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

On 4/26/21 7:17 PM, piliu wrote: > > 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. Sorry for the limited knowledge of this field. I have more question during the reviewing. -1.is this reproducible with SW TAGS? -2. HW TAGS aims for malloc, while here I see the handling LR, PC. It seems that they are more related to "Pointer Authentication"

Thanks, Pingfan >> >> " >> 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