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With this patch, kdump uses the firmware soft-reset NMI for two purposes:
1) Initiate the kdump (take a crash dump) by issuing a soft-reset.
2) Break a CPU out of a deadlock condition that is detected during kdump
processing.
When a soft-reset is initiated each CPU will enter
system_reset_exception() and set its corresponding bit in the global
bit-array cpus_in_sr then call die(). When die() finds the CPU's bit set
in cpu_in_sr crash_kexec() is called to initiate a crash dump. The first
CPU to enter crash_kexec() is called the "crashing CPU". All other CPUs
are "secondary CPUs". The secondary CPU's pass through to
crash_kexec_secondary() and sleep. The crashing CPU waits for all CPUs
to enter via soft-reset then boots the kdump kernel (see
crash_soft_reset_check())
When the system crashes due to a panic or exception, crash_kexec() is
called by panic() or die(). The crashing CPU sends an IPI to all other
CPUs to notify them of the pending shutdown. If a CPU is in a deadlock
or hung state with interrupts disabled, the IPI will not be delivered.
The result being, that the kdump kernel is not booted. This problem is
solved with the use of a firmware generated soft-reset. After the
crashing_cpu has issued the IPI, it waits for 10 sec for all CPUs to
enter crash_ipi_callback(). A CPU signifies its entry to
crash_ipi_callback() by setting its corresponding bit in the
cpus_in_crash bit array. After 10 sec, if one or more CPUs have not set
their bit in cpus_in_crash we assume that the CPU(s) is deadlocked. The
operator is then prompted to generate a soft-reset to break the
deadlock. Each CPU enters the soft reset handler as described above.
Two conditions must be handled at this point:
1) The system crashed because the operator generated a soft-reset. See
2) The system had crashed before the soft-reset was generated ( in the
case of a Panic or oops).
The first CPU to enter crash_kexec() uses the state of the kexec_lock to
determine this state. If kexec_lock is already held then condition 2 is
true and crash_kexec_secondary() is called, else; this CPU is flagged as
the crashing CPU, the kexec_lock is acquired and crash_kexec() proceeds
as described above.
Each additional CPUs responding to the soft-reset will pass through
crash_kexec() to kexec_secondary(). All secondary CPUs call
crash_ipi_callback() readying them self's for the shutdown. When ready
they clear their bit in cpus_in_sr. The crashing CPU waits in
kexec_secondary() until all other CPUs have cleared their bits in
cpus_in_sr. The kexec kernel boot is then started.
Signed-off-by: Haren Myneni <haren@us.ibm.com>
Signed-off-by: David Wilder <dwilder@us.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
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* git://git.kernel.org/pub/scm/linux/kernel/git/sam/kbuild: (40 commits)
kbuild: trivial fixes in Makefile
kbuild: adding symbols in Kconfig and defconfig to TAGS
kbuild: replace abort() with exit(1)
kbuild: support for %.symtypes files
kbuild: fix silentoldconfig recursion
kbuild: add option for stripping modules while installing them
kbuild: kill some false positives from modpost
kbuild: export-symbol usage report generator
kbuild: fix make -rR breakage
kbuild: append -dirty for updated but uncommited changes
kbuild: append git revision for all untagged commits
kbuild: fix module.symvers parsing in modpost
kbuild: ignore make's built-in rules & variables
kbuild: bugfix with initramfs
kbuild: modpost build fix
kbuild: check license compatibility when building modules
kbuild: export-type enhancement to modpost.c
kbuild: add dependency on kernel.release to the package targets
kbuild: `make kernelrelease' speedup
kconfig: KCONFIG_OVERWRITECONFIG
...
