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Steven Rostedt eb4a03780d function-graph: disable when both x86_32 and optimize for size are configured 
On x86_32, when optimize for size is set, gcc may align the frame pointer
and make a copy of the the return address inside the stack frame.
The return address that is located in the stack frame may not be
the one used to return to the calling function. This will break the
function graph tracer.

The function graph tracer replaces the return address with a jump to a hook
function that can trace the exit of the function. If it only replaces
a copy, then the hook will not be called when the function returns.
Worse yet, when the parent function returns, the function graph tracer
will return back to the location of the child function which will
easily crash the kernel with weird results.

To see the problem, when i386 is compiled with -Os we get:

c106be03:       57                      push   %edi
c106be04:       8d 7c 24 08             lea    0x8(%esp),%edi
c106be08:       83 e4 e0                and    $0xffffffe0,%esp
c106be0b:       ff 77 fc                pushl  0xfffffffc(%edi)
c106be0e:       55                      push   %ebp
c106be0f:       89 e5                   mov    %esp,%ebp
c106be11:       57                      push   %edi
c106be12:       56                      push   %esi
c106be13:       53                      push   %ebx
c106be14:       81 ec 8c 00 00 00       sub    $0x8c,%esp
c106be1a:       e8 f5 57 fb ff          call   c1021614 <mcount>

When it is compiled with -O2 instead we get:

c10896f0:       55                      push   %ebp
c10896f1:       89 e5                   mov    %esp,%ebp
c10896f3:       83 ec 28                sub    $0x28,%esp
c10896f6:       89 5d f4                mov    %ebx,0xfffffff4(%ebp)
c10896f9:       89 75 f8                mov    %esi,0xfffffff8(%ebp)
c10896fc:       89 7d fc                mov    %edi,0xfffffffc(%ebp)
c10896ff:       e8 d0 08 fa ff          call   c1029fd4 <mcount>

The compile with -Os will align the stack pointer then set up the
frame pointer (%ebp), and it copies the return address back into
the stack frame. The change to the return address in mcount is done
to the copy and not the real place holder of the return address.

Then compile with -O2 sets up the frame pointer first, this makes
the change to the return address by mcount affect where the function
will jump on exit.

