linux/kernel
Oleg Nesterov e0a7021710 posix-cpu-timers: workaround to suppress the problems with mt exec
posix-cpu-timers.c correctly assumes that the dying process does
posix_cpu_timers_exit_group() and removes all !CPUCLOCK_PERTHREAD
timers from signal->cpu_timers list.

But, it also assumes that timer->it.cpu.task is always the group
leader, and thus the dead ->task means the dead thread group.

This is obviously not true after de_thread() changes the leader.
After that almost every posix_cpu_timer_ method has problems.

It is not simple to fix this bug correctly. First of all, I think
that timer->it.cpu should use struct pid instead of task_struct.
Also, the locking should be reworked completely. In particular,
tasklist_lock should not be used at all. This all needs a lot of
nontrivial and hard-to-test changes.

Change __exit_signal() to do posix_cpu_timers_exit_group() when
the old leader dies during exec. This is not the fix, just the
temporary hack to hide the problem for 2.6.37 and stable. IOW,
this is obviously wrong but this is what we currently have anyway:
cpu timers do not work after mt exec.

In theory this change adds another race. The exiting leader can
detach the timers which were attached to the new leader. However,
the window between de_thread() and release_task() is small, we
can pretend that sys_timer_create() was called before de_thread().

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-11-05 14:16:03 -07:00
..
debug debug_core,x86,blackfin: Clean up hw debug disable API 2010-10-29 13:14:41 -05:00
gcov llseek: automatically add .llseek fop 2010-10-15 15:53:27 +02:00
irq Merge branches 'irq-core-for-linus' and 'core-locking-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2010-10-31 20:40:24 -04:00
power use clear_page()/copy_page() in favor of memset()/memcpy() on whole pages 2010-10-26 16:52:13 -07:00
time ntp: Clamp PLL update interval 2010-09-09 20:48:37 +02:00
trace Merge branch 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2010-10-27 18:48:00 -07:00
.gitignore
acct.c pass a struct path to vfs_statfs 2010-08-09 16:48:42 -04:00
async.c async: use workqueue for worker pool 2010-07-14 11:29:46 +02:00
audit_tree.c in untag_chunk() we need to do alloc_chunk() a bit earlier 2010-10-30 02:18:32 -04:00
audit_watch.c audit: make functions static 2010-10-30 01:42:19 -04:00
audit.c audit: Use rcu for task lookup protection 2010-10-30 08:45:42 -04:00
audit.h audit: make functions static 2010-10-30 01:42:19 -04:00
auditfilter.c Audit: add support to match lsm labels on user audit messages 2010-10-30 01:41:57 -04:00
auditsc.c audit mmap 2010-10-30 08:45:43 -04:00
backtracetest.c
bounds.c
capability.c sched: Remove remaining USER_SCHED code 2010-04-02 20:12:00 +02:00
cgroup_freezer.c cgroup_freezer: update_freezer_state() does incorrect state transitions 2010-10-27 18:03:08 -07:00
cgroup.c convert cgroup and cpuset 2010-10-29 04:17:06 -04:00
compat.c compat: Make compat_alloc_user_space() incorporate the access_ok() 2010-09-14 16:08:45 -07:00
configs.c llseek: automatically add .llseek fop 2010-10-15 15:53:27 +02:00
cpu.c sched: adjust when cpu_active and cpuset configurations are updated during cpu on/offlining 2010-06-08 21:40:36 +02:00
cpuset.c convert cgroup and cpuset 2010-10-29 04:17:06 -04:00
cred.c signals: move cred_guard_mutex from task_struct to signal_struct 2010-10-27 18:03:12 -07:00
delayacct.c
dma.c
elfcore.c elf coredump: add extended numbering support 2010-03-06 11:26:46 -08:00
exec_domain.c sys_personality: remove the bogus checks in sys_personality()->__set_personality() path 2010-08-09 20:45:05 -07:00
exit.c posix-cpu-timers: workaround to suppress the problems with mt exec 2010-11-05 14:16:03 -07:00
extable.c
fork.c signals: move cred_guard_mutex from task_struct to signal_struct 2010-10-27 18:03:12 -07:00
freezer.c
futex_compat.c futex: Change 3rd arg of fetch_robust_entry() to unsigned int* 2010-09-18 12:19:21 +02:00
