[Crash-utility] [PATCH 2/2] arm64: make crash CONFIG_KASAN_HW_TAGS aware
piliu
piliu at redhat.com
Mon Apr 26 11:17:44 UTC 2021
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 at gmail.com>
> ---
> 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;
> };
>
> --
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