[PATCH v3 0/5] Fix some GDB command error and add some GDB commands

[PATCH v3 0/5] Fix some GDB command error and add some GDB commands

[Kuan-Ying Lee]

Fix some GDB command errors and add some useful GDB commands.

Patch 1:
 - Fix timerlist parsing issue
Patch 2-3:
 - Add rbtree inorder traverse.
 - Fix 'lx-mounts' command error.
Patch 4:
 - Add 'lx-stack_depot_lookup' command to provides
   users with backtrace of a handle.
Patch 5:
 - Add 'lx-kasan_mem_to_shadow' command to translate
   the memory address to kasan shadow memory address.

v1->v2:
 - Add patch to fix 'lx-mounts' and 'lx-timerlist' gdb command errors.

v2->v3:
 - Rebase on linux-next:next-20240722.

Kuan-Ying Lee (5):
  scripts/gdb: fix timerlist parsing issue
  scripts/gdb: add iteration function for rbtree
  scripts/gdb: fix lx-mounts command error
  scripts/gdb: Add 'lx-stack_depot_lookup' command.
  scripts/gdb: Add 'lx-kasan_mem_to_shadow' command

 scripts/gdb/linux/kasan.py      | 44 +++++++++++++++++++++++++++++++++
 scripts/gdb/linux/proc.py       |  4 +--
 scripts/gdb/linux/rbtree.py     | 12 +++++++++
 scripts/gdb/linux/stackdepot.py | 27 ++++++++++++++++++++
 scripts/gdb/linux/timerlist.py  | 31 ++++++++++++-----------
 scripts/gdb/vmlinux-gdb.py      |  1 +
 6 files changed, 102 insertions(+), 17 deletions(-)
 create mode 100644 scripts/gdb/linux/kasan.py

-- 
2.34.1

[PATCH v3 1/5] scripts/gdb: fix timerlist parsing issue

[Kuan-Ying Lee]

Commit 7988e5ae2be7 ("tick: Split nohz and highres features from
nohz_mode") and commit 7988e5ae2be7 ("tick: Split nohz and
highres features from nohz_mode") move 'tick_stopped' and 'nohz_mode'
to flags field which will break the gdb lx-mounts command:

(gdb) lx-timerlist
Python Exception <class 'gdb.error'>: There is no member named nohz_mode.
Error occurred in Python: There is no member named nohz_mode.

(gdb) lx-timerlist
Python Exception <class 'gdb.error'>: There is no member named tick_stopped.
Error occurred in Python: There is no member named tick_stopped.

We move 'tick_stopped' and 'nohz_mode' to flags field instead.

Fixes: a478ffb2ae23 ("tick: Move individual bit features to debuggable mask accesses")
Fixes: 7988e5ae2be7 ("tick: Split nohz and highres features from nohz_mode")
Cc: <stable@vger.kernel.org>
Signed-off-by: Kuan-Ying Lee <kuan-ying.lee@canonical.com>
---
 scripts/gdb/linux/timerlist.py | 31 ++++++++++++++++---------------
 1 file changed, 16 insertions(+), 15 deletions(-)

diff --git a/scripts/gdb/linux/timerlist.py b/scripts/gdb/linux/timerlist.py
index 64bc87191003..98445671fe83 100644
--- a/scripts/gdb/linux/timerlist.py
+++ b/scripts/gdb/linux/timerlist.py
@@ -87,21 +87,22 @@ def print_cpu(hrtimer_bases, cpu, max_clock_bases):
             text += "\n"
 
