The first two patches fix the debugfs README file to reflect better
the new features added to 3.14. The third patch is a minor bugfix to the trace_puts() functions that will crash the system if a developer adds one before the tracing system is setup. It also affects trace_printk() if it has no arguments, as the code will convert it to a trace_puts() as well. Note, this bug will not affect unmodified kernels, as trace_printk() and trace_puts() should only be used by developers for testing. -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.15 (GNU/Linux) iQEcBAABAgAGBQJS5oAkAAoJEKQekfcNnQGuOfkH/1ScwoRslERCCjhPEZu958bG VugNvliB/uDwq3qkmBcncMHwqkFBgJay9ieah+JFeK6x3G6mO/uf+UhN5cmLzVBh vA5dKR2zW6WTxKYSvXYapD7OzC7R+V6CLvpMl5WMZ1t3ESQhR6gUrpPdigecBWs9 015rMVA2xXjNnHNDM1nem1PhnMba78A/N98lFErYGpvVBjkCpB8mSt8adds9bYp8 a83P6tGUfXvsYO3sOqqBnOOqcfzCjjJbmr94v/F+SmLyuxuV0tVzBkIwXkKTNhEK bQZj9Pfe+1oIkldXxstn5jWaOvI6RlAGW4b4qXt30AgrGRSyEo5xpvfLfyNUif4= =N3kq -----END PGP SIGNATURE----- Merge tag 'trace-fixes-3.14' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace Pull tracing fixes from Steven Rostedt: "The first two patches fix the debugfs README file to reflect better the new features added to 3.14. The third patch is a minor bugfix to the trace_puts() functions that will crash the system if a developer adds one before the tracing system is setup. It also affects trace_printk() if it has no arguments, as the code will convert it to a trace_puts() as well. Note, this bug will not affect unmodified kernels, as trace_printk() and trace_puts() should only be used by developers for testing" * tag 'trace-fixes-3.14' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: tracing: Check if tracing is enabled in trace_puts() tracing: Fix formatting of trace README file tracing/README: Add event file usage to tracing mini-HOWTO
This commit is contained in:
Linus Torvalds
Коммит
ba635f8cd2
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@ -455,6 +455,9 @@ int __trace_puts(unsigned long ip, const char *str, int size)
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unsigned long irq_flags;
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int alloc;
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if (unlikely(tracing_selftest_running || tracing_disabled))
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return 0;
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alloc = sizeof(*entry) + size + 2; /* possible \n added */
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local_save_flags(irq_flags);
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@ -495,6 +498,9 @@ int __trace_bputs(unsigned long ip, const char *str)
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unsigned long irq_flags;
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int size = sizeof(struct bputs_entry);
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if (unlikely(tracing_selftest_running || tracing_disabled))
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return 0;
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local_save_flags(irq_flags);
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buffer = global_trace.trace_buffer.buffer;
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event = trace_buffer_lock_reserve(buffer, TRACE_BPUTS, size,
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@ -3519,60 +3525,103 @@ static const char readme_msg[] =
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" instances\t\t- Make sub-buffers with: mkdir instances/foo\n"
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"\t\t\t Remove sub-buffer with rmdir\n"
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" trace_options\t\t- Set format or modify how tracing happens\n"
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"\t\t\t Disable an option by adding a suffix 'no' to the option name\n"
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"\t\t\t Disable an option by adding a suffix 'no' to the\n"
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"\t\t\t option name\n"
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#ifdef CONFIG_DYNAMIC_FTRACE
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"\n available_filter_functions - list of functions that can be filtered on\n"
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" set_ftrace_filter\t- echo function name in here to only trace these functions\n"
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" accepts: func_full_name, *func_end, func_begin*, *func_middle*\n"
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" modules: Can select a group via module\n"
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" Format: :mod:<module-name>\n"
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" example: echo :mod:ext3 > set_ftrace_filter\n"
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" triggers: a command to perform when function is hit\n"
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" Format: <function>:<trigger>[:count]\n"
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" trigger: traceon, traceoff\n"
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" enable_event:<system>:<event>\n"
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" disable_event:<system>:<event>\n"
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" set_ftrace_filter\t- echo function name in here to only trace these\n"
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"\t\t\t functions\n"
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"\t accepts: func_full_name, *func_end, func_begin*, *func_middle*\n"
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"\t modules: Can select a group via module\n"
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"\t Format: :mod:<module-name>\n"
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"\t example: echo :mod:ext3 > set_ftrace_filter\n"
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"\t triggers: a command to perform when function is hit\n"
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"\t Format: <function>:<trigger>[:count]\n"
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"\t trigger: traceon, traceoff\n"
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"\t\t enable_event:<system>:<event>\n"
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"\t\t disable_event:<system>:<event>\n"
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#ifdef CONFIG_STACKTRACE
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" stacktrace\n"
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"\t\t stacktrace\n"
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#endif
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#ifdef CONFIG_TRACER_SNAPSHOT
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" snapshot\n"
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"\t\t snapshot\n"
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#endif
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" example: echo do_fault:traceoff > set_ftrace_filter\n"
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" echo do_trap:traceoff:3 > set_ftrace_filter\n"
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" The first one will disable tracing every time do_fault is hit\n"
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" The second will disable tracing at most 3 times when do_trap is hit\n"
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" The first time do trap is hit and it disables tracing, the counter\n"
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" will decrement to 2. If tracing is already disabled, the counter\n"
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" will not decrement. It only decrements when the trigger did work\n"
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" To remove trigger without count:\n"
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" echo '!<function>:<trigger> > set_ftrace_filter\n"
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" To remove trigger with a count:\n"
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" echo '!<function>:<trigger>:0 > set_ftrace_filter\n"
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"\t example: echo do_fault:traceoff > set_ftrace_filter\n"
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"\t echo do_trap:traceoff:3 > set_ftrace_filter\n"
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"\t The first one will disable tracing every time do_fault is hit\n"
