Messages in this thread | | | Date | Wed, 27 Oct 2021 23:45:49 -0700 (PDT) | Subject | Re: [PATCH 1/2] riscv: Fix asan-stack clang build | From | Palmer Dabbelt <> |
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On Wed, 27 Oct 2021 22:34:32 PDT (-0700), alexandre.ghiti@canonical.com wrote: > On Thu, Oct 28, 2021 at 7:30 AM Alexandre Ghiti > <alexandre.ghiti@canonical.com> wrote: >> >> On Thu, Oct 28, 2021 at 7:02 AM Palmer Dabbelt <palmer@dabbelt.com> wrote: >> > >> > On Wed, 27 Oct 2021 21:15:28 PDT (-0700), alexandre.ghiti@canonical.com wrote: >> > > On Thu, Oct 28, 2021 at 1:06 AM Palmer Dabbelt <palmer@dabbelt.com> wrote: >> > >> >> > >> On Tue, 26 Oct 2021 21:58:42 PDT (-0700), alexandre.ghiti@canonical.com wrote: >> > >> > Nathan reported that because KASAN_SHADOW_OFFSET was not defined in >> > >> > Kconfig, it prevents asan-stack from getting disabled with clang even >> > >> > when CONFIG_KASAN_STACK is disabled: fix this by defining the >> > >> > corresponding config. >> > >> > >> > >> > Reported-by: Nathan Chancellor <nathan@kernel.org> >> > >> > Signed-off-by: Alexandre Ghiti <alexandre.ghiti@canonical.com> >> > >> > --- >> > >> > arch/riscv/Kconfig | 6 ++++++ >> > >> > arch/riscv/include/asm/kasan.h | 3 +-- >> > >> > arch/riscv/mm/kasan_init.c | 3 +++ >> > >> > 3 files changed, 10 insertions(+), 2 deletions(-) >> > >> > >> > >> > diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig >> > >> > index c1abbc876e5b..79250b1ed54e 100644 >> > >> > --- a/arch/riscv/Kconfig >> > >> > +++ b/arch/riscv/Kconfig >> > >> > @@ -162,6 +162,12 @@ config PAGE_OFFSET >> > >> > default 0xffffffff80000000 if 64BIT && MAXPHYSMEM_2GB >> > >> > default 0xffffffe000000000 if 64BIT && MAXPHYSMEM_128GB >> > >> > >> > >> > +config KASAN_SHADOW_OFFSET >> > >> > + hex >> > >> > + depends on KASAN_GENERIC >> > >> > + default 0xdfffffc800000000 if 64BIT >> > >> > + default 0xffffffff if 32BIT >> > >> >> > >> I thought I posted this somewhere, but this is exactly what my first >> > >> guess was. The problem is that it's hanging on boot for me. I don't >> > >> really have anything exotic going on, it's just a defconfig with >> > >> CONFIG_KASAN=y running in QEMU. >> > >> >> > >> Does this boot for you? >> > > >> > > Yes with the 2nd patch of this series which fixes the issue >> > > encountered here. And that's true I copied/pasted this part of your >> > > patch which was better than what I had initially done, sorry I should >> > > have mentioned you did that, please add a Codeveloped-by or something >> > > like that.
OK, those should probably be in the opposite order (though it looks like they're inter-dependent, which makes things a bit trickier).
>> > >> > Not sure if I'm missing something, but it's still not booting for me. >> > I've put what I'm testing on palmer/to-test, it's these two on top of >> > fixes and merged into Linus' tree >> > >> > * 6d7d351902ff - (HEAD -> to-test, palmer/to-test) Merge remote-tracking branch 'palmer/fixes' into to-test (7 minutes ago) <Palmer Dabbelt> >> > |\ >> > | * 782551edf8f8 - (palmer/fixes) riscv: Fix CONFIG_KASAN_STACK build (6 hours ago) <Alexandre Ghiti> >> > | * 47383e5b3c4f - riscv: Fix asan-stack clang build (6 hours ago) <Alexandre Ghiti> >> > | * 64a19591a293 - (riscv/fixes) riscv: fix misalgned trap vector base address (9 hours ago) <Chen Lu> >> > * | 1fc596a56b33 - (palmer/master, linus/master, linus/HEAD, master) Merge tag 'trace-v5.15-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace (11 hours ago) <Linus Torvalds> >> > >> > Am I missing something else? >> >> Hmm, that's weird, I have just done the same: cherry-picked both my >> commits on top of fixes (64a19591a293) and it boots fine with KASAN >> enabled. Maybe a config thing? I pushed my branch here: >> https://github.com/AlexGhiti/riscv-linux/tree/int/alex/kasan_stack_fixes_rebase > > I pushed the config I use and that boots in that branch, maybe there's > another issue somewhere.
CONFIG_KASAN_VMALLOC=n is what's causing the failure. I'm testing both polarities of that, looks like your config has =y. I haven't looked any further as I'm pretty much cooked for tonight, but if you don't have time then I'll try to find some time tomorrow.
> >> >> > >> > > >> > > Thanks, >> > > >> > > Alex >> > > >> > >> >> > >> > + >> > >> > config ARCH_FLATMEM_ENABLE >> > >> > def_bool !NUMA >> > >> > >> > >> > diff --git a/arch/riscv/include/asm/kasan.h b/arch/riscv/include/asm/kasan.h >> > >> > index a2b3d9cdbc86..b00f503ec124 100644 >> > >> > --- a/arch/riscv/include/asm/kasan.h >> > >> > +++ b/arch/riscv/include/asm/kasan.h >> > >> > @@ -30,8 +30,7 @@ >> > >> > #define KASAN_SHADOW_SIZE (UL(1) << ((CONFIG_VA_BITS - 1) - KASAN_SHADOW_SCALE_SHIFT)) >> > >> > #define KASAN_SHADOW_START KERN_VIRT_START >> > >> > #define KASAN_SHADOW_END (KASAN_SHADOW_START + KASAN_SHADOW_SIZE) >> > >> > -#define KASAN_SHADOW_OFFSET (KASAN_SHADOW_END - (1ULL << \ >> > >> > - (64 - KASAN_SHADOW_SCALE_SHIFT))) >> > >> > +#define KASAN_SHADOW_OFFSET _AC(CONFIG_KASAN_SHADOW_OFFSET, UL) >> > >> > >> > >> > void kasan_init(void); >> > >> > asmlinkage void kasan_early_init(void); >> > >> > diff --git a/arch/riscv/mm/kasan_init.c b/arch/riscv/mm/kasan_init.c >> > >> > index d7189c8714a9..8175e98b9073 100644 >> > >> > --- a/arch/riscv/mm/kasan_init.c >> > >> > +++ b/arch/riscv/mm/kasan_init.c >> > >> > @@ -17,6 +17,9 @@ asmlinkage void __init kasan_early_init(void) >> > >> > uintptr_t i; >> > >> > pgd_t *pgd = early_pg_dir + pgd_index(KASAN_SHADOW_START); >> > >> > >> > >> > + BUILD_BUG_ON(KASAN_SHADOW_OFFSET != >> > >> > + KASAN_SHADOW_END - (1UL << (64 - KASAN_SHADOW_SCALE_SHIFT))); >> > >> > + >> > >> > for (i = 0; i < PTRS_PER_PTE; ++i) >> > >> > set_pte(kasan_early_shadow_pte + i, >> > >> > mk_pte(virt_to_page(kasan_early_shadow_page),
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