kernel_optimize_test/kernel/sched
Gustavo A. R. Silva 04f5c362ec sched/fair: Replace zero-length array with flexible-array
The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:

struct foo {
        int stuff;
        struct boo array[];
};

By making use of the mechanism above, we will get a compiler warning
in case the flexible array does not occur last in the structure, which
will help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.

Also, notice that, dynamic memory allocations won't be affected by
this change:

"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]

sizeof(flexible-array-member) triggers a warning because flexible array
members have incomplete type[1]. There are some instances of code in
which the sizeof operator is being incorrectly/erroneously applied to
zero-length arrays and the result is zero. Such instances may be hiding
some bugs. So, this work (flexible-array member conversions) will also
help to get completely rid of those sorts of issues.

This issue was found with the help of Coccinelle.

[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 7649773293 ("cxgb3/l2t: Fix undefined behaviour")

Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200507192141.GA16183@embeddedor
2020-05-19 20:34:14 +02:00
..
autogroup.c
autogroup.h
clock.c sched/clock: Use static_branch_likely() with sched_clock_running 2019-11-29 08:10:54 +01:00
completion.c completion: Use lockdep_assert_RT_in_threaded_ctx() in complete_all() 2020-03-23 18:40:25 +01:00
core.c sched: Make scheduler_ipi inline 2020-05-12 17:10:49 +02:00
cpuacct.c sched/cpuacct: Use __this_cpu_add() instead of this_cpu_ptr() 2020-05-19 20:34:13 +02:00
cpudeadline.c
cpudeadline.h
cpufreq_schedutil.c sched/uclamp: Rename uclamp_util_with() into uclamp_rq_util_with() 2019-12-25 10:42:08 +01:00
cpufreq.c cpufreq: Avoid leaving stale IRQ work items during CPU offline 2019-12-12 17:59:43 +01:00
cpupri.c sched/rt: cpupri_find: Trigger a full search as fallback 2020-03-20 13:06:20 +01:00
cpupri.h sched/rt: Optimize cpupri_find() on non-heterogenous systems 2020-03-06 12:57:27 +01:00
cputime.c sched/vtime: Work around an unitialized variable warning 2020-04-15 11:06:50 +02:00
deadline.c sched/deadline: Make two functions static 2020-03-06 12:57:24 +01:00
debug.c Merge branch 'sched/urgent' 2020-05-19 20:34:12 +02:00
fair.c sched/fair: Replace zero-length array with flexible-array 2020-05-19 20:34:14 +02:00
features.h sched/fair/util_est: Implement faster ramp-up EWMA on utilization increases 2019-10-29 10:01:07 +01:00
idle.c idle: fix spelling mistake "iterrupts" -> "interrupts" 2020-01-17 10:19:22 +01:00
isolation.c sched/isolation: Allow "isolcpus=" to skip unknown sub-parameters 2020-04-15 10:38:26 +02:00
loadavg.c timers/nohz: Update NOHZ load in remote tick 2020-01-28 21:36:44 +01:00
Makefile
membarrier.c membarrier: Fix RCU locking bug caused by faulty merge 2019-10-01 21:27:50 +02:00
pelt.c sched/pelt: Sync util/runnable_sum with PELT window when propagating 2020-05-19 20:34:14 +02:00
pelt.h sched/pelt: Add support to track thermal pressure 2020-03-06 12:57:17 +01:00
psi.c psi: Move PF_MEMSTALL out of task->flags 2020-03-20 13:06:19 +01:00
rt.c sched/rt: Remove unnecessary push for unfit tasks 2020-03-06 12:57:29 +01:00
sched-pelt.h
sched.h sched/fair: Replace zero-length array with flexible-array 2020-05-19 20:34:14 +02:00
stats.c
stats.h psi: Move PF_MEMSTALL out of task->flags 2020-03-20 13:06:19 +01:00
stop_task.c sched/core: Further clarify sched_class::set_next_task() 2019-11-11 08:35:21 +01:00
swait.c sched/swait: Prepare usage in completions 2020-03-21 16:00:23 +01:00
topology.c sched/topology: Kill SD_LOAD_BALANCE 2020-04-30 20:14:39 +02:00
wait_bit.c sched/wait: fix ___wait_var_event(exclusive) 2019-12-17 13:32:50 +01:00
wait.c Add wake_up_interruptible_sync_poll_locked() 2019-10-31 15:12:23 +00:00