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linux-2.6/kernel
Thomas Gleixner d0725992c8 futex: Fix the write access fault problem for real
commit 64d1304a64 (futex: setup writeable mapping for futex ops which
modify user space data) did address only half of the problem of write
access faults.

The patch was made on two wrong assumptions:

1) access_ok(VERIFY_WRITE,...) would actually check write access.

   On x86 it does _NOT_. It's a pure address range check.

2) a RW mapped region can not go away under us.

   That's wrong as well. Nobody can prevent another thread to call
   mprotect(PROT_READ) on that region where the futex resides. If that
   call hits between the get_user_pages_fast() verification and the
   actual write access in the atomic region we are toast again.

The solution is to not rely on access_ok and get_user() for any write
access related fault on private and shared futexes. Instead we need to
fault it in with verification of write access.

There is no generic non destructive write mechanism which would fault
the user page in trough a #PF, but as we already know that we will
fault we can as well call get_user_pages() directly and avoid the #PF
overhead.

If get_user_pages() returns -EFAULT we know that we can not fix it
anymore and need to bail out to user space.

Remove a bunch of confusing comments on this issue as well.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@kernel.org
2009-06-24 21:27:35 +02:00
..
gcov gcov: enable GCOV_PROFILE_ALL for x86_64 2009-06-18 13:03:58 -07:00
irq Merge branch 'irq-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2009-06-20 11:30:01 -07:00
power mm, PM/Freezer: Disable OOM killer when tasks are frozen 2009-06-16 19:47:40 -07:00
time Merge branch 'timers-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2009-06-20 10:51:44 -07:00
trace Merge branch 'tracing-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2009-06-20 10:56:46 -07:00
.gitignore
Kconfig.freezer
Kconfig.hz
Kconfig.preempt rcu: provide RCU options on non-preempt architectures too 2008-12-25 09:31:28 +01:00
Makefile audit: seperate audit inode watches into a subfile 2009-06-23 23:50:59 -04:00
acct.c [CVE-2009-0029] System call wrappers part 04 2009-01-14 14:15:19 +01:00
async.c async: Fix lack of boot-time console due to insufficient synchronization 2009-06-08 12:31:53 -07:00
audit.c Fix rule eviction order for AUDIT_DIR 2009-06-24 00:02:38 -04:00
audit.h Fix rule eviction order for AUDIT_DIR 2009-06-24 00:02:38 -04:00
audit_tree.c Fix rule eviction order for AUDIT_DIR 2009-06-24 00:02:38 -04:00
audit_watch.c Audit: clean up all op= output to include string quoting 2009-06-24 00:00:52 -04:00
auditfilter.c Audit: clean up all op= output to include string quoting 2009-06-24 00:00:52 -04:00
auditsc.c Fix rule eviction order for AUDIT_DIR 2009-06-24 00:02:38 -04:00
backtracetest.c
bounds.c
capability.c [CVE-2009-0029] System call wrappers part 04 2009-01-14 14:15:19 +01:00
cgroup.c cgroups: forbid noprefix if mounting more than just cpuset subsystem 2009-06-18 13:03:46 -07:00
cgroup_debug.c debug cgroup: remove unneeded cgroup_lock 2009-04-02 19:04:54 -07:00
cgroup_freezer.c freezer_cg: disable writing freezer.state of root cgroup 2008-11-12 17:17:16 -08:00
compat.c signals: implement sys_rt_tgsigqueueinfo 2009-04-30 19:24:24 +02:00
configs.c
cpu.c mm/init: cpu_hotplug_init() must be initialized before SLAB 2009-06-22 21:18:12 -07:00
cpuset.c cpuset,mm: update tasks' mems_allowed in time 2009-06-16 19:47:31 -07:00
cred-internals.h CRED: Inaugurate COW credentials 2008-11-14 10:39:23 +11:00
cred.c CRED: Rename cred_exec_mutex to reflect that it's a guard against ptrace 2009-05-11 08:15:36 +10:00
delayacct.c schedstat: consolidate per-task cpu runtime stats 2008-12-18 13:54:01 +01:00
dma-coherent.c dma-coherent: Restore dma_alloc_from_coherent() large alloc fall back policy. 2009-01-21 18:51:53 +09:00
dma.c
exec_domain.c Get rid of indirect include of fs_struct.h 2009-03-31 23:00:27 -04:00
exit.c ptrace: wait_task_zombie: do not account traced sub-threads 2009-06-19 16:46:06 -07:00
