12 Apr, 2013
1 commit
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The smpboot threads rely on the park/unpark mechanism which binds per
cpu threads on a particular core. Though the functionality is racy:CPU0 CPU1 CPU2
unpark(T) wake_up_process(T)
clear(SHOULD_PARK) T runs
leave parkme() due to !SHOULD_PARK
bind_to(CPU2) BUG_ON(wrong CPU)We cannot let the tasks move themself to the target CPU as one of
those tasks is actually the migration thread itself, which requires
that it starts running on the target cpu right away.The solution to this problem is to prevent wakeups in park mode which
are not from unpark(). That way we can guarantee that the association
of the task to the target cpu is working correctly.Add a new task state (TASK_PARKED) which prevents other wakeups and
use this state explicitly for the unpark wakeup.Peter noticed: Also, since the task state is visible to userspace and
all the parked tasks are still in the PID space, its a good hint in ps
and friends that these tasks aren't really there for the moment.The migration thread has another related issue.
CPU0 CPU1
Bring up CPU2
create_thread(T)
park(T)
wait_for_completion()
parkme()
complete()
sched_set_stop_task()
schedule(TASK_PARKED)The sched_set_stop_task() call is issued while the task is on the
runqueue of CPU1 and that confuses the hell out of the stop_task class
on that cpu. So we need the same synchronizaion before
sched_set_stop_task().Reported-by: Dave Jones
Reported-and-tested-by: Dave Hansen
Reported-and-tested-by: Borislav Petkov
Acked-by: Peter Ziljstra
Cc: Srivatsa S. Bhat
Cc: dhillf@gmail.com
Cc: Ingo Molnar
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/alpine.LFD.2.02.1304091635430.21884@ionos
Signed-off-by: Thomas Gleixner
28 Jan, 2013
1 commit
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This is in preparation for the full dynticks feature. While
remotely reading the cputime of a task running in a full
dynticks CPU, we'll need to do some extra-computation. This
way we can account the time it spent tickless in userspace
since its last cputime snapshot.Signed-off-by: Frederic Weisbecker
Cc: Andrew Morton
Cc: Ingo Molnar
Cc: Li Zhong
Cc: Namhyung Kim
Cc: Paul E. McKenney
Cc: Paul Gortmaker
Cc: Peter Zijlstra
Cc: Steven Rostedt
Cc: Thomas Gleixner
18 Dec, 2012
6 commits
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Merge misc patches from Andrew Morton:
"Incoming:- lots of misc stuff
- backlight tree updates
- lib/ updates
- Oleg's percpu-rwsem changes
- checkpatch
- rtc
- aoe
- more checkpoint/restart support
I still have a pile of MM stuff pending - Pekka should be merging
later today after which that is good to go. A number of other things
are twiddling thumbs awaiting maintainer merges."* emailed patches from Andrew Morton : (180 commits)
scatterlist: don't BUG when we can trivially return a proper error.
