Tejun Heo
fb1d910c17
ptrace: implement TRAP_NOTIFY and use it for group stop events ...
Currently there's no way for ptracer to find out whether group stop
finished other than polling with INTERRUPT - GETSIGINFO - CONT
sequence. This patch implements group stop notification for ptracer
using STOP traps.
When group stop state of a seized tracee changes, JOBCTL_TRAP_NOTIFY
is set, which schedules a STOP trap which is sticky - it isn't cleared
by other traps and at least one STOP trap will happen eventually.
STOP trap is synchronization point for event notification and the
tracer can determine the current group stop state by looking at the
signal number portion of exit code (si_status from waitid(2) or
si_code from PTRACE_GETSIGINFO).
Notifications are generated both on start and end of group stops but,
because group stop participation always happens before STOP trap, this
doesn't cause an extra trap while tracee is participating in group
stop. The symmetry will be useful later.
Note that this notification works iff tracee is not trapped.
Currently there is no way to be notified of group stop state changes
while tracee is trapped. This will be addressed by a later patch.
An example program follows.
#define PTRACE_SEIZE 0x4206
#define PTRACE_INTERRUPT 0x4207
#define PTRACE_SEIZE_DEVEL 0x80000000
static const struct timespec ts1s = { .tv_sec = 1 };
int main(int argc, char **argv)
{
pid_t tracee, tracer;
int i;
tracee = fork();
if (!tracee)
while (1)
pause();
tracer = fork();
if (!tracer) {
siginfo_t si;
ptrace(PTRACE_SEIZE, tracee, NULL,
(void *)(unsigned long)PTRACE_SEIZE_DEVEL);
ptrace(PTRACE_INTERRUPT, tracee, NULL, NULL);
repeat:
waitid(P_PID, tracee, NULL, WSTOPPED);
ptrace(PTRACE_GETSIGINFO, tracee, NULL, &si);
if (!si.si_code) {
printf("tracer: SIG %d\n", si.si_signo);
ptrace(PTRACE_CONT, tracee, NULL,
(void *)(unsigned long)si.si_signo);
goto repeat;
}
printf("tracer: stopped=%d signo=%d\n",
si.si_signo != SIGTRAP, si.si_signo);
ptrace(PTRACE_CONT, tracee, NULL, NULL);
goto repeat;
}
for (i = 0; i < 3; i++) {
nanosleep(&ts1s, NULL);
printf("mother: SIGSTOP\n");
kill(tracee, SIGSTOP);
nanosleep(&ts1s, NULL);
printf("mother: SIGCONT\n");
kill(tracee, SIGCONT);
}
nanosleep(&ts1s, NULL);
kill(tracer, SIGKILL);
kill(tracee, SIGKILL);
return 0;
}
In the above program, tracer keeps tracee running and gets
notification of each group stop state changes.
# ./test-notify
tracer: stopped=0 signo=5
mother: SIGSTOP
tracer: SIG 19
tracer: stopped=1 signo=19
mother: SIGCONT
tracer: stopped=0 signo=5
tracer: SIG 18
mother: SIGSTOP
tracer: SIG 19
tracer: stopped=1 signo=19
mother: SIGCONT
tracer: stopped=0 signo=5
tracer: SIG 18
mother: SIGSTOP
tracer: SIG 19
tracer: stopped=1 signo=19
mother: SIGCONT
tracer: stopped=0 signo=5
tracer: SIG 18
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
2011-06-16 21:41:53 +02:00
Fix common misspellings
2011-03-31 11:26:23 -03:00
perf: Fix SIGIO handling
2011-05-28 17:04:59 +02:00
Merge branch 'trivial' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild-2.6
2011-03-20 18:14:55 -07:00
irq: Remove smp_affinity_list when unregister irq proc
2011-05-26 13:15:28 +02:00
PM / Hibernate: Update kerneldoc comments in hibernate.c
2011-05-24 23:36:06 +02:00
hrtimers: Avoid touching inactive timer bases
2011-05-23 13:59:54 +02:00
ftrace: Add internal recursive checks
2011-05-25 22:13:49 -04:00
netlink: kill loginuid/sessionid/sid members from struct netlink_skb_parms
2011-03-03 10:55:40 -08:00
audit: make functions static
2010-10-30 01:42:19 -04:00
Fix common misspellings
2011-03-31 11:26:23 -03:00
kill path_lookup()
2011-03-14 09:15:23 -04:00
netlink: kill loginuid/sessionid/sid members from struct netlink_skb_parms
2011-03-03 10:55:40 -08:00
audit: acquire creds selectively to reduce atomic op overhead
2011-04-27 15:11:03 +02:00
memcg: remove direct page_cgroup-to-page pointer
2011-03-23 19:46:28 -07:00
Merge branch 'master' into next
2011-05-19 18:51:57 +10:00
cgroup: remove the ns_cgroup
