From: Philipp Rudo prudo@linux.ibm.com
commit 8ebf6da9db1b2a20bb86cc1bee2552e894d03308 upstream.
Switching tracers include instruction patching. To prevent that a instruction is patched while it's read the instruction patching is done in stop_machine 'context'. This also means that any function called during stop_machine must not be traced. Thus add 'notrace' to all functions called within stop_machine.
Fixes: 1ec2772e0c3c ("s390/diag: add a statistic for diagnose calls") Fixes: 38f2c691a4b3 ("s390: improve wait logic of stop_machine") Fixes: 4ecf0a43e729 ("processor: get rid of cpu_relax_yield") Signed-off-by: Philipp Rudo prudo@linux.ibm.com Signed-off-by: Vasily Gorbik gor@linux.ibm.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- arch/s390/kernel/diag.c | 2 +- arch/s390/kernel/smp.c | 4 ++-- arch/s390/kernel/trace.c | 2 +- 3 files changed, 4 insertions(+), 4 deletions(-)
--- a/arch/s390/kernel/diag.c +++ b/arch/s390/kernel/diag.c @@ -133,7 +133,7 @@ void diag_stat_inc(enum diag_stat_enum n } EXPORT_SYMBOL(diag_stat_inc);
-void diag_stat_inc_norecursion(enum diag_stat_enum nr) +void notrace diag_stat_inc_norecursion(enum diag_stat_enum nr) { this_cpu_inc(diag_stat.counter[nr]); trace_s390_diagnose_norecursion(diag_map[nr].code); --- a/arch/s390/kernel/smp.c +++ b/arch/s390/kernel/smp.c @@ -403,7 +403,7 @@ int smp_find_processor_id(u16 address) return -1; }
-bool arch_vcpu_is_preempted(int cpu) +bool notrace arch_vcpu_is_preempted(int cpu) { if (test_cpu_flag_of(CIF_ENABLED_WAIT, cpu)) return false; @@ -413,7 +413,7 @@ bool arch_vcpu_is_preempted(int cpu) } EXPORT_SYMBOL(arch_vcpu_is_preempted);
-void smp_yield_cpu(int cpu) +void notrace smp_yield_cpu(int cpu) { if (!MACHINE_HAS_DIAG9C) return; --- a/arch/s390/kernel/trace.c +++ b/arch/s390/kernel/trace.c @@ -14,7 +14,7 @@ EXPORT_TRACEPOINT_SYMBOL(s390_diagnose);
static DEFINE_PER_CPU(unsigned int, diagnose_trace_depth);
-void trace_s390_diagnose_norecursion(int diag_nr) +void notrace trace_s390_diagnose_norecursion(int diag_nr) { unsigned long flags; unsigned int *depth;