extable.c Merge branch 'tracing-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2009-04-05 11:04:19 -07:00
fork.c copy_process(): remove the unneeded clear_tsk_thread_flag(TIF_SIGPENDING) 2009-06-18 13:03:52 -07:00
freezer.c freezer_cg: use thaw_process() in unfreeze_cgroup() 2008-10-30 11:38:45 -07:00
futex.c futex: Fix the write access fault problem for real 2009-06-24 21:27:35 +02:00
futex_compat.c CRED: Use RCU to access another task's creds and to release a task's own creds 2008-11-14 10:39:19 +11:00
groups.c groups: move code to kernel/groups.c 2009-06-16 19:47:48 -07:00
hrtimer.c Merge branch 'linux-next' of git://git.infradead.org/ubifs-2.6 2009-06-17 09:46:33 -07:00
hung_task.c softlockup: ensure the task has been switched out once 2009-02-11 11:04:16 +01:00
itimer.c timers: split process wide cpu clocks/timers 2009-02-05 13:04:33 +01:00
kallsyms.c kernel/kallsyms.c: replace deprecated __initcall with device_initcall and fix whitespace 2009-06-09 22:37:52 +02:00
kexec.c PM core: rename suspend and resume functions 2009-06-12 21:32:31 +02:00
kfifo.c kernel/kfifo.c: replace conditional test with is_power_of_2() 2009-06-16 19:47:47 -07:00
kgdb.c sysrq, intel_fb: fix sysrq g collision 2009-05-15 07:56:24 -05:00
kmod.c kmod: Release sub_info on cred allocation failure. 2009-05-26 12:11:19 -07:00
kprobes.c kprobes: fix to use text_mutex around arm/disarm kprobe 2009-05-08 16:23:48 -07:00
ksysfs.c kernel/ksysfs.c:fix dependence on CONFIG_NET 2009-01-06 10:44:31 -08:00
kthread.c kthreads: rework kthread_stop() 2009-06-18 13:03:54 -07:00
latencytop.c sched, latencytop: incorporate review feedback from Andrew Morton 2009-02-11 10:18:04 +01:00
lockdep.c Merge branch 'linus' into tracing/core 2009-05-07 11:17:34 +02:00
lockdep_internals.h lockdep: increase MAX_LOCKDEP_ENTRIES and MAX_LOCKDEP_CHAINS 2009-05-12 19:59:52 +02:00
lockdep_proc.c lockstat: warn about disabled lock debugging 2009-02-14 23:28:28 +01:00
lockdep_states.h lockdep: move state bit definitions around 2009-02-14 23:27:59 +01:00
marker.c markers/tracpoints: fix non-modular build 2008-11-16 09:52:03 +01:00
module.c kernel: constructor support 2009-06-18 13:03:57 -07:00
mutex-debug.c mutex: implement adaptive spinning 2009-01-14 18:09:02 +01:00
mutex-debug.h mutex: implement adaptive spinning 2009-01-14 18:09:02 +01:00
mutex.c Merge branch 'linus' into perfcounters/core 2009-06-11 17:55:42 +02:00
mutex.h mutex: implement adaptive spinning 2009-01-14 18:09:02 +01:00
notifier.c Merge commit 'v2.6.28-rc6' into core/debug 2008-11-26 08:22:50 +01:00
ns_cgroup.c cgroups: relax ns_can_attach checks to allow attaching to grandchild cgroups 2009-04-02 19:04:53 -07:00
nsproxy.c nsproxy: extract create_nsproxy() 2009-06-18 13:03:56 -07:00
panic.c Fix caller information for warn_slowpath_null 2009-05-16 13:41:28 -07:00
params.c module_param: allow 'bool' module_params to be bool, not just int. 2009-06-12 21:46:58 +09:30
perf_counter.c perf_counter: Push perf_sample_data through the swcounter code 2009-06-20 12:30:30 +02:00
pid.c pids: clean up find_task_by_pid variants 2009-06-18 13:03:55 -07:00
pid_namespace.c pidns: rewrite copy_pid_ns() 2009-06-18 13:03:55 -07:00
pm_qos_params.c
posix-cpu-timers.c kernel/posix-cpu-timers.c: fix sparse warning 2009-04-30 08:08:31 +02:00
posix-timers.c [CVE-2009-0029] System call wrappers part 05 2009-01-14 14:15:20 +01:00
printk.c printk: Add KERN_DEFAULT printk log-level 2009-06-16 11:02:28 -07:00
profile.c page allocator: do not check NUMA node ID when the caller knows the node is valid 2009-06-16 19:47:32 -07:00
ptrace.c ptrace: don't take tasklist to get/set ->last_siginfo 2009-06-18 13:03:52 -07:00
rcuclassic.c kmemtrace, rcu: fix linux/rcutree.h and linux/rcuclassic.h dependencies 2009-04-03 12:23:02 +02:00
rcupdate.c RCU: Don't try and predeclare inline funcs as it upsets some versions of gcc 2009-04-15 13:55:14 -07:00
rcupreempt.c rcu: rcu_sched_grace_period(): kill the bogus flush_signals() 2009-05-05 20:28:05 +02:00
rcupreempt_trace.c "Tree RCU": scalable classic RCU implementation 2008-12-18 21:56:04 +01:00
rcutorture.c cpumask: convert rcutorture.c 2009-03-30 22:05:16 +10:30