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"\t The second will disable tracing at most 3 times when do_trap is hit\n"
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"\t The first time do trap is hit and it disables tracing, the\n"
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"\t counter will decrement to 2. If tracing is already disabled,\n"
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"\t the counter will not decrement. It only decrements when the\n"
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"\t trigger did work\n"
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"\t To remove trigger without count:\n"
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"\t echo '!<function>:<trigger> > set_ftrace_filter\n"
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"\t To remove trigger with a count:\n"
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"\t echo '!<function>:<trigger>:0 > set_ftrace_filter\n"
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" set_ftrace_notrace\t- echo function name in here to never trace.\n"
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" accepts: func_full_name, *func_end, func_begin*, *func_middle*\n"
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" modules: Can select a group via module command :mod:\n"
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" Does not accept triggers\n"
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"\t accepts: func_full_name, *func_end, func_begin*, *func_middle*\n"
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"\t modules: Can select a group via module command :mod:\n"
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"\t Does not accept triggers\n"
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#endif /* CONFIG_DYNAMIC_FTRACE */
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#ifdef CONFIG_FUNCTION_TRACER
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" set_ftrace_pid\t- Write pid(s) to only function trace those pids (function)\n"
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" set_ftrace_pid\t- Write pid(s) to only function trace those pids\n"
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"\t\t (function)\n"
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#endif
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#ifdef CONFIG_FUNCTION_GRAPH_TRACER
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" set_graph_function\t- Trace the nested calls of a function (function_graph)\n"
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" max_graph_depth\t- Trace a limited depth of nested calls (0 is unlimited)\n"
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#endif
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#ifdef CONFIG_TRACER_SNAPSHOT
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"\n snapshot\t\t- Like 'trace' but shows the content of the static snapshot buffer\n"
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"\t\t\t Read the contents for more information\n"
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"\n snapshot\t\t- Like 'trace' but shows the content of the static\n"
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"\t\t\t snapshot buffer. Read the contents for more\n"
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"\t\t\t information\n"
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#endif
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#ifdef CONFIG_STACK_TRACER
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" stack_trace\t\t- Shows the max stack trace when active\n"
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" stack_max_size\t- Shows current max stack size that was traced\n"
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"\t\t\t Write into this file to reset the max size (trigger a new trace)\n"
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"\t\t\t Write into this file to reset the max size (trigger a\n"
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"\t\t\t new trace)\n"
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#ifdef CONFIG_DYNAMIC_FTRACE
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" stack_trace_filter\t- Like set_ftrace_filter but limits what stack_trace traces\n"
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" stack_trace_filter\t- Like set_ftrace_filter but limits what stack_trace\n"
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"\t\t\t traces\n"
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#endif
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#endif /* CONFIG_STACK_TRACER */
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" events/\t\t- Directory containing all trace event subsystems:\n"
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" enable\t\t- Write 0/1 to enable/disable tracing of all events\n"
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" events/<system>/\t- Directory containing all trace events for <system>:\n"
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" enable\t\t- Write 0/1 to enable/disable tracing of all <system>\n"
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"\t\t\t events\n"
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" filter\t\t- If set, only events passing filter are traced\n"
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" events/<system>/<event>/\t- Directory containing control files for\n"
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"\t\t\t <event>:\n"
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" enable\t\t- Write 0/1 to enable/disable tracing of <event>\n"
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" filter\t\t- If set, only events passing filter are traced\n"
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" trigger\t\t- If set, a command to perform when event is hit\n"
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"\t Format: <trigger>[:count][if <filter>]\n"
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"\t trigger: traceon, traceoff\n"
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"\t enable_event:<system>:<event>\n"
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"\t disable_event:<system>:<event>\n"
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#ifdef CONFIG_STACKTRACE
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"\t\t stacktrace\n"
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#endif
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#ifdef CONFIG_TRACER_SNAPSHOT
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"\t\t snapshot\n"
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#endif
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"\t example: echo traceoff > events/block/block_unplug/trigger\n"
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"\t echo traceoff:3 > events/block/block_unplug/trigger\n"
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"\t echo 'enable_event:kmem:kmalloc:3 if nr_rq > 1' > \\\n"
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"\t events/block/block_unplug/trigger\n"
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"\t The first disables tracing every time block_unplug is hit.\n"
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"\t The second disables tracing the first 3 times block_unplug is hit.\n"
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"\t The third enables the kmalloc event the first 3 times block_unplug\n"
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"\t is hit and has value of greater than 1 for the 'nr_rq' event field.\n"
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"\t Like function triggers, the counter is only decremented if it\n"
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"\t enabled or disabled tracing.\n"
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"\t To remove a trigger without a count:\n"
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"\t echo '!<trigger> > <system>/<event>/trigger\n"
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"\t To remove a trigger with a count:\n"
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"\t echo '!<trigger>:0 > <system>/<event>/trigger\n"
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"\t Filters can be ignored when removing a trigger.\n"
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;
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static ssize_t
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