The patch titled
Documentation: add hint about call traces & module symbols to BUG-HUNTING
has been added to the -mm tree. Its filename is
documentation-add-hint-about-call-traces-module-symbols-to-bug-hunting.patch
*** Remember to use Documentation/SubmitChecklist when testing your code ***
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: Documentation: add hint about call traces & module symbols to BUG-HUNTING
From: Richard Kennedy <richard@xxxxxxxxxxxxxxx>
Here's a couple of small additions to BUG-HUNTING.
1. point out that you can list code in gdb with only one command
(gdb) l *(<symbol> + offset)
2. give a very brief hint how to decode module symbols in call traces
Signed-off-by: Richard Kennedy <richard@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
Documentation/BUG-HUNTING | 17 +++++++++++++++++
1 file changed, 17 insertions(+)
diff -puN Documentation/BUG-HUNTING~documentation-add-hint-about-call-traces-module-symbols-to-bug-hunting Documentation/BUG-HUNTING
--- a/Documentation/BUG-HUNTING~documentation-add-hint-about-call-traces-module-symbols-to-bug-hunting
+++ a/Documentation/BUG-HUNTING
@@ -214,6 +214,23 @@ And recompile the kernel with CONFIG_DEB
gdb vmlinux
(gdb) p vt_ioctl
(gdb) l *(0x<address of vt_ioctl> + 0xda8)
+or, as one command
+ (gdb) l *(vt_ioctl + 0xda8)
+
+If you have a call trace, such as :-
+>Call Trace:
+> [<ffffffff8802c8e9>] :jbd:log_wait_commit+0xa3/0xf5
+> [<ffffffff810482d9>] autoremove_wake_function+0x0/0x2e
+> [<ffffffff8802770b>] :jbd:journal_stop+0x1be/0x1ee
+> ...
+this shows the problem in the :jbd: module. You can load that module in gdb
+and list the relevant code.
+ gdb fs/jbd/jbd.ko
+ (gdb) p log_wait_commit
+ (gdb) l *(0x<address> + 0xa3)
+or
+ (gdb) l *(log_wait_commit + 0xa3)
+
Another very useful option of the Kernel Hacking section in menuconfig is
Debug memory allocations. This will help you see whether data has been
_
Patches currently in -mm which might be from richard@xxxxxxxxxxxxxxx are
documentation-add-hint-about-call-traces-module-symbols-to-bug-hunting.patch
-
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