docs: update documentation about /proc//fdinfo/ fanotify output
fs, fanotify: add @mflags field to fanotify output
docs: add documentation about /proc//fdinfo/ output
fs, notify: add procfs fdinfo helper
fs, exportfs: add exportfs_encode_inode_fh() helper
fs, exportfs: escape nil dereference if no s_export_op present
fs, epoll: add procfs fdinfo helper
fs, eventfd: add procfs fdinfo helper
procfs: add ability to plug in auxiliary fdinfo providers
tools/testing/selftests/kcmp/kcmp_test.c: print reason for failure in kcmp_test
breakpoint selftests: print failure status instead of cause make error
kcmp selftests: print fail status instead of cause make error
kcmp selftests: make run_tests fix
mem-hotplug selftests: print failure status instead of cause make error
cpu-hotplug selftests: print failure status instead of cause make error
mqueue selftests: print failure status instead of cause make error
vm selftests: print failure status instead of cause make error
ubifs: use prandom_bytes
mtd: nandsim: use prandom_bytes
... -
This allows us to print out eventpoll target file descriptor, events and
data, the /proc/pid/fdinfo/fd consists of| pos: 0
| flags: 02
| tfd: 5 events: 1d data: ffffffffffffffff enabled: 1[avagin@: fix for unitialized ret variable]
Signed-off-by: Cyrill Gorcunov
Acked-by: Pavel Emelyanov
Cc: Oleg Nesterov
Cc: Andrey Vagin
Cc: Al Viro
Cc: Alexey Dobriyan
Cc: James Bottomley
Cc: "Aneesh Kumar K.V"
Cc: Alexey Dobriyan
Cc: Matthew Helsley
Cc: "J. Bruce Fields"
Cc: "Aneesh Kumar K.V"
Cc: Tvrtko Ursulin
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
We display a list of supplementary group for each process in
/proc//status. However, we show only the first 32 groups, not all of
them.Although this is rare, but sometimes processes do have more than 32
supplementary groups, and this kernel limitation breaks user-space apps
that rely on the group list in /proc//status.Number 32 comes from the internal NGROUPS_SMALL macro which defines the
length for the internal kernel "small" groups buffer. There is no
apparent reason to limit to this value.This patch removes the 32 groups printing limit.
The Linux kernel limits the amount of supplementary groups by NGROUPS_MAX,
which is currently set to 65536. And this is the maximum count of groups
we may possibly print.Signed-off-by: Artem Bityutskiy
Acked-by: Serge E. Hallyn
Acked-by: Kees Cook
Cc:
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
It is currently impossible to examine the state of seccomp for a given
process. While attaching with gdb and attempting "call
prctl(PR_GET_SECCOMP,...)" will work with some situations, it is not
reliable. If the process is in seccomp mode 1, this query will kill the
process (prctl not allowed), if the process is in mode 2 with prctl not
allowed, it will similarly be killed, and in weird cases, if prctl is
filtered to return errno 0, it can look like seccomp is disabled.When reviewing the state of running processes, there should be a way to
externally examine the seccomp mode. ("Did this build of Chrome end up
using seccomp?" "Did my distro ship ssh with seccomp enabled?")This adds the "Seccomp" line to /proc/$pid/status.
Signed-off-by: Kees Cook
Reviewed-by: Cyrill Gorcunov
Cc: Andrea Arcangeli
Cc: James Morris
Acked-by: Serge E. Hallyn
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Without this patch it is really hard to interpret a bounding set, if
CAP_LAST_CAP is unknown for a current kernel.Non-existant capabilities can not be deleted from a bounding set with help
of prctl.E.g.: Here are two examples without/with this patch.
CapBnd: ffffffe0fdecffff
CapBnd: 00000000fdecffffI suggest to hide non-existent capabilities. Here is two reasons.
* It's logically and easier for using.
* It helps to checkpoint-restore capabilities of tasks, because tasks
can be restored on another kernel, where CAP_LAST_CAP is bigger.Signed-off-by: Andrew Vagin
Cc: Andrew G. Morgan
Reviewed-by: Serge E. Hallyn
Cc: Pavel Emelyanov
Reviewed-by: Kees Cook
Cc: KAMEZAWA Hiroyuki
Cc: James Morris
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Pull user namespace changes from Eric Biederman:
"While small this set of changes is very significant with respect to
containers in general and user namespaces in particular. The user
space interface is now complete.This set of changes adds support for unprivileged users to create user
namespaces and as a user namespace root to create other namespaces.
