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charset=us-ascii Content-Disposition: inline In-Reply-To: <20240311112330.372158-1-changbin.du@huawei.com> X-Rspam-User: X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: A513780018 X-Stat-Signature: wnnrkxqppckoy6hb5356hoo44b5htofk X-HE-Tag: 1710157360-466331 X-HE-Meta: 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Mon, Mar 11, 2024 at 07:23:30PM +0800, Changbin Du wrote: > This disables msan check for preempt_count_{add,sub} to fix a > instrumentation recursion issue on preempt_count: > > __msan_metadata_ptr_for_load_4() -> kmsan_virt_addr_valid() -> > preempt_disable() -> __msan_metadata_ptr_for_load_4() > > With this fix, I was able to run kmsan kernel with: > o CONFIG_DEBUG_KMEMLEAK=n > o CONFIG_KFENCE=n > o CONFIG_LOCKDEP=n > > KMEMLEAK and KFENCE generate too many false positives in unwinding code. > LOCKDEP still introduces instrumenting recursions issue. But these are > other issues expected to be fixed. > > Cc: Marco Elver > Signed-off-by: Changbin Du > --- > kernel/sched/core.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/kernel/sched/core.c b/kernel/sched/core.c > index 9116bcc90346..5b63bb98e60a 100644 > --- a/kernel/sched/core.c > +++ b/kernel/sched/core.c > @@ -5848,7 +5848,7 @@ static inline void preempt_latency_start(int val) > } > } > > -void preempt_count_add(int val) > +void __no_kmsan_checks preempt_count_add(int val) > { > #ifdef CONFIG_DEBUG_PREEMPT > /* > @@ -5880,7 +5880,7 @@ static inline void preempt_latency_stop(int val) > trace_preempt_on(CALLER_ADDR0, get_lock_parent_ip()); > } What prevents a larger loop via one of the calles of preempt_count_{add,sub}() For example, via preempt_latency_{start,stop}() ? ... or via some *other* instrumentation that might be placed in those? I suspect we should be using noinstr or __always_inline in a bunch of places to clean this up properly. Mark.