[PATCH 2/8] scripts/gdb/modules: add get module text support

Kuan-Ying Lee Kuan-Ying.Lee at mediatek.com
Tue Jul 25 02:34:52 PDT 2023


When we get an text address from coredump and we cannot find
this address in vmlinux, it might located in kernel module.

We want to know which kernel module it located in.

This GDB scripts can help us to find the target kernel module.

(gdb) lx-getmod-by-textaddr 0xffff800002d305ac
0xffff800002d305ac is in kasan_test.ko

Signed-off-by: Kuan-Ying Lee <Kuan-Ying.Lee at mediatek.com>
---
 scripts/gdb/linux/modules.py | 32 +++++++++++++++++++++++++++++++-
 1 file changed, 31 insertions(+), 1 deletion(-)

diff --git a/scripts/gdb/linux/modules.py b/scripts/gdb/linux/modules.py
index 261f28640f4c..54bb7fcad41d 100644
--- a/scripts/gdb/linux/modules.py
+++ b/scripts/gdb/linux/modules.py
@@ -91,5 +91,35 @@ class LxLsmod(gdb.Command):
 
             gdb.write("\n")
 
-
 LxLsmod()
+
+def help():
+    t = """Usage: lx-getmod-by-textaddr [Heximal Address]
+    Example: lx-getmod-by-textaddr 0xffff800002d305ac\n"""
+    gdb.write("Unrecognized command\n")
+    raise gdb.GdbError(t)
+
+class LxFindTextAddrinMod(gdb.Command):
+    '''Look up loaded kernel module by text address.'''
+
+    def __init__(self):
+        super(LxFindTextAddrinMod, self).__init__('lx-getmod-by-textaddr', gdb.COMMAND_SUPPORT)
+
+    def invoke(self, arg, from_tty):
+        args = gdb.string_to_argv(arg)
+
+        if len(args) != 1:
+            help()
+
+        addr = gdb.Value(int(args[0], 16)).cast(utils.get_ulong_type())
+        for mod in module_list():
+            mod_text_start = mod['mem'][constants.LX_MOD_TEXT]['base']
+            mod_text_end = mod_text_start + mod['mem'][constants.LX_MOD_TEXT]['size'].cast(utils.get_ulong_type())
+
+            if addr >= mod_text_start and addr < mod_text_end:
+                s = "0x%x" % addr + " is in " + mod['name'].string() + ".ko\n"
+                gdb.write(s)
+                return
+        gdb.write("0x%x is not in any module text section\n" % addr)
+
+LxFindTextAddrinMod()
-- 
2.18.0




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