linux/kernel
Mathieu Desnoyers 6549864629 tracepoints: Fix section alignment using pointer array
Make the tracepoints more robust, making them solid enough to handle compiler
changes by not relying on anything based on compiler-specific behavior with
respect to structure alignment. Implement an approach proposed by David Miller:
use an array of const pointers to refer to the individual structures, and export
this pointer array through the linker script rather than the structures per se.
It will consume 32 extra bytes per tracepoint (24 for structure padding and 8
for the pointers), but are less likely to break due to compiler changes.

History:

commit 7e066fb8 tracepoints: add DECLARE_TRACE() and DEFINE_TRACE()
added the aligned(32) type and variable attribute to the tracepoint structures
to deal with gcc happily aligning statically defined structures on 32-byte
multiples.

One attempt was to use a 8-byte alignment for tracepoint structures by applying
both the variable and type attribute to tracepoint structures definitions and
declarations. It worked fine with gcc 4.5.1, but broke with gcc 4.4.4 and 4.4.5.

The reason is that the "aligned" attribute only specify the _minimum_ alignment
for a structure, leaving both the compiler and the linker free to align on
larger multiples. Because tracepoint.c expects the structures to be placed as an
array within each section, up-alignment cause NULL-pointer exceptions due to the
extra unexpected padding.

(this patch applies on top of -tip)

