kernel_optimize_test/kernel
Marco Elver 7e8cad8788 kcsan: Rewrite kcsan_prandom_u32_max() without prandom_u32_state()
[ Upstream commit 71a076f4a61a6c779794ad286f356b39725edc3b ]

Rewrite kcsan_prandom_u32_max() to not depend on code that might be
instrumented, removing any dependency on lib/random32.c. The rewrite
implements a simple linear congruential generator, that is sufficient
for our purposes (for udelay() and skip_watch counter randomness).

The initial motivation for this was to allow enabling KCSAN for
kernel/sched (remove KCSAN_SANITIZE := n from kernel/sched/Makefile),
with CONFIG_DEBUG_PREEMPT=y. Without this change, we could observe
recursion:

	check_access() [via instrumentation]
	  kcsan_setup_watchpoint()
	    reset_kcsan_skip()
	      kcsan_prandom_u32_max()
	        get_cpu_var()
		  preempt_disable()
		    preempt_count_add() [in kernel/sched/core.c]
		      check_access() [via instrumentation]

Note, while this currently does not affect an unmodified kernel, it'd be
good to keep a KCSAN kernel working when KCSAN_SANITIZE := n is removed
from kernel/sched/Makefile to permit testing scheduler code with KCSAN
if desired.

Fixes: cd290ec246 ("kcsan: Use tracing-safe version of prandom")
Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-03-04 11:37:37 +01:00
..
bpf bpf: Clear subreg_def for global function return values 2021-03-04 11:37:34 +01:00
cgroup cgroup-v1: add disabled controller check in cgroup1_parse_param() 2021-02-17 11:02:25 +01:00
configs
debug kdb: Make memory allocations more robust 2021-03-04 11:37:18 +01:00
dma swiotlb: remove the tbl_dma_addr argument to swiotlb_tbl_map_single 2020-11-02 10:10:39 -05:00
entry entry: Fix the incorrect ordering of lockdep and RCU check 2020-11-04 18:06:14 +01:00
events exec: Transform exec_update_mutex into a rw_semaphore 2021-01-09 13:46:24 +01:00
gcov
irq genirq/msi: Activate Multi-MSI early when MSI_FLAG_ACTIVATE_EARLY is set 2021-02-10 09:29:17 +01:00
kcsan kcsan: Rewrite kcsan_prandom_u32_max() without prandom_u32_state() 2021-03-04 11:37:37 +01:00
livepatch kernel/: fix repeated words in comments 2020-10-16 11:11:19 -07:00
locking locking/lockdep: Avoid noinstr warning for DEBUG_LOCKDEP 2021-02-07 15:37:14 +01:00
power PM: hibernate: flush swap writer after marking 2021-02-03 23:28:40 +01:00
printk printk: fix string termination for record_print_text() 2021-01-30 13:55:20 +01:00
rcu rcu-tasks: Move RCU-tasks initialization to before early_initcall() 2021-01-19 18:27:28 +01:00
sched sched: Reenable interrupts in do_sched_yield() 2020-12-30 11:52:59 +01:00
time tick/sched: Remove bogus boot "safety" check 2021-01-06 14:56:55 +01:00
trace bpf: Unbreak BPF_PROG_TYPE_KPROBE when kprobe is called via do_int3 2021-02-17 11:02:25 +01:00
.gitignore
acct.c kernel: acct.c: fix some kernel-doc nits 2020-10-16 11:11:19 -07:00
async.c
audit_fsnotify.c fsnotify: generalize handle_inode_event() 2020-12-30 11:54:18 +01:00
audit_tree.c fsnotify: generalize handle_inode_event() 2020-12-30 11:54:18 +01:00
audit_watch.c fsnotify: generalize handle_inode_event() 2020-12-30 11:54:18 +01:00
audit.c
audit.h
auditfilter.c
auditsc.c
backtracetest.c
bounds.c
capability.c LSM: Signal to SafeSetID when setting group IDs 2020-10-13 09:17:34 -07:00
compat.c
configs.c
context_tracking.c
cpu_pm.c
cpu.c kernel/cpu: add arch override for clear_tasks_mm_cpumask() mm handling 2020-11-27 00:10:39 +11:00
crash_core.c
crash_dump.c
cred.c
delayacct.c
dma.c
exec_domain.c
exit.c kernel/io_uring: cancel io_uring before task works 2021-01-30 13:55:18 +01:00
extable.c
fail_function.c fail_function: Remove a redundant mutex unlock 2020-11-19 11:58:16 -08:00
