Re: [Crash-utility] [PATCH 2/2] arm64: make crash CONFIG_KASAN_HW_TAGS aware

Hi Vinayak, On 3/30/21 9:52 PM, Vinayak Menon wrote: > With CONFIG_KASAN_HW_TAGS enabled kvaddr can be tagged > and this results in readmem, vtop etc. fail like below.

> > " > please wait... (gathering kmem slab cache data) > crash: invalid kernel virtual address: f0ffff878000201c  type: > "kmem_cache objsize/object_size" > crash: get_active_set: no tasks found? > please wait... (gathering task table data) > crash: invalid kernel virtual address: f1ffff87f51e3530  type: > "xa_node shift" > " > > Make the mask introduced for pointer authentication generic > and use it in vtop and kvaddr validation. > > Signed-off-by: Vinayak Menon <vinayakm.list(a)gmail.com&gt; > --- >   arm64.c | 50 +++++++++++++++++++++++++++++++------------------- >   defs.h  |  2 +- >   2 files changed, 32 insertions(+), 20 deletions(-) > > diff --git a/arm64.c b/arm64.c > index 5b59972..bb41cbb 100644 > --- a/arm64.c > +++ b/arm64.c > @@ -85,7 +85,8 @@ static int arm64_get_kvaddr_ranges(struct > vaddr_range *); >   static void arm64_get_crash_notes(void); >   static void arm64_calc_VA_BITS(void); >   static int arm64_is_uvaddr(ulong, struct task_context *); > -static void arm64_calc_KERNELPACMASK(void); > +static int arm64_is_kvaddr(ulong); > +static void arm64_calc_KERNELTAGMASK(void); >   /* > @@ -215,7 +216,7 @@ arm64_init(int when) >           machdep->pagemask = ~((ulonglong)machdep->pageoffset); >           arm64_calc_VA_BITS(); > -        arm64_calc_KERNELPACMASK(); > +        arm64_calc_KERNELTAGMASK(); >           ms = machdep->machspec; >           if (ms->VA_BITS_ACTUAL) { >               ms->page_offset = ARM64_PAGE_OFFSET_ACTUAL; > @@ -228,7 +229,7 @@ arm64_init(int when) >               machdep->kvbase = ARM64_VA_START; >               ms->userspace_top = ARM64_USERSPACE_TOP; >           } > -        machdep->is_kvaddr = generic_is_kvaddr; > +        machdep->is_kvaddr = arm64_is_kvaddr; >           machdep->kvtop = arm64_kvtop; >           if (machdep->flags & NEW_VMEMMAP) { >               struct syment *sp; > @@ -477,7 +478,7 @@ arm64_init(int when) >       case LOG_ONLY: >           machdep->machspec = &arm64_machine_specific; >           arm64_calc_VA_BITS(); > -        arm64_calc_KERNELPACMASK(); > +        arm64_calc_KERNELTAGMASK(); >           arm64_calc_phys_offset(); >           machdep->machspec->page_offset = ARM64_PAGE_OFFSET; >           arm64_calc_physvirt_offset(); > @@ -608,7 +609,7 @@ arm64_dump_machdep_table(ulong arg) >       fprintf(fp, "          dis_filter: arm64_dis_filter()\n"); >       fprintf(fp, "            cmd_mach: arm64_cmd_mach()\n"); >       fprintf(fp, "        get_smp_cpus: arm64_get_smp_cpus()\n"); > -    fprintf(fp, "           is_kvaddr: generic_is_kvaddr()\n"); > +    fprintf(fp, "           is_kvaddr: arm64_is_kvaddr()\n"); >       fprintf(fp, "           is_uvaddr: arm64_is_uvaddr()\n"); >       fprintf(fp, "     value_to_symbol: > generic_machdep_value_to_symbol()\n"); >       fprintf(fp, "     init_kernel_pgd: arm64_init_kernel_pgd\n"); > @@ -668,9 +669,9 @@ arm64_dump_machdep_table(ulong arg) >           fprintf(fp, "%ld\n", ms->VA_BITS_ACTUAL); >       else >           fprintf(fp, "(unused)\n"); > -    fprintf(fp, "CONFIG_ARM64_KERNELPACMASK: "); > -    if (ms->CONFIG_ARM64_KERNELPACMASK) > -        fprintf(fp, "%lx\n", ms->CONFIG_ARM64_KERNELPACMASK); > +    fprintf(fp, "CONFIG_ARM64_KERNELTAGMASK: "); > +    if (ms->CONFIG_ARM64_KERNELTAGMASK) > +        fprintf(fp, "%lx\n", ms->CONFIG_ARM64_KERNELTAGMASK); >       else >           fprintf(fp, "(unused)\n"); >       fprintf(fp, "         userspace_top: %016lx\n", ms->userspace_top); > @@ -1208,6 +1209,9 @@ arm64_kvtop(struct task_context *tc, ulong > kvaddr, physaddr_t *paddr, int verbos >       if (!IS_KVADDR(kvaddr)) >           return FALSE; > +    if (kvaddr & (1UL << 63)) > +        kvaddr |= machdep->machspec->CONFIG_ARM64_KERNELTAGMASK; > + >       if (!vt->vmalloc_start) { >           *paddr = VTOP(kvaddr); >           return TRUE; > @@ -1828,7 +1832,7 @@ arm64_is_kernel_exception_frame(struct bt_info > *bt, ulong stkptr) >       if (INSTACK(regs->sp, bt) && INSTACK(regs->regs[29], bt) && >           !