The tyranny of supporting suid root preventing unprivileged users from
using cool new kernel features is broken.This set of changes completes the work on setns, adding support for
the pid, user, mount namespaces.This set of changes includes a bunch of basic pid namespace
cleanups/simplifications. Of particular significance is the rework of
the pid namespace cleanup so it no longer requires sending out
tendrils into all kinds of unexpected cleanup paths for operation. At
least one case of broken error handling is fixed by this cleanup.The files under /proc//ns/ have been converted from regular files
to magic symlinks which prevents incorrect caching by the VFS,
ensuring the files always refer to the namespace the process is
currently using and ensuring that the ptrace_mayaccess permission
checks are always applied.The files under /proc//ns/ have been given stable inode numbers
so it is now possible to see if different processes share the same
namespaces.Through the David Miller's net tree are changes to relax many of the
permission checks in the networking stack to allowing the user
namespace root to usefully use the networking stack. Similar changes
for the mount namespace and the pid namespace are coming through my
tree.Two small changes to add user namespace support were commited here adn
in David Miller's -net tree so that I could complete the work on the
/proc//ns/ files in this tree.Work remains to make it safe to build user namespaces and 9p, afs,
ceph, cifs, coda, gfs2, ncpfs, nfs, nfsd, ocfs2, and xfs so the
Kconfig guard remains in place preventing that user namespaces from
being built when any of those filesystems are enabled.Future design work remains to allow root users outside of the initial
user namespace to mount more than just /proc and /sys."* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (38 commits)
proc: Usable inode numbers for the namespace file descriptors.
proc: Fix the namespace inode permission checks.
proc: Generalize proc inode allocation
userns: Allow unprivilged mounts of proc and sysfs
userns: For /proc/self/{uid,gid}_map derive the lower userns from the struct file
procfs: Print task uids and gids in the userns that opened the proc file
userns: Implement unshare of the user namespace
userns: Implent proc namespace operations
userns: Kill task_user_ns
userns: Make create_new_namespaces take a user_ns parameter
userns: Allow unprivileged use of setns.
userns: Allow unprivileged users to create new namespaces
userns: Allow setting a userns mapping to your current uid.
userns: Allow chown and setgid preservation
userns: Allow unprivileged users to create user namespaces.
userns: Ignore suid and sgid on binaries if the uid or gid can not be mapped
userns: fix return value on mntns_install() failure
vfs: Allow unprivileged manipulation of the mount namespace.
vfs: Only support slave subtrees across different user namespaces
vfs: Add a user namespace reference from struct mnt_namespace
...
29 Nov, 2012
1 commit
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We have thread_group_cputime() and thread_group_times(). The naming
doesn't provide enough information about the difference between
these two APIs.To lower the confusion, rename thread_group_times() to
thread_group_cputime_adjusted(). This name better suggests that
it's a version of thread_group_cputime() that does some stabilization
on the raw cputime values. ie here: scale on top of CFS runtime
stats and bound lower value for monotonicity.Signed-off-by: Frederic Weisbecker
Cc: Ingo Molnar
Cc: Peter Zijlstra
Cc: Thomas Gleixner
Cc: Steven Rostedt
Cc: Paul Gortmaker
20 Nov, 2012
1 commit
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Instead of using current_userns() use the userns of the opener
of the file so that if the file is passed between processes
the contents of the file do not change.Acked-by: Serge E. Hallyn
Signed-off-by: "Eric W. Biederman"
01 Jun, 2012
3 commits
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We would like to have an ability to restore command line arguments and
program environment pointers but first we need to obtain them somehow.
Thus we put these values into /proc/$pid/stat. The exit_code is needed to
restore zombie tasks.Signed-off-by: Cyrill Gorcunov
Acked-by: Kees Cook
Cc: Pavel Emelyanov
Cc: Serge Hallyn
Cc: KAMEZAWA Hiroyuki
Cc: Alexey Dobriyan
Cc: Tejun Heo
Cc: Andrew Vagin
Cc: Vasiliy Kulikov
Cc: Alexey Dobriyan
Cc: "Eric W. Biederman"
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
When we do checkpoint of a task we need to know the list of children the
task, has but there is no easy and fast way to generate reverse
parent->children chain from arbitrary (while a parent pid is
provided in "PPid" field of /proc//status).So instead of walking over all pids in the system (creating one big
process tree in memory, just to figure out which children a task has) --
we add explicit /proc//task//children entry, because the kernel
already has this kind of information but it is not yet exported.This is a first level children, not the whole process tree.