fork.c exec: Transform exec_update_mutex into a rw_semaphore 2021-01-09 13:46:24 +01:00
freezer.c
futex.c futex: Handle faults correctly for PI futexes 2021-01-30 13:55:17 +01:00
gen_kheaders.sh
groups.c LSM: Signal to SafeSetID when setting group IDs 2020-10-13 09:17:34 -07:00
hung_task.c kernel/hung_task.c: make type annotations consistent 2020-11-02 12:14:19 -08:00
iomem.c
irq_work.c
jump_label.c kernel/: fix repeated words in comments 2020-10-16 11:11:19 -07:00
kallsyms.c treewide: Convert macro and uses of __section(foo) to __section("foo") 2020-10-25 14:51:49 -07:00
kcmp.c exec: Transform exec_update_mutex into a rw_semaphore 2021-01-09 13:46:24 +01:00
Kconfig.freezer
Kconfig.hz
Kconfig.locks
Kconfig.preempt
kcov.c
kexec_core.c kernel: kexec: remove the lock operation of system_transition_mutex 2021-02-03 23:28:37 +01:00
kexec_elf.c
kexec_file.c kernel/resource: move and rename IORESOURCE_MEM_DRIVER_MANAGED 2020-10-16 11:11:18 -07:00
kexec_internal.h
kexec.c
kheaders.c
kmod.c
kprobes.c kretprobe: Avoid re-registration of the same kretprobe earlier 2021-02-10 09:29:16 +01:00
ksysfs.c
kthread.c kthread: Extract KTHREAD_IS_PER_CPU 2021-02-07 15:37:17 +01:00
latencytop.c
Makefile elfcore: fix building with clang 2020-12-11 14:02:14 -08:00
module_signature.c
module_signing.c
module-internal.h
module.c module: delay kobject uevent until after module init call 2021-01-06 14:56:54 +01:00
notifier.c
nsproxy.c
padata.c
panic.c panic: don't dump stack twice on warn 2020-11-14 11:26:04 -08:00
params.c params: Replace zero-length array with flexible-array member 2020-10-29 17:22:59 -05:00
pid_namespace.c kernel/: fix repeated words in comments 2020-10-16 11:11:19 -07:00
pid.c exec: Transform exec_update_mutex into a rw_semaphore 2021-01-09 13:46:24 +01:00
profile.c
ptrace.c ptrace: Set PF_SUPERPRIV when checking capability 2020-11-17 12:53:22 -08:00
range.c kernel.h: split out min()/max() et al. helpers 2020-10-16 11:11:19 -07:00
reboot.c reboot: fix overflow parsing reboot cpu number 2020-11-14 11:26:03 -08:00
regset.c
relay.c kernel/relay.c: drop unneeded initialization 2020-10-16 11:11:22 -07:00
resource.c kernel/resource: make iomem_resource implicit in release_mem_region_adjustable() 2020-10-16 11:11:18 -07:00
rseq.c
scftorture.c
scs.c
seccomp.c seccomp: Set PF_SUPERPRIV when checking capability 2020-11-17 12:53:22 -08:00
signal.c ptrace: fix task_join_group_stop() for the case when current is traced 2020-11-02 12:14:19 -08:00
smp.c Merge tag 'core-rcu-2020-10-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2020-10-18 14:34:50 -07:00
smpboot.c kthread: Extract KTHREAD_IS_PER_CPU 2021-02-07 15:37:17 +01:00
smpboot.h
softirq.c
stackleak.c
stacktrace.c
static_call.c
stop_machine.c stop_machine, rcu: Mark functions as notrace 2020-10-26 12:12:27 +01:00
sys_ni.c mm/madvise: introduce process_madvise() syscall: an external memory hinting API 2020-10-18 09:27:10 -07:00
sys.c kernel/sys.c: fix prototype of prctl_get_tid_address() 2020-10-25 11:44:16 -07:00
sysctl-test.c
sysctl.c
task_work.c task_work: cleanup notification modes 2020-10-17 15:05:30 -06:00
taskstats.c
test_kprobes.c
torture.c
tracepoint.c tracepoint: Replace zero-length array with flexible-array member 2020-10-29 17:22:59 -05:00
tsacct.c
ucount.c
uid16.c
uid16.h
umh.c
up.c
user_namespace.c kernel/: fix repeated words in comments 2020-10-16 11:11:19 -07:00
user-return-notifier.c
user.c
usermode_driver.c
utsname_sysctl.c
utsname.c
watch_queue.c
watchdog_hld.c
watchdog.c kernel/watchdog: fix watchdog_allowed_mask not used warning 2020-11-14 11:26:03 -08:00
workqueue_internal.h
workqueue.c workqueue: Restrict affinity change to rescuer 2021-02-07 15:37:17 +01:00