2011-05-26 17:12:34 -07:00
cgroups: add per-thread subsystem callbacks
2011-05-26 17:12:34 -07:00
Merge git://git.kernel.org/pub/scm/linux/kernel/git/cmetcalf/linux-tile
2011-05-25 15:35:32 -07:00
llseek: automatically add .llseek fop
2010-10-15 15:53:27 +02:00
Fix common misspellings
2011-03-31 11:26:23 -03:00
cpuset: Fix cpuset_cpus_allowed_fallback(), don't update tsk->rt.nr_cpus_allowed
2011-05-28 17:02:57 +02:00
crash_dump: export is_kdump_kernel to modules, consolidate elfcorehdr_addr, setup_elfcorehdr and saved_max_pfn
2011-03-23 19:47:19 -07:00
Merge branch 'docs-move' of git://git.kernel.org/pub/scm/linux/kernel/git/rdunlap/linux-docs
2011-05-27 10:25:02 -07:00
Merge branch 'ptrace' of git://git.kernel.org/pub/scm/linux/kernel/git/oleg/misc
2011-05-20 13:33:21 -07:00
extable, core_kernel_data(): Make sure all archs define _sdata
2011-05-20 08:56:56 +02:00
mm: Fix boot crash in mm_alloc()
2011-05-29 11:32:28 -07:00
Freezer: Use SMP barriers
2011-05-17 23:19:17 +02:00
futex: Set FLAGS_HAS_TIMEOUT during futex_wait restart setup
2011-04-15 16:34:32 +02:00
userns: user namespaces: convert several capable() calls
2011-03-23 19:47:08 -07:00
userns: user namespaces: convert several capable() calls
2011-03-23 19:47:08 -07:00
hrtimers: Fix typo causing erratic timers
2011-05-25 15:31:58 -07:00
watchdog, hung_task_timeout: Add Kconfig configurable default
2011-04-28 09:13:17 +02:00
irq_work: Use per cpu atomics instead of regular atomics
2010-12-18 15:54:48 +01:00
jump_label: Check entries limit in __jump_label_update
2011-05-25 19:56:36 -04:00
Merge branch 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
2011-03-25 17:52:22 -07:00
arch:Kconfig.locks Remove unused config option.
2011-04-10 17:01:05 +02:00
PM: Remove sysdev suspend, resume and shutdown operations
2011-05-11 21:37:15 +02:00
kfifo: fix scatterlist usage
2010-10-01 10:50:58 -07:00
Merge branch 'next' into for-linus
2011-05-24 22:55:24 +10:00
Merge branch 'for-2.6.38' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu
2011-01-07 17:02:58 -08:00
kernel/ksysfs.c: expose file_caps_enabled in sysfs
2011-04-19 16:45:51 -07:00
cpuset: Fix cpuset_cpus_allowed_fallback(), don't update tsk->rt.nr_cpus_allowed
2011-05-28 17:02:57 +02:00
Fix common misspellings
2011-03-31 11:26:23 -03:00
lockdep: Remove cmpxchg to update nr_chain_hlocks
2011-04-22 11:06:59 +02:00
lockdep: Remove unused 'factor' variable from lockdep_stats_show()
2011-03-23 13:54:47 +01:00
cgroup: remove the ns_cgroup
2011-05-26 17:12:34 -07:00
Merge branch 'staging-next' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging-2.6
2011-05-23 12:49:28 -07:00
mutex: Use p->on_cpu for the adaptive spin
2011-04-14 08:52:33 +02:00
mutex: Use p->on_cpu for the adaptive spin
2011-04-14 08:52:33 +02:00
lockdep, mutex: provide mutex_lock_nest_lock
2011-05-25 08:39:17 -07:00
mutex: Use p->on_cpu for the adaptive spin
2011-04-14 08:52:33 +02:00
cgroup: remove the ns_cgroup
2011-05-26 17:12:34 -07:00
Fix common misspellings
2011-03-31 11:26:23 -03:00
move x86 specific oops=panic to generic code
2011-03-22 17:44:11 -07:00
params.c: Use new strtobool function to process boolean inputs
2011-05-19 16:55:28 +09:30
next_pidmap: fix overflow condition
2011-04-18 10:35:30 -07:00
pidns: call pid_ns_prepare_proc() from create_pid_namespace()
2011-03-23 19:46:58 -07:00
Merge branch 'idle-release' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux-idle-2.6
2011-05-29 11:18:09 -07:00
hrtimers: Avoid touching inactive timer bases
2011-05-23 13:59:54 +02:00
posix-timers: RCU conversion
2011-05-24 12:10:51 +02:00
printk: allocate kernel log buffer earlier
2011-05-25 08:39:48 -07:00
kernel/profile.c: remove some duplicate code from profile_hits()
2011-05-26 17:12:37 -07:00
ptrace: implement PTRACE_INTERRUPT
2011-06-16 21:41:53 +02:00
kernel/range.c: fix clean_sort_range() for the case of full array
2010-11-12 07:55:31 -08:00
rcu: Use WARN_ON_ONCE for DEBUG_OBJECTS_RCU_HEAD warnings
2011-05-05 23:16:57 -07:00
