do_exit() and exec_mmap() call sync_mm_rss() before mm_release() does
put_user(clear_child_tid) which can update task->rss_stat and thus make
mm->rss_stat inconsistent. This triggers the "BUG:" printk in check_mm().
Let's fix this bug in the safest way, and optimize/cleanup this later.
Reported-by: Markus Trippelsdorf <markus@trippelsdorf.de>
Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When we fixed the race between atomic_dec and css_refcnt, we missed
the fact that css_refcnt internally subtracts CSS_DEACT_BIAS to get
the actual reference count. This can potentially cause a refcount leak
if __css_put races with cgroup_clear_css_refs.
Signed-off-by: Salman Qazi <sqazi@google.com>
Acked-by: Li Zefan <lizefan@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Originally from Peter Zijlstra. The helper migrates perf events
from one cpu to another cpu.
Signed-off-by: Zheng Yan <zheng.z.yan@intel.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1339741902-8449-5-git-send-email-zheng.z.yan@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Allow the pmu->event_init callback to change event->cpu, so the PMU driver
can choose the CPU on which to install events.
Signed-off-by: Zheng Yan <zheng.z.yan@intel.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1339741902-8449-4-git-send-email-zheng.z.yan@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
perf_event_open() requires the cpu on which to install event is online,
but the cpu can go offline after perf_event_open checks that. Add a
get_online_cpus()/put_online_cpus() pair to avoid the race.
Signed-off-by: Zheng Yan <zheng.z.yan@intel.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1339741902-8449-3-git-send-email-zheng.z.yan@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
An rmdir pushes css's ref count to zero. However, if the associated
directory is open at the time, the dentry ref count is non-zero. If
the fd for this directory is then passed into perf_event_open, it
does a css_get(). This bounces the ref count back up from zero. This
is a problem by itself. But what makes it turn into a crash is the
fact that we end up doing an extra dput, since we perform a dput
when css_put sees the ref count go down to zero.
css_tryget() does not fall into that trap. So, we use that instead.
Reproduction test-case for the bug:
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <linux/unistd.h>
#include <linux/perf_event.h>
#include <string.h>
#include <errno.h>
#include <stdio.h>
#define PERF_FLAG_PID_CGROUP (1U << 2)
int perf_event_open(struct perf_event_attr *hw_event_uptr,
pid_t pid, int cpu, int group_fd, unsigned long flags) {
return syscall(__NR_perf_event_open,hw_event_uptr, pid, cpu,
group_fd, flags);
}
/*
* Directly poke at the perf_event bug, since it's proving hard to repro
* depending on where in the kernel tree. what moved?
*/
int main(int argc, char **argv)
{
int fd;
struct perf_event_attr attr;
memset(&attr, 0, sizeof(attr));
attr.exclude_kernel = 1;
attr.size = sizeof(attr);
mkdir("/dev/cgroup/perf_event/blah", 0777);
fd = open("/dev/cgroup/perf_event/blah", O_RDONLY);
perror("open");
rmdir("/dev/cgroup/perf_event/blah");
sleep(2);
perf_event_open(&attr, fd, 0, -1, PERF_FLAG_PID_CGROUP);
perror("perf_event_open");
close(fd);
return 0;
}
Signed-off-by: Salman Qazi <sqazi@google.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Tejun Heo <tj@kernel.org>
Link: http://lkml.kernel.org/r/20120614223108.1025.2503.stgit@dungbeetle.mtv.corp.google.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Just like what devkmsg_read() does, return -EINVAL if the message len is
bigger than the buf size, or it will trigger a segfault error.
Acked-by: Kay Sievers <kay@vrfy.org>
Acked-by: Fengguang Wu <wfg@linux.intel.com>
Signed-off-by: Yuanhan Liu <yuanhan.liu@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Although syslog_seq and log_next_seq stuff are protected by logbuf_lock
spin log, it's not enough. Say we have two processes A and B, and let
syslog_seq = N, while log_next_seq = N + 1, and the two processes both
come to syslog_print at almost the same time. And No matter which
process get the spin lock first, it will increase syslog_seq by one,
then release spin lock; thus later, another process increase syslog_seq
by one again. In this case, syslog_seq is bigger than syslog_next_seq.
And latter, it would make:
wait_event_interruptiable(log_wait, syslog != log_next_seq)
don't wait any more even there is no new write comes. Thus it introduce
a infinite loop reading.