Reported-by: Jake Edge <jake@lwn.net>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
 		2009-06-18 18:39:30 -04:00
..
irq irq: slab alloc for default irq_affinity 2009-06-12 13:50:23 +03:00
power Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2009-06-14 13:46:25 -07:00
time Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6 2009-06-11 09:01:14 +03:00
trace function-graph: disable when both x86_32 and optimize for size are configured 2009-06-18 18:39:30 -04:00
.gitignore
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Kconfig.freezer container freezer: implement freezer cgroup subsystem 2008-10-20 08:52:34 -07:00
Kconfig.hz
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Kconfig.preempt rcu: provide RCU options on non-preempt architectures too 2008-12-25 09:31:28 +01:00
Makefile Merge branch 'linus' into perfcounters/core 2009-06-11 17:55:42 +02:00
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 Audit: remove spaces from audit_log_d_path 2009-04-05 13:49:04 -04:00
audit.h fixing audit rule ordering mess, part 1 2009-01-04 15:14:41 -05:00
audit_tree.c Switch collect_mounts() to struct path 2009-06-11 21:36:01 -04:00
auditfilter.c inotify: use GFP_NOFS in kernel_event() to work around a lockdep false-positive 2009-05-06 16:36:09 -07:00
auditsc.c Audit: remove spaces from audit_log_d_path 2009-04-05 13:49:04 -04:00
backtracetest.c
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bounds.c
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capability.c [CVE-2009-0029] System call wrappers part 04 2009-01-14 14:15:19 +01:00
cgroup.c Push BKL down into ->remount_fs() 2009-06-11 21:36:11 -04:00
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 kernel/configs.c: remove useless comments 2008-10-20 08:52:34 -07:00
cpu.c cpumask: use set_cpu_active in init/main.c 2009-03-30 22:05:12 +10:30
cpuset.c x86: remove some alloc_bootmem_cpumask_var calling 2009-06-11 19:27:07 +03:00
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 kernel/dma.c: remove a CVS keyword 2008-10-16 11:21:30 -07:00
exec_domain.c Get rid of indirect include of fs_struct.h 2009-03-31 23:00:27 -04:00
exit.c Merge branch 'perfcounters-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2009-06-11 14:01:07 -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 Merge branch 'linus' into perfcounters/core 2009-06-11 17:55:42 +02:00
freezer.c freezer_cg: use thaw_process() in unfreeze_cgroup() 2008-10-30 11:38:45 -07:00
futex.c futex: fix restart in wait_requeue_pi 2009-05-20 10:34:32 +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
hrtimer.c hrtimer: fix rq->lock inversion (again) 2009-03-31 14:52:52 +02:00
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
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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 tracing/events: move trace point headers into include/trace/events 2009-04-14 22:05:43 -04:00
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 module: trim exception table on init free. 2009-06-12 21:47:04 +09:30
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 User namespaces: set of cleanups (v2) 2008-11-24 18:57:41 -05:00
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: Add forward/backward attribute ABI compatibility 2009-06-12 14:28:52 +02:00
pid.c pids: refactor vnr/nr_ns helpers to make them safe 2009-04-02 19:05:02 -07:00
pid_namespace.c signals: zap_pid_ns_process() should use force_sig() 2009-04-02 19:04:58 -07:00
pm_qos_params.c
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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 Merge branch 'printk-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2009-04-05 10:23:25 -07:00
profile.c x86: remove some alloc_bootmem_cpumask_var calling 2009-06-11 19:27:07 +03:00
ptrace.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/security-testing-2.6 2009-06-11 10:01:41 -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: memory cgroup resource counters for hierarchy 2009-01-08 08:31:05 -08:00
resource.c Remove 'recurse into child resources' logic from 'reserve_region_with_split()' 2009-04-18 21:44:24 -07:00
rtmutex-debug.c
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rtmutex-debug.h
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rtmutex-tester.c
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rtmutex.c trivial: fix ETIMEOUT -> ETIMEDOUT typos 2009-06-12 18:01:50 +02:00
rtmutex.h
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rtmutex_common.h rt_mutex: add proxy lock routines 2009-04-06 11:14:02 +02:00
rwsem.c
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sched.c sched: export kick_process 2009-06-12 22:27:01 +09:30
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: use slab in cpupri_init() 2009-06-11 19:27:12 +03:00
sched_cpupri.h cpumask: remove cpumask_t from core 2009-03-30 22:05:17 +10:30
sched_debug.c sched: remove unused fields from struct rq 2009-03-24 23:16:51 +01:00
sched_fair.c sched: remove redundant hierarchy walk in check_preempt_wakeup 2009-04-09 08:19:08 +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
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signal.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/security-testing-2.6 2009-06-11 10:01:41 -07:00
slow-work.c slow_work_thread() should do the exclusive wait 2009-06-11 11:26:38 -07:00
smp.c cpumask: alloc zeroed cpumask for static cpumask_var_ts 2009-06-09 22:30:27 +09:30
softirq.c Merge branch 'tracing-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2009-06-10 19:53:40 -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
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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 Merge branch 'linus' into perfcounters/core 2009-04-29 14:47:05 +02:00
sys_ni.c Merge commit 'v2.6.29-rc2' into perfcounters/core 2009-01-21 16:37:27 +01:00
sysctl.c Merge branch 'perfcounters-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2009-06-11 14:01:07 -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
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timer.c Merge branch 'linus' into x86/mce3 2009-06-11 23:31:52 +02:00
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 Merge branch 'master' into next 2009-03-24 10:52:46 +11:00
user_namespace.c Fix recursive lock in free_uid()/free_user_ns() 2009-02-27 16:26:21 -08:00
utsname.c
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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