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* x86-64: (83 commits)
[PATCH] x86_64: x86_64 stack usage debugging
[PATCH] x86_64: (resend) x86_64 stack overflow debugging
[PATCH] x86_64: msi_apic.c build fix
[PATCH] x86_64: i386/x86-64 Add nmi watchdog support for new Intel CPUs
[PATCH] x86_64: Avoid broadcasting NMI IPIs
[PATCH] x86_64: fix apic error on bootup
[PATCH] x86_64: enlarge window for stack growth
[PATCH] x86_64: Minor string functions optimizations
[PATCH] x86_64: Move export symbols to their C functions
[PATCH] x86_64: Standardize i386/x86_64 handling of NMI_VECTOR
[PATCH] x86_64: Fix modular pc speaker
[PATCH] x86_64: remove sys32_ni_syscall()
[PATCH] x86_64: Do not use -ffunction-sections for modules
[PATCH] x86_64: Add cpu_relax to apic_wait_icr_idle
[PATCH] x86_64: adjust kstack_depth_to_print default
[PATCH] i386/x86-64: adjust /proc/interrupts column headings
[PATCH] x86_64: Fix race in cpu_local_* on preemptible kernels
[PATCH] x86_64: Fix fast check in safe_smp_processor_id
[PATCH] x86_64: x86_64 setup.c - printing cmp related boottime information
[PATCH] i386/x86-64/ia64: Move polling flag into thread_info_status
...
Manual resolve of trivial conflict in arch/i386/kernel/Makefile
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During some profiling I noticed that default_idle causes a lot of
memory traffic. I think that is caused by the atomic operations
to clear/set the polling flag in thread_info. There is actually
no reason to make this atomic - only the idle thread does it
to itself, other CPUs only read it. So I moved it into ti->status.
Converted i386/x86-64/ia64 for now because that was the easiest
way to fix ACPI which also manipulates these flags in its idle
function.
Cc: Nick Piggin <npiggin@novell.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Len Brown <len.brown@intel.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Add proper conditionals to be able to build with CONFIG_MODULES=n.
Signed-off-by: Jan Beulich <jbeulich@novell.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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If no unwinding is possible at all for a certain exception instance,
fall back to the old style call trace instead of not showing any trace
at all.
Also, allow setting the stack trace mode at the command line.
Signed-off-by: Jan Beulich <jbeulich@novell.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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These are the generic bits needed to enable reliable stack traces based
on Dwarf2-like (.eh_frame) unwind information. Subsequent patches will
enable x86-64 and i386 to make use of this.
Thanks to Andi Kleen and Ingo Molnar, who pointed out several possibilities
for improvement.
Signed-off-by: Jan Beulich <jbeulich@novell.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Sometimes e.g. with crashme the compat layer warnings can be noisy.
Add a way to turn them off by gating all output through compat_printk
that checks a global sysctl. The default is not changed.
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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The introduction of SCHED_BATCH scheduling class with a value of 3 means
that the expression (p->policy & SCHED_FIFO) will return true if policy
is SCHED_BATCH or SCHED_FIFO.
Unfortunately, this expression is used in sys_sched_rr_get_interval()
and in the absence of a comment to say that this is intentional I
presume that it is unintentional and erroneous.
The fix is to change the expression to (p->policy == SCHED_FIFO).
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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After the previous patch SIGNAL_GROUP_EXIT implies a pending SIGKILL, we
can remove this check from copy_process() because we already checked
!signal_pending().
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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With this patch zap_process() sets SIGNAL_GROUP_EXIT while sending SIGKILL to
the thread group. This means that a TASK_TRACED task
1. Will be awakened by signal_wake_up(1)
2. Can't sleep again via ptrace_notify()
3. Can't go to do_signal_stop() after return
from ptrace_stop() in get_signal_to_deliver()
So we can remove all ptrace related stuff from coredump path.
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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In process of getting proc_fd_access_allowed to work it has developed a few
warts. In particular the special case that always allows introspection and
the special case to allow inspection of kernel threads.
The special case for introspection is needed for /proc/self/mem.
The special case for kernel threads really should be overridable
by security modules.
So consolidate these checks into ptrace.c:may_attach().
The check to always allow introspection is trivial.
The check to allow access to kernel threads, and zombies is a little
trickier. mem_read and mem_write already verify an mm exists so it isn't
needed twice. proc_fd_access_allowed only doesn't want a check to verify
task->mm exits, s it prevents all access to kernel threads. So just move
the task->mm check into ptrace_attach where it is needed for practical
reasons.
