commit d7824370e2 upstream.
This commit makes the stack guard page somewhat less visible to user
space. It does this by:
- not showing the guard page in /proc/<pid>/maps
It looks like lvm-tools will actually read /proc/self/maps to figure
out where all its mappings are, and effectively do a specialized
"mlockall()" in user space. By not showing the guard page as part of
the mapping (by just adding PAGE_SIZE to the start for grows-up
pages), lvm-tools ends up not being aware of it.
- by also teaching the _real_ mlock() functionality not to try to lock
the guard page.
That would just expand the mapping down to create a new guard page,
so there really is no point in trying to lock it in place.
It would perhaps be nice to show the guard page specially in
/proc/<pid>/maps (or at least mark grow-down segments some way), but
let's not open ourselves up to more breakage by user space from programs
that depends on the exact deails of the 'maps' file.
Special thanks to Henrique de Moraes Holschuh for diving into lvm-tools
source code to see what was going on with the whole new warning.
Reported-and-tested-by: François Valenduc <francois.valenduc@tvcablenet.be
Reported-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
commit 0cf55e1ec0 upstream.
This is a real fix for problem of utime/stime values decreasing
described in the thread:
http://lkml.org/lkml/2009/11/3/522
Now cputime is accounted in the following way:
- {u,s}time in task_struct are increased every time when the thread
is interrupted by a tick (timer interrupt).
- When a thread exits, its {u,s}time are added to signal->{u,s}time,
after adjusted by task_times().
- When all threads in a thread_group exits, accumulated {u,s}time
(and also c{u,s}time) in signal struct are added to c{u,s}time
in signal struct of the group's parent.
So {u,s}time in task struct are "raw" tick count, while
{u,s}time and c{u,s}time in signal struct are "adjusted" values.
And accounted values are used by:
- task_times(), to get cputime of a thread:
This function returns adjusted values that originates from raw
{u,s}time and scaled by sum_exec_runtime that accounted by CFS.
- thread_group_cputime(), to get cputime of a thread group:
This function returns sum of all {u,s}time of living threads in
the group, plus {u,s}time in the signal struct that is sum of
adjusted cputimes of all exited threads belonged to the group.
The problem is the return value of thread_group_cputime(),
because it is mixed sum of "raw" value and "adjusted" value:
group's {u,s}time = foreach(thread){{u,s}time} + exited({u,s}time)
This misbehavior can break {u,s}time monotonicity.
Assume that if there is a thread that have raw values greater
than adjusted values (e.g. interrupted by 1000Hz ticks 50 times
but only runs 45ms) and if it exits, cputime will decrease (e.g.
-5ms).
To fix this, we could do:
group's {u,s}time = foreach(t){task_times(t)} + exited({u,s}time)
But task_times() contains hard divisions, so applying it for
every thread should be avoided.
This patch fixes the above problem in the following way:
- Modify thread's exit (= __exit_signal()) not to use task_times().
It means {u,s}time in signal struct accumulates raw values instead
of adjusted values. As the result it makes thread_group_cputime()
to return pure sum of "raw" values.
- Introduce a new function thread_group_times(*task, *utime, *stime)
that converts "raw" values of thread_group_cputime() to "adjusted"
values, in same calculation procedure as task_times().
- Modify group's exit (= wait_task_zombie()) to use this introduced
thread_group_times(). It make c{u,s}time in signal struct to
have adjusted values like before this patch.
- Replace some thread_group_cputime() by thread_group_times().
This replacements are only applied where conveys the "adjusted"
cputime to users, and where already uses task_times() near by it.
(i.e. sys_times(), getrusage(), and /proc/<PID>/stat.)
This patch have a positive side effect:
- Before this patch, if a group contains many short-life threads
(e.g. runs 0.9ms and not interrupted by ticks), the group's
cputime could be invisible since thread's cputime was accumulated
after adjusted: imagine adjustment function as adj(ticks, runtime),
{adj(0, 0.9) + adj(0, 0.9) + ....} = {0 + 0 + ....} = 0.
After this patch it will not happen because the adjustment is
applied after accumulated.
v2:
- remove if()s, put new variables into signal_struct.
Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Spencer Candland <spencer@bluehost.com>
Cc: Americo Wang <xiyou.wangcong@gmail.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Stanislaw Gruszka <sgruszka@redhat.com>
LKML-Reference: <4B162517.8040909@jp.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
commit 34441427aa upstream.
Originally, commit d899bf7b ("procfs: provide stack information for
threads") attempted to introduce a new feature for showing where the
threadstack was located and how many pages are being utilized by the
stack.
Commit c44972f1 ("procfs: disable per-task stack usage on NOMMU") was
applied to fix the NO_MMU case.
Commit 89240ba0 ("x86, fs: Fix x86 procfs stack information for threads on
64-bit") was applied to fix a bug in ia32 executables being loaded.
Commit 9ebd4eba7 ("procfs: fix /proc/<pid>/stat stack pointer for kernel
threads") was applied to fix a bug which had kernel threads printing a
userland stack address.
Commit 1306d603f ('proc: partially revert "procfs: provide stack
information for threads"') was then applied to revert the stack pages
being used to solve a significant performance regression.
