It's a feature of PTRACE_SEIZE. So we need to do something, only
if we want to change the state.
[xemul: If task _was_ in stopped state before dump and we want them
to stay alive after dump, the existing code queues one more STOP
to it. This affects subsequent dump, as we seize a stopped task
with STOP in queue.
One more item in TODO list -- support stopped tasks with STOP in
queue :)
]
Signed-off-by: Andrew Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
We read /proc/pid/status to determine a task state, but if a task is
running in this moment, its state may be changed.
This patch stops tasks before reading their /proc/pid/status
Signed-off-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
When pr_perror is used, an error message is appended with a comma
and an strerror(errno), so we should not put a period at the end,
otherwise we'll end up with something like this:
Error: Can't bind.: Permission denied
Found by git grep -w pr_perror | grep '\."'
Signed-off-by: Kir Kolyshkin <kir@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
crtools.h is too heavy to be included in many sources
Signed-off-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
Currently we catch processes on the exit point from sigreturn.
If a task must be restored in the stopped state, we can send SIGSTOP
before detaching from it.
v2: add more descriptive comment about skipping SIGSTOP in ptrace.c
Signed-off-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
According to the commit message in the kernel git, a new trap flag
JOBCTL_TRAP_INTERRUPT is added, which is set on PTRACE_INTERRUPT and
cleared when any trap happens.
Currently we have a race window beetwen PTRACE_CONT and
PTRACE_INTERRUPT. If a process stops before PTRACE_INTERRUPT,
the flag JOBCTL_TRAP_INTERRUPT will be set once again.
https://bugzilla.openvz.org/show_bug.cgi?id=2569
Signed-off-by: Andrey Vagin <avagin@openvz.org>
Acked-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
This is less useful than fixing typos in output messages, but anyway.
Signed-off-by: Kir Kolyshkin <kir@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
The ptrace seize may fail for various reasons. E.g. -- no enough perms
to get the ptrace access to the tasks, or various selinux restrictions.
Print what exactly has happened when ptrace failed.
Reported-by: Kevin Wilson <wkevils@gmail.com>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
* The following files goes into the directory arch/x86/include/asm unmodified:
- include/atomic.h,
- include/linkage.h,
- include/memcpy_64.h,
- include/types.h,
- include/bitops.h,
- pie/parasite-head-x86-64.S,
- include/processor-flags.h,
- include/syscall-x86-64.def.
* Changed include directives in the source files that include the headers
listed above.
* Modified build scripts to reflect the source moves.
Signed-off-by: Alexander Kartashov <alekskartashov@parallels.com>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
Since 3.4-rc the seize-devel flag is removed, the stop event
is renamed (great) and the way si_code should be parsed has
been fixed.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
Command below was executed several times:
sed 's/\(pr_.*[^%,x,X]\)\(\%[0-9,l,L]*x\)/\10x\2/g' -i *.c
Signed-off-by: Stanislav Kinsbursky <skinsbursky@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
I store them on _entry since sids can only be inherited or
set to current's pid. Thus the best we can do it restore sids
at fork time, thus save them in the image we use to fork.
Maybe when we submit patches that will give us ability to set
arbitrary pgid and sid we'll change this, but this is in the
future.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
This is not very good practice :) Just leave them in the state they've been to before
dumping. Plz note, that tasks segfault for some reason after unseizeing, but this is
another story.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
The messages are filtered by their type
LOG_MSG - plain messages, they escape any (!) log level
filtration and go to stdout
LOG_ERROR - error messages
LOG_WARN - warning messages
LOG_INFO - informative messages
LOG_DEBUG - debug messages
By default the LOG_WARN log level is used, thus LOG_INFO
and LOG_DEBUG messages will not appear in output stream.
pr_panic helper was replaced with pr_err, pr_warning
shorthanded to pr_warn and old printk if rather pr_msg
now.
Because we share messages between "show" and "dump" actions,
before the "show" action proceed we need to tune up
log level and set it to LOG_INFO.
Also note that printing of VMA and siginfo now
became LOG_INFO messages, it was not that correct
to print them regardless the log level.
