Hi Tao,
Thank you for your suggestions for patch. I followed your suggestion and
provided a new patch. Please help to review it, thanks.
>From 831701099a7097662ddec9de464131ad50c7134b Mon Sep 17 00:00:00 2001
From: wonderzyp <wonder...@qq.com>
Date: Wed, 17 Jul 2024 11:02:06 +0800
Subject: [PATCH] A segfault issue was observed on KASAN enabled arm64 kernel
due to the incorrect irq_stack_size, 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 was caused by not setting irq_stack_size correctly, and this
patch will fix the issue by two ways:
1. if CONFIG_IKCONFIG is set, calculate the irq_stack_size according to
kernel source code
2. if CONFIG_IKCONFIG is not set, get THREAD_SHIFT value by disassembling
the tbnz instruction to calculate the irq_stack_size
Signed-off-by: Yeping.Zheng <yeping.zh...@nio.com>
---
arm64.c | 86 +++++++++++++++++++++++++++++++++++++++++++++++++++++++--
1 file changed, 84 insertions(+), 2 deletions(-)
diff --git a/arm64.c b/arm64.c
index b3040d7..8347ba1 100644
--- a/arm64.c
+++ b/arm64.c
@@ -93,6 +93,7 @@ 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_get_vmcoreinfo(unsigned long *vaddr, const char *label,
int base);
+static ulong arm64_set_irq_stack_size(struct machine_specific *ms);
struct kernel_range {
unsigned long modules_vaddr, modules_end;
@@ -2223,8 +2224,10 @@ 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);
+ ms->irq_stack_size = (res > 0) ? res : ARM64_IRQ_STACK_SIZE;
+ }
machdep->flags |= IRQ_STACKS;
@@ -4921,6 +4924,85 @@ static void arm64_calc_KERNELPACMASK(void)
}
}
+static ulong arm64_set_irq_stack_size(struct machine_specific *ms)
+{
+ char *string;
+ int ret;
+ int kasan_thread_shift = 0;
+ int min_thread_shift;
+ ulong arm64_page_shift;
+ ulong thread_shift = 0;
+ ulong thread_size;
+ struct syment *sp;
+ const char* tbnz_str = "tbnz";
+
+ if (kt->ikconfig_flags & IKCONFIG_AVAIL) {
+ if ((ret = get_kernel_config("CONFIG_KASAN_GENERIC", NULL) == IKCONFIG_Y)
||
+ (ret = get_kernel_config("CONFIG_KASAN_SW_TAGS", NULL) == IKCONFIG_Y)) {
+ kasan_thread_shift = 1;
+ }
+ min_thread_shift = 14 + kasan_thread_shift;
+
+ if ((ret = get_kernel_config("CONFIG_VMAP_STACK", NULL)) == IKCONFIG_Y){
+ if ((ret = get_kernel_config("CONFIG_ARM64_PAGE_SHIFT", &string)) ==
IKCONFIG_STR){
+ arm64_page_shift = atol(string);
+ }
+ if (min_thread_shift < arm64_page_shift){
+ thread_shift = arm64_page_shift;
+ } else {
+ thread_shift = min_thread_shift;
+ }
+ }
+ } else {
+
+ if (!(sp = symbol_search("vectors"))) {
+ return -1;
+ }
+
+ const char* tbnz_str = "tbnz";
+ struct gnu_request *req;
+ req = (struct gnu_request *)GETBUF(sizeof(struct gnu_request));
+ req->command = GNU_PASS_THROUGH;
+ req->buf = GETBUF(BUFSIZE);
+ strcat(req->buf, "x/1024i ");
+
+ char tmp[100];
+ sprintf(tmp, "0x%lx", sp->value);
+ strcat(req->buf, tmp);
+ req->flags = (GNU_RETURN_ON_ERROR);
+ open_tmpfile();
+ req->fp = pc->tmpfile;
+ gdb_interface(req);
+
+
+ rewind(pc->tmpfile);
+ char line[BUFSIZE];
+ while (fgets(line, BUFSIZE, pc->tmpfile) != NULL) {
+ // printf("the buffer is not null\n");
+ char* tbnz_pos = strstr(line, tbnz_str);
+ if (tbnz_pos != NULL) {
+ char* thread_shift_pos = strstr(tbnz_pos, "#");
+ if (sscanf(thread_shift_pos + 1, "%ld", &thread_shift) == 1) {
+ if (CRASHDEBUG(1)){
+ error(INFO, "Detect thread shift via tbnz %ld\n", thread_shift);
+ }
+ break;
+ }
+ }
+ }
+ close_tmpfile();
+ FREEBUF(req->buf);
+ FREEBUF(req);
+ }
+
+ if (thread_shift == 0) {
+ return -1;
+ }
+
+ thread_size = ((1UL) << thread_shift);
+ return thread_size;
+}
+
#endif /* ARM64 */
--
2.25.1
Tao Liu <l...@redhat.com> 于2024年7月16日周二 16:22写道：
> Hi Yeping,
>
> Thanks for the fix.
