linux/kernel
Anders Roxell 6347244316 kernel/kcov.c: mark write_comp_data() as notrace
Since __sanitizer_cov_trace_const_cmp4 is marked as notrace, the
function called from __sanitizer_cov_trace_const_cmp4 shouldn't be
traceable either.  ftrace_graph_caller() gets called every time func
write_comp_data() gets called if it isn't marked 'notrace'.  This is the
backtrace from gdb:

 #0  ftrace_graph_caller () at ../arch/arm64/kernel/entry-ftrace.S:179
 #1  0xffffff8010201920 in ftrace_caller () at ../arch/arm64/kernel/entry-ftrace.S:151
 #2  0xffffff8010439714 in write_comp_data (type=5, arg1=0, arg2=0, ip=18446743524224276596) at ../kernel/kcov.c:116
 #3  0xffffff8010439894 in __sanitizer_cov_trace_const_cmp4 (arg1=<optimized out>, arg2=<optimized out>) at ../kernel/kcov.c:188
 #4  0xffffff8010201874 in prepare_ftrace_return (self_addr=18446743524226602768, parent=0xffffff801014b918, frame_pointer=18446743524223531344) at ./include/generated/atomic-instrumented.h:27
 #5  0xffffff801020194c in ftrace_graph_caller () at ../arch/arm64/kernel/entry-ftrace.S:182

Rework so that write_comp_data() that are called from
__sanitizer_cov_trace_*_cmp*() are marked as 'notrace'.

Commit 903e8ff867 ("kernel/kcov.c: mark funcs in __sanitizer_cov_trace_pc() as notrace")
missed to mark write_comp_data() as 'notrace'. When that patch was
created gcc-7 was used. In lib/Kconfig.debug
config KCOV_ENABLE_COMPARISONS
	depends on $(cc-option,-fsanitize-coverage=trace-cmp)

That code path isn't hit with gcc-7. However, it were that with gcc-8.

Link: http://lkml.kernel.org/r/20181206143011.23719-1-anders.roxell@linaro.org
Signed-off-by: Anders Roxell <anders.roxell@linaro.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Co-developed-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-01-04 13:13:47 -08:00
..
bpf
cgroup Merge branch 'for-4.21' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup 2018-12-29 10:57:20 -08:00
configs
debug kdb: use bool for binary state indicators 2018-12-30 08:31:52 +00:00
dma DMA mapping updates for Linux 4.21 2018-12-28 14:12:21 -08:00
events mm/mmu_notifier: use structure for invalidate_range_start/end calls v2 2018-12-28 12:11:50 -08:00
gcov
irq
livepatch
locking Merge branch 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-12-26 14:25:52 -08:00
power mm: convert totalram_pages and totalhigh_pages variables to atomic 2018-12-28 12:11:47 -08:00
printk Printk changes for 4.21 2018-12-27 11:24:43 -08:00
rcu
sched sched/fair: Fix infinite loop in update_blocked_averages() by reverting a9e7f6544b 2018-12-30 13:54:31 +01:00
time y2038: more syscalls and cleanups 2018-12-28 12:45:04 -08:00
trace Tracing changes for v4.21: 2018-12-31 11:46:59 -08:00
.gitignore
acct.c
async.c
audit.c
audit.h
audit_fsnotify.c
audit_tree.c
audit_watch.c
auditfilter.c
auditsc.c
backtracetest.c
bounds.c
capability.c
compat.c
configs.c
context_tracking.c
cpu.c
cpu_pm.c
crash_core.c
crash_dump.c
cred.c
delayacct.c
dma.c
elfcore.c
exec_domain.c
exit.c
extable.c
fail_function.c
fork.c fork: fix some -Wmissing-prototypes warnings 2019-01-04 13:13:47 -08:00
freezer.c
futex.c y2038: more syscalls and cleanups 2018-12-28 12:45:04 -08:00
groups.c
hung_task.c kernel/hung_task.c: break RCU locks based on jiffies 2019-01-04 13:13:45 -08:00
iomem.c
irq_work.c
jump_label.c
kallsyms.c
kcmp.c
Kconfig.freezer
Kconfig.hz
Kconfig.locks
Kconfig.preempt
kcov.c kernel/kcov.c: mark write_comp_data() as notrace 2019-01-04 13:13:47 -08:00
kexec.c
kexec_core.c mm: convert totalram_pages and totalhigh_pages variables to atomic 2018-12-28 12:11:47 -08:00
kexec_file.c
kexec_internal.h
kmod.c
kprobes.c Merge branch 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-12-26 14:45:18 -08:00
ksysfs.c
kthread.c
latencytop.c
Makefile y2038: more syscalls and cleanups 2018-12-28 12:45:04 -08:00
memremap.c mm/hmm: fix memremap.h, move dev_page_fault_t callback to hmm 2018-12-28 12:11:52 -08:00
module-internal.h
module.c Driver core patches for 4.21-rc1 2018-12-28 20:44:29 -08:00
module_signing.c
notifier.c
nsproxy.c
padata.c
panic.c kernel/sysctl: add panic_print into sysctl 2019-01-04 13:13:47 -08:00
params.c
pid.c Fix failure path in alloc_pid() 2018-12-28 12:42:30 -08:00
pid_namespace.c
profile.c
ptrace.c
range.c
reboot.c
relay.c
resource.c kernel, resource: check for IORESOURCE_SYSRAM in release_mem_region_adjustable 2018-12-28 12:11:49 -08:00
rseq.c
seccomp.c
signal.c
smp.c
smpboot.c
smpboot.h
softirq.c
stackleak.c
stacktrace.c
stop_machine.c
sys.c
sys_ni.c
sysctl.c kernel/sysctl: add panic_print into sysctl 2019-01-04 13:13:47 -08:00
sysctl_binary.c kernel/sysctl: add panic_print into sysctl 2019-01-04 13:13:47 -08:00
task_work.c
taskstats.c
test_kprobes.c
torture.c
tracepoint.c
tsacct.c
ucount.c
uid16.c
uid16.h
umh.c
up.c
user-return-notifier.c
user.c
user_namespace.c
utsname.c
utsname_sysctl.c
watchdog.c
watchdog_hld.c
workqueue.c
workqueue_internal.h