         if constants.LX_CONFIG_TICK_ONESHOT:
-            fmts = [("  .{}      : {}", 'nohz_mode'),
-                    ("  .{}      : {} nsecs", 'last_tick'),
-                    ("  .{}   : {}", 'tick_stopped'),
-                    ("  .{}   : {}", 'idle_jiffies'),
-                    ("  .{}     : {}", 'idle_calls'),
-                    ("  .{}    : {}", 'idle_sleeps'),
-                    ("  .{} : {} nsecs", 'idle_entrytime'),
-                    ("  .{}  : {} nsecs", 'idle_waketime'),
-                    ("  .{}  : {} nsecs", 'idle_exittime'),
-                    ("  .{} : {} nsecs", 'idle_sleeptime'),
-                    ("  .{}: {} nsecs", 'iowait_sleeptime'),
-                    ("  .{}   : {}", 'last_jiffies'),
-                    ("  .{}     : {}", 'next_timer'),
-                    ("  .{}   : {} nsecs", 'idle_expires')]
-            text += "\n".join([s.format(f, ts[f]) for s, f in fmts])
+            TS_FLAG_STOPPED = 1 << 1
+            TS_FLAG_NOHZ = 1 << 4
+            text += f"  .{'nohz':15s}: {int(bool(ts['flags'] & TS_FLAG_NOHZ))}\n"
+            text += f"  .{'last_tick':15s}: {ts['last_tick']}\n"
+            text += f"  .{'tick_stopped':15s}: {int(bool(ts['flags'] & TS_FLAG_STOPPED))}\n"
+            text += f"  .{'idle_jiffies':15s}: {ts['idle_jiffies']}\n"
+            text += f"  .{'idle_calls':15s}: {ts['idle_calls']}\n"
+            text += f"  .{'idle_sleeps':15s}: {ts['idle_sleeps']}\n"
+            text += f"  .{'idle_entrytime':15s}: {ts['idle_entrytime']} nsecs\n"
+            text += f"  .{'idle_waketime':15s}: {ts['idle_waketime']} nsecs\n"
+            text += f"  .{'idle_exittime':15s}: {ts['idle_exittime']} nsecs\n"
+            text += f"  .{'idle_sleeptime':15s}: {ts['idle_sleeptime']} nsecs\n"
+            text += f"  .{'iowait_sleeptime':15s}: {ts['iowait_sleeptime']} nsecs\n"
+            text += f"  .{'last_jiffies':15s}: {ts['last_jiffies']}\n"
+            text += f"  .{'next_timer':15s}: {ts['next_timer']}\n"
+            text += f"  .{'idle_expires':15s}: {ts['idle_expires']} nsecs\n"
             text += "\njiffies: {}\n".format(jiffies)
 
         text += "\n"
-- 
2.34.1

[PATCH v3 2/5] scripts/gdb: add iteration function for rbtree

[Kuan-Ying Lee]

Add inorder iteration function for rbtree usage.

This is a preparation patch for the next patch to
fix the gdb mounts issue.

Fixes: 2eea9ce4310d ("mounts: keep list of mounts in an rbtree")
Cc: <stable@vger.kernel.org>
Signed-off-by: Kuan-Ying Lee <kuan-ying.lee@canonical.com>
---
 scripts/gdb/linux/rbtree.py | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/scripts/gdb/linux/rbtree.py b/scripts/gdb/linux/rbtree.py
index fe462855eefd..fcbcc5f4153c 100644
--- a/scripts/gdb/linux/rbtree.py
+++ b/scripts/gdb/linux/rbtree.py
@@ -9,6 +9,18 @@ from linux import utils
 rb_root_type = utils.CachedType("struct rb_root")
 rb_node_type = utils.CachedType("struct rb_node")
 
+def rb_inorder_for_each(root):
+    def inorder(node):
+        if node:
+            yield from inorder(node['rb_left'])
+            yield node
+            yield from inorder(node['rb_right'])
+
+    yield from inorder(root['rb_node'])
+
+def rb_inorder_for_each_entry(root, gdbtype, member):
+    for node in rb_inorder_for_each(root):
+        yield utils.container_of(node, gdbtype, member)
 
 def rb_first(root):
     if root.type == rb_root_type.get_type():
-- 
2.34.1

[PATCH v3 3/5] scripts/gdb: fix lx-mounts command error

[Kuan-Ying Lee]

(gdb) lx-mounts
      mount          super_block     devname pathname fstype options
Python Exception <class 'gdb.error'>: There is no member named list.
Error occurred in Python: There is no member named list.

We encoutner the above issue after commit 2eea9ce4310d ("mounts: keep
list of mounts in an rbtree"). The commit move a mount from list into
rbtree.