I can easily see this kind of issue by the following steps:
# cat /proc/kmsg # at meantime, I don't kill rsyslog
# So they are the two processes.
# xinit # I added drm.debug=6 in the kernel parameter line,
# so that it will produce lots of message and let that
# issue happen
It's 100% reproducable on my side. And my disk will be filled up by
/var/log/messages in a quite short time.
So, introduce a mutex_lock to stop syslog_seq from going wild just like
what devkmsg_read() does. It does fix this issue as expected.
v2: use mutex_lock_interruptiable() instead (comments from Kay)
Signed-off-by: Yuanhan Liu <yuanhan.liu@linux.intel.com>
Reviewed-by: Fengguang Wu <fengguang.wu@intel.com>
Acked-By: Kay Sievers <kay@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
1. __copy_insn() needs "loff_t offset", not "unsigned long",
to read the file.
2. use pgoff_t for "idx" and remove the unnecessary typecast.
3. fix the typo, "&=" is not what we want
4. can't resist, rename off1 to off.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Acked-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Anton Arapov <anton@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20120615154359.GA9625@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
loff_t looks confusing when it is used for the virtual address.
Change map_info and install_breakpoint/remove_breakpoint paths
to use "unsigned long".
The patch doesn't change vma_address(), it can't return "long"
because it is used to verify the mapping. But probably this
needs some cleanups too.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Anton Arapov <anton@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Acked-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20120615154355.GA9622@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
uprobe->pending_list is only used to create the temporary list,
it has no meaning after we drop uprobes_mmap_hash(inode).
No need to initialize this node or remove it from tmp_list, and
we can use list_for_each_entry().
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Anton Arapov <anton@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/r/20120615154353.GA9614@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
write_opcode() ensures that UPROBE_SWBP_INSN doesn't cross the
page boundary. This looks a bit confusing, the check does not
depend on vaddr and it is enough to do it only once right after
install_breakpoint()->arch_uprobe_analyze_insn().
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Acked-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Anton Arapov <anton@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20120615154350.GA9611@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
write_opcode() is called by register_for_each_vma() and
uprobe_mmap() paths. In both cases the caller has already
verified this vaddr under mmap_sem, no need to re-check.
Note also that this check is wrong anyway, we should not
truncate loff_t returned by vma_address() if we do not trust
this mapping.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Acked-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Anton Arapov <anton@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20120615154347.GA9604@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
copy_insn() returns -ENOMEM if the first __copy_insn() fails,
it should return the correct error code.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Acked-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Anton Arapov <anton@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20120615154344.GA9601@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
1. copy_insn() doesn't need "addr", it can use uprobe->offset.
Remove this argument.
2. Change copy_insn/__copy_insn to accept "struct file*" instead
of vma.
copy_insn() is called only once and mm/vma/vaddr are random, it
shouldn't depend on them.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Acked-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Anton Arapov <anton@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20120615154342.GA9598@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Because the mind is treacherous and makes us forget we need to
write stuff down.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Anton Arapov <anton@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/r/20120615154339.GA9591@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
build_map_info() doesn't allocate the memory under i_mmap_mutex
to avoid the deadlock with page reclaim. But it can try
GFP_NOWAIT first, it should work in the likely case and thus we
almost never need the pre-alloc-and-retry path.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Anton Arapov <anton@redhat.com>
Link: http://lkml.kernel.org/r/20120615154336.GA9588@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Currently register_for_each_vma() is O(n ** 2) + O(n ** 3),
every time find_next_vma_info() "restarts" the
vma_prio_tree_foreach() loop and each iteration rechecks the
whole try_list. This also means that try_list can grow
"indefinitely" if register/unregister races with munmap/mmap
activity even if the number of mapping is bounded at any time.
With this patch register_for_each_vma() builds the list of
mm/vaddr structures only once and does install_breakpoint() for
each entry.
We do not care about the new mappings which can be created after
build_map_info() drops mapping->i_mmap_mutex, uprobe_mmap()
should do its work.
Note that we do not allocate map_info under i_mmap_mutex, this
can deadlock with page reclaim (but see the next patch). So we
use 2 lists, "curr" which we are going to return, and "prev"
which holds the already allocated memory. The main loop deques
the entry from "prev" (initially it is empty), and if "prev"
becomes empty again it counts the number of entries we need to
pre-allocate outside of i_mmap_mutex.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Anton Arapov <anton@redhat.com>
Link: http://lkml.kernel.org/r/20120615154333.GA9581@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
install_breakpoint() returns -EEXIST if is_swbp_insn(orig_insn)
== T, the caller treats this code as success.