rcutree.c rcu: Add __rcu_pending tracing to hierarchical RCU 2009-04-14 11:33:43 +02:00
rcutree.h kmemtrace, rcu: fix rcu_tree_trace.c data structure dependencies 2009-04-03 12:23:03 +02:00
rcutree_trace.c rcu: Add __rcu_pending tracing to hierarchical RCU 2009-04-14 11:33:43 +02:00
relay.c Merge branch 'tracing-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2009-04-05 11:04:19 -07:00
res_counter.c memcg: add interface to reset limits 2009-06-18 13:03:48 -07:00
resource.c Remove 'recurse into child resources' logic from 'reserve_region_with_split()' 2009-04-18 21:44:24 -07:00
rtmutex-debug.c
rtmutex-debug.h
rtmutex-tester.c
rtmutex.c trivial: fix ETIMEOUT -> ETIMEDOUT typos 2009-06-12 18:01:50 +02:00
rtmutex.h
rtmutex_common.h rt_mutex: add proxy lock routines 2009-04-06 11:14:02 +02:00
rwsem.c
sched.c Merge branch 'perfcounters-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2009-06-20 11:29:32 -07:00
sched_clock.c sched: Fix fallback sched_clock()'s offset when using jiffies 2009-05-09 10:08:19 +02:00
sched_cpupri.c sched: Remove unneeded __ref tag 2009-06-17 16:08:04 +02:00
sched_cpupri.h cpumask: remove cpumask_t from core 2009-03-30 22:05:17 +10:30
sched_debug.c sched: Hide runqueues from direct refer at source code level 2009-06-17 18:29:42 +02:00
sched_fair.c sched: Fix out of scope variable access in sched_slice() 2009-06-17 18:37:54 +02:00
sched_features.h Merge branch 'locking-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2009-03-30 17:17:35 -07:00
sched_idletask.c sched, timers: move calc_load() to scheduler 2009-05-15 15:32:45 +02:00
sched_rt.c cpumask: alloc zeroed cpumask for static cpumask_var_ts 2009-06-09 22:30:27 +09:30
sched_stats.h sched: remove unused fields from struct rq 2009-03-24 23:16:51 +01:00
seccomp.c x86-64: seccomp: fix 32/64 syscall hole 2009-03-02 15:41:30 -08:00
semaphore.c
signal.c ptrace: do_notify_parent_cldstop: fix the wrong ->nsproxy usage 2009-06-18 13:03:52 -07:00
slow-work.c slow-work: use round_jiffies() for thread pool's cull and OOM timers 2009-06-16 19:47:49 -07:00
smp.c cpumask: alloc zeroed cpumask for static cpumask_var_ts 2009-06-09 22:30:27 +09:30
softirq.c softirq: introduce statistics for softirq 2009-06-18 13:03:40 -07:00
softlockup.c softlockup: decouple hung tasks check from softlockup detection 2009-01-16 14:06:04 +01:00
spinlock.c Allow rwlocks to re-enable interrupts 2009-04-02 19:05:11 -07:00
srcu.c
stacktrace.c stacktrace: provide save_stack_trace_tsk() weak alias 2008-12-25 11:44:43 +01:00
stop_machine.c cpumask: remove cpumask_t from core 2009-03-30 22:05:17 +10:30
sys.c groups: move code to kernel/groups.c 2009-06-16 19:47:48 -07:00
sys_ni.c Merge commit 'v2.6.29-rc2' into perfcounters/core 2009-01-21 16:37:27 +01:00
sysctl.c sysctl.c: remove unused variable 2009-06-18 13:03:54 -07:00
sysctl_check.c net: add ARP notify option for devices 2009-02-01 01:04:33 -08:00
taskstats.c cpumask: convert rest of files in kernel/ 2009-01-01 10:12:28 +10:30
test_kprobes.c kprobes: add tests for register_kprobes 2009-01-06 15:59:20 -08:00
time.c [CVE-2009-0029] System call wrappers part 01 2009-01-14 14:15:18 +01:00
timeconst.pl
timer.c Merge branch 'timers-for-linus-migration' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2009-06-15 10:06:19 -07:00
tracepoint.c tracepoints: dont update zero-sized tracepoint sections 2009-03-18 19:55:00 +01:00
tsacct.c Fix fixpoint divide exception in acct_update_integrals 2009-03-09 08:13:35 -07:00
uid16.c [CVE-2009-0029] System call wrappers part 19 2009-01-14 14:15:26 +01:00
up.c smp_call_function_single(): be slightly less stupid, fix #2 2009-01-12 16:04:37 +01:00
user.c sched: delayed cleanup of user_struct 2009-06-15 21:30:23 -07:00
user_namespace.c Fix recursive lock in free_uid()/free_user_ns() 2009-02-27 16:26:21 -08:00
utsname.c utsns: extract creeate_uts_ns() 2009-06-18 13:03:55 -07:00
utsname_sysctl.c proc_sysctl: use CONFIG_PROC_SYSCTL around ipc and utsname proc_handlers 2009-04-02 19:05:01 -07:00
wait.c wait: don't use __wake_up_common() 2009-04-14 17:17:16 +02:00
workqueue.c ftrace, workqueuetrace: make workqueue tracepoints use TRACE_EVENT macro 2009-06-02 01:10:40 +02:00