>
> On Thu, Jul 11, 2024 at 1:38 PM <wonder...@gmail.com> wrote:
> >
> > When using the crash tool to parse the ARM64 dump file with KASAN
> enabled, I found that using the bt -a command will cause this tool to
> crash, the following is the backtrace infomation.
> >
> > (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
> > Eventually, I found that it was may caused by not setting irq_stack_size
> properly, and provide this patch to solve it.
> >
>
> Could you please re-draft your commit message? The original one looks
> informal. E.g:
>
> A segfault issue was observed on KASAN enabled arm64 kernel due to the
> incorrect irq_stack_size, see the following stack trace:
> ...
> The issue was caused by ...., and this patch will fix the issue by ....
>
> >
> > From 34b28aa8c11e77d20adec4f7705a14d239c8a55f Mon Sep 17 00:00:00 2001
> > From: wonderzyp <wonder...@qq.com>
> > Date: Mon, 8 Jul 2024 20:11:38 +0800
> > Subject: [PATCH 1131/1131] set_arm64_irq_stack_size
> >
> > Signed-off-by: Yeping Zheng <wonder...@gmail.com>
> > ---
> > arm64.c | 49 +++++++++++++++++++++++++++++++++++++++++++++++--
> > 1 file changed, 47 insertions(+), 2 deletions(-)
> >
> > diff --git a/arm64.c b/arm64.c
> > index b3040d7..39d891b 100644
> > --- a/arm64.c
> > +++ b/arm64.c
> > @@ -93,6 +93,7 @@ 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_get_vmcoreinfo(unsigned long *vaddr, const char
> *label, int base);
> > +static ulong arm64_set_irq_stack_size(struct machine_specific *ms);
> >
> > struct kernel_range {
> > unsigned long modules_vaddr, modules_end;
> > @@ -2223,8 +2224,14 @@ 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);
> > + if (res > 0){
> > + ms->irq_stack_size = res;
> > + } else {
> > + ms->irq_stack_size =
> ARM64_IRQ_STACK_SIZE;
> > + }
> > + }
> >
> > machdep->flags |= IRQ_STACKS;
> >
> > @@ -4921,6 +4928,44 @@ static void arm64_calc_KERNELPACMASK(void)
> > }
> > }
> >
> > +static ulong arm64_set_irq_stack_size(struct machine_specific *ms)
> > +{
> > + char *string;
> > + int ret;
> > + int KASAN_THREAD_SHIFT = 0;
> > + int MIN_THREAD_SHIFT;
> > + ulong ARM64_PAGE_SHIFT;
> > + ulong THREAD_SHIFT = 0;
> > + ulong THREAD_SIZE;
>
> I guess the upper case of variable names is not encouraged, though it
> is the variable that comes from kernel config file.