sanitize <linux/prefetch.h> usage
2011-05-20 12:50:29 -07:00
rcu: Converge TINY_RCU expedited and normal boosting
2011-05-05 23:16:58 -07:00
rcu: mark rcutorture boosting callback as being on-stack
2011-05-05 23:16:57 -07:00
rcu: Cure load woes
2011-05-31 10:01:48 +02:00
rcu: Remove waitqueue usage for cpu, node, and boost kthreads
2011-05-28 17:41:52 +02:00
rcu: Cure load woes
2011-05-31 10:01:48 +02:00
rcu: Decrease memory-barrier usage based on semi-formal proof
2011-05-26 09:42:23 -07:00
Clean up relay_alloc_page_array() slightly by using vzalloc rather than vmalloc and memset
2010-11-05 08:21:34 -07:00
memcg: res_counter_read_u64(): fix potential races on 32-bit machines
2011-03-23 19:46:22 -07:00
resources: add arch hook for preventing allocation in reserved areas
2010-12-17 10:01:09 -08:00
rtmutex: Simplify PI algorithm and make highest prio task get lock
2011-01-27 21:13:51 -05:00
rtmutex: tester: Remove the remaining BKL leftovers
2011-02-22 22:07:22 +01:00
rtmutex: Simplify PI algorithm and make highest prio task get lock
2011-01-27 21:13:51 -05:00
rtmutex: Simplify PI algorithm and make highest prio task get lock
2011-01-27 21:13:51 -05:00
cpuset: Fix cpuset_cpus_allowed_fallback(), don't update tsk->rt.nr_cpus_allowed
2011-05-28 17:02:57 +02:00
Fix common misspellings
2011-03-31 11:26:23 -03:00
sched, autogroup: Stop going ahead if autogroup is disabled
2011-02-23 11:33:59 +01:00
sched: Add some clock info to sched_debug
2010-11-23 10:29:08 +01:00
sched: Get rid of lock_depth
2011-04-24 13:18:38 +02:00
sched: Fix ->min_vruntime calculation in dequeue_entity()
2011-05-28 17:02:56 +02:00
sched: Move the second half of ttwu() to the remote cpu
2011-04-14 08:52:41 +02:00
sched: Drop the rq argument to sched_class::select_task_rq()
2011-04-14 08:52:36 +02:00
sched: More sched_domain iterations fixes
2011-05-28 17:02:54 +02:00
sched: More sched_domain iterations fixes
2011-05-28 17:02:54 +02:00
sched: Drop the rq argument to sched_class::select_task_rq()
2011-04-14 08:52:36 +02:00
ptrace: implement TRAP_NOTIFY and use it for group stop events
2011-06-16 21:41:53 +02:00
smp: move smp setup functions to kernel/smp.c
2011-03-22 17:44:11 -07:00
rcu: move TREE_RCU from softirq to kthread
2011-05-05 23:16:54 -07:00
rcu: demote SRCU_SYNCHRONIZE_DELAY from kernel-parameter status
2011-01-14 04:56:49 -08:00
kthread: use kthread_create_on_node()
2011-03-22 17:44:01 -07:00
Merge branch 'driver-core-next' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core-2.6
2011-05-19 18:24:11 -07:00
ipc: Add missing sys_ni entries for ipc/compat.c functions
2011-05-20 13:53:02 -07:00
Merge git://git.kernel.org/pub/scm/linux/kernel/git/cmetcalf/linux-tile
2011-05-25 15:35:32 -07:00
open-style analog of vfs_path_lookup()
2011-03-14 09:15:28 -04:00
sysctl_check: drop dead code
2011-03-23 19:46:51 -07:00
taskstats: use appropriate printk priority level
2011-03-23 19:47:14 -07:00
kprobes: Fix selftest to clear flags field for reusing probes
2010-10-14 08:55:27 +02:00
Merge branch 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
2011-03-15 18:53:35 -07:00
Merge branch 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
2011-03-15 18:53:35 -07:00
jump label: Introduce static_branch() interface
2011-04-04 12:48:08 -04:00
taskstats: use real microsecond granularity for CPU times
2010-10-27 18:03:17 -07:00
userns: user namespaces: convert several capable() calls
2011-03-23 19:47:08 -07:00
Fix common misspellings
2011-03-31 11:26:23 -03:00
userns: add a user_namespace as creator/owner of uts_namespace
2011-03-23 19:46:59 -07:00
user_ns: improve the user_ns on-the-slab packaging
2011-01-13 08:03:18 -08:00
ns proc: Add support for the uts namespace
2011-05-10 14:35:35 -07:00
Fix common misspellings
2011-03-31 11:26:23 -03:00
kernel/watchdog.c: Use proper ANSI C prototypes
2011-05-23 21:07:40 -07:00
Merge branch 'for-2.6.40' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu
2011-05-24 11:53:42 -07:00
fb1d910c17