I did a quick audit and none of the security modules in the kernel seem to
care if they are passed a task without an mm into security_ptrace. So the
above move should be safe and it allows security modules to come up with
more restrictive policy.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Cc: Stephen Smalley <sds@tycho.nsa.gov>
Cc: Chris Wright <chrisw@sous-sol.org>
Cc: James Morris <jmorris@namei.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Incrementally update my proc-dont-lock-task_structs-indefinitely patches so
that they work with struct pid instead of struct task_ref.
Mostly this is a straight 1-1 substitution.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Every inode in /proc holds a reference to a struct task_struct. If a
directory or file is opened and remains open after the the task exits this
pinning continues. With 8K stacks on a 32bit machine the amount pinned per
file descriptor is about 10K.
Normally I would figure a reasonable per user process limit is about 100
processes. With 80 processes, with a 1000 file descriptors each I can trigger
the 00M killer on a 32bit kernel, because I have pinned about 800MB of useless
data.
This patch replaces the struct task_struct pointer with a pointer to a struct
task_ref which has a struct task_struct pointer. The so the pinning of dead
tasks does not happen.
The code now has to contend with the fact that the task may now exit at any
time. Which is a little but not muh more complicated.
With this change it takes about 1000 processes each opening up 1000 file
descriptors before I can trigger the OOM killer. Much better.
[mlp@google.com: task_mmu small fixes]
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Cc: Paul Jackson <pj@sgi.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Albert Cahalan <acahalan@gmail.com>
Signed-off-by: Prasanna Meda <mlp@google.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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To keep the dcache from filling up with dead /proc entries we flush them on
process exit. However over the years that code has gotten hairy with a
dentry_pointer and a lock in task_struct and misdocumented as a correctness
feature.
I have rewritten this code to look and see if we have a corresponding entry in
the dcache and if so flush it on process exit. This removes the extra fields
in the task_struct and allows me to trivially handle the case of a
/proc/<tgid>/task/<pid> entry as well as the current /proc/<pid> entries.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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With this patch Kprobes now registers for page fault notifications only when
their is an active probe registered. Once all the active probes are
unregistered their is no need to be notified of page faults and kprobes
unregisters itself from the page fault notifications. Hence we will have ZERO
side effects when no probes are active.
Signed-off-by: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Kprobes now registers for page fault notifications.
Signed-off-by: Anil S Keshavamurthy <anil.s.keshavmurthy@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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If there are multi kprobes on the same probepoint, there will be one extra
aggr_kprobe on the head of kprobe list. The aggr_kprobe has
aggr_post_handler/aggr_break_handler whether the other kprobe
post_hander/break_handler is NULL or not. This patch modifies this, only
when there is one or more kprobe in the list whose post_handler is not
NULL, post_handler of aggr_kprobe will be set as aggr_post_handler.
[soshima@redhat.com: !CONFIG_PREEMPT fix]
Signed-off-by: bibo, mao <bibo.mao@intel.com>
Cc: Masami Hiramatsu <hiramatu@sdl.hitachi.co.jp>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: "Keshavamurthy, Anil S" <anil.s.keshavamurthy@intel.com>
Cc: Prasanna S Panchamukhi <prasanna@in.ibm.com>
Cc: Jim Keniston <jkenisto@us.ibm.com>
Cc: Yumiko Sugita <sugita@sdl.hitachi.co.jp>
Cc: Hideo Aoki <haoki@redhat.com>
Signed-off-by: Satoshi Oshima <soshima@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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This fixes the clock source updates in update_wall_time() to correctly
track the time coming in via current_tick_length(). Optimize the fast
paths to be as short as possible to keep the overhead low.
Signed-off-by: Roman Zippel <zippel@linux-m68k.org>
Acked-by: John Stultz <johnstul@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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As suggested by Roman Zippel, change clocksource functions to use
clocksource_xyz rather then xyz_clocksource to avoid polluting the
namespace.
Signed-off-by: John Stultz <johnstul@us.ibm.com>
Cc: Roman Zippel <zippel@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Implement the time sources for i386 (acpi_pm, cyclone, hpet, pit, and tsc).
