修改led为gpio

hc

2024-10-12 a5969cabbb4660eab42b6ef0412cbbd1200cf14d

 kernel/Documentation/admin-guide/tainted-kernels.rst
..
..
@@ -1,59 +1,164 @@
1
1
 Tainted kernels
2
2
 ---------------
3
3
 
4
-Some oops reports contain the string **'Tainted: '** after the program
5
-counter. This indicates that the kernel has been tainted by some
6
-mechanism.  The string is followed by a series of position-sensitive
7
-characters, each representing a particular tainted value.
4
+The kernel will mark itself as 'tainted' when something occurs that might be
5
+relevant later when investigating problems. Don't worry too much about this,
6
+most of the time it's not a problem to run a tainted kernel; the information is
7
+mainly of interest once someone wants to investigate some problem, as its real
8
+cause might be the event that got the kernel tainted. That's why bug reports
9
+from tainted kernels will often be ignored by developers, hence try to reproduce
10
+problems with an untainted kernel.
8
11
 
9
- 1)  ``G`` if all modules loaded have a GPL or compatible license, ``P`` if
12
+Note the kernel will remain tainted even after you undo what caused the taint
13
+(i.e. unload a proprietary kernel module), to indicate the kernel remains not
14
+trustworthy. That's also why the kernel will print the tainted state when it
15
+notices an internal problem (a 'kernel bug'), a recoverable error
16
+('kernel oops') or a non-recoverable error ('kernel panic') and writes debug
17
+information about this to the logs ``dmesg`` outputs. It's also possible to
18
+check the tainted state at runtime through a file in ``/proc/``.
19
+
20
+
21
+Tainted flag in bugs, oops or panics messages
22
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
23
+
24
+You find the tainted state near the top in a line starting with 'CPU:'; if or
25
+why the kernel was tainted is shown after the Process ID ('PID:') and a shortened
26
+name of the command ('Comm:') that triggered the event::
27
+
28
+	BUG: unable to handle kernel NULL pointer dereference at 0000000000000000
29
+	Oops: 0002 [#1] SMP PTI
30
+	CPU: 0 PID: 4424 Comm: insmod Tainted: P        W  O      4.20.0-0.rc6.fc30 #1
31
+	Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2011
32
+	RIP: 0010:my_oops_init+0x13/0x1000 [kpanic]
33
+	[...]
34
+
35
+You'll find a 'Not tainted: ' there if the kernel was not tainted at the
36
+time of the event; if it was, then it will print 'Tainted: ' and characters
37
+either letters or blanks. In above example it looks like this::
38
+
39
+	Tainted: P        W  O
40
+
41
+The meaning of those characters is explained in the table below. In this case
42
+the kernel got tainted earlier because a proprietary Module (``P``) was loaded,
43
+a warning occurred (``W``), and an externally-built module was loaded (``O``).
44
+To decode other letters use the table below.
45
+
46
+
47
+Decoding tainted state at runtime
48
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
49
+
50
+At runtime, you can query the tainted state by reading
51
+``cat /proc/sys/kernel/tainted``. If that returns ``0``, the kernel is not
52
+tainted; any other number indicates the reasons why it is. The easiest way to
53
+decode that number is the script ``tools/debugging/kernel-chktaint``, which your
54
+distribution might ship as part of a package called ``linux-tools`` or
55
+``kernel-tools``; if it doesn't you can download the script from
56
+`git.kernel.org <https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/plain/tools/debugging/kernel-chktaint>`_
57
+and execute it with ``sh kernel-chktaint``, which would print something like
58
+this on the machine that had the statements in the logs that were quoted earlier::
59
+
60
+	Kernel is Tainted for following reasons:
61
+	 * Proprietary module was loaded (#0)
62
+	 * Kernel issued warning (#9)
63
+	 * Externally-built ('out-of-tree') module was loaded  (#12)
64
+	See Documentation/admin-guide/tainted-kernels.rst in the Linux kernel or
65
+	 https://www.kernel.org/doc/html/latest/admin-guide/tainted-kernels.html for
66
+	 a more details explanation of the various taint flags.
67
+	Raw taint value as int/string: 4609/'P        W  O     '
68
+
69
+You can try to decode the number yourself. That's easy if there was only one
70
+reason that got your kernel tainted, as in this case you can find the number
71
+with the table below. If there were multiple reasons you need to decode the
72
+number, as it is a bitfield, where each bit indicates the absence or presence of
73
+a particular type of taint. It's best to leave that to the aforementioned
74
+script, but if you need something quick you can use this shell command to check
75
+which bits are set::
76
+
77
+	$ for i in $(seq 18); do echo $(($i-1)) $(($(cat /proc/sys/kernel/tainted)>>($i-1)&1));done
78
+
79
+Table for decoding tainted state
80
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
81
+
82
+===  ===  ======  ========================================================
83
+Bit  Log  Number  Reason that got the kernel tainted
84
+===  ===  ======  ========================================================
85
+  0  G/P       1  proprietary module was loaded
86
+  1  _/F       2  module was force loaded
87
+  2  _/S       4  SMP kernel oops on an officially SMP incapable processor
88
+  3  _/R       8  module was force unloaded
89
+  4  _/M      16  processor reported a Machine Check Exception (MCE)
90
+  5  _/B      32  bad page referenced or some unexpected page flags
91
+  6  _/U      64  taint requested by userspace application
92
+  7  _/D     128  kernel died recently, i.e. there was an OOPS or BUG
93
+  8  _/A     256  ACPI table overridden by user
94
+  9  _/W     512  kernel issued warning
95
+ 10  _/C    1024  staging driver was loaded
96
+ 11  _/I    2048  workaround for bug in platform firmware applied
97
+ 12  _/O    4096  externally-built ("out-of-tree") module was loaded
98
+ 13  _/E    8192  unsigned module was loaded
99
+ 14  _/L   16384  soft lockup occurred
100
+ 15  _/K   32768  kernel has been live patched
101
+ 16  _/X   65536  auxiliary taint, defined for and used by distros
102
+ 17  _/T  131072  kernel was built with the struct randomization plugin
103
+===  ===  ======  ========================================================
104
+
105
+Note: The character ``_`` is representing a blank in this table to make reading
106
+easier.
107
+
108
+More detailed explanation for tainting
109
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
110
+
111
+ 0)  ``G`` if all modules loaded have a GPL or compatible license, ``P`` if
10
112
      any proprietary module has been loaded.  Modules without a
11
113
      MODULE_LICENSE or with a MODULE_LICENSE that is not recognised by
12
114
      insmod as GPL compatible are assumed to be proprietary.
13
115
 