Signed-off-by: Cyrill Gorcunov
Reviewed-by: Oleg Nesterov
Reviewed-by: Kees Cook
Cc: Pavel Emelyanov
Cc: Serge Hallyn
Cc: KAMEZAWA Hiroyuki
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
- use int fpr priority and nice, since task_nice()/task_prio() return that
- field 24: get_mm_rss() returns unsigned long
Signed-off-by: Jan Engelhardt
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
16 May, 2012
1 commit
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Acked-by: Serge Hallyn
Signed-off-by: Eric W. Biederman
03 May, 2012
1 commit
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As a first step to converting struct cred to be all kuid_t and kgid_t
values convert the group values stored in group_info to always be
kgid_t values. Unless user namespaces are used this change should
have no effect.Acked-by: Serge Hallyn
Signed-off-by: Eric W. Biederman
29 Mar, 2012
1 commit
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bda7bad62bc4 ("procfs: speed up /proc/pid/stat, statm") broke /proc/statm
- 'text' is printed twice by mistake.Signed-off-by: KAMEZAWA Hiroyuki
Reported-by: Ulrich Drepper
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
24 Mar, 2012
1 commit
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Process accounting applications as top, ps visit some files under
/proc/. With seq_put_decimal_ull(), we can optimize /proc//stat
and /proc//statm files.This patch adds
- seq_put_decimal_ll() for signed values.
- allow delimiter == 0.
- convert seq_printf() to seq_put_decimal_ull/ll in /proc/stat, statm.Test result on a system with 2000+ procs.
Before patch:
[kamezawa@bluextal test]$ top -b -n 1 | wc -l
2223
[kamezawa@bluextal test]$ time top -b -n 1 > /dev/nullreal 0m0.675s
user 0m0.044s
sys 0m0.121s[kamezawa@bluextal test]$ time ps -elf > /dev/null
real 0m0.236s
user 0m0.056s
sys 0m0.176sAfter patch:
kamezawa@bluextal ~]$ time top -b -n 1 > /dev/nullreal 0m0.657s
user 0m0.052s
sys 0m0.100s[kamezawa@bluextal ~]$ time ps -elf > /dev/null
real 0m0.198s
user 0m0.050s
sys 0m0.145sConsidering top, ps tend to scan /proc periodically, this will reduce cpu
consumption by top/ps to some extent.[akpm@linux-foundation.org: checkpatch fixes]
Signed-off-by: KAMEZAWA Hiroyuki
Cc: Alexey Dobriyan
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
15 Jan, 2012
1 commit
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* 'for-linus' of git://selinuxproject.org/~jmorris/linux-security:
capabilities: remove __cap_full_set definition
security: remove the security_netlink_recv hook as it is equivalent to capable()
ptrace: do not audit capability check when outputing /proc/pid/stat
capabilities: remove task_ns_* functions
capabitlies: ns_capable can use the cap helpers rather than lsm call
capabilities: style only - move capable below ns_capable
capabilites: introduce new has_ns_capabilities_noaudit
capabilities: call has_ns_capability from has_capability
capabilities: remove all _real_ interfaces
capabilities: introduce security_capable_noaudit
capabilities: reverse arguments to security_capable
capabilities: remove the task from capable LSM hook entirely
selinux: sparse fix: fix several warnings in the security server cod
selinux: sparse fix: fix warnings in netlink code
selinux: sparse fix: eliminate warnings for selinuxfs
selinux: sparse fix: declare selinux_disable() in security.h
selinux: sparse fix: move selinux_complete_init
selinux: sparse fix: make selinux_secmark_refcount static
SELinux: Fix RCU deref check warning in sel_netport_insert()Manually fix up a semantic mis-merge wrt security_netlink_recv():
- the interface was removed in commit fd7784615248 ("security: remove
the security_netlink_recv hook as it is equivalent to capable()")- a new user of it appeared in commit a38f7907b926 ("crypto: Add
userspace configuration API")causing no automatic merge conflict, but Eric Paris pointed out the
issue.
