On 10/07/2019 14:25, Will Deacon wrote: > On Wed, Jul 10, 2019 at 02:04:52PM +0100, Vincenzo Frascino wrote: >> Prior to the introduction of Unified vDSO support and compat layer for >> vDSO on arm64, AT_SYSINFO_EHDR was not defined for compat tasks. >> In the current implementation, AT_SYSINFO_EHDR is defined even if the >> compat vdso layer is not built and this causes a regression in the >> expected behavior of the ABI. >> >> Restore the ABI behavior making sure that AT_SYSINFO_EHDR for compat >> tasks is defined only when CONFIG_GENERIC_COMPAT_VDSO and >> CONFIG_COMPAT_VDSO are enabled. > > I think you could do a better job in the changelog of explaining what's > actually going on here. The problem seems to be that you're advertising > the presence of a non-existent vDSO to userspace. > >> Reported-by: John Stultz <[email protected]> >> Signed-off-by: Vincenzo Frascino <[email protected]> >> --- >> arch/arm64/include/asm/elf.h | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/arch/arm64/include/asm/elf.h b/arch/arm64/include/asm/elf.h >> index 3c7037c6ba9b..b7992bb9d414 100644 >> --- a/arch/arm64/include/asm/elf.h >> +++ b/arch/arm64/include/asm/elf.h >> @@ -202,7 +202,7 @@ typedef compat_elf_greg_t >> compat_elf_gregset_t[COMPAT_ELF_NGREG]; >> ({ \ >> set_thread_flag(TIF_32BIT); \ >> }) >> -#ifdef CONFIG_GENERIC_COMPAT_VDSO >> +#if defined(CONFIG_COMPAT_VDSO) && defined(CONFIG_GENERIC_COMPAT_VDSO) > > Can't this just be #ifdef CONFIG_COMPAT_VDSO ? >
Yes, I realized it after I pushed the patch that CONFIG_GENERIC_COMPAT_VDSO can be removed. Posting v2 shortly. > John -- can you give this a whirl, please? > > Cheers, > > Will > -- Regards, Vincenzo