This patch nearly undoes the effect of all these patches.
The reason for reverting these is it provides an unusable value in
field 28. For x86_64, a fork will result in the task->stack_start
value being updated to the current user top of stack and not the stack
start address. This unpredictability of the stack_start value makes
it worthless. That includes the intended use of showing how much stack
space a thread has.
Other architectures will get different values. As an example, ia64
gets 0. The do_fork() and copy_process() functions appear to treat the
stack_start and stack_size parameters as architecture specific.
I only partially reverted c44972f1 ("procfs: disable per-task stack usage
on NOMMU") . If I had completely reverted it, I would have had to change
mm/Makefile only build pagewalk.o when CONFIG_PROC_PAGE_MONITOR is
configured. Since I could not test the builds without significant effort,
I decided to not change mm/Makefile.
I only partially reverted 89240ba0 ("x86, fs: Fix x86 procfs stack
information for threads on 64-bit") . I left the KSTK_ESP() change in
place as that seemed worthwhile.
Signed-off-by: Robin Holt <holt@sgi.com>
Cc: Stefani Seibold <stefani@seibold.net>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
commit 1306d603fc upstream.
Commit d899bf7b (procfs: provide stack information for threads) introduced
to show stack information in /proc/{pid}/status. But it cause large
performance regression. Unfortunately /proc/{pid}/status is used ps
command too and ps is one of most important component. Because both to
take mmap_sem and page table walk are heavily operation.
If many process run, the ps performance is,
[before d899bf7b]
% perf stat ps >/dev/null
Performance counter stats for 'ps':
4090.435806 task-clock-msecs # 0.032 CPUs
229 context-switches # 0.000 M/sec
0 CPU-migrations # 0.000 M/sec
234 page-faults # 0.000 M/sec
8587565207 cycles # 2099.425 M/sec
9866662403 instructions # 1.149 IPC
3789415411 cache-references # 926.409 M/sec
30419509 cache-misses # 7.437 M/sec
128.859521955 seconds time elapsed
[after d899bf7b]
% perf stat ps > /dev/null
Performance counter stats for 'ps':
4305.081146 task-clock-msecs # 0.028 CPUs
480 context-switches # 0.000 M/sec
2 CPU-migrations # 0.000 M/sec
237 page-faults # 0.000 M/sec
9021211334 cycles # 2095.480 M/sec
10605887536 instructions # 1.176 IPC
3612650999 cache-references # 839.160 M/sec
23917502 cache-misses # 5.556 M/sec
152.277819582 seconds time elapsed
Thus, this patch revert it. Fortunately /proc/{pid}/task/{tid}/smaps
provide almost same information. we can use it.
Commit d899bf7b introduced two features:
1) Add the annotattion of [thread stack: xxxx] mark to
/proc/{pid}/task/{tid}/maps.
2) Add StackUsage field to /proc/{pid}/status.
I only revert (2), because I haven't seen (1) cause regression.
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Stefani Seibold <stefani@seibold.net>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Randy Dunlap <randy.dunlap@oracle.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andi Kleen <andi@firstfloor.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
commit b95c35e76b upstream.
proc_oom_score(task) has a reference to task_struct, but that is all.
If this task was already released before we take tasklist_lock
- we can't use task->group_leader, it points to nowhere
- it is not safe to call badness() even if this task is
->group_leader, has_intersects_mems_allowed() assumes
it is safe to iterate over ->thread_group list.
- even worse, badness() can hit ->signal == NULL
Add the pid_alive() check to ensure __unhash_process() was not called.
Also, use "task" instead of task->group_leader. badness() should return
the same result for any sub-thread. Currently this is not true, but
this should be changed anyway.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Daniel Lezcano reported a leak in 'struct pid' and 'struct pid_namespace'
that is discussed in:
http://lkml.org/lkml/2009/10/2/159.
To summarize the thread, when container-init is terminated, it sets the
PF_EXITING flag, zaps other processes in the container and waits to reap
them. As a part of reaping, the container-init should flush any /proc
dentries associated with the processes. But because the container-init is
itself exiting and the following PF_EXITING check, the dentries are not
flushed, resulting in leak in /proc inodes and dentries.
This fix reverts the commit 7766755a2f ("Fix /proc dcache deadlock
in do_exit") which introduced the check for PF_EXITING. At the time of
the commit, shrink_dcache_parent() flushed dentries from other filesystems
also and could have caused a deadlock which the commit fixed. But as
pointed out by Eric Biederman, after commit 0feae5c47a,
shrink_dcache_parent() no longer affects other filesystems. So reverting
the commit is now safe.
As pointed out by Jan Kara, the leak is not as critical since the
unclaimed space will be reclaimed under memory pressure or by:
echo 3 > /proc/sys/vm/drop_caches
But since this check is no longer required, its best to remove it.