13 Jan, 2012
1 commit
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The mm->start_code/end_code, mm->start_data/end_data, mm->start_brk are
involved into calculation of program text/data segment sizes (which might
be seen in /proc//statm) and into brk() call final address.For restore we need to know all these values. While
mm->start_code/end_code already present in /proc/$pid/stat, the rest
members are not, so this patch brings them in.The restore procedure of these members is addressed in another patch using
prctl().Signed-off-by: Cyrill Gorcunov
Acked-by: Serge Hallyn
Reviewed-by: Kees Cook
Reviewed-by: KAMEZAWA Hiroyuki
Cc: Alexey Dobriyan
Cc: Tejun Heo
Cc: Andrew Vagin
Cc: Vasiliy Kulikov
Cc: Alexey Dobriyan
Cc: "Eric W. Biederman"
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
06 Jan, 2012
1 commit
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Reading /proc/pid/stat of another process checks if one has ptrace permissions
on that process. If one does have permissions it outputs some data about the
process which might have security and attack implications. If the current
task does not have ptrace permissions the read still works, but those fields
are filled with inocuous (0) values. Since this check and a subsequent denial
is not a violation of the security policy we should not audit such denials.This can be quite useful to removing ptrace broadly across a system without
flooding the logs when ps is run or something which harmlessly walks proc.Signed-off-by: Eric Paris
Acked-by: Serge E. Hallyn
15 Dec, 2011
1 commit
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Make cputime_t and cputime64_t nocast to enable sparse checking to
detect incorrect use of cputime. Drop the cputime macros for simple
scalar operations. The conversion macros are still needed.Signed-off-by: Martin Schwidefsky
23 Jun, 2011
1 commit
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tracehook.h is on the way out. Rename tracehook_tracer_task() to
ptrace_parent() and move it from tracehook.h to ptrace.h.Signed-off-by: Tejun Heo
Cc: Christoph Hellwig
Cc: John Johansen
Cc: Stephen Smalley
Signed-off-by: Oleg Nesterov
27 May, 2011
1 commit
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No need for this local array to be writable, so mark it const.
Signed-off-by: Mike Frysinger
Cc: Alexey Dobriyan
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
24 Mar, 2011
1 commit
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While mm->start_stack was protected from cross-uid viewing (commit
f83ce3e6b02d5 ("proc: avoid information leaks to non-privileged
processes")), the start_code and end_code values were not. This would
allow the text location of a PIE binary to leak, defeating ASLR.Note that the value "1" is used instead of "0" for a protected value since
"ps", "killall", and likely other readers of /proc/pid/stat, take
start_code of "0" to mean a kernel thread and will misbehave. Thanks to
Brad Spengler for pointing this out.Addresses CVE-2011-0726
Signed-off-by: Kees Cook
Cc:
Cc: Alexey Dobriyan
Cc: David Howells
Cc: Eugene Teo
Cc: Martin Schwidefsky
Cc: Brad Spengler
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
15 Feb, 2011
1 commit
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task_show_regs used to be a debugging aid in the early bringup days
of Linux on s390. /proc//status is a world readable file, it
is not a good idea to show the registers of a process. The only
correct fix is to remove task_show_regs.Reported-by: Al Viro
Signed-off-by: Martin Schwidefsky
Signed-off-by: Linus Torvalds
14 Jan, 2011
2 commits
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For string without format specifiers, use seq_puts().
For seq_printf("\n"), use seq_putc('\n').text data bss dec hex filename
61866 488 112 62466 f402 fs/proc/proc.o
61729 488 112 62329 f379 fs/proc/proc.o
----------------------------------------------------
-139Signed-off-by: Alexey Dobriyan
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
/proc/*/statm code needlessly truncates data from unsigned long to int.
