kernel_optimize_test/kernel
Marco Elver 14e2ac8de0 kcsan: Support compounded read-write instrumentation
Add support for compounded read-write instrumentation if supported by
the compiler. Adds the necessary instrumentation functions, and a new
type which is used to generate a more descriptive report.

Furthermore, such compounded memory access instrumentation is excluded
from the "assume aligned writes up to word size are atomic" rule,
because we cannot assume that the compiler emits code that is atomic for
compound ops.

LLVM/Clang added support for the feature in:
785d41a261

The new instrumentation is emitted for sets of memory accesses in the
same basic block to the same address with at least one read appearing
before a write. These typically result from compound operations such as
++, --, +=, -=, |=, &=, etc. but also equivalent forms such as "var =
var + 1". Where the compiler determines that it is equivalent to emit a
call to a single __tsan_read_write instead of separate __tsan_read and
__tsan_write, we can then benefit from improved performance and better
reporting for such access patterns.

The new reports now show that the ops are both reads and writes, for
example:

	read-write to 0xffffffff90548a38 of 8 bytes by task 143 on cpu 3:
	 test_kernel_rmw_array+0x45/0xa0
	 access_thread+0x71/0xb0
	 kthread+0x21e/0x240
	 ret_from_fork+0x22/0x30

	read-write to 0xffffffff90548a38 of 8 bytes by task 144 on cpu 2:
	 test_kernel_rmw_array+0x45/0xa0
	 access_thread+0x71/0xb0
	 kthread+0x21e/0x240
	 ret_from_fork+0x22/0x30

Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-08-24 15:09:32 -07:00
..
bpf bpf: Delete repeated words in comments 2020-08-07 18:57:24 +02:00
cgroup for-5.9/block-20200802 2020-08-03 11:57:03 -07:00
configs
debug Remove uninitialized_var() macro for v5.9-rc1 2020-08-04 13:49:43 -07:00
dma Cleanup, SECCOMP_FILTER support, message printing fixes, and other 2020-08-15 18:50:32 -07:00
entry entry: Correct 'noinstr' attributes 2020-07-26 15:42:20 +02:00
events Misc fixes, an expansion of perf syscall access to CAP_PERFMON privileged tools, 2020-08-15 10:34:24 -07:00
gcov treewide: replace '---help---' in Kconfig files with 'help' 2020-06-14 01:57:21 +09:00
irq genirq: Unlock irq descriptor after errors 2020-08-13 09:35:59 +02:00
kcsan kcsan: Support compounded read-write instrumentation 2020-08-24 15:09:32 -07:00
livepatch livepatch: Make klp_apply_object_relocs static 2020-05-11 00:31:38 +02:00
locking A set of locking fixes and updates: 2020-08-10 19:07:44 -07:00
power libnvdimm for 5.9 2020-08-11 10:59:19 -07:00
printk Printk changes for 5.9 2020-08-04 22:22:25 -07:00
rcu rcu: kasan: record and print call_rcu() call stack 2020-08-07 11:33:28 -07:00
sched Two fixes: fix a new tracepoint's output value, and fix the formatting of show-state syslog printouts. 2020-08-15 10:36:40 -07:00
time A set oftimekeeping/VDSO updates: 2020-08-14 14:26:08 -07:00
trace Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2020-08-13 20:03:11 -07:00
.gitignore
acct.c mmap locking API: convert mmap_sem comments 2020-06-09 09:39:14 -07:00
async.c treewide: Remove uninitialized_var() usage 2020-07-16 12:35:15 -07:00
audit_fsnotify.c fsnotify: create method handle_inode_event() in fsnotify_operations 2020-07-27 23:25:50 +02:00
audit_tree.c \n 2020-08-06 19:29:51 -07:00
audit_watch.c fsnotify: create method handle_inode_event() in fsnotify_operations 2020-07-27 23:25:50 +02:00
audit.c audit/stable-5.9 PR 20200803 2020-08-04 14:20:26 -07:00
audit.h revert: 1320a4052e ("audit: trigger accompanying records when no rules present") 2020-07-29 10:00:36 -04:00
auditfilter.c
auditsc.c audit/stable-5.9 PR 20200803 2020-08-04 14:20:26 -07:00
backtracetest.c treewide: Replace DECLARE_TASKLET() with DECLARE_TASKLET_OLD() 2020-07-30 11:15:58 -07:00
bounds.c
capability.c
compat.c
configs.c
context_tracking.c context_tracking: Ensure that the critical path cannot be instrumented 2020-06-11 15:14:36 +02:00
cpu_pm.c kernel/cpu_pm: Fix uninitted local in cpu_pm 2020-05-15 11:44:34 -07:00
cpu.c The changes in this cycle are: 2020-06-03 13:06:42 -07:00
crash_core.c kdump: append kernel build-id string to VMCOREINFO 2020-08-12 10:58:01 -07:00
crash_dump.c
cred.c exec: Teach prepare_exec_creds how exec treats uids & gids 2020-05-20 14:44:21 -05:00
delayacct.c
dma.c
elfcore.c
exec_domain.c
exit.c kernel: add a kernel_wait helper 2020-08-12 10:57:59 -07:00
extable.c
fail_function.c
fork.c A set of locking fixes and updates: 2020-08-10 19:07:44 -07:00
freezer.c
futex.c futex: Convert to use the preferred 'fallthrough' macro 2020-08-13 21:02:12 +02:00
gen_kheaders.sh kbuild: add variables for compression tools 2020-06-06 23:42:01 +09:00
groups.c mm: remove the pgprot argument to __vmalloc 2020-06-02 10:59:11 -07:00
hung_task.c kernel/hung_task.c: introduce sysctl to print all traces when a hung task is detected 2020-06-08 11:05:56 -07:00
iomem.c
irq_work.c irq_work, smp: Allow irq_work on call_single_queue 2020-05-28 10:54:15 +02:00
jump_label.c
kallsyms.c Linux 5.8-rc7 2020-07-28 13:18:01 +02:00
kcmp.c
Kconfig.freezer
Kconfig.hz
Kconfig.locks
Kconfig.preempt
kcov.c kcov: make some symbols static 2020-08-12 10:58:02 -07:00
kexec_core.c
kexec_elf.c
kexec_file.c Misc fixes and small updates all around the place: 2020-08-15 10:38:03 -07:00
kexec_internal.h
kexec.c
kheaders.c
kmod.c kmod: remove redundant "be an" in the comment 2020-08-12 10:58:01 -07:00
kprobes.c Tracing updates for 5.9 2020-08-07 18:29:15 -07:00
ksysfs.c
kthread.c uaccess: add force_uaccess_{begin,end} helpers 2020-08-12 10:57:59 -07:00
latencytop.c
Makefile all arch: remove system call sys_sysctl 2020-08-14 19:56:56 -07:00
module_signature.c
module_signing.c
module-internal.h
module.c Modules updates for v5.9 2020-08-14 11:07:02 -07:00
notifier.c mm: remove vmalloc_sync_(un)mappings() 2020-06-02 10:59:12 -07:00
nsproxy.c nsproxy: support CLONE_NEWTIME with setns() 2020-07-08 11:14:22 +02:00
padata.c padata: remove padata_parallel_queue 2020-07-23 17:34:18 +10:00
panic.c panic: make print_oops_end_marker() static 2020-08-12 10:58:02 -07:00
params.c
pid_namespace.c pid_namespace: use checkpoint_restore_ns_capable() for ns_last_pid 2020-07-19 20:14:42 +02:00
pid.c cap-checkpoint-restore-v5.9 2020-08-04 15:02:07 -07:00
profile.c
ptrace.c
range.c
reboot.c arch: remove unicore32 port 2020-07-01 12:09:13 +03:00
regset.c regset: kill ->get() 2020-07-27 14:31:12 -04:00
relay.c mmap locking API: convert mmap_sem comments 2020-06-09 09:39:14 -07:00
resource.c /dev/mem: Revoke mappings when a driver claims the region 2020-05-27 11:10:05 +02:00
rseq.c
scs.c mm: memcontrol: account kernel stack per node 2020-08-07 11:33:25 -07:00
seccomp.c seccomp: Introduce addfd ioctl to seccomp user notifier 2020-07-14 16:29:42 -07:00
signal.c task_work: only grab task signal lock when needed 2020-08-13 09:01:38 -06:00
smp.c smp: Fix a potential usage of stale nr_cpus 2020-07-22 10:22:04 +02:00
smpboot.c
smpboot.h
softirq.c tasklets API update for v5.9-rc1 2020-08-04 13:40:35 -07:00
stackleak.c gcc-plugins/stackleak: Use asm instrumentation to avoid useless register saving 2020-06-24 07:48:28 -07:00
stacktrace.c uaccess: add force_uaccess_{begin,end} helpers 2020-08-12 10:57:59 -07:00
stop_machine.c
sys_ni.c all arch: remove system call sys_sysctl 2020-08-14 19:56:56 -07:00
sys.c prctl: exe link permission error changed from -EINVAL to -EPERM 2020-07-19 20:14:42 +02:00
sysctl-test.c
sysctl.c mm: use unsigned types for fragmentation score 2020-08-12 10:57:56 -07:00
task_work.c task_work: only grab task signal lock when needed 2020-08-13 09:01:38 -06:00
taskstats.c
test_kprobes.c
torture.c torture: Dump ftrace at shutdown only if requested 2020-06-29 12:01:45 -07:00
tracepoint.c
tsacct.c
ucount.c
uid16.c
uid16.h
umh.c kernel: add a kernel_wait helper 2020-08-12 10:57:59 -07:00
up.c
user_namespace.c
user-return-notifier.c
user.c user.c: make uidhash_table static 2020-06-04 19:06:24 -07:00
usermode_driver.c umd: Stop using split_argv 2020-07-07 11:58:59 -05:00
utsname_sysctl.c
utsname.c
watch_queue.c Notifications over pipes + Keyring notifications 2020-06-13 09:56:21 -07:00
watchdog_hld.c
watchdog.c kernel/watchdog.c: convert {soft/hard}lockup boot parameters to sysctl aliases 2020-06-08 11:05:56 -07:00
workqueue_internal.h
workqueue.c maccess: rename probe_kernel_{read,write} to copy_{from,to}_kernel_nofault 2020-06-17 10:57:41 -07:00