>
> > + if (kt->ikconfig_flags & IKCONFIG_AVAIL) {
> > + if ((ret = get_kernel_config("CONFIG_KASAN_GENERIC",
> NULL) == IKCONFIG_Y) ||
> > + (ret = get_kernel_config("CONFIG_KASAN_SW_TAGS",
> NULL) == IKCONFIG_Y)) {
> > + KASAN_THREAD_SHIFT = 1;
> > + }
> > + }
> > + MIN_THREAD_SHIFT = 14 + KASAN_THREAD_SHIFT;
> > +
> > + if (kt->ikconfig_flags & IKCONFIG_AVAIL) {
>
> Could the if condition be merged with the prior one?
>
> > + if ((ret = get_kernel_config("CONFIG_VMAP_STACK", NULL))
> == IKCONFIG_Y){
> > + if ((ret =
> get_kernel_config("CONFIG_ARM64_PAGE_SHIFT", &string)) == IKCONFIG_STR){
> > + ARM64_PAGE_SHIFT = atol(string);
> > + }
> > + if (MIN_THREAD_SHIFT < ARM64_PAGE_SHIFT){
> > + THREAD_SHIFT = ARM64_PAGE_SHIFT;
> > + } else {
> > + THREAD_SHIFT = MIN_THREAD_SHIFT;
> > + }
> > + }
> > + }
> > +
> > + if (THREAD_SHIFT == 0) {
> > + return -1;
> > + }
> > +
> > + THREAD_SIZE = ((1UL) << THREAD_SHIFT);
> > + return THREAD_SIZE;
> > +}
>
> I'm OK with the approach above, since it directly came from the kernel
> source. However I'm not a fan of checking kernel configs, there might
> be kernels which are compiled without CONFIG_IKCONFIG.
>
> Could we add an approach here, to get the value from disassembly when
> CONFIG_IKCONFIG is negative?
>
> kernel source: arch/arm64/kernel/entry.S:
>
> .macro kernel_ventry, el:req, ht:req, regsize:req, label:req
> ....
> add sp, sp, x0 // sp' = sp + x0
> sub x0, sp, x0 // x0' = sp' - x0 = (sp + x0) - x0 = sp
> tbnz x0, #THREAD_SHIFT, 0f <<<<<<<<
>
> $ objdump -d vmlinux
> ...
> ffff800080010800 <vectors>:
> ffff800080010800: d10543ff sub sp, sp, #0x150
> ffff800080010804: 8b2063ff add sp, sp, x0
> ffff800080010808: cb2063e0 sub x0, sp, x0
> ffff80008001080c: 37800080 tbnz w0, #16,
> ffff80008001081c <vectors+0x1c> <<<<<<<<<<
>
> It is easy to get the THREAD_SHIFT value by disassembling the tbnz
> instruction. What do you think @Lianbo Jiang
>
> Thanks,
> Tao Liu
>
> > +
> > #endif /* ARM64 */
> >
> >
> > --
> > 2.25.1
> > --
> > Crash-utility mailing list -- devel@lists.crash-utility.osci.io
> > To unsubscribe send an email to devel-le...@lists.crash-utility.osci.io
> > https://${domain_name}/admin/lists/devel.lists.crash-utility.osci.io/
> > Contribution Guidelines: https://github.com/crash-utility/crash/wiki
>
>
From 831701099a7097662ddec9de464131ad50c7134b Mon Sep 17 00:00:00 2001
From: wonderzyp <wonder...@qq.com>
Date: Wed, 17 Jul 2024 11:02:06 +0800
Subject: [PATCH] A segfault issue was observed on KASAN enabled arm64 kernel
due to the incorrect irq_stack_size, 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 was caused by not setting irq_stack_size correctly, and this patch will fix the issue by two ways:
1. if CONFIG_IKCONFIG is set, calculate the irq_stack_size according to kernel source code
2. if CONFIG_IKCONFIG is not set, get THREAD_SHIFT value by disassembling the tbnz instruction to calculate the irq_stack_size