futex.c new helper: ihold() 2010-10-25 21:26:11 -04:00
groups.c kernel/groups.c: fix integer overflow in groups_search 2010-09-09 18:57:24 -07:00
hrtimer.c hrtimer: Preserve timer state in remove_hrtimer() 2010-10-14 13:29:59 +02:00
hung_task.c lockup detector: Fix grammar by adding a missing "to" in the comments 2010-08-17 09:11:52 +02:00
hw_breakpoint.c perf, hw_breakpoint: Fix crash in hw_breakpoint creation 2010-10-18 19:58:55 +02:00
irq_work.c irq_work: Add generic hardirq context callbacks 2010-10-18 19:58:50 +02:00
itimer.c
jump_label.c jump label: Make arch_jump_label_text_poke_early() optional 2010-10-29 12:56:13 -04:00
kallsyms.c kdb: core for kgdb back end (2 of 2) 2010-05-20 21:04:21 -05:00
Kconfig.freezer
Kconfig.hz
Kconfig.locks
Kconfig.preempt
kexec.c use clear_page()/copy_page() in favor of memset()/memcpy() on whole pages 2010-10-26 16:52:13 -07:00
kfifo.c kfifo: fix scatterlist usage 2010-10-01 10:50:58 -07:00
kmod.c Make do_execve() take a const filename pointer 2010-08-17 18:07:43 -07:00
kprobes.c jump label: Fix error with preempt disable holding mutex 2010-10-29 12:55:55 -04:00
ksysfs.c sysfs: add struct file* to bin_attr callbacks 2010-05-21 09:37:31 -07:00
kthread.c kthread: implement kthread_data() 2010-06-29 10:07:09 +02:00
latencytop.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
lockdep_internals.h lockdep: No need to disable preemption in debug atomic ops 2010-05-04 05:38:16 +02:00
lockdep_proc.c lockstat: Make lockstat counting per cpu 2010-04-06 00:15:37 +02:00
lockdep_states.h
lockdep.c lockdep: Check the depth of subclass 2010-10-18 18:44:26 +02:00
Makefile Merge branch 'core-memblock-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2010-10-21 18:52:11 -07:00
module.c (trivial) Fix compiler warning in kernel/modules.c 2010-10-27 20:33:05 +10:30
mutex-debug.c
mutex-debug.h
mutex.c mutex: Fix annotations to include it in kernel-locking docbook 2010-09-03 08:19:51 +02:00
mutex.h
notifier.c sched: Use lockdep-based checking on rcu_dereference() 2010-02-25 10:34:26 +01:00
ns_cgroup.c cgroup: notify ns_cgroup deprecated 2010-10-27 18:03:09 -07:00
nsproxy.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
padata.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2010-08-04 15:23:14 -07:00
panic.c lib/bug.c: add oops end marker to WARN implementation 2010-08-11 08:59:22 -07:00
params.c param: locking for kernel parameters 2010-08-11 23:04:20 +09:30
perf_event.c perf_events: Fix for transaction recovery in group_sched_in() 2010-10-22 14:18:27 +02:00
pid_namespace.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
pid.c Add RCU check for find_task_by_vpid(). 2010-08-19 17:18:02 -07:00
pm_qos_params.c Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2010-10-24 13:41:39 -07:00
posix-cpu-timers.c Merge branch 'writable_limits' of git://decibel.fi.muni.cz/~xslaby/linux 2010-08-10 12:07:51 -07:00
posix-timers.c posix_timer: Move copy_to_user(created_timer_id) down in timer_create() 2010-07-23 15:08:12 +02:00
printk.c printk: change type of 'boot_delay' to int * 2010-10-26 16:52:16 -07:00
profile.c llseek: automatically add .llseek fop 2010-10-15 15:53:27 +02:00
ptrace.c signals: move cred_guard_mutex from task_struct to signal_struct 2010-10-27 18:03:12 -07:00
range.c kernel/range: remove unused definition of ARRAY_SIZE() 2010-08-09 20:45:06 -07:00
rcupdate.c Merge branch 'rcu/urgent' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-2.6-rcu into core/rcu 2010-10-07 09:43:11 +02:00
rcutiny_plugin.h rcu: performance fixes to TINY_PREEMPT_RCU callback checking 2010-08-27 10:51:17 -07:00
rcutiny.c rcu: Add a TINY_PREEMPT_RCU 2010-08-20 08:55:00 -07:00
rcutorture.c rcu: fix sparse errors in rcutorture.c 2010-09-23 09:16:42 -07:00
rcutree_plugin.h rcu: fix _oddness handling of verbose stall warnings 2010-09-02 16:15:30 -07:00
