| Message ID | 20210909104925.809674-1-elver@google.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | kasan: double -Wframe-larger-than threshold if KASAN | expand |
On Thu, 9 Sept 2021 at 12:49, Marco Elver <elver@google.com> wrote: > All architectures at least double stack size when using one of the KASAN > software modes that rely on compiler instrumentation. > > Until now, warnings emitted by -Wframe-larger-than could easily be > ignored, as we would still get a working kernel. > > However, with the introduction of -Werror (CONFIG_WERROR=y), it makes > sense to at least double the -Wframe-larger-than threshold for > software-based KASAN modes to reflect the already increased stack sizes > when building a kernel with KASAN enabled. > > Link: https://lkml.kernel.org/r/YTbOs13waorzamZ6@Ryzen-9-3900X.localdomain > Signed-off-by: Marco Elver <elver@google.com> FWIW, there's still no consensus if this is what we want, and the discussion continues at: https://lkml.kernel.org/r/CANpmjNPBdx4b7bp=reNJPMzSNetdyrk+503_1LLoxNMYwUhSHg@mail.gmail.com > --- > lib/Kconfig.debug | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug > index ed4a31e34098..2055bbb6724a 100644 > --- a/lib/Kconfig.debug > +++ b/lib/Kconfig.debug > @@ -345,6 +345,8 @@ endif # DEBUG_INFO > config FRAME_WARN > int "Warn for stack frames larger than" > range 0 8192 > + default 4096 if 64BIT && (KASAN_GENERIC || KASAN_SW_TAGS) > + default 2048 if !64BIT && (KASAN_GENERIC || KASAN_SW_TAGS) > default 2048 if GCC_PLUGIN_LATENT_ENTROPY > default 1536 if (!64BIT && PARISC) > default 1024 if (!64BIT && !PARISC) > -- > 2.33.0.153.gba50c8fa24-goog >
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index ed4a31e34098..2055bbb6724a 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -345,6 +345,8 @@ endif # DEBUG_INFO config FRAME_WARN int "Warn for stack frames larger than" range 0 8192 + default 4096 if 64BIT && (KASAN_GENERIC || KASAN_SW_TAGS) + default 2048 if !64BIT && (KASAN_GENERIC || KASAN_SW_TAGS) default 2048 if GCC_PLUGIN_LATENT_ENTROPY default 1536 if (!64BIT && PARISC) default 1024 if (!64BIT && !PARISC)
All architectures at least double stack size when using one of the KASAN software modes that rely on compiler instrumentation. Until now, warnings emitted by -Wframe-larger-than could easily be ignored, as we would still get a working kernel. However, with the introduction of -Werror (CONFIG_WERROR=y), it makes sense to at least double the -Wframe-larger-than threshold for software-based KASAN modes to reflect the already increased stack sizes when building a kernel with KASAN enabled. Link: https://lkml.kernel.org/r/YTbOs13waorzamZ6@Ryzen-9-3900X.localdomain Signed-off-by: Marco Elver <elver@google.com> --- lib/Kconfig.debug | 2 ++ 1 file changed, 2 insertions(+)