One needs only 8+ TB of RAM to make truncation visible.Signed-off-by: Alexey Dobriyan
Reviewed-by: WANG Cong
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
30 Jul, 2010
1 commit
-
It's possible for get_task_cred() as it currently stands to 'corrupt' a set of
credentials by incrementing their usage count after their replacement by the
task being accessed.What happens is that get_task_cred() can race with commit_creds():
TASK_1 TASK_2 RCU_CLEANER
-->get_task_cred(TASK_2)
rcu_read_lock()
__cred = __task_cred(TASK_2)
-->commit_creds()
old_cred = TASK_2->real_cred
TASK_2->real_cred = ...
put_cred(old_cred)
call_rcu(old_cred)
[__cred->usage == 0]
get_cred(__cred)
[__cred->usage == 1]
rcu_read_unlock()
-->put_cred_rcu()
[__cred->usage == 1]
panic()However, since a tasks credentials are generally not changed very often, we can
reasonably make use of a loop involving reading the creds pointer and using
atomic_inc_not_zero() to attempt to increment it if it hasn't already hit zero.If successful, we can safely return the credentials in the knowledge that, even
if the task we're accessing has released them, they haven't gone to the RCU
cleanup code.We then change task_state() in procfs to use get_task_cred() rather than
calling get_cred() on the result of __task_cred(), as that suffers from the
same problem.Without this change, a BUG_ON in __put_cred() or in put_cred_rcu() can be
tripped when it is noticed that the usage count is not zero as it ought to be,
for example:kernel BUG at kernel/cred.c:168!
invalid opcode: 0000 [#1] SMP
last sysfs file: /sys/kernel/mm/ksm/run
CPU 0
Pid: 2436, comm: master Not tainted 2.6.33.3-85.fc13.x86_64 #1 0HR330/OptiPlex
745
RIP: 0010:[] [] __put_cred+0xc/0x45
RSP: 0018:ffff88019e7e9eb8 EFLAGS: 00010202
RAX: 0000000000000001 RBX: ffff880161514480 RCX: 00000000ffffffff
RDX: 00000000ffffffff RSI: ffff880140c690c0 RDI: ffff880140c690c0
RBP: ffff88019e7e9eb8 R08: 00000000000000d0 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000040 R12: ffff880140c690c0
R13: ffff88019e77aea0 R14: 00007fff336b0a5c R15: 0000000000000001
FS: 00007f12f50d97c0(0000) GS:ffff880007400000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f8f461bc000 CR3: 00000001b26ce000 CR4: 00000000000006f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Process master (pid: 2436, threadinfo ffff88019e7e8000, task ffff88019e77aea0)
Stack:
ffff88019e7e9ec8 ffffffff810698cd ffff88019e7e9ef8 ffffffff81069b45
ffff880161514180 ffff880161514480 ffff880161514180 0000000000000000
ffff88019e7e9f28 ffffffff8106aace 0000000000000001 0000000000000246
Call Trace:
[] put_cred+0x13/0x15
[] commit_creds+0x16b/0x175
[] set_current_groups+0x47/0x4e
[] sys_setgroups+0xf6/0x105
[] system_call_fastpath+0x16/0x1b
Code: 48 8d 71 ff e8 7e 4e 15 00 85 c0 78 0b 8b 75 ec 48 89 df e8 ef 4a 15 00
48 83 c4 18 5b c9 c3 55 8b 07 8b 07 48 89 e5 85 c0 74 04 0b eb fe 65 48 8b
04 25 00 cc 00 00 48 3b b8 58 04 00 00 75
RIP [] __put_cred+0xc/0x45
RSP
---[ end trace df391256a100ebdd ]---Signed-off-by: David Howells
Acked-by: Jiri Olsa
Signed-off-by: Linus Torvalds
28 May, 2010
1 commit
-
Now that task->signal can't go away get_nr_threads() doesn't need
->siglock to read signal->count.Also, make it inline, move into sched.h, and convert 2 other proc users of
signal->count to use this (now trivial) helper.Henceforth get_nr_threads() is the only valid user of signal->count, we
are ready to turn it into "int nr_threads" or, perhaps, kill it.Signed-off-by: Oleg Nesterov
Cc: Alexey Dobriyan
Cc: David Howells
Cc: "Eric W. Biederman"
Acked-by: Roland McGrath
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
12 May, 2010
1 commit
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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//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
Cc: Stefani Seibold
Cc: KOSAKI Motohiro
Cc: Michal Simek
Cc: Ingo Molnar
Cc:
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
30 Mar, 2010
1 commit
-
…it slab.h inclusion from percpu.h
percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files. percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.percpu.h -> slab.h dependency is about to be removed. Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability. As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.http://userweb.kernel.org/~tj/misc/slabh-sweep.py
The script does the followings.