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Acked-by: Pavel Emelyanov <xemul@parallels.com>
When seizing a task and waiting for it to stop, we can receive an event
from kernel, that the task didn't stop, but caught a signal. Don't treat
this as an error, let the victim handle it and proceed.
The transition/fork test should work OK now.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Remove CR_TASK_XXX states, use the TASK_XXX ones (for image). This is
required to unseize tasks properly in the next patches.
Plus, make sure that pstree_list and the seized set coincide (i.e.
handle error in collect_task).
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
While we try to seize task it can die and give its pid to
somebody else. This can break pstree consistency. Check for
parent being valid after task is seized.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Move proc checks for Z-state into seize_task().
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
- make control block to keep all information
needed to run injected syscall and parasite
blobs
- add ptrace_swap_area helper
- handle both parasite engine calls and injected
syscalls by single __parasite_execute function
- drop jerr() usage
- bring back handling of inflight signals from
original program inside parasite code
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
According to Oleg the PTRACE_KILL doesn't and was-not-supposed-to work.
Thus, kill tasks to final state explicitly and just detach from them.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Strange fact, but a task seems to live for some time after PTRACE_KILL :(
Don't know yet why this happens, I'm poking Oleg on that, but this one makes
it die right at once.
The streaming file read test passes after this.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
This commit brings the former "Rewrite task/threads stopping engine"
commit back. Handling it separately is too complex so better try
to handle it in-place.
Note some tests might fault, it's expected.
---
Stopping tasks with STOP and proceeding with SEIZE is actually excessive --
the SEIZE if enough. Moreover, just killing a task with STOP is also racy,
since task should be given some time to come to sleep before its proc
can be parsed.
Rewrite all this code to SEIZE task and all its threads from the very beginning.
With this we can distinguish stopped task state and migrate it properly (not
supported now, need to implement).
This thing however has one BIG problem -- after we SEIZE-d a task we should
seize
it's threads, but we should do it in a loop -- reading /proc/pid/task and
seizing
them again and again, until the contents of this dir stops changing (not done
now).
Besides, after we seized a task and all its threads we cannot scan it's children
list once -- task can get reparented to init and any task's child can call clone
with CLONE_PARENT flag thus repopulating the children list of the already seized
task (not done also)
This patch is ugly, yes, but splitting it doesn't help to review it much, sorry
:(
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Stopping tasks with STOP and proceeding with SEIZE is actually excessive --
the SEIZE if enough. Moreover, just killing a task with STOP is also racy,
since task should be given some time to come to sleep before its proc
can be parsed.
Rewrite all this code to SEIZE task and all its threads from the very beginning.
With this we can distinguish stopped task state and migrate it properly (not
supported now, need to implement).
This thing however has one BIG problem -- after we SEIZE-d a task we should seize
it's threads, but we should do it in a loop -- reading /proc/pid/task and seizing
them again and again, until the contents of this dir stops changing (not done now).
Besides, after we seized a task and all its threads we cannot scan it's children
list once -- task can get reparented to init and any task's child can call clone
with CLONE_PARENT flag thus repopulating the children list of the already seized
task (not done also)
This patch is ugly, yes, but splitting it doesn't help to review it much, sorry :(
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
This is a standard convention to print error message (i.e. strerror(errno))
at the end of line, like this:
Cannot remove file: Permission denied
So pr_perror is fixed to follow this convention (using GNU extension
%m helps a lot here). Unfortunately, due to this we have to make
pr_perror() print a new line character, too, so we had to strip it
from the all pr_perror() invocations.
That (appending a newline) also makes pr_perror() a black sheep
in the herd of pr_* helpers, but what can we do? Worst case scenario
is an extra newline after an error message, not too harmful.
An alternative approach (stripping the newline from the passed format
string and re-adding it) was discussed thoroughly, and it was decided
that such a hack looks a bit too dirty.
Signed-off-by: Kir Kolyshkin <kir@openvz.org>
Acked-by: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
I'd appreciate if we get rid of these misleading macros at all eventually...
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Introduce a helper for walking the list and sending signals.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