This is doubly wrong. The successful return should set
UPROBE_COPY_INSN, but the real problem is that it shouldn't
succeed. If the probed insn is int3 the application should get
SIGTRAP, this won't happen with uprobe.
Probably we can fix this, we can add the UPROBE_SHARED_BP flag
and teach handle_swbp/set_orig_insn to handle this case
correctly. But this needs some complications and we have other
insns which can't be probed, lets make a simple fix for now.
I think this needs a cleanup. UPROBE_COPY_INSN should die,
copy_insn() should be called by alloc_uprobe().
arch_uprobe_analyze_insn() depends on ->mm (ia32_compat) but it
is called only once.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Anton Arapov <anton@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20120615154331.GA9578@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
write_opcode() gets old_page via get_user_pages() and then calls
__replace_page() which assumes that this old_page is still
mapped after pte_offset_map_lock().
This is not true if this old_page was already try_to_unmap()'ed,
and in this case everything __replace_page() does with old_page
is wrong. Just for example, put_page() is not balanced.
I think it is possible to teach __replace_page() to handle this
unlikely case correctly, but this patch simply changes it to use
page_check_address() and return -EAGAIN if it fails. The caller
should notice this error code and retry.
Note: write_opcode() asks for the cleanups, I'll try to do this
in a separate patch.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Anton Arapov <anton@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20120615154328.GA9571@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
__copy_insn() blindly calls read_mapping_page(), this will crash
the kernel if ->readpage == NULL, add the necessary check. For
example, hugetlbfs_aops->readpage is NULL. Perhaps we should
change read_mapping_page() instead.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Anton Arapov <anton@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20120615154325.GA9568@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
__replace_page() obviously can't work with the hugetlbfs
mappings, uprobe_register() will likely crash the kernel. Change
valid_vma() to check VM_HUGETLB as well.
As for PageTransHuge() no need to worry, vma->vm_file != NULL.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Anton Arapov <anton@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20120615154322.GA9561@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Pull perf fixes from Ingo Molnar.
* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
watchdog: Quiet down the boot messages
perf/x86: Fix broken LBR fixup code
tracing: Have tracing_off() actually turn tracing off
Pull core updates (RCU and locking) from Ingo Molnar:
"Most of the diffstat comes from the RCU slow boot regression fixes,
but there's also a debuggability improvements/fixes."
* 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
memblock: Document memblock_is_region_{memory,reserved}()
rcu: Precompute RCU_FAST_NO_HZ timer offsets
rcu: Move RCU_FAST_NO_HZ per-CPU variables to rcu_dynticks structure
rcu: Update RCU_FAST_NO_HZ tracing for lazy callbacks
rcu: RCU_FAST_NO_HZ detection of callback adoption
spinlock: Indicate that a lockup is only suspected
kdump: Execute kmsg_dump(KMSG_DUMP_PANIC) after smp_send_stop()
panic: Make panic_on_oops configurable
Provide an iterator to receive the log buffer content, and convert all
kmsg_dump() users to it.
The structured data in the kmsg buffer now contains binary data, which
should no longer be copied verbatim to the kmsg_dump() users.
The iterator should provide reliable access to the buffer data, and also
supports proper log line-aware chunking of data while iterating.
Signed-off-by: Kay Sievers <kay@vrfy.org>
Tested-by: Tony Luck <tony.luck@intel.com>
Reported-by: Anton Vorontsov <anton.vorontsov@linaro.org>
Tested-by: Anton Vorontsov <anton.vorontsov@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
All trace events including ftrace internel events (like trace_printk
and function tracing), register functions that describe how to print
their output. The events may be recorded as soon as the ring buffer
is allocated, but they are just raw binary in the buffer. The mapping
of event ids to how to print them are held within a structure that
is registered on system boot.
If a crash happens in boot up before these functions are registered
then their output (via ftrace_dump_on_oops) will be useless:
Dumping ftrace buffer:
---------------------------------
<...>-1 0.... 319705us : Unknown type 6
---------------------------------
This can be quite frustrating for a kernel developer trying to see
what is going wrong.
There's no reason to register them so late in the boot up process.
They can be registered by early_initcall().
Reported-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
register_ftrace_function() checks ftrace_disabled and calls
__register_ftrace_function which does it again.
Drop the first check and add the unlikely hint to the second one. Also,
drop the label as John correctly notices.
