From ea08eeccae9297f7aabd2ef7f0c2517ac4549acc Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Tue, 20 Feb 2024 01:18:26 +0000
Subject: [PATCH] write in 30M
---
kernel/Documentation/admin-guide/dynamic-debug-howto.rst | 41 +++++++++++++++++++++++++----------------
1 files changed, 25 insertions(+), 16 deletions(-)
diff --git a/kernel/Documentation/admin-guide/dynamic-debug-howto.rst b/kernel/Documentation/admin-guide/dynamic-debug-howto.rst
index 1c9b4ac..6c04aea 100644
--- a/kernel/Documentation/admin-guide/dynamic-debug-howto.rst
+++ b/kernel/Documentation/admin-guide/dynamic-debug-howto.rst
@@ -13,6 +13,11 @@
``print_hex_dump_debug()``/``print_hex_dump_bytes()`` calls can be dynamically
enabled per-callsite.
+If you do not want to enable dynamic debug globally (i.e. in some embedded
+system), you may set ``CONFIG_DYNAMIC_DEBUG_CORE`` as basic support of dynamic
+debug and add ``ccflags := -DDYNAMIC_DEBUG_MODULE`` into the Makefile of any
+modules which you'd like to dynamically debug later.
+
If ``CONFIG_DYNAMIC_DEBUG`` is not set, ``print_hex_dump_debug()`` is just
shortcut for ``print_hex_dump(KERN_DEBUG)``.
@@ -65,10 +70,10 @@
nullarbor:~ # cat <debugfs>/dynamic_debug/control
# filename:lineno [module]function flags format
- /usr/src/packages/BUILD/sgi-enhancednfs-1.4/default/net/sunrpc/svc_rdma.c:323 [svcxprt_rdma]svc_rdma_cleanup =_ "SVCRDMA Module Removed, deregister RPC RDMA transport\012"
- /usr/src/packages/BUILD/sgi-enhancednfs-1.4/default/net/sunrpc/svc_rdma.c:341 [svcxprt_rdma]svc_rdma_init =_ "\011max_inline : %d\012"
- /usr/src/packages/BUILD/sgi-enhancednfs-1.4/default/net/sunrpc/svc_rdma.c:340 [svcxprt_rdma]svc_rdma_init =_ "\011sq_depth : %d\012"
- /usr/src/packages/BUILD/sgi-enhancednfs-1.4/default/net/sunrpc/svc_rdma.c:338 [svcxprt_rdma]svc_rdma_init =_ "\011max_requests : %d\012"
+ net/sunrpc/svc_rdma.c:323 [svcxprt_rdma]svc_rdma_cleanup =_ "SVCRDMA Module Removed, deregister RPC RDMA transport\012"
+ net/sunrpc/svc_rdma.c:341 [svcxprt_rdma]svc_rdma_init =_ "\011max_inline : %d\012"
+ net/sunrpc/svc_rdma.c:340 [svcxprt_rdma]svc_rdma_init =_ "\011sq_depth : %d\012"
+ net/sunrpc/svc_rdma.c:338 [svcxprt_rdma]svc_rdma_init =_ "\011max_requests : %d\012"
...
@@ -88,7 +93,7 @@
nullarbor:~ # awk '$3 != "=_"' <debugfs>/dynamic_debug/control
# filename:lineno [module]function flags format
- /usr/src/packages/BUILD/sgi-enhancednfs-1.4/default/net/sunrpc/svcsock.c:1603 [sunrpc]svc_send p "svc_process: st_sendto returned %d\012"
+ net/sunrpc/svcsock.c:1603 [sunrpc]svc_send p "svc_process: st_sendto returned %d\012"
Command Language Reference
==========================
@@ -113,8 +118,8 @@
~# cat query-batch-file > <debugfs>/dynamic_debug/control
-A another way is to use wildcard. The match rule support ``*`` (matches
-zero or more characters) and ``?`` (matches exactly one character).For
+Another way is to use wildcards. The match rule supports ``*`` (matches
+zero or more characters) and ``?`` (matches exactly one character). For
example, you can match all usb drivers::
~# echo "file drivers/usb/* +p" > <debugfs>/dynamic_debug/control
@@ -159,15 +164,18 @@
of each callsite. Example::
func svc_tcp_accept
+ func *recv* # in rfcomm, bluetooth, ping, tcp
file
- The given string is compared against either the full pathname, the
- src-root relative pathname, or the basename of the source file of
- each callsite. Examples::
+ The given string is compared against either the src-root relative
+ pathname, or the basename of the source file of each callsite.
+ Examples::
file svcsock.c
- file kernel/freezer.c
- file /usr/src/packages/BUILD/sgi-enhancednfs-1.4/default/net/sunrpc/svcsock.c
+ file kernel/freezer.c # ie column 1 of control file
+ file drivers/usb/* # all callsites under it
+ file inode.c:start_* # parse :tail as a func (above)
+ file inode.c:1-100 # parse :tail as a line-range (above)
module
The given string is compared against the module name
@@ -177,6 +185,7 @@
module sunrpc
module nfsd
+ module drm* # both drm, drm_kms_helper
format
The given string is searched for in the dynamic debug format
@@ -246,8 +255,8 @@
bootloader may impose lower limits.
These ``dyndbg`` params are processed just after the ddebug tables are
-processed, as part of the arch_initcall. Thus you can enable debug
-messages in all code run after this arch_initcall via this boot
+processed, as part of the early_initcall. Thus you can enable debug
+messages in all code run after this early_initcall via this boot
parameter.
On an x86 system for example ACPI enablement is a subsys_initcall and::
@@ -261,7 +270,7 @@
If ``foo`` module is not built-in, ``foo.dyndbg`` will still be processed at
boot time, without effect, but will be reprocessed when module is
-loaded later. ``dyndbg_query=`` and bare ``dyndbg=`` are only processed at
+loaded later. ``ddebug_query=`` and bare ``dyndbg=`` are only processed at
boot.
@@ -304,7 +313,7 @@
For ``CONFIG_DYNAMIC_DEBUG`` kernels, any settings given at boot-time (or
enabled by ``-DDEBUG`` flag during compilation) can be disabled later via
-the sysfs interface if the debug messages are no longer needed::
+the debugfs interface if the debug messages are no longer needed::
echo "module module_name -p" > <debugfs>/dynamic_debug/control
--
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