14
- 2)  ``F`` if any module was force loaded by ``insmod -f``, ``' '`` if all
116
+ 1)  ``F`` if any module was force loaded by ``insmod -f``, ``' '`` if all
15
117
      modules were loaded normally.
16
118
 
17
- 3)  ``S`` if the oops occurred on an SMP kernel running on hardware that
119
+ 2)  ``S`` if the oops occurred on an SMP kernel running on hardware that
18
120
      hasn't been certified as safe to run multiprocessor.
19
121
      Currently this occurs only on various Athlons that are not
20
122
      SMP capable.
21
123
 
22
- 4)  ``R`` if a module was force unloaded by ``rmmod -f``, ``' '`` if all
124
+ 3)  ``R`` if a module was force unloaded by ``rmmod -f``, ``' '`` if all
23
125
      modules were unloaded normally.
24
126
 
25
- 5)  ``M`` if any processor has reported a Machine Check Exception,
127
+ 4)  ``M`` if any processor has reported a Machine Check Exception,
26
128
      ``' '`` if no Machine Check Exceptions have occurred.
27
129
 
28
- 6)  ``B`` if a page-release function has found a bad page reference or
29
-     some unexpected page flags.
130
+ 5)  ``B`` If a page-release function has found a bad page reference or some
131
+     unexpected page flags. This indicates a hardware problem or a kernel bug;
132
+     there should be other information in the log indicating why this tainting
133
+     occurred.
30
134
 
31
- 7)  ``U`` if a user or user application specifically requested that the
135
+ 6)  ``U`` if a user or user application specifically requested that the
32
136
      Tainted flag be set, ``' '`` otherwise.
33
137
 
34
- 8)  ``D`` if the kernel has died recently, i.e. there was an OOPS or BUG.
138
+ 7)  ``D`` if the kernel has died recently, i.e. there was an OOPS or BUG.
35
139
 
36
- 9)  ``A`` if the ACPI table has been overridden.
140
+ 8)  ``A`` if an ACPI table has been overridden.
37
141
 
38
- 10) ``W`` if a warning has previously been issued by the kernel.
142
+ 9)  ``W`` if a warning has previously been issued by the kernel.
39
143
      (Though some warnings may set more specific taint flags.)
40
144
 
41
- 11) ``C`` if a staging driver has been loaded.
145
+ 10) ``C`` if a staging driver has been loaded.
42
146
 
43
- 12) ``I`` if the kernel is working around a severe bug in the platform
147
+ 11) ``I`` if the kernel is working around a severe bug in the platform
44
148
      firmware (BIOS or similar).
45
149
 
46
- 13) ``O`` if an externally-built ("out-of-tree") module has been loaded.
150
+ 12) ``O`` if an externally-built ("out-of-tree") module has been loaded.
47
151
 
48
- 14) ``E`` if an unsigned module has been loaded in a kernel supporting
152
+ 13) ``E`` if an unsigned module has been loaded in a kernel supporting
49
153
      module signature.
50
154
 
51
- 15) ``L`` if a soft lockup has previously occurred on the system.
155
+ 14) ``L`` if a soft lockup has previously occurred on the system.
52
156
 
53
- 16) ``K`` if the kernel has been live patched.
157
+ 15) ``K`` if the kernel has been live patched.
54
158
 
55
-The primary reason for the **'Tainted: '** string is to tell kernel
56
-debuggers if this is a clean kernel or if anything unusual has
57
-occurred.  Tainting is permanent: even if an offending module is
58
-unloaded, the tainted value remains to indicate that the kernel is not
59
-trustworthy.
159
+ 16) ``X`` Auxiliary taint, defined for and used by Linux distributors.
160
+
161
+ 17) ``T`` Kernel was build with the randstruct plugin, which can intentionally
162
+     produce extremely unusual kernel structure layouts (even performance
163
+     pathological ones), which is important to know when debugging. Set at
164
+     build time.