* Scan files for gfp and slab usages and update includes such that
only the necessary includes are there. ie. if only gfp is used,
gfp.h, if slab is used, slab.h.* When the script inserts a new include, it looks at the include
blocks and try to put the new include such that its order conforms
to its surrounding. It's put in the include block which contains
core kernel includes, in the same order that the rest are ordered -
alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
doesn't seem to be any matching order.* If the script can't find a place to put a new include (mostly
because the file doesn't have fitting include block), it prints out
an error message indicating which .h file needs to be added to the
file.The conversion was done in the following steps.
1. The initial automatic conversion of all .c files updated slightly
over 4000 files, deleting around 700 includes and adding ~480 gfp.h
and ~3000 slab.h inclusions. The script emitted errors for ~400
files.2. Each error was manually checked. Some didn't need the inclusion,
some needed manual addition while adding it to implementation .h or
embedding .c file was more appropriate for others. This step added
inclusions to around 150 files.3. The script was run again and the output was compared to the edits
from #2 to make sure no file was left behind.4. Several build tests were done and a couple of problems were fixed.
e.g. lib/decompress_*.c used malloc/free() wrappers around slab
APIs requiring slab.h to be added manually.5. The script was run on all .h files but without automatically
editing them as sprinkling gfp.h and slab.h inclusions around .h
files could easily lead to inclusion dependency hell. Most gfp.h
inclusion directives were ignored as stuff from gfp.h was usually
wildly available and often used in preprocessor macros. Each
slab.h inclusion directive was examined and added manually as
necessary.6. percpu.h was updated not to include slab.h.
7. Build test were done on the following configurations and failures
were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my
distributed build env didn't work with gcov compiles) and a few
more options had to be turned off depending on archs to make things
build (like ipr on powerpc/64 which failed due to missing writeq).* x86 and x86_64 UP and SMP allmodconfig and a custom test config.
* powerpc and powerpc64 SMP allmodconfig
* sparc and sparc64 SMP allmodconfig
* ia64 SMP allmodconfig
* s390 SMP allmodconfig
* alpha SMP allmodconfig
* um on x86_64 SMP allmodconfig8. percpu.h modifications were reverted so that it could be applied as
a separate patch and serve as bisection point.Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.Signed-off-by: Tejun Heo <tj@kernel.org>
Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
07 Mar, 2010
1 commit
-
Make sure compiler won't do weird things with limits. E.g. fetching them
twice may return 2 different values after writable limits are implemented.I.e. either use rlimit helpers added in commit 3e10e716abf3 ("resource:
add helpers for fetching rlimits") or ACCESS_ONCE if not applicable.Signed-off-by: Jiri Slaby
Cc: Alexander Viro
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
25 Feb, 2010
1 commit
-
Add lockdep-ified RCU primitives to alloc_fd(), files_fdtable()
and fcheck_files().Cc: Alexander Viro
Signed-off-by: Paul E. McKenney
Cc: laijs@cn.fujitsu.com
Cc: dipankar@in.ibm.com
