Hi Yeping,
On Wed, Aug 14, 2024 at 1:42 PM yp z <wonderzyp@xxxxxxxxx> wrote:
>
> Hi Tao,
>
> I have tested this new patch-v2, and it works well in both branches.
>
Thanks for the testing, let's wait for Lianbo's comments for this.
Thanks,
Tao Liu
> Thanks,
> Yeping
>
> Tao Liu <ltao@xxxxxxxxxx> 于2024年8月14日周三 07:41写道：
>>
>> See the following stack trace:
>> (gdb) bt
>> #0 0x00005635ac2b166b in arm64_unwind_frame (frame=0x7ffdaf35cb70,
>> bt=0x7ffdaf35d430) at arm64.c:2821
>> #1 arm64_back_trace_cmd (bt=0x7ffdaf35d430) at arm64.c:3306
>> #2 0x00005635ac27b108 in back_trace (bt=bt@entry=0x7ffdaf35d430) at
>> kernel.c:3239
>> #3 0x00005635ac2880ae in cmd_bt () at kernel.c:2863
>> #4 0x00005635ac1f16dc in exec_command () at main.c:893
>> #5 0x00005635ac1f192a in main_loop () at main.c:840
>> #6 0x00005635ac50df81 in captured_main (data=<optimized out>) at main.c:1284
>> #7 gdb_main (args=<optimized out>) at main.c:1313
>> #8 0x00005635ac50e000 in gdb_main_entry (argc=<optimized out>,
>> argv=<optimized out>) at main.c:1338
>> #9 0x00005635ac1ea2a5 in main (argc=5, argv=0x7ffdaf35dde8) at main.c:721
>>
>> The issue may be encountered when thread_union symbol not found in vmlinux
>> due to compiling optimization.
>>
>> This patch will try the following 2 methods to get the irq_stack_size
>> when thread_union symbol unavailable:
>>
>> 1. change the thread_shift when KASAN is enabled and with vmcoreinfo.
>> In arm64/include/asm/memory.h:
>>
>> #if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS)
>> ...
>> #define IRQ_STACK_SIZE THREAD_SIZE
>>
>> Since enabling the KASAN will affect the final value,
>> this patch reset IRQ_STACK_SIZE according to the calculation process in
>> kernel code.
>>
>> 2. Try getting the value from kernel code disassembly, to get
>> THREAD_SHIFT directly from tbnz instruction.
>>
>> In arch/arm64/kernel/entry.S:
>> .macro kernel_ventry, el:req, ht:req, regsize:req, label:req
>> ...
>> add sp, sp, x0
>> sub x0, sp, x0
>> tbnz x0, #THREAD_SHIFT, 0f
>>
>> $ gdb vmlinux
>> (gdb) disass vectors
>> Dump of assembler code for function vectors:
>> ...
>> 0xffff800080010804 <+4>: add sp, sp, x0
>> 0xffff800080010808 <+8>: sub x0, sp, x0
>> 0xffff80008001080c <+12>: tbnz w0, #16, 0xffff80008001081c <vectors+28>
>>
>> Signed-off-by: yeping.zheng <yeping.zheng@xxxxxxx>
>> Improved-by: Tao Liu <ltao@xxxxxxxxxx>
>> ---
>>
>> v2 -> v1: Add stack_vm_area member check for task_struct, and kernel
>> file reference.
>>
>> Hi Yeping & lianbo,
>>
>> Please have a test on this version of patch, I guess this will be the
>> last version if test is passed. Thanks in advance!
>>
>> Thanks,
>> Tao Liu
>>
>> ---
>> arm64.c | 63 +++++++++++++++++++++++++++++++++++++++++++++++++++++++--
>> 1 file changed, 61 insertions(+), 2 deletions(-)
>>
>> diff --git a/arm64.c b/arm64.c
>> index 067c879..332e3f0 100644
>> --- a/arm64.c
>> +++ b/arm64.c
>> @@ -95,6 +95,7 @@ static int arm64_is_uvaddr(ulong, struct task_context *);
>> static void arm64_calc_KERNELPACMASK(void);
>> static void arm64_recalc_KERNELPACMASK(void);
>> static int arm64_get_vmcoreinfo(unsigned long *vaddr, const char *label, int base);
>> +static ulong arm64_set_irq_stack_size(void);
>>
>> struct kernel_range {
>> unsigned long modules_vaddr, modules_end;
>> @@ -2340,8 +2341,10 @@ arm64_irq_stack_init(void)
>> if (MEMBER_EXISTS("thread_union", "stack")) {
>> if ((sz = MEMBER_SIZE("thread_union", "stack")) > 0)
>> ms->irq_stack_size = sz;
>> - } else
>> - ms->irq_stack_size = ARM64_IRQ_STACK_SIZE;
>> + } else {
>> + ulong res = arm64_set_irq_stack_size();
>> + ms->irq_stack_size = (res > 0) ? res : ARM64_IRQ_STACK_SIZE;
>> + }
>>
>> machdep->flags |= IRQ_STACKS;
>>
>> @@ -5056,6 +5059,62 @@ static void arm64_recalc_KERNELPACMASK(void){
>> }
>> }
>>
>> +static ulong arm64_set_irq_stack_size(void)
>> +{
>> + int min_thread_shift = 14;
>> + ulong thread_shift = 0;
>> + char buf1[BUFSIZE];
>> + char *pos1, *pos2;
>> + int errflag = 0;
>> +
>> + if (kernel_symbol_exists("vmcoreinfo_data") &&
>> + kernel_symbol_exists("vmcoreinfo_size")) {
>> + /*
>> + * Referring to arch/arm64/include/asm/memory.h
>> + */
>> + if (kernel_symbol_exists("kasan_enable_current")) {
>> + min_thread_shift += 1;
>> + }
>> + if (MEMBER_EXISTS("task_struct", "stack_vm_area") &&
>> + min_thread_shift < machdep->pageshift) {
>> + thread_shift = machdep->pageshift;
>> + } else {
>> + thread_shift = min_thread_shift;
>> + }
>> + } else {
>> + sprintf(buf1, "x/32i vectors");
>> + open_tmpfile();
>> + if (!gdb_pass_through(buf1, pc->tmpfile, GNU_RETURN_ON_ERROR)) {
>> + goto out;
>> + }
>> + rewind(pc->tmpfile);
>> + while (fgets(buf1, BUFSIZE, pc->tmpfile)) {
>> + if ((pos1 = strstr(buf1, "tbnz"))) {
>> + if ((pos2 = strchr(pos1, '#'))) {
>> + pos2 += 1;
>> + for (pos1 = pos2;
>> + *pos2 != '\0' && *pos2 != ',';
>> + pos2++);
>> + *pos2 = '\0';
>> + thread_shift = stol(pos1,
>> + RETURN_ON_ERROR|QUIET, &errflag);
>> + if (errflag) {
>> + thread_shift = 0;
>> + }
>> + break;
>> + }
>> + }
>> + }
>> +out:
>> + close_tmpfile();
>> + }
>> +
>> + if (thread_shift)
>> + return ((1UL) << thread_shift);
>> + else
>> + return 0;
>> +}
>> +
>> #endif /* ARM64 */
>>
>>
>> --
>> 2.40.1
>> --
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