(regs->pstate & (0xffffffff00000000ULL | PSR_MODE32_BIT)) && >           is_kernel_text(regs->pc) && > -        is_kernel_text(regs->regs[30] | > ms->CONFIG_ARM64_KERNELPACMASK)) { > +        is_kernel_text(regs->regs[30] | > ms->CONFIG_ARM64_KERNELTAGMASK)) { >           switch (regs->pstate & PSR_MODE_MASK) >           { >           case PSR_MODE_EL1t: > @@ -2198,8 +2202,8 @@ arm64_unwind_frame(struct bt_info *bt, struct > arm64_stackframe *frame) >       frame->sp = fp + 0x10; >       frame->fp = GET_STACK_ULONG(fp); >       frame->pc = GET_STACK_ULONG(fp + 8); > -    if (is_kernel_text(frame->pc | ms->CONFIG_ARM64_KERNELPACMASK)) > -        frame->pc |= ms->CONFIG_ARM64_KERNELPACMASK; > +    if (is_kernel_text(frame->pc | ms->CONFIG_ARM64_KERNELTAGMASK)) > +        frame->pc |= ms->CONFIG_ARM64_KERNELTAGMASK; >       if ((frame->fp == 0) && (frame->pc == 0)) >           return FALSE; > @@ -2869,8 +2873,8 @@ arm64_print_text_symbols(struct bt_info *bt, > struct arm64_stackframe *frame, FIL >       for (i = (start - bt->stackbase)/sizeof(ulong); i < > LONGS_PER_STACK; i++) { >           up = (ulong *)(&bt->stackbuf[i*sizeof(ulong)]); >           val = *up; > -        if (is_kernel_text(val | ms->CONFIG_ARM64_KERNELPACMASK)) { > -            val |= ms->CONFIG_ARM64_KERNELPACMASK; > +        if (is_kernel_text(val | ms->CONFIG_ARM64_KERNELTAGMASK)) { > +            val |= ms->CONFIG_ARM64_KERNELTAGMASK; >               name = closest_symbol(val); >               fprintf(ofp, "  %s[%s] %s at %lx", >                   bt->flags & BT_ERROR_MASK ? > @@ -3205,8 +3209,8 @@ arm64_print_exception_frame(struct bt_info *bt, > ulong pt_regs, int mode, FILE *o >           rows = 4; >       } else { >           LR = regs->regs[30]; > -        if (is_kernel_text (LR | ms->CONFIG_ARM64_KERNELPACMASK)) > -            LR |= ms->CONFIG_ARM64_KERNELPACMASK; > +        if (is_kernel_text (LR | ms->CONFIG_ARM64_KERNELTAGMASK)) > +            LR |= ms->CONFIG_ARM64_KERNELTAGMASK; >           SP = regs->sp; >           top_reg = 29; >           is_64_bit = TRUE; > @@ -4102,6 +4106,14 @@ arm64_calc_virtual_memory_ranges(void) >   } >   static int > +arm64_is_kvaddr(ulong addr) > +{ > +    if (addr & (1UL << 63)) > +        addr |= machdep->machspec->CONFIG_ARM64_KERNELTAGMASK; > +    return generic_is_kvaddr(addr); > +} > + > +static int >   arm64_is_uvaddr(ulong addr, struct task_context *tc) >   { >           return (addr < machdep->machspec->userspace_top); > @@ -4129,21 +4141,21 @@ arm64_swp_offset(ulong pte) >       return pte; >   } > -static void arm64_calc_KERNELPACMASK(void) > +static void arm64_calc_KERNELTAGMASK(void) >   { >       ulong value = 0; >       char *string; > -    if ((string = pc->read_vmcoreinfo("NUMBER(KERNELPACMASK)"))) { > +    if ((string = pc->read_vmcoreinfo("NUMBER(KERNELTAGMASK)"))) { I git grep 5.12 kernel, but did not find this. Do you plan to do it in kernel firstly? Thanks, Pingfan >           value = htol(string, QUIET, NULL); >           free(string); >       } else if (machdep->machspec->tag_mask) { >           value = machdep->machspec->tag_mask; >       } > -    machdep->machspec->CONFIG_ARM64_KERNELPACMASK = value; > +    machdep->machspec->CONFIG_ARM64_KERNELTAGMASK = value; >       if (CRASHDEBUG(1)) > -        fprintf(fp, "CONFIG_ARM64_KERNELPACMASK: %lx\n", value); > +        fprintf(fp, "CONFIG_ARM64_KERNELTAGMASK: %lx\n", value); >   } >   #endif  /* ARM64 */ > diff --git a/defs.h b/defs.h > index d406f5f..770c335 100644 > --- a/defs.h > +++ b/defs.h > @@ -3329,7 +3329,7 @@ struct machine_specific { >       ulong VA_BITS_ACTUAL; >       ulong CONFIG_ARM64_VA_BITS; >       ulong VA_START; > -    ulong CONFIG_ARM64_KERNELPACMASK; > +    ulong CONFIG_ARM64_KERNELTAGMASK; >       ulong physvirt_offset; >       ulong tag_mask; >   }; > > -- > Crash-utility mailing list > Crash-utility(a)redhat.com > https://listman.redhat.com/mailman/listinfo/crash-utility > -- Crash-utility mailing list Crash-utility(a)redhat.com https://listman.redhat.com/mailman/listinfo/crash-utility