No functional change.
Link: http://lkml.kernel.org/r/20120329171140.GE6409@aftab
Cc: Borislav Petkov <bp@amd64.org>
Cc: John Kacur <jkacur@redhat.com>
Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
A bunch of bugzillas have complained how noisy the nmi_watchdog
is during boot-up especially with its expected failure cases
(like virt and bios resource contention).
This is my attempt to quiet them down and keep it less confusing
for the end user. What I did is print the message for cpu0 and
save it for future comparisons. If future cpus have an
identical message as cpu0, then don't print the redundant info.
However, if a future cpu has a different message, happily print
that loudly.
Before the change, you would see something like:
..TIMER: vector=0x30 apic1=0 pin1=2 apic2=-1 pin2=-1
CPU0: Intel(R) Core(TM)2 Quad CPU Q9550 @ 2.83GHz stepping 0a
Performance Events: PEBS fmt0+, Core2 events, Intel PMU driver.
... version: 2
... bit width: 40
... generic registers: 2
... value mask: 000000ffffffffff
... max period: 000000007fffffff
... fixed-purpose events: 3
... event mask: 0000000700000003
NMI watchdog enabled, takes one hw-pmu counter.
Booting Node 0, Processors #1
NMI watchdog enabled, takes one hw-pmu counter.
#2
NMI watchdog enabled, takes one hw-pmu counter.
#3 Ok.
NMI watchdog enabled, takes one hw-pmu counter.
Brought up 4 CPUs
Total of 4 processors activated (22607.24 BogoMIPS).
After the change, it is simplified to:
..TIMER: vector=0x30 apic1=0 pin1=2 apic2=-1 pin2=-1
CPU0: Intel(R) Core(TM)2 Quad CPU Q9550 @ 2.83GHz stepping 0a
Performance Events: PEBS fmt0+, Core2 events, Intel PMU driver.
... version: 2
... bit width: 40
... generic registers: 2
... value mask: 000000ffffffffff
... max period: 000000007fffffff
... fixed-purpose events: 3
... event mask: 0000000700000003
NMI watchdog: enabled on all CPUs, permanently consumes one hw-PMU counter.
Booting Node 0, Processors #1#2#3 Ok.
Brought up 4 CPUs
V2: little changes based on Joe Perches' feedback
V3: printk cleanup based on Ingo's feedback; checkpatch fix
V4: keep printk as one long line
V5: Ingo fix ups
Reported-and-tested-by: Nathan Zimmer <nzimmer@sgi.com>
Signed-off-by: Don Zickus <dzickus@redhat.com>
Cc: nzimmer@sgi.com
Cc: joe@perches.com
Link: http://lkml.kernel.org/r/1339594548-17227-1-git-send-email-dzickus@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Dave Jones reported a kernel BUG at mm/slub.c:3474! triggered
by splice_shrink_spd() called from vmsplice_to_pipe()
commit 35f3d14dbb (pipe: add support for shrinking and growing pipes)
added capability to adjust pipe->buffers.
Problem is some paths don't hold pipe mutex and assume pipe->buffers
doesn't change for their duration.
Fix this by adding nr_pages_max field in struct splice_pipe_desc, and
use it in place of pipe->buffers where appropriate.
splice_shrink_spd() loses its struct pipe_inode_info argument.
Reported-by: Dave Jones <davej@redhat.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Tom Herbert <therbert@google.com>
Cc: stable <stable@vger.kernel.org> # 2.6.35
Tested-by: Dave Jones <davej@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Commit 7ff9554bb5, printk: convert
byte-buffer to variable-length record buffer, causes systems using
EABI to crash very early in the boot cycle. The first entry in struct
log is a u64, which for EABI must be 8 byte aligned.
Make use of __alignof__() so the compiler to decide the alignment, but
allow it to be overridden using CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS,
for systems which can perform unaligned access and want to save
a few bytes of space.
Tested on Orion5x and Kirkwood.
Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Tested-by: Stephen Warren <swarren@wwwdotorg.org>
Acked-by: Stephen Warren <swarren@wwwdotorg.org>
Acked-by: Kay Sievers <kay@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Merge RCU fixes from Paul E. McKenney:
" This series has four patches, the major point of which is to eliminate
some slowdowns (including boot-time slowdowns) resulting from some
RCU_FAST_NO_HZ changes. The issue with the changes is that posting timers
from the idle loop has no effect if the CPU has entered dyntick-idle
mode because the CPU has already computed its wakeup time, and posting
a timer does not cause it to be recomputed. The short-term fix is for
RCU to precompute the timeout value so that the CPU's calculation is
correct. "
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Fix lots of new kernel-doc warnings in kernel/sched/fair.c:
Warning(kernel/sched/fair.c:3625): No description found for parameter 'env'
Warning(kernel/sched/fair.c:3625): Excess function parameter 'sd' description in 'update_sg_lb_stats'
Warning(kernel/sched/fair.c:3735): No description found for parameter 'env'
Warning(kernel/sched/fair.c:3735): Excess function parameter 'sd' description in 'update_sd_pick_busiest'
Warning(kernel/sched/fair.c:3735): Excess function parameter 'this_cpu' description in 'update_sd_pick_busiest'
.. more warnings
Signed-off-by: Randy Dunlap <rdunlap@xenotime.net>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull perf fixes from Ingo Molnar:
"A bit larger than what I'd wish for - half of it is due to hw driver
updates to Intel Ivy-Bridge which info got recently released,
cycles:pp should work there now too, amongst other things. (but we
are generally making exceptions for hardware enablement of this type.)
There are also callchain fixes in it - responding to mostly
theoretical (but valid) concerns. The tooling side sports perf.data
endianness/portability fixes which did not make it for the merge
window - and various other fixes as well."
* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (26 commits)
perf/x86: Check user address explicitly in copy_from_user_nmi()
perf/x86: Check if user fp is valid
perf: Limit callchains to 127
perf/x86: Allow multiple stacks
perf/x86: Update SNB PEBS constraints
perf/x86: Enable/Add IvyBridge hardware support
perf/x86: Implement cycles:p for SNB/IVB
perf/x86: Fix Intel shared extra MSR allocation
x86/decoder: Fix bsr/bsf/jmpe decoding with operand-size prefix
perf: Remove duplicate invocation on perf_event_for_each
perf uprobes: Remove unnecessary check before strlist__delete
perf symbols: Check for valid dso before creating map
perf evsel: Fix 32 bit values endianity swap for sample_id_all header
perf session: Handle endianity swap on sample_id_all header data
perf symbols: Handle different endians properly during symbol load
perf evlist: Pass third argument to ioctl explicitly
perf tools: Update ioctl documentation for PERF_IOC_FLAG_GROUP
perf tools: Make --version show kernel version instead of pull req tag
perf tools: Check if callchain is corrupted
perf callchain: Make callchain cursors TLS
...
Pull leap second timer fix from Thomas Gleixner.
* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
timekeeping: Fix CLOCK_MONOTONIC inconsistency during leapsecond
This reverts commit 40af1bbdca.
It's horribly and utterly broken for at least the following reasons:
- calling sync_mm_rss() from mmput() is fundamentally wrong, because
there's absolutely no reason to believe that the task that does the
mmput() always does it on its own VM. Example: fork, ptrace, /proc -
you name it.
- calling it *after* having done mmdrop() on it is doubly insane, since
the mm struct may well be gone now.
- testing mm against NULL before you call it is insane too, since a
NULL mm there would have caused oopses long before.
.. and those are just the three bugs I found before I decided to give up
looking for me and revert it asap. I should have caught it before I
even took it, but I trusted Andrew too much.
Cc: Konstantin Khlebnikov <khlebnikov@openvz.org>
Cc: Markus Trippelsdorf <markus@trippelsdorf.de>
Cc: Hugh Dickins <hughd@google.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mm->rss_stat counters have per-task delta: task->rss_stat. Before
changing task->mm pointer the kernel must flush this delta with
sync_mm_rss().
do_exit() already calls sync_mm_rss() to flush the rss-counters before
committing the rss statistics into task->signal->maxrss, taskstats,
audit and other stuff. Unfortunately the kernel does this before
calling mm_release(), which can call put_user() for processing
task->clear_child_tid. So at this point we can trigger page-faults and
task->rss_stat becomes non-zero again. As a result mm->rss_stat becomes
inconsistent and check_mm() will print something like this:
| BUG: Bad rss-counter state mm:ffff88020813c380 idx:1 val:-1
| BUG: Bad rss-counter state mm:ffff88020813c380 idx:2 val:1
This patch moves sync_mm_rss() into mm_release(), and moves mm_release()
out of do_exit() and calls it earlier. After mm_release() there should
be no pagefaults.
