-off-by: Colin Cross <[email protected]>
Signed-off-by: Rafael J. Wysocki <[email protected]>
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When ftrace ops modifies the functions that it will trace, the update
to the function mcount callers may need to be modified. Consolidate
the two places that do the checks to see if an update is required
with a wrapper function for those checks.
Signed-off-by: Steven Rostedt <[email protected]>
|