Signed-off-by: Sukadev Bhattiprolu <sukadev@us.ibm.com>
Reported-by: Daniel Lezcano <dlezcano@fr.ibm.com>
Acked-by: Eric W. Biederman <ebiederm@xmission.com>
Acked-by: Jan Kara <jack@ucw.cz>
Cc: Andrea Arcangeli <andrea@cpushare.com>
Cc: Serge Hallyn <serue@us.ibm.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Given such a long name, the kB count in /proc/meminfo's HardwareCorrupted
line is being shown too far right (it does align with x86_64's VmallocChunk
above, but I hope nobody will ever have that much corrupted!). Align it.
Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Cc: Andi Kleen <andi@firstfloor.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* 'hwpoison' of git://git.kernel.org/pub/scm/linux/kernel/git/ak/linux-mce-2.6: (21 commits)
HWPOISON: Enable error_remove_page on btrfs
HWPOISON: Add simple debugfs interface to inject hwpoison on arbitary PFNs
HWPOISON: Add madvise() based injector for hardware poisoned pages v4
HWPOISON: Enable error_remove_page for NFS
HWPOISON: Enable .remove_error_page for migration aware file systems
HWPOISON: The high level memory error handler in the VM v7
HWPOISON: Add PR_MCE_KILL prctl to control early kill behaviour per process
HWPOISON: shmem: call set_page_dirty() with locked page
HWPOISON: Define a new error_remove_page address space op for async truncation
HWPOISON: Add invalidate_inode_page
HWPOISON: Refactor truncate to allow direct truncating of page v2
HWPOISON: check and isolate corrupted free pages v2
HWPOISON: Handle hardware poisoned pages in try_to_unmap
HWPOISON: Use bitmask/action code for try_to_unmap behaviour
HWPOISON: x86: Add VM_FAULT_HWPOISON handling to x86 page fault handler v2
HWPOISON: Add poison check to page fault handling
HWPOISON: Add basic support for poisoned pages in fault handler v3
HWPOISON: Add new SIGBUS error codes for hardware poison signals
HWPOISON: Add support for poison swap entries v2
HWPOISON: Export some rmap vma locking to outside world
...
Git commit 79741dd changes idle cputime accounting, but unfortunately
the /proc/uptime file hasn't caught up. Here the idle time calculation
from /proc/stat is copied over.
Signed-off-by: Michael Abbott <michael.abbott@diamond.ac.uk>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
After memory hotplug (or other events in future), kcore size can be
modified.
To update inode->i_size, we have to know inode/dentry but we can't get it
from inside /proc directly. But considerinyg memory hotplug, kcore image
is updated only when it's opened. Then, updating inode->i_size at open()
is enough.
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: WANG Cong <xiyou.wangcong@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Presently the size of /proc/kcore which can be read by 'ls -l' is 0. But
it's not the correct value.
On x86-64, ls -l shows
... root root 140737486266368 2009-09-17 10:29 /proc/kcore
Then, 7FFFFFFE02000. This comes from vmalloc area's size.
(*) This shows "core" size, not memory size.
This patch shows the size by updating "size" field in struct
proc_dir_entry. Later, lookup routine will create inode and fill
inode->i_size based on this value. Then, this has a problem.
- Once inode is cached, inode->i_size will never be updated.
Then, this patch is not memory-hotplug-aware.
To update inode->i_size, we have to know dentry or inode.
But there is no way to lookup them by inside kernel. Hmmm....
Next patch will try it.
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: WANG Cong <xiyou.wangcong@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Benjamin Herrenschmidt <benh@kernel.crashing.org> pointed out that vmemmap
range is not included in KCORE_RAM, KCORE_VMALLOC ....
This adds KCORE_VMEMMAP if SPARSEMEM_VMEMMAP is used. By this, vmemmap
can be readable via /proc/kcore
Because it's not vmalloc area, vread/vwrite cannot be used. But the range
is static against the memory layout, this patch handles vmemmap area by
the same scheme with physical memory.
This patch assumes SPARSEMEM_VMEMMAP range is not in VMALLOC range. It's
correct now.
[akpm@linux-foundation.org: fix typo]
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Jiri Slaby <jirislaby@gmail.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: WANG Cong <xiyou.wangcong@gmail.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
For /proc/kcore, each arch registers its memory range by kclist_add().
In usual,
- range of physical memory
- range of vmalloc area
- text, etc...
are registered but "range of physical memory" has some troubles. It
doesn't updated at memory hotplug and it tend to include unnecessary
memory holes. Now, /proc/iomem (kernel/resource.c) includes required
physical memory range information and it's properly updated at memory
hotplug. Then, it's good to avoid using its own code(duplicating
information) and to rebuild kclist for physical memory based on
/proc/iomem.
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Jiri Slaby <jirislaby@gmail.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: WANG Cong <xiyou.wangcong@gmail.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Some 64bit arch has special segment for mapping kernel text. It should be
entried to /proc/kcore in addtion to direct-linear-map, vmalloc area.
This patch unifies KCORE_TEXT entry scattered under x86 and ia64.
I'm not familiar with other archs (mips has its own even after this patch)
but range of [_stext ..._end) is a valid area of text and it's not in
direct-map area, defining CONFIG_ARCH_PROC_KCORE_TEXT is only a necessary
thing to do.
Note: I left mips as it is now.
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: WANG Cong <xiyou.wangcong@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
