On Tue 24-11-20 11:28:14, Borislav Petkov wrote: > On Tue, Nov 24, 2020 at 11:20:33AM +0100, Jan Kara wrote: > > On Tue 24-11-20 09:45:07, Borislav Petkov wrote: > > > On Mon, Nov 23, 2020 at 11:46:51PM +0100, Paweł Jasiak wrote: > > > > On 23/11/20, Jan Kara wrote: > > > > > OK, with a help of Boris Petkov I think I have a fix that looks correct > > > > > (attach). Can you please try whether it works for you? Thanks! > > > > > > > > Unfortunately I am getting a linker error. > > > > > > > > ld: arch/x86/entry/syscall_32.o:(.rodata+0x54c): undefined reference to `__ia32_sys_ia32_fanotify_mark' > > > > > > Because CONFIG_COMPAT is not set in your .config. > > > > > > Jan, look at 121b32a58a3a and especially this hunk > > > > > > diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile > > > index 9b294c13809a..b8f89f78b8cd 100644 > > > --- a/arch/x86/kernel/Makefile > > > +++ b/arch/x86/kernel/Makefile > > > @@ -53,6 +53,8 @@ obj-y += setup.o x86_init.o i8259.o irqinit.o > > > obj-$(CONFIG_JUMP_LABEL) += jump_label.o > > > obj-$(CONFIG_IRQ_WORK) += irq_work.o > > > obj-y += probe_roms.o > > > +obj-$(CONFIG_X86_32) += sys_ia32.o > > > +obj-$(CONFIG_IA32_EMULATION) += sys_ia32.o > > > > > > how it enables the ia32 syscalls depending on those config items. Now, > > > you have > > > > > > #ifdef CONFIG_COMPAT > > > -COMPAT_SYSCALL_DEFINE6(fanotify_mark, > > > +SYSCALL_DEFINE6(ia32_fanotify_mark, > > > > > > which is under CONFIG_COMPAT which is not set in Paweł's config. > > > > > > config COMPAT > > > def_bool y > > > depends on IA32_EMULATION || X86_X32 > > > > > > but it depends on those two config items. > > > > > > However, it looks to me like ia32_fanotify_mark's definition should be > > > simply under CONFIG_X86_32 because: > > > > > > IA32_EMULATION is 32-bit emulation on 64-bit kernels > > > X86_X32 is for the x32 ABI > > > > Thanks for checking! I didn't realize I needed to change the ifdefs as well > > (I missed that bit in 121b32a58a3a). So do I understand correctly that > > whenever the kernel is 64-bit, 64-bit syscall args (e.g. defined as u64) are > > passed just fine regardless of whether the userspace is 32-bit or not? > > > > Also how about other 32-bit archs? Because I now realized that > > CONFIG_COMPAT as well as the COMPAT_SYSCALL_DEFINE6() is also utilized by > > other 32-bit archs (I can see a reference to compat_sys_fanotify_mark e.g. > > in sparc, powerpc, and other args). So I probably need to actually keep > > that for other archs but do the modification only for x86, don't I? > > Hmm, you raise a good point and looking at that commit again, the > intention is to supply those ia32 wrappers as both 32-bit native *and* > 32-bit emulation ones. > > So I think this > > > -#ifdef CONFIG_COMPAT > > +#if defined(CONFIG_COMPAT) || defined(CONFIG_X86_32) > > +#ifdef CONFIG_X86_32 > > +SYSCALL_DEFINE6(ia32_fanotify_mark, > > +#elif CONFIG_COMPAT > > COMPAT_SYSCALL_DEFINE6(fanotify_mark, > > +#endif > > should be > > if defined(CONFIG_X86_32) || defined(CONFIG_IA32_EMULATION) > SYSCALL_DEFINE6(ia32_fanotify_mark, > #elif CONFIG_COMPAT > COMPAT_SYSCALL_DEFINE6(fanotify_mark, > #endif > > or so. > > Meaning that 32-bit native or 32-bit emulation supplies > ia32_fanotify_mark() as a syscall wrapper and other arches doing > CONFIG_COMPAT, still do the COMPAT_SYSCALL_DEFINE6() thing. Yeah, looking again at what those config options mean I agree. Patch updated. > But I'd prefer if someone more knowledgeable than me in that whole > syscall macros muck to have a look... I'd prefer that as well but if nobody pops up, I'll just push this to my tree next week and will see what breaks :) Honza -- Jan Kara <jack@xxxxxxxx> SUSE Labs, CR