rcutree_trace.c rcu: Add tracing data to support queueing models 2010-09-23 09:16:53 -07:00
rcutree.c rcu: using ACCESS_ONCE() to observe the jiffies_stall/rnp->qsmask value 2010-10-07 10:41:06 -07:00
rcutree.h rcu: Add tracing data to support queueing models 2010-09-23 09:16:53 -07:00
relay.c Clean up relay_alloc_page_array() slightly by using vzalloc rather than vmalloc and memset 2010-11-05 08:21:34 -07:00
res_counter.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
resource.c Merge branch 'linux-next' of git://git.kernel.org/pub/scm/linux/kernel/git/jbarnes/pci-2.6 2010-10-28 11:59:52 -07:00
rtmutex_common.h
rtmutex-debug.c
rtmutex-debug.h
rtmutex-tester.c rtmutex-tester: make it build without BKL 2010-10-19 11:29:56 +02:00
rtmutex.c
rtmutex.h
rwsem.c
sched_clock.c sched_clock: Add local_clock() API and improve documentation 2010-06-09 10:34:49 +02:00
sched_cpupri.c sched: No need for bootmem special cases 2010-07-17 12:06:22 +02:00
sched_cpupri.h sched: No need for bootmem special cases 2010-07-17 12:06:22 +02:00
sched_debug.c sched: Use correct macro to display sched_child_runs_first in /proc/sched_debug 2010-07-21 21:46:12 +02:00
sched_fair.c Merge branch 'sched-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2010-10-29 08:05:33 -07:00
sched_features.h sched: Remove irq time from available CPU power 2010-10-18 20:52:27 +02:00
sched_idletask.c sched: Cure load average vs NO_HZ woes 2010-04-23 11:02:02 +02:00
sched_rt.c sched: Do not account irq time to current task 2010-10-18 20:52:26 +02:00
sched_stats.h sched_stat: Update sched_info_queue/dequeue() code comments 2010-10-24 13:29:01 +02:00
sched_stoptask.c sched: Create special class for stop/migrate work 2010-10-18 18:41:58 +02:00
sched.c Merge branch 'sched-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2010-10-29 08:05:33 -07:00
seccomp.c
semaphore.c
signal.c signals: annotate lock context change on ptrace_stop() 2010-10-27 18:03:12 -07:00
smp.c Typedef SMP call function pointer 2010-10-27 17:28:36 +01:00
softirq.c Merge branch 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2010-10-27 18:48:00 -07:00
spinlock.c
srcu.c kernel: Remove undead ifdef CONFIG_DEBUG_LOCK_ALLOC 2010-09-23 09:14:51 -07:00
stacktrace.c
stop_machine.c stop_machine: convert cpu notifier to return encapsulate errno value 2010-10-26 16:52:15 -07:00
sys_ni.c powerpc: define a compat_sys_recv cond_syscall 2010-09-23 17:03:55 +10:00
sys.c pid: make setpgid() system call use RCU read-side critical section 2010-08-31 17:00:18 -07:00
sysctl_binary.c sysctl: don't use own implementation of hex_to_bin() 2010-05-25 08:07:05 -07:00
sysctl_check.c sysctl: min/max bounds are optional 2010-10-15 14:42:24 -07:00
sysctl.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6 2010-10-26 17:58:44 -07:00
taskstats.c taskstats: split fill_pid function 2010-10-27 18:03:17 -07:00
test_kprobes.c kprobes: Fix selftest to clear flags field for reusing probes 2010-10-14 08:55:27 +02:00
time.c time: Kill off CONFIG_GENERIC_TIME 2010-07-27 12:40:54 +02:00
timeconst.pl
timer.c irq_work: Add generic hardirq context callbacks 2010-10-18 19:58:50 +02:00
tracepoint.c jump_label: Use more consistent naming 2010-10-18 19:58:56 +02:00
tsacct.c taskstats: use real microsecond granularity for CPU times 2010-10-27 18:03:17 -07:00
uid16.c
up.c
user_namespace.c user_ns: Introduce user_nsmap_uid and user_ns_map_gid. 2010-06-16 14:55:34 -07:00
user-return-notifier.c
user.c kernel/user.c: add lock release annotation on free_user() 2010-10-26 16:52:15 -07:00
utsname_sysctl.c
utsname.c
wait.c docbook: add more wait/wake/completion to device-drivers docbook 2010-10-26 17:32:41 -07:00
watchdog.c Merge branch 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2010-10-21 12:54:49 -07:00
workqueue_sched.h workqueue: implement concurrency managed dynamic worker pool 2010-06-29 10:07:14 +02:00
workqueue.c workqueues: s/ON_STACK/ONSTACK/ 2010-10-26 16:52:14 -07:00