修改led为gpio

hc

2024-10-12 a5969cabbb4660eab42b6ef0412cbbd1200cf14d

 kernel/Documentation/dev-tools/kmemleak.rst
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 ===========================
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 Kmemleak provides a way of detecting possible kernel memory leaks in a
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-way similar to a tracing garbage collector
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-(https://en.wikipedia.org/wiki/Garbage_collection_%28computer_science%29#Tracing_garbage_collectors),
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+way similar to a `tracing garbage collector
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+<https://en.wikipedia.org/wiki/Tracing_garbage_collection>`_,
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 with the difference that the orphan objects are not freed but only
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 reported via /sys/kernel/debug/kmemleak. A similar method is used by the
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 Valgrind tool (``memcheck --leak-check``) to detect the memory leaks in
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 user-space applications.
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-Kmemleak is supported on x86, arm, powerpc, sparc, sh, microblaze, ppc, mips, s390 and tile.
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 Usage
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 -----
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 CONFIG_DEBUG_KMEMLEAK in "Kernel hacking" has to be enabled. A kernel
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 thread scans the memory every 10 minutes (by default) and prints the
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-number of new unreferenced objects found. To display the details of all
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-the possible memory leaks::
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+number of new unreferenced objects found. If the ``debugfs`` isn't already
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+mounted, mount with::
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   # mount -t debugfs nodev /sys/kernel/debug/
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+To display the details of all the possible scanned memory leaks::
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   # cat /sys/kernel/debug/kmemleak
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 To trigger an intermediate memory scan::
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 Memory may be allocated or freed before kmemleak is initialised and
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 these actions are stored in an early log buffer. The size of this buffer
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-is configured via the CONFIG_DEBUG_KMEMLEAK_EARLY_LOG_SIZE option.
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+is configured via the CONFIG_DEBUG_KMEMLEAK_MEM_POOL_SIZE option.
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 If CONFIG_DEBUG_KMEMLEAK_DEFAULT_OFF are enabled, the kmemleak is
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 disabled by default. Passing ``kmemleak=on`` on the kernel command
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 line enables the function. 
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+If you are getting errors like "Error while writing to stdout" or "write_loop:
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+Invalid argument", make sure kmemleak is properly enabled.
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 Basic Algorithm
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 ---------------
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 macro or the pointer is stored in a location not scanned by kmemleak.
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 Page allocations and ioremap are not tracked.
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+Testing with kmemleak-test
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+--------------------------
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+To check if you have all set up to use kmemleak, you can use the kmemleak-test
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+module, a module that deliberately leaks memory. Set CONFIG_DEBUG_KMEMLEAK_TEST
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+as module (it can't be used as built-in) and boot the kernel with kmemleak
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+enabled. Load the module and perform a scan with::
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+        # modprobe kmemleak-test
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+        # echo scan > /sys/kernel/debug/kmemleak
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+
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+Note that the you may not get results instantly or on the first scanning. When
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+kmemleak gets results, it'll log ``kmemleak: <count of leaks> new suspected
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+memory leaks``. Then read the file to see then::
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+        # cat /sys/kernel/debug/kmemleak
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+        unreferenced object 0xffff89862ca702e8 (size 32):
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+          comm "modprobe", pid 2088, jiffies 4294680594 (age 375.486s)
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+          hex dump (first 32 bytes):
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+            6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b  kkkkkkkkkkkkkkkk
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+            6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b a5  kkkkkkkkkkkkkkk.
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+          backtrace:
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+            [<00000000e0a73ec7>] 0xffffffffc01d2036
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+            [<000000000c5d2a46>] do_one_initcall+0x41/0x1df
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+            [<0000000046db7e0a>] do_init_module+0x55/0x200
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+            [<00000000542b9814>] load_module+0x203c/0x2480
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+            [<00000000c2850256>] __do_sys_finit_module+0xba/0xe0
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+            [<000000006564e7ef>] do_syscall_64+0x43/0x110
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+            [<000000007c873fa6>] entry_SYSCALL_64_after_hwframe+0x44/0xa9
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+        ...
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+
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+Removing the module with ``rmmod kmemleak_test`` should also trigger some
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+kmemleak results.