With this patch, the conversion of the i386 arch to the generic timekeeping
code should be complete.
The patch should be fairly straight forward, only adding the new clocksources.
[hirofumi@mail.parknet.co.jp: acpi_pm cleanup]
Signed-off-by: John Stultz <johnstul@us.ibm.com>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
Signed-off-by: John Stultz <johnstul@us.ibm.com>
Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Introduces clocksource switching code and the arch generic time accessor
functions that use the clocksource infrastructure.
Signed-off-by: John Stultz <johnstul@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Instead of incrementing xtime by tick_nsec + ntp adjustments, use the
clocksource abstraction to increment and scale time. Using the clocksource
abstraction allows other clocksources to be used consistently in the face of
late or lost ticks, while preserving the existing behavior via the jiffies
clocksource.
This removes the need to keep time_phase adjustments as we just use the
current_tick_length() function as the NTP interface and accumulate time using
shifted nanoseconds.
The basics of this design was by Roman Zippel, however it is my own
interpretation and implementation, so the credit should go to him and the
blame to me.
Signed-off-by: John Stultz <johnstul@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Change the current_tick_length() function so it takes an argument which
specifies how much precision to return in shifted nanoseconds. This provides
a simple way to convert between NTPs internal nanoseconds shifted by
(SHIFT_SCALE - 10) to other shifted nanosecond units that are used by the
clocksource abstraction.
Signed-off-by: John Stultz <johnstul@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Modify the update_wall_time function so it increments time using the
clocksource abstraction instead of jiffies. Since the only clocksource driver
currently provided is the jiffies clocksource, this should result in no
functional change. Additionally, a timekeeping_init and timekeeping_resume
function has been added to initialize and maintain some of the new timekeping
state.
[hirofumi@mail.parknet.co.jp: fixlet]
Signed-off-by: John Stultz <johnstul@us.ibm.com>
Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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This introduces the clocksource management infrastructure. A clocksource is a
driver-like architecture generic abstraction of a free-running counter. This
code defines the clocksource structure, and provides management code for
registering, selecting, accessing and scaling clocksources.
Additionally, this includes the trivial jiffies clocksource, a lowest common
denominator clocksource, provided mainly for use as an example.
[hirofumi@mail.parknet.co.jp: Don't enable IRQ too early]
Signed-off-by: John Stultz <johnstul@us.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
Signed-off-by: John Stultz <johnstul@us.ibm.com>
Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Convert kernel/cpu.c from semaphore to mutex.
I've reviewed all lock_cpu_hotplug() critical sections, and they all seem to
fit mutex semantics.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Ashok Raj <ashok.raj@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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It seems ppc64 wants to lock mutexes in early bootup code, with interrupts
disabled, and they expect interrupts to stay disabled, else they crash.
Work around this bug by making mutex debugging variants save/restore irq
flags.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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This reverts commits
3e3318dee0878d42ed62a19c292a2ac284135db3 [PATCH] swsusp: x86_64 mark special saveable/unsaveable pages
b6370d96e09944c6e3ae8d5743ca8a8ab1f79f6c [PATCH] swsusp: i386 mark special saveable/unsaveable pages
ce4ab0012b32c1a4a1d6e934aeb73bf3151c48d9 [PATCH] swsusp: add architecture special saveable pages support
because not only do they apparently cause page faults on x86, the
infrastructure doesn't compile on powerpc.
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Not that x86-64 and other architecture support should be difficult to
add (trivial fixups to the data format and add the proper linker script
entry).
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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In current 2.6.17 implementation, signal_struct refered from task_struct is
used for per-process data structure. The pacct facility also uses it as a
per-process data structure to store stime, utime, minflt, majflt. But those
members are saved in __exit_signal(). It's too late.
For example, if some threads exits at same time, pacct facility has a
possibility to drop accountings for a part of those threads. (see, the
following 'The results of original 2.6.17 kernel') I think accounting
information should be completely collected into the per-process data structure
before writing out an accounting record.
This patch fixes this matter. Accumulation of stime, utime, minflt and majflt
are done before generating accounting record.
