From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Sasha Levin Subject: [PATCH AUTOSEL 5.4 42/57] s390/ftrace: fix potential crashes when switching tracers Date: Thu, 30 Apr 2020 09:52:03 -0400 Message-Id: <20200430135218.20372-42-sashal@kernel.org> In-Reply-To: <20200430135218.20372-1-sashal@kernel.org> References: <20200430135218.20372-1-sashal@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Philipp Rudo , Vasily Gorbik , Sasha Levin , linux-s390@vger.kernel.org From: Philipp Rudo [ Upstream commit 8ebf6da9db1b2a20bb86cc1bee2552e894d03308 ] 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 Signed-off-by: Vasily Gorbik Signed-off-by: Sasha Levin --- 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(-) diff --git a/arch/s390/kernel/diag.c b/arch/s390/kernel/diag.c index 61f2b0412345a..ccba63aaeb470 100644 --- a/arch/s390/kernel/diag.c +++ b/arch/s390/kernel/diag.c @@ -133,7 +133,7 @@ void diag_stat_inc(enum diag_stat_enum nr) } 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); diff --git a/arch/s390/kernel/smp.c b/arch/s390/kernel/smp.c index f468a10e52062..66bf050d785cf 100644 --- 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) { diag_stat_inc_norecursion(DIAG_STAT_X09C); diff --git a/arch/s390/kernel/trace.c b/arch/s390/kernel/trace.c index 490b52e850145..11a669f3cc93c 100644 --- 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; -- 2.20.1