Signed-off-by: Yeping.Zheng <yeping.zh...@nio.com>
---
arm64.c | 86 +++++++++++++++++++++++++++++++++++++++++++++++++++++++--
1 file changed, 84 insertions(+), 2 deletions(-)
diff --git a/arm64.c b/arm64.c
index b3040d7..8347ba1 100644
--- a/arm64.c
+++ b/arm64.c
@@ -93,6 +93,7 @@ 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_get_vmcoreinfo(unsigned long *vaddr, const char *label, int base);
+static ulong arm64_set_irq_stack_size(struct machine_specific *ms);
struct kernel_range {
unsigned long modules_vaddr, modules_end;
@@ -2223,8 +2224,10 @@ 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);
+ ms->irq_stack_size = (res > 0) ? res : ARM64_IRQ_STACK_SIZE;
+ }
machdep->flags |= IRQ_STACKS;
@@ -4921,6 +4924,85 @@ static void arm64_calc_KERNELPACMASK(void)
}
}
+static ulong arm64_set_irq_stack_size(struct machine_specific *ms)
+{
+ char *string;
+ int ret;
+ int kasan_thread_shift = 0;
+ int min_thread_shift;
+ ulong arm64_page_shift;
+ ulong thread_shift = 0;
+ ulong thread_size;
+ struct syment *sp;
+ const char* tbnz_str = "tbnz";
+
+ if (kt->ikconfig_flags & IKCONFIG_AVAIL) {
+ if ((ret = get_kernel_config("CONFIG_KASAN_GENERIC", NULL) == IKCONFIG_Y) ||
+ (ret = get_kernel_config("CONFIG_KASAN_SW_TAGS", NULL) == IKCONFIG_Y)) {
+ kasan_thread_shift = 1;
+ }
+ min_thread_shift = 14 + kasan_thread_shift;
+
+ if ((ret = get_kernel_config("CONFIG_VMAP_STACK", NULL)) == IKCONFIG_Y){
+ if ((ret = get_kernel_config("CONFIG_ARM64_PAGE_SHIFT", &string)) == IKCONFIG_STR){
+ arm64_page_shift = atol(string);
+ }
+ if (min_thread_shift < arm64_page_shift){
+ thread_shift = arm64_page_shift;
+ } else {
+ thread_shift = min_thread_shift;
+ }
+ }
+ } else {
+
+ if (!(sp = symbol_search("vectors"))) {
+ return -1;
+ }
+
+ const char* tbnz_str = "tbnz";
+ struct gnu_request *req;
+ req = (struct gnu_request *)GETBUF(sizeof(struct gnu_request));
+ req->command = GNU_PASS_THROUGH;
+ req->buf = GETBUF(BUFSIZE);
+ strcat(req->buf, "x/1024i ");
+
+ char tmp[100];
+ sprintf(tmp, "0x%lx", sp->value);
+ strcat(req->buf, tmp);
+ req->flags = (GNU_RETURN_ON_ERROR);
+ open_tmpfile();
+ req->fp = pc->tmpfile;
+ gdb_interface(req);
+
+
+ rewind(pc->tmpfile);
+ char line[BUFSIZE];
+ while (fgets(line, BUFSIZE, pc->tmpfile) != NULL) {
+ // printf("the buffer is not null\n");
+ char* tbnz_pos = strstr(line, tbnz_str);
+ if (tbnz_pos != NULL) {
+ char* thread_shift_pos = strstr(tbnz_pos, "#");
+ if (sscanf(thread_shift_pos + 1, "%ld", &thread_shift) == 1) {
+ if (CRASHDEBUG(1)){
+ error(INFO, "Detect thread shift via tbnz %ld\n", thread_shift);
+ }
+ break;
+ }
+ }
+ }
+ close_tmpfile();
+ FREEBUF(req->buf);
+ FREEBUF(req);
+ }
+
+ if (thread_shift == 0) {
+ return -1;
+ }
+
+ thread_size = ((1UL) << thread_shift);
+ return thread_size;
+}
+
#endif /* ARM64 */
--
2.25.1
--
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