[mingo@elte.hu: fix acct_collect() siglock bug found by lockdep]
Signed-off-by: KaiGai Kohei <kaigai@ak.jp.nec.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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process
When pacct facility generate an 'ac_flag' field in accounting record, it
refers a task_struct of the thread which died last in the process. But any
other task_structs are ignored.
Therefore, pacct facility drops ASU flag even if root-privilege operations are
used by any other threads except the last one. In addition, AFORK flag is
always set when the thread of group-leader didn't die last, although this
process has called execve() after fork().
We have a same matter in ac_exitcode. The recorded ac_exitcode is an exit
code of the last thread in the process. There is a possibility this exitcode
is not the group leader's one.
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The pacct facility need an i/o operation when an accounting record is
generated. There is a possibility to wake OOM killer up. If OOM killer is
activated, it kills some processes to make them release process memory
regions.
But acct_process() is called in the killed processes context before calling
exit_mm(), so those processes cannot release own memory. In the results, any
processes stop in this point and it finally cause a system stall.
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Move kthread API kernel-doc from kthread.h to kthread.c & fix it.
Add kthread API to kernel-api DocBook.
Signed-off-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Fix kernel-doc formatting in ktime.h and hrtimer.[ch] files.
Signed-off-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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If a cpu hotplug callback fails on CPU_UP_PREPARE, all callbacks will be
called with CPU_UP_CANCELED. A few of these callbacks assume that on
CPU_UP_PREPARE a pointer to task has been stored in a percpu array. This
assumption is not true if CPU_UP_PREPARE fails and the following calls to
kthread_bind() in CPU_UP_CANCELED will cause an addressing exception
because of passing a NULL pointer.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Ashok Raj <ashok.raj@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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- Update stop_machine.c to spawn stop_machine as kthreads rather than the
deprecated kernel_threads.
- Update stop_machine to use the more efficient kthread_bind() before
running task in place of set_cpus_allowed() after.
[akpm@osdl.org: remove now-wrong set_cpus_allowed()]
Signed-off-by: Serge E. Hallyn <serue@us.ibm.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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If futexes are disabled we fail to link on ppc64.
Signed-off-by: Anton Blanchard <anton@samba.org>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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I'm testing glibc on MIPS64, little-endian, N32, O32 and N64 multilibs.
Among the NPTL test failures seen are some arising from sigsuspend problems
for N32: it blocks the wrong signals, so SIGCANCEL (SIGRTMIN) is blocked
despite glibc's carefully excluding it from sets of signals to block.
Specifically, testing suggests it blocks signal N^32 instead of signal N,
so (in the example tested) blocking SIGUSR1 (17) blocks signal 49 instead.
glibc's sigset_t uses an array of unsigned long, as does the kernel.
In both cases, signal N+1 is represented as
(1UL << (N % (8 * sizeof (unsigned long)))) in word number
(N / (8 * sizeof (unsigned long))).
Thus the N32 glibc uses an array of 32-bit words and the N64 kernel uses an
array of 64-bit words. For little-endian, the layout is the same, with
signals 1-32 in the first 4 bytes, signals 33-64 in the second, etc.; for
big-endian, userspace has that layout while in the kernel each 8 bytes have
the two halves swapped from the userspace layout.
The N32 sigsuspend syscall uses sigset_from_compat to convert the userspace
sigset to kernel format. If __COMPAT_ENDIAN_SWAP__ is *not* set, this uses
logic of the form
set->sig[0] = compat->sig[0] | (((long)compat->sig[1]) << 32 )
to convert the userspace sigset to a kernel one. This looks correct to me
for both big and little endian, given that in userspace compat->sig[1] will
represent signals 33-64, and so will the high 32 bits of set->sig[0] in the
kernel. If however __COMPAT_ENDIAN_SWAP__ *is* set, as it is for
__MIPSEL__, it uses
set->sig[0] = compat->sig[1] | (((long)compat->sig[0]) << 32 );
which seems incorrect for both big and little endian, and would
explain the observed symptoms.
This code is the only use of __COMPAT_ENDIAN_SWAP__, so if incorrect
then that macro serves no purpose, in which case something like the
following patch would seem appropriate to remove it.