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Acked-by: David S. Miller <davem@davemloft.net>
LKML-Reference: <20110126222622.GA10794@Krystal>
CC: Frederic Weisbecker <fweisbec@gmail.com>
CC: Ingo Molnar <mingo@elte.hu>
CC: Thomas Gleixner <tglx@linutronix.de>
CC: Andrew Morton <akpm@linux-foundation.org>
CC: Peter Zijlstra <peterz@infradead.org>
CC: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2011-02-03 09:28:46 -05:00
..
debug Merge branch 'master' into for-next 2010-12-22 18:57:02 +01:00
gcov llseek: automatically add .llseek fop 2010-10-15 15:53:27 +02:00
irq genirq: Remove __do_IRQ 2011-01-21 11:55:31 +01:00
power Merge branch 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux-acpi-2.6 2011-01-13 20:15:35 -08:00
time hrtimers: Notify hrtimer users of switches to NOHZ mode 2011-01-19 20:08:15 +01:00
trace tracing: Replace trace_event struct array with pointer array 2011-02-02 21:37:13 -05:00
.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: error message typo correction 2010-11-03 13:49:58 -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
cgroup_freezer.c cgroup_freezer: update_freezer_state() does incorrect state transitions 2010-10-27 18:03:08 -07:00
cgroup.c Merge branch 'vfs-scale-working' of git://git.kernel.org/pub/scm/linux/kernel/git/npiggin/linux-npiggin 2011-01-14 09:08:29 -08:00
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 Merge branches 'x86-alternatives-for-linus', 'x86-fpu-for-linus', 'x86-hwmon-for-linus', 'x86-paravirt-for-linus', 'core-locking-for-linus' and 'irq-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2011-01-06 11:11:50 -08:00
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
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 Merge branch 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2011-01-11 11:02:13 -08:00
extable.c
fork.c thp: khugepaged 2011-01-13 17:32:43 -08:00
freezer.c Freezer: Fix a race during freezing of TASK_STOPPED tasks 2010-12-24 15:02:40 +01:00
futex_compat.c futex: Address compiler warnings in exit_robust_list 2010-11-10 13:27:50 +01:00
futex.c Merge branches 'core-fixes-for-linus', 'x86-fixes-for-linus', 'timers-fixes-for-linus' and 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2011-01-15 12:45:00 -08:00
groups.c kernel/groups.c: fix integer overflow in groups_search 2010-09-09 18:57:24 -07:00
hrtimer.c Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2011-01-13 10:05:56 -08:00
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: Dynamic pmu types 2010-12-16 11:36:43 +01:00
irq_work.c irq_work: Use per cpu atomics instead of regular atomics 2010-12-18 15:54:48 +01:00
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 Revert "kernel: make /proc/kallsyms mode 400 to reduce ease of attacking" 2010-11-19 11:54:40 -08:00
Kconfig.freezer
Kconfig.hz
Kconfig.locks
Kconfig.preempt
kexec.c tree-wide: fix comment/printk typos 2010-11-01 15:38:34 -04:00
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 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
ksysfs.c sysfs: add struct file* to bin_attr callbacks 2010-05-21 09:37:31 -07:00
kthread.c sched: Constify function scope static struct sched_param usage 2011-01-07 15:55:45 +01:00
latencytop.c fs/proc/base.c, kernel/latencytop.c: convert sprintf_symbol() to %ps 2011-01-13 08:03:16 -08:00
lockdep_internals.h lockdep: No need to disable preemption in debug atomic ops 2010-05-04 05:38:16 +02:00
lockdep_proc.c locking, lockdep: Convert sprintf_symbol to %pS 2010-11-10 10:23:58 +01:00
lockdep_states.h
lockdep.c lockdep: Move early boot local IRQ enable/disable status to init/main.c 2011-01-20 13:32:33 +01:00
Makefile kernel: clean up USE_GENERIC_SMP_HELPERS 2011-01-13 08:03:08 -08:00
module.c tracepoints: Fix section alignment using pointer array 2011-02-03 09:28:46 -05:00
mutex-debug.c
mutex-debug.h
mutex.c mutexes, sched: Introduce arch_mutex_cpu_relax() 2010-11-26 15:05:34 +01:00
mutex.h
notifier.c
ns_cgroup.c cgroup: notify ns_cgroup deprecated 2010-10-27 18:03:09 -07:00
nsproxy.c
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 ACPI, APEI, Generic Hardware Error Source POLL/IRQ/NMI notification type support 2011-01-12 03:06:19 -05:00
params.c module: show version information for built-in modules in sysfs 2011-01-24 14:32:51 +10:30
perf_event.c perf: Fix alloc_callchain_buffers() 2011-01-27 19:21:50 +01:00
pid_namespace.c
pid.c Add RCU check for find_task_by_vpid(). 2010-08-19 17:18:02 -07:00
pm_qos_params.c PM / PM QoS: Fix reversed min and max 2010-11-15 22:45:22 +01:00
posix-cpu-timers.c posix-cpu-timers: Rcu_read_lock/unlock protect find_task_by_vpid call 2010-11-10 13:07:06 +01:00
posix-timers.c posix-timers: Annotate lock_timer() 2010-10-21 17:30:06 +02:00
printk.c console: rename acquire/release_console_sem() to console_lock/unlock() 2011-01-26 10:50:06 +10:00
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.c: fix clean_sort_range() for the case of full array 2010-11-12 07:55:31 -08:00
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: Distinguish between boosting and boosted 2010-11-29 22:01:56 -08:00
rcutiny.c rcu: avoid pointless blocked-task warnings 2011-01-14 04:58:08 -08:00
rcutorture.c rcu: add priority-inversion testing to rcutorture 2010-10-07 10:41:08 -07:00
rcutree_plugin.h rcu: increase synchronize_sched_expedited() batching 2010-12-17 12:34:08 -08:00
rcutree_trace.c rcu,cleanup: simplify the code when cpu is dying 2010-11-29 22:01:58 -08:00
rcutree.c 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
rcutree.h rcu: limit rcu_node leaf-level fanout 2010-12-17 12:34:20 -08:00
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
resource.c resources: add arch hook for preventing allocation in reserved areas 2010-12-17 10:01:09 -08:00
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_autogroup.c sched, autogroup: Fix CONFIG_RT_GROUP_SCHED sched_setscheduler() failure 2011-01-18 15:09:42 +01:00
sched_autogroup.h sched, autogroup: Fix CONFIG_RT_GROUP_SCHED sched_setscheduler() failure 2011-01-18 15:09:42 +01:00
sched_clock.c sched: Add some clock info to sched_debug 2010-11-23 10:29:08 +01:00
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: Replace rq->bkl_count with rq->rq_sched_info.bkl_count 2011-01-18 15:09:43 +01:00
sched_fair.c sched: Fix poor interactivity on UP systems due to group scheduler nice tune bug 2011-01-24 11:47:50 +01:00
sched_features.h sched: Rewrite tg_shares_up) 2010-11-18 13:27:46 +01:00
sched_idletask.c
sched_rt.c sched: Implement on-demand (active) cfs_rq list 2010-11-18 13:27:47 +01:00
sched_stats.h sched_stat: Update sched_info_queue/dequeue() code comments 2010-10-24 13:29:01 +02:00
sched_stoptask.c sched: Fix cross-sched-class wakeup preemption 2010-11-11 14:37:23 +01:00
sched.c Merge branch 'sched-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2011-01-20 16:37:55 -08:00
seccomp.c
semaphore.c
signal.c signals: annotate lock context change on ptrace_stop() 2010-10-27 18:03:12 -07:00
smp.c Merge branch 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2011-01-20 18:30:37 -08:00
softirq.c kernel: clean up USE_GENERIC_SMP_HELPERS 2011-01-13 08:03:08 -08:00
spinlock.c
srcu.c rcu: demote SRCU_SYNCHRONIZE_DELAY from kernel-parameter status 2011-01-14 04:56:49 -08:00
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 kmsg_dump: add kmsg_dump() calls to the reboot, halt, poweroff and emergency_restart paths 2011-01-13 08:03:07 -08:00
sysctl_binary.c Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2011-01-13 10:05:56 -08:00
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/dtor/input 2011-01-26 16:31:44 +10:00
taskstats.c taskstats: use better ifdef for alignment 2011-01-13 08:03:19 -08:00
test_kprobes.c kprobes: Fix selftest to clear flags field for reusing probes 2010-10-14 08:55:27 +02:00
time.c Kill off a bunch of warning: ‘inline’ is not at beginning of declaration 2010-11-28 23:08:04 +01:00
timeconst.pl
timer.c Merge branch 'timers-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2011-01-06 10:42:43 -08:00
tracepoint.c tracepoints: Fix section alignment using pointer array 2011-02-03 09:28:46 -05:00
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: improve the user_ns on-the-slab packaging 2011-01-13 08:03:18 -08:00
user-return-notifier.c
user.c fix freeing user_struct in user cache 2010-12-29 11:31:38 -08:00
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 watchdog: Don't change watchdog state on read of sysctl 2011-01-31 13:22:43 +01:00
workqueue_sched.h workqueue: implement concurrency managed dynamic worker pool 2010-06-29 10:07:14 +02:00
workqueue.c workqueue: note the nested NOT_RUNNING test in worker_clr_flags() isn't a noop 2011-01-11 16:03:14 +01:00