So we can instead use rbtree to iterate all mounts information.

Fixes: 2eea9ce4310d ("mounts: keep list of mounts in an rbtree")
Cc: <stable@vger.kernel.org>
Signed-off-by: Kuan-Ying Lee <kuan-ying.lee@canonical.com>
---
 scripts/gdb/linux/proc.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/scripts/gdb/linux/proc.py b/scripts/gdb/linux/proc.py
index 43c687e7a69d..65dd1bd12964 100644
--- a/scripts/gdb/linux/proc.py
+++ b/scripts/gdb/linux/proc.py
@@ -18,6 +18,7 @@ from linux import utils
 from linux import tasks
 from linux import lists
 from linux import vfs
+from linux import rbtree
 from struct import *
 
 
@@ -172,8 +173,7 @@ values of that process namespace"""
         gdb.write("{:^18} {:^15} {:>9} {} {} options\n".format(
                   "mount", "super_block", "devname", "pathname", "fstype"))
 
-        for mnt in lists.list_for_each_entry(namespace['list'],
-                                             mount_ptr_type, "mnt_list"):
+        for mnt in rbtree.rb_inorder_for_each_entry(namespace['mounts'], mount_ptr_type, "mnt_node"):
             devname = mnt['mnt_devname'].string()
             devname = devname if devname else "none"
 
-- 
2.34.1

[PATCH v3 4/5] scripts/gdb: Add 'lx-stack_depot_lookup' command.

[Kuan-Ying Lee]

This command allows users to quickly retrieve a stacktrace
using a handle obtained from a memory coredump.

Example output:
(gdb) lx-stack_depot_lookup 0x00c80300
   0xffff8000807965b4 <kmem_cache_alloc_noprof+660>:    mov     x20, x0
   0xffff800081a077d8 <kmem_cache_oob_alloc+76>:        mov     x1, x0
   0xffff800081a079a0 <test_version_show+100>:  cbnz    w0, 0xffff800081a07968 <test_version_show+44>
   0xffff800082f4a3fc <kobj_attr_show+60>:      ldr     x19, [sp, #16]
   0xffff800080a0fb34 <sysfs_kf_seq_show+460>:  ldp     x3, x4, [sp, #96]
   0xffff800080a0a550 <kernfs_seq_show+296>:    ldp     x19, x20, [sp, #16]
   0xffff8000808e7b40 <seq_read_iter+836>:      mov     w5, w0
   0xffff800080a0b8ac <kernfs_fop_read_iter+804>:       mov     x23, x0
   0xffff800080914a48 <copy_splice_read+972>:   mov     x6, x0
   0xffff8000809151c4 <do_splice_read+348>:     ldr     x21, [sp, #32]

Signed-off-by: Kuan-Ying Lee <kuan-ying.lee@canonical.com>
---
 scripts/gdb/linux/stackdepot.py | 27 +++++++++++++++++++++++++++
 1 file changed, 27 insertions(+)

diff --git a/scripts/gdb/linux/stackdepot.py b/scripts/gdb/linux/stackdepot.py
index bb3a0f843931..37313a5a51a0 100644
--- a/scripts/gdb/linux/stackdepot.py
+++ b/scripts/gdb/linux/stackdepot.py
@@ -13,6 +13,13 @@ if constants.LX_CONFIG_STACKDEPOT:
     stack_record_type = utils.CachedType('struct stack_record')
     DEPOT_STACK_ALIGN = 4
 
