linux-kernel - [PATCH v2 2/8] scripts/gdb/modules: add get module text support

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Date:   Tue, 8 Aug 2023 16:30:12 +0800
From:   Kuan-Ying Lee <Kuan-Ying.Lee@...iatek.com>
To:     Jan Kiszka <jan.kiszka@...mens.com>,
        Kieran Bingham <kbingham@...nel.org>,
        Matthias Brugger <matthias.bgg@...il.com>,
        AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@...labora.com>
CC:     <chinwen.chang@...iatek.com>, <qun-wei.lin@...iatek.com>,
        <linux-mm@...ck.org>, <linux-modules@...r.kernel.org>,
        <casper.li@...iatek.com>, <akpm@...ux-foundation.org>,
        <linux-arm-kernel@...ts.infradead.org>,
        Kuan-Ying Lee <Kuan-Ying.Lee@...iatek.com>,
        <linux-kernel@...r.kernel.org>,
        <linux-mediatek@...ts.infradead.org>
Subject: [PATCH v2 2/8] scripts/gdb/modules: add get module text support

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@...iatek.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 f76a43bfa15f..298dfcc25eae 100644
--- a/scripts/gdb/linux/modules.py
+++ b/scripts/gdb/linux/modules.py
@@ -97,5 +97,35 @@ 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