linux_dsm_epyc7002/kernel/locking
Gustavo A. R. Silva db78538c75 locking/lockdep: 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/20200507185804.GA15036@embeddedor
2020-05-19 20:34:18 +02:00
..
lock_events_list.h locking/rwsem: Adaptive disabling of reader optimistic spinning 2019-06-17 12:28:09 +02:00
lock_events.c locking/lock_events: Don't show pvqspinlock events on bare metal 2019-04-10 10:56:05 +02:00
lock_events.h locking/lock_events: Use raw_cpu_{add,inc}() for stats 2019-06-03 12:32:56 +02:00
lockdep_internals.h locking/lockdep: Reuse freed chain_hlocks entries 2020-02-11 13:10:52 +01:00
lockdep_proc.c locking/lockdep: Reuse freed chain_hlocks entries 2020-02-11 13:10:52 +01:00
lockdep_states.h locking/lockdep: Rework FS_RECLAIM annotation 2017-08-10 12:29:03 +02:00
lockdep.c locking/lockdep: Replace zero-length array with flexible-array 2020-05-19 20:34:18 +02:00
locktorture.c locktorture: Forgive apparent unfairness if CPU hotplug 2020-02-20 15:59:59 -08:00
Makefile locking/rwsem: Merge rwsem.h and rwsem-xadd.c into rwsem.c 2019-06-17 12:27:57 +02:00
mcs_spinlock.h locking/mcs: Use smp_cond_load_acquire() in MCS spin loop 2018-04-27 09:48:49 +02:00
mutex-debug.c lockdep: Introduce wait-type checks 2020-03-21 16:00:24 +01:00
mutex-debug.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
mutex.c Revert "locking/mutex: Complain upon mutex API misuse in IRQ contexts" 2019-12-11 00:27:43 +01:00
mutex.h mutex: Fix up mutex_waiter usage 2019-08-08 09:09:25 +02:00
osq_lock.c locking/osq: Use optimized spinning loop for arm64 2020-01-17 10:19:30 +01:00
percpu-rwsem.c locking/percpu-rwsem: Fix a task_struct refcount 2020-04-08 12:05:06 +02:00
qrwlock.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 157 2019-05-30 11:26:37 -07:00
qspinlock_paravirt.h Revert "locking/pvqspinlock: Don't wait if vCPU is preempted" 2019-09-25 10:22:37 +02:00
qspinlock_stat.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 157 2019-05-30 11:26:37 -07:00
qspinlock.c locking/qspinlock: Fix inaccessible URL of MCS lock paper 2020-01-17 10:19:30 +01:00
rtmutex_common.h locking/rtmutex: Handle non enqueued waiters gracefully in remove_waiter() 2018-03-28 23:01:30 +02:00
rtmutex-debug.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
rtmutex-debug.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
rtmutex.c locking/rtmutex: Remove unused rt_mutex_cmpxchg_relaxed() 2020-04-27 12:26:40 +02:00
rtmutex.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
rwsem.c lockdep: Introduce wait-type checks 2020-03-21 16:00:24 +01:00
rwsem.h locking/percpu-rwsem: Remove the embedded rwsem 2020-02-11 13:10:56 +01:00
semaphore.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 436 2019-06-05 17:37:17 +02:00
spinlock_debug.c lockdep: Introduce wait-type checks 2020-03-21 16:00:24 +01:00
spinlock.c asm-generic/mmiowb: Add generic implementation of mmiowb() tracking 2019-04-08 11:59:39 +01:00
test-ww_mutex.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 9 2019-05-21 11:28:40 +02:00