+def help():
+    t = """Usage: lx-stack_depot_lookup [Hex handle value]
+    Example:
+        lx-stack_depot_lookup 0x00c80300\n"""
+    gdb.write("Unrecognized command\n")
+    raise gdb.GdbError(t)
+
 def stack_depot_fetch(handle):
     global DEPOT_STACK_ALIGN
     global stack_record_type
@@ -57,3 +64,23 @@ def stack_depot_print(handle):
                 gdb.execute("x /i 0x%x" % (int(entries[i])))
             except Exception as e:
                 gdb.write("%s\n" % e)
+
+class StackDepotLookup(gdb.Command):
+    """Search backtrace by handle"""
+
+    def __init__(self):
+        if constants.LX_CONFIG_STACKDEPOT:
+            super(StackDepotLookup, self).__init__("lx-stack_depot_lookup", gdb.COMMAND_SUPPORT)
+
+    def invoke(self, args, from_tty):
+        if not constants.LX_CONFIG_STACKDEPOT:
+            raise gdb.GdbError('CONFIG_STACKDEPOT is not set')
+
+        argv = gdb.string_to_argv(args)
+        if len(argv) == 1:
+            handle = int(argv[0], 16)
+            stack_depot_print(gdb.Value(handle).cast(utils.get_uint_type()))
+        else:
+            help()
+
+StackDepotLookup()
-- 
2.34.1

[PATCH v3 5/5] scripts/gdb: Add 'lx-kasan_mem_to_shadow' command

[Kuan-Ying Lee]

This command allows users to quickly translate memory address
to the kasan shadow memory address.

Example output:
(gdb) lx-kasan_mem_to_shadow 0xffff000019acc008
shadow addr: 0xffff600003359801

Signed-off-by: Kuan-Ying Lee <kuan-ying.lee@canonical.com>
---
 scripts/gdb/linux/kasan.py | 44 ++++++++++++++++++++++++++++++++++++++
 scripts/gdb/vmlinux-gdb.py |  1 +
 2 files changed, 45 insertions(+)
 create mode 100644 scripts/gdb/linux/kasan.py

diff --git a/scripts/gdb/linux/kasan.py b/scripts/gdb/linux/kasan.py
new file mode 100644
index 000000000000..56730b3fde0b
--- /dev/null
+++ b/scripts/gdb/linux/kasan.py
@@ -0,0 +1,44 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# Copyright 2024 Canonical Ltd.
+#
+# Authors:
+#  Kuan-Ying Lee <kuan-ying.lee@canonical.com>
+#
+
+import gdb
+from linux import constants, mm
+
+def help():
+    t = """Usage: lx-kasan_mem_to_shadow [Hex memory addr]
+    Example:
+        lx-kasan_mem_to_shadow 0xffff000008eca008\n"""
+    gdb.write("Unrecognized command\n")
+    raise gdb.GdbError(t)
+
+class KasanMemToShadow(gdb.Command):
+    """Translate memory address to kasan shadow address"""
+
+    p_ops = None
+
+    def __init__(self):
+        if constants.LX_CONFIG_KASAN_GENERIC or constants.LX_CONFIG_KASAN_SW_TAGS:
+            super(KasanMemToShadow, self).__init__("lx-kasan_mem_to_shadow", gdb.COMMAND_SUPPORT)
+
+    def invoke(self, args, from_tty):
+        if not constants.LX_CONFIG_KASAN_GENERIC or constants.LX_CONFIG_KASAN_SW_TAGS:
+            raise gdb.GdbError('CONFIG_KASAN_GENERIC or CONFIG_KASAN_SW_TAGS is not set')
+
+        argv = gdb.string_to_argv(args)
+        if len(argv) == 1:
+            if self.p_ops is None:
+                self.p_ops = mm.page_ops().ops
+            addr = int(argv[0], 16)
+            shadow_addr = self.kasan_mem_to_shadow(addr)
+            gdb.write('shadow addr: 0x%x\n' % shadow_addr)
+        else:
+            help()
+    def kasan_mem_to_shadow(self, addr):
+        return (addr >> self.p_ops.KASAN_SHADOW_SCALE_SHIFT) + self.p_ops.KASAN_SHADOW_OFFSET
+
+KasanMemToShadow()
diff --git a/scripts/gdb/vmlinux-gdb.py b/scripts/gdb/vmlinux-gdb.py
index fc53cdf286f1..d4eeed4506fd 100644
--- a/scripts/gdb/vmlinux-gdb.py
+++ b/scripts/gdb/vmlinux-gdb.py
@@ -49,3 +49,4 @@ else:
     import linux.page_owner
     import linux.slab
     import linux.vmalloc
+    import linux.kasan
-- 
2.34.1