[akpm@linux-foundation.org: tweak comment]
Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org>
Reported-by: Markus Trippelsdorf <markus@trippelsdorf.de>
Cc: Hugh Dickins <hughd@google.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: <stable@vger.kernel.org> [3.4.x]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In commit b76437579d ("procfs: mark thread stack correctly in
proc/<pid>/maps") the stack allocated via clone() is marked in
/proc/<pid>/maps as [stack:%d] thus it might be out of the former
mm->start_stack/end_stack values (and even has some custom VMA flags
set).
So to be able to restore mm->start_stack/end_stack drop vma flags test,
but still require the underlying VMA to exist.
As always note this feature is under CONFIG_CHECKPOINT_RESTORE and
requires CAP_SYS_RESOURCE to be granted.
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: Pavel Emelyanov <xemul@parallels.com>
Cc: Serge Hallyn <serge.hallyn@canonical.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Zero is written at clear_tid_address when the process exits. This
functionality is used by pthread_join().
We already have sys_set_tid_address() to change this address for the
current task but there is no way to obtain it from user space.
Without the ability to find this address and dump it we can't restore
pthread'ed apps which call pthread_join() once they have been restored.
This patch introduces the PR_GET_TID_ADDRESS prctl option which allows
the current process to obtain own clear_tid_address.
This feature is available iif CONFIG_CHECKPOINT_RESTORE is set.
[akpm@linux-foundation.org: fix prctl numbering]
Signed-off-by: Andrew Vagin <avagin@openvz.org>
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Pedro Alves <palves@redhat.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Pavel Emelyanov <xemul@parallels.com>
Cc: Tejun Heo <tj@kernel.org>
Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
A fix for commit b32dfe3771 ("c/r: prctl: add ability to set new
mm_struct::exe_file").
After removing mm->num_exe_file_vmas kernel keeps mm->exe_file until
final mmput(), it never becomes NULL while task is alive.
We can check for other mapped files in mm instead of checking
mm->num_exe_file_vmas, and mark mm with flag MMF_EXE_FILE_CHANGED in
order to forbid second changing of mm->exe_file.
Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org>
Reviewed-by: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Matt Helsley <matthltc@us.ibm.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When a CPU is entering dyntick-idle mode, tick_nohz_stop_sched_tick()
calls rcu_needs_cpu() see if RCU needs that CPU, and, if not, computes the
next wakeup time based on the timer wheels. Only later, when actually
entering the idle loop, rcu_prepare_for_idle() will be invoked. In some
cases, rcu_prepare_for_idle() will post timers to wake the CPU back up.
But all for naught: The next wakeup time for the CPU has already been
computed, and posting a timer afterwards does not force that wakeup
time to be recomputed. This means that rcu_prepare_for_idle()'s have
no effect.
This is not a problem on a busy system because something else will wake
up the CPU soon enough. However, on lightly loaded systems, the CPU
might stay asleep for a considerable length of time. If that CPU has
a callback that the rest of the system is waiting on, the system might
run very slowly or (in theory) even hang.
This commit avoids this problem by having rcu_needs_cpu() give
tick_nohz_stop_sched_tick() an estimate of when RCU will need the CPU
to wake back up, which tick_nohz_stop_sched_tick() takes into account
when programming the CPU's wakeup time. An alternative approach is
for rcu_prepare_for_idle() to use hrtimers instead of normal timers,
but timers are much more efficient than are hrtimers for frequently
and repeatedly posting and cancelling a given timer, which is exactly
what RCU_FAST_NO_HZ does.
Reported-by: Pascal Chapperon <pascal.chapperon@wanadoo.fr>
Reported-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Tested-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Tested-by: Pascal Chapperon <pascal.chapperon@wanadoo.fr>
The RCU_FAST_NO_HZ code relies on a number of per-CPU variables.
This works, but is hidden from someone scanning the data structures
in rcutree.h. This commit therefore converts these per-CPU variables
to fields in the per-CPU rcu_dynticks structures.
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Tested-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Tested-by: Pascal Chapperon <pascal.chapperon@wanadoo.fr>
In the current code, a short dyntick-idle interval (where there is
at least one non-lazy callback on the CPU) and a long dyntick-idle
interval (where there are only lazy callbacks on the CPU) are traced
identically, which can be less than helpful. This commit therefore
emits different event traces in these two cases.
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Tested-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Tested-by: Pascal Chapperon <pascal.chapperon@wanadoo.fr>