Signed-off-by: Joseph Myers <joseph@codesourcery.com>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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The table is empty, why does it still exist?
Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Currently, enabling/disabling printk timestamps is only possible through
reboot (bootparam) or recompile. I normally do not run with timestamps
(since syslog handles that in a good manner), but for measuring small
kernel delays (e.g. irq probing - see parport thread) I needed subsecond
precision, but then again, just for some minutes rather than all kernel
messages to come. The following patch adds a module_param() with which the
timestamps can be en-/disabled in a live system through
/sys/modules/printk/parameters/printk_time.
Signed-off-by: Jan Engelhardt <jengelh@gmx.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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copy_process() appears to be the only caller of acct_clear_integrals() and
does not pass in NULL task pointers. Remove the unecessary check.
Signed-off-by: Matt Helsley <matthltc@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Signed-off-by: Andreas Mohr <andi@lisas.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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schedule_on_each_cpu() presently does a large kmalloc - 96 kbytes on 1024 CPU
64-bit.
Rework it so that we do one 8192-byte allocation and then a pile of tiny ones,
via alloc_percpu(). This has a much higher chance of success (100% in the
current VM).
This also has the effect of reducing the memory requirements from NR_CPUS*n to
num_possible_cpus()*n.
Cc: Christoph Lameter <clameter@engr.sgi.com>
Cc: Andi Kleen <ak@muc.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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- proper prototypes for the following functions:
- ctrl_alt_del() (in include/linux/reboot.h)
- getrusage() (in include/linux/resource.h)
- make the following needlessly global functions static:
- kernel_restart_prepare()
- kernel_kexec()
[akpm@osdl.org: compile fix]
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Currently printk is no use for early debugging because it refuses to
actually print anything to the console unless
cpu_online(smp_processor_id()) is true.
The stated explanation is that console drivers may require per-cpu
resources, or otherwise barf, because the system is not yet setup
correctly. Fair enough.
However some console drivers might be quite happy running early during
boot, in fact we have one, and so it'd be nice if printk understood that.
So I added a flag (which I would have called CON_BOOT, but that's taken)
called CON_ANYTIME, which indicates that a console is happy to be called
anytime, even if the cpu is not yet online.
Tested on a Power 5 machine, with both a CON_ANYTIME driver and a bogus
console driver that BUG()s if called while offline. No problems AFAICT.
Built for i386 UP & SMP.
Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Since raw_notifier chains don't benefit from any centralized locking
protections, they shouldn't suffer from the associated limitations. Under
some circumstances it might make sense for a raw_notifier callout routine
to unregister itself from the notifier chain. This patch (as678) changes
the notifier core to allow for such things.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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There are several instances of per_cpu(foo, raw_smp_processor_id()), which
is semantically equivalent to __get_cpu_var(foo) but without the warning
that smp_processor_id() can give if CONFIG_DEBUG_PREEMPT is enabled. For
those architectures with optimized per-cpu implementations, namely ia64,
powerpc, s390, sparc64 and x86_64, per_cpu() turns into more and slower
code than __get_cpu_var(), so it would be preferable to use __get_cpu_var
on those platforms.
This defines a __raw_get_cpu_var(x) macro which turns into per_cpu(x,
raw_smp_processor_id()) on architectures that use the generic per-cpu
implementation, and turns into __get_cpu_var(x) on the architectures that
have an optimized per-cpu implementation.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Acked-by: David S. Miller <davem@davemloft.net>
Acked-by: Ingo Molnar <mingo@elte.hu>
Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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If CONFIG_KALLSYMS is defined and if it should happen that is_exported() is
given a NULL 'mod' and lookup_symbol(name, __start___ksymtab,
__stop___ksymtab) returns 0, then we'll end up dereferencing a NULL
pointer.
Signed-off-by: Jesper Juhl <jesper.juhl@gmail.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Considering that there isn't a lot of hw we can depend on during resume,
this is about as good as it gets.
This is x86-only for now, although the basic concept (and most of the
code) will certainly work on almost any platform.
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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