On Tue, Jul 09, 2024 at 02:26:08PM -0700, Nathan Chancellor wrote: > On Tue, Jul 09, 2024 at 03:27:37PM +0300, Leon Romanovsky wrote: > > On Tue, Jul 09, 2024 at 06:52:42PM +0800, flyingpenghao@xxxxxxxxx wrote: > > > From: Peng Hao <flyingpeng@xxxxxxxxxxx> > > > > > > When building kernel with clang, which will typically > > > have sanitizers enabled, there is a warning about a large stack frame. > > > > > > drivers/infiniband/hw/ocrdma/ocrdma_stats.c:686:16: error: stack frame size (20664) exceeds limit (8192) in 'ocrdma_dbgfs_ops_read' [-Werror,-Wframe-larger-than] > > > static ssize_t ocrdma_dbgfs_ops_read(struct file *filp, char __user *buffer, > > > ^ > > > > Please fix it, not hide it. > > Agreed, this is far from an acceptable solution. No details were > provided around compiler, architecture, or configuration, so I can only > speculate what is happening here. From reading the code, I suspect that > ocrdma_add_stat() is getting inlined into all of its callsites but the > stack slot for buff[128] is not getting reused, which may be related to > a missing lifetime marker like [1] or sanitizer instrumentation. I am > guessing that marking ocrdma_dbgfs_ops_read() as noinline_for_stack > would resolve this. > > static noinline_for_stack int ocrdma_add_stat(char *start, char *pcur, This is a good solution, but first let's see if the author can provide more details. > > If this is not tolerable for all configurations, it could be made more > pointed with something like > > static > #if defined(CONFIG_CC_IS_CLANG) && (defined(CONFIG_KASAN) || defined(CONFIG_KCSAN)) > noinline_for_stack > #endif > int ocrdma_add_stat(char *start, char *pcur, > > but I am aware that is quite ugly. > > [1]: https://github.com/llvm/llvm-project/issues/38157#issuecomment-1756321571 > > Cheers, > Nathan > > > > Increase the frame size by 20% to set. > > > > > > Signed-off-by: Peng Hao <flyingpeng@xxxxxxxxxxx> > > > --- > > > drivers/infiniband/hw/ocrdma/Makefile | 6 ++++++ > > > 1 file changed, 6 insertions(+) > > > > > > diff --git a/drivers/infiniband/hw/ocrdma/Makefile b/drivers/infiniband/hw/ocrdma/Makefile > > > index 14fba95021d8..a1e9fcc04751 100644 > > > --- a/drivers/infiniband/hw/ocrdma/Makefile > > > +++ b/drivers/infiniband/hw/ocrdma/Makefile > > > @@ -3,4 +3,10 @@ ccflags-y := -I $(srctree)/drivers/net/ethernet/emulex/benet > > > > > > obj-$(CONFIG_INFINIBAND_OCRDMA) += ocrdma.o > > > > > > +ifneq ($(CONFIG_FRAME_WARN),0) > > > +ifeq ($(filter y,$(CONFIG_KASAN)$(CONFIG_KCSAN)),y) > > > +CFLAGS_ocrdma_stats.o = -Wframe-larger-than=22664 > > > +endif > > > +endif > > > + > > > ocrdma-y := ocrdma_main.o ocrdma_verbs.o ocrdma_hw.o ocrdma_ah.o ocrdma_stats.o > > > -- > > > 2.27.0 > > > > > >