Cc: mathieu.desnoyers@polymtl.ca
Cc: josh@joshtriplett.org
Cc: dvhltc@us.ibm.com
Cc: niv@us.ibm.com
Cc: peterz@infradead.org
Cc: rostedt@goodmis.org
Cc: Valdis.Kletnieks@vt.edu
Cc: dhowells@redhat.com
Cc: Alexander Viro
LKML-Reference:
Signed-off-by: Ingo Molnar
12 Jan, 2010
1 commit
-
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/sec128.859521955 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/sec152.277819582 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
Cc: Stefani Seibold
Cc: Ingo Molnar
Cc: Peter Zijlstra
Cc: Alexey Dobriyan
Cc: "Eric W. Biederman"
Cc: Randy Dunlap
Cc: Andrew Morton
Cc: Andi Kleen
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
17 Dec, 2009
2 commits
-
Since everybody is lazy and prone to forgetting things, make the
compiler help us a bit.Signed-off-by: Peter Zijlstra
LKML-Reference:
Signed-off-by: Ingo Molnar -
Neglected because its hidden... (who reads comments anyway)
Signed-off-by: Peter Zijlstra
LKML-Reference:
Signed-off-by: Ingo Molnar
06 Dec, 2009
1 commit
-
…/git/tip/linux-2.6-tip
* 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (35 commits)
sched, cputime: Introduce thread_group_times()
sched, cputime: Cleanups related to task_times()
Revert "sched, x86: Optimize branch hint in __switch_to()"
sched: Fix isolcpus boot option
sched: Revert 498657a478c60be092208422fefa9c7b248729c2
sched, time: Define nsecs_to_jiffies()
sched: Remove task_{u,s,g}time()
sched: Introduce task_times() to replace task_{u,s}time() pair
sched: Limit the number of scheduler debug messages
sched.c: Call debug_show_all_locks() when dumping all tasks
sched, x86: Optimize branch hint in __switch_to()
sched: Optimize branch hint in context_switch()
sched: Optimize branch hint in pick_next_task_fair()
sched_feat_write(): Update ppos instead of file->f_pos
sched: Sched_rt_periodic_timer vs cpu hotplug
sched, kvm: Fix race condition involving sched_in_preempt_notifers
sched: More generic WAKE_AFFINE vs select_idle_sibling()
sched: Cleanup select_task_rq_fair()
sched: Fix granularity of task_u/stime()
sched: Fix/add missing update_rq_clock() calls
...
03 Dec, 2009
1 commit
-
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//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
Acked-by: Peter Zijlstra
Cc: Spencer Candland
Cc: Americo Wang
Cc: Oleg Nesterov
Cc: Balbir Singh
Cc: Stanislaw Gruszka
LKML-Reference:
Signed-off-by: Ingo Molnar
26 Nov, 2009
2 commits
-
Now all task_{u,s}time() pairs are replaced by task_times().
And task_gtime() is too simple to be an inline function.Cleanup them all.
Signed-off-by: Hidetoshi Seto
Acked-by: Peter Zijlstra
Cc: Stanislaw Gruszka
Cc: Spencer Candland
Cc: Oleg Nesterov
Cc: Balbir Singh
Cc: Americo Wang
LKML-Reference:
Signed-off-by: Ingo Molnar -
Functions task_{u,s}time() are called in pair in almost all
cases. However task_stime() is implemented to call task_utime()
from its inside, so such paired calls run task_utime() twice.It means we do heavy divisions (div_u64 + do_div) twice to get
utime and stime which can be obtained at same time by one set
of divisions.This patch introduces a function task_times(*tsk, *utime,
*stime) to retrieve utime and stime at once in better, optimized
way.Signed-off-by: Hidetoshi Seto
Acked-by: Peter Zijlstra
Cc: Stanislaw Gruszka
Cc: Spencer Candland
Cc: Oleg Nesterov
Cc: Balbir Singh
Cc: Americo Wang
LKML-Reference:
Signed-off-by: Ingo Molnar