Hi, Tao and Alex
Thank you for working on this.
On Fri, Jan 3, 2025 at 1:54 PM <devel-request@xxxxxxxxxxxxxxxxxxxxxxxxxxx> wrote:
Date: Fri, 3 Jan 2025 18:48:14 +1300
From: Tao Liu <ltao@xxxxxxxxxx>
Subject: [PATCH v1 2/5] Call cmd_bt silently after
"set pid"
To: devel@xxxxxxxxxxxxxxxxxxxxxxxxxxx
Cc: alexey.makhalov@xxxxxxxxxxxx
Message-ID: <20250103054817.364053-3-ltao@xxxxxxxxxx>
Content-Type: text/plain; charset="US-ASCII"; x-default=true
Cmd bt will list multi-stacks of one task. After we "set <pid>" switch
context to one task, we first need a bt call to detect the multi-stacks,
however we don't want any console output from it, so a nullfp is used for
output receive. The silent bt call is only triggered once as part of task
context switch by cmd set.
A array of user_regs pointers is reserved for each supported arch. If one
extra stack found, a user_regs structure will be allocated for storing regs
value of the stack.
Co-developed-by: Alexey Makhalov <alexey.makhalov@xxxxxxxxxxxx>
Co-developed-by: Tao Liu <ltao@xxxxxxxxxx>
Signed-off-by: Tao Liu <ltao@xxxxxxxxxx>
---
arm64.c | 4 ++++
crash_target.c | 5 +++++
gdb-10.2.patch | 2 +-
kernel.c | 20 ++++++++++++++++++++
ppc64.c | 4 ++++
x86_64.c | 3 +++
6 files changed, 37 insertions(+), 1 deletion(-)
diff --git a/arm64.c b/arm64.c
index 1cdde5f..8291301 100644
--- a/arm64.c
+++ b/arm64.c
@@ -126,6 +126,10 @@ struct user_regs_bitmap_struct {
ulong bitmap[32];
};
I have no more comments about the patchset, only two things:
[1] This was defined in various architectures such as X86 64, aarch64 and ppc64, can it be defined in a common file and included with define macros such as "#if defined(X86_64) || defined(ARM64) || defined(PPC64)"?
+#define MAX_EXCEPTION_STACKS 7
+ulong extra_stacks_idx = 0;
+struct user_regs_bitmap_struct *extra_stacks_regs[MAX_EXCEPTION_STACKS] = {0};
+
And also add code comments to say why it(max exception stacks) is 7.
[2] build warning
cc -c -g -DX86_64 -DLZO -DGDB_10_2 kernel.c -I./gdb-10.2/bfd -I./gdb-10.2/include -Wall -O2 -Wstrict-prototypes -Wmissing-prototypes -fstack-protector -Wformat-security kernel.c:12009:6: warning: no previous prototype for ‘silent_call_bt’ [-Wmissing-prototypes]
12009 | void silent_call_bt(void)
| ^~~~~~~~~~~~~~
static inline bool is_mte_kvaddr(ulong addr)
{
/* check for ARM64_MTE enabled */
diff --git a/crash_target.c b/crash_target.c
index c5ad1df..8cfa744 100644
--- a/crash_target.c
+++ b/crash_target.c
@@ -31,6 +31,9 @@ extern "C" int crash_get_current_task_reg (int regno, const char *regname,
extern "C" int gdb_change_thread_context (void);
extern "C" int gdb_add_substack (int);
extern "C" void crash_get_current_task_info(unsigned long *pid, char **comm);
+#if defined (TARGET_X86_64) || defined (TARGET_ARM64) || defined (TARGET_PPC64)
+extern "C" void silent_call_bt(void);
+#endif
/* The crash target. */
@@ -164,6 +165,10 @@ gdb_change_thread_context (void)
/* 3rd, refresh regcache for tid 0 */
target_fetch_registers(get_current_regcache(), -1);
reinit_frame_cache();
+#if defined (TARGET_X86_64) || defined (TARGET_ARM64) || defined (TARGET_PPC64)
+ /* 4th, invoke bt silently to refresh the additional stacks */
+ silent_call_bt();
This looks tricky, but I have no idea for the time being, maybe we can improve it in the future.
Other changes are fine to me.
Thanks
Lianbo
+#endif
return TRUE;
}
diff --git a/gdb-10.2.patch b/gdb-10.2.patch
index c867660..7baa925 100644
--- a/gdb-10.2.patch
+++ b/gdb-10.2.patch
@@ -55,7 +55,7 @@ exit 0
# your system doesn't have fcntl.h in /usr/include (which is where it
# should be according to Posix).
-DEFS = @DEFS@
-+DEFS = -DCRASH_MERGE @DEFS@
++DEFS = -DCRASH_MERGE -DTARGET_${CRASH_TARGET} @DEFS@
GDB_CFLAGS = -I. -I$(srcdir) -I$(srcdir)/config \
-DLOCALEDIR="\"$(localedir)\"" $(DEFS)
diff --git a/kernel.c b/kernel.c
index 8c2e0ca..1c8f500 100644
--- a/kernel.c
+++ b/kernel.c
@@ -12001,3 +12001,23 @@ int get_linux_banner_from_vmlinux(char *buf, size_t size)
return TRUE;
}
+
+#if defined(X86_64) || defined(ARM64) || defined(PPC64)
+extern ulong extra_stacks_idx;
+extern void *extra_stacks_regs[];
+void silent_call_bt(void)
+{
+ FILE *fp_save = fp;
+ fp = pc->nullfp;
+
+ for (int i = 0; i < extra_stacks_idx; i++) {
+ FREEBUF(extra_stacks_regs[i]);
+ extra_stacks_regs[i] = NULL;
+ }
+ sprintf(pc->command_line, "bt\n");
+ argcnt = parse_line(pc->command_line, args);
+ optind = 1;
+ cmd_bt();
+ fp = fp_save;
+}
+#endif
\ No newline at end of file
diff --git a/ppc64.c b/ppc64.c
index 7ac12fe..532eb3f 100644
--- a/ppc64.c
+++ b/ppc64.c
@@ -80,6 +80,10 @@ struct user_regs_bitmap_struct {
ulong bitmap[32];
};
+#define MAX_EXCEPTION_STACKS 7
+ulong extra_stacks_idx = 0;
+struct user_regs_bitmap_struct *extra_stacks_regs[MAX_EXCEPTION_STACKS] = {0};
+
static int is_opal_context(ulong sp, ulong nip)
{
uint64_t opal_start, opal_end;
diff --git a/x86_64.c b/x86_64.c
index 53ae3ef..e544be8 100644
--- a/x86_64.c
+++ b/x86_64.c
@@ -160,6 +160,9 @@ struct user_regs_bitmap_struct {
ulong bitmap[32];
};
+ulong extra_stacks_idx = 0;
+struct user_regs_bitmap_struct *extra_stacks_regs[MAX_EXCEPTION_STACKS] = {0};
+
/*
* Do all necessary machine-specific setup here. This is called several
* times during initialization.
--
2.47.0
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