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linux/drivers/base/trace.h

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devres: Enable trace events In some cases the printf() mechanism is too heavy and can't be used. For example, when debugging a race condition involving devres API. When CONFIG_DEBUG_DEVRES is enabled I can't reproduce an issue, and otherwise it's quite visible with a useful information being collected. Enable trace events for devres part of the driver core. Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Link: https://lore.kernel.org/r/20210517122946.53161-4-andriy.shevchenko@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-05-17 15:29:46 +03:00
/* SPDX-License-Identifier: GPL-2.0 */
/*
* Device core Trace Support
* Copyright (C) 2021, Intel Corporation
*
* Author: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
*/
#undef TRACE_SYSTEM
#define TRACE_SYSTEM dev
#if !defined(__DEV_TRACE_H) || defined(TRACE_HEADER_MULTI_READ)
#define __DEV_TRACE_H
#include <linux/device.h>
#include <linux/tracepoint.h>
#include <linux/types.h>
DECLARE_EVENT_CLASS(devres,
TP_PROTO(struct device *dev, const char *op, void *node, const char *name, size_t size),
TP_ARGS(dev, op, node, name, size),
TP_STRUCT__entry(
__string(devname, dev_name(dev))
__field(struct device *, dev)
__field(const char *, op)
__field(void *, node)
devres: Fix page faults when tracing devres from unloaded modules The devres ftrace event logs the name of the devres node, which is often a function name (e.g., "devm_work_drop") stringified by macros like devm_add_action. Currently, ftrace stores this name as a string literal address, which can become invalid when the module containing the string is unloaded. This results in page faults when ftrace tries to access the name. This behavior is problematic because the devres ftrace event is designed to trace resource management throughout a device driver's lifecycle, including during module unload. The event should be available even after the module is unloaded to properly diagnose resource issues. Fix the issue by copying the devres node name into the ftrace ring buffer using __assign_str(), instead of storing just the address. This ensures that ftrace can always access the name, even if the module is unloaded. This change increases the memory usage for each of the ftrace entry by 12-16 bytes assuming the average devres node name is 20 bytes long, depending on the size of const char *. Note that this change does not affect anything unless all of following conditions are met. - CONFIG_DEBUG_DEVRES is enabled - ftrace tracing is enabled - The devres event is enabled in ftrace tracing Fixes: 09705dcb63d2 ("devres: Enable trace events") Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Keita Morisaki <keyz@google.com> Link: https://lore.kernel.org/r/20240928125005.714781-1-keyz@google.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-09-28 20:50:05 +08:00
__string(name, name)
devres: Enable trace events In some cases the printf() mechanism is too heavy and can't be used. For example, when debugging a race condition involving devres API. When CONFIG_DEBUG_DEVRES is enabled I can't reproduce an issue, and otherwise it's quite visible with a useful information being collected. Enable trace events for devres part of the driver core. Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Link: https://lore.kernel.org/r/20210517122946.53161-4-andriy.shevchenko@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-05-17 15:29:46 +03:00
__field(size_t, size)
),
TP_fast_assign(
tracing/treewide: Remove second parameter of __assign_str() With the rework of how the __string() handles dynamic strings where it saves off the source string in field in the helper structure[1], the assignment of that value to the trace event field is stored in the helper value and does not need to be passed in again. This means that with: __string(field, mystring) Which use to be assigned with __assign_str(field, mystring), no longer needs the second parameter and it is unused. With this, __assign_str() will now only get a single parameter. There's over 700 users of __assign_str() and because coccinelle does not handle the TRACE_EVENT() macro I ended up using the following sed script: git grep -l __assign_str | while read a ; do sed -e 's/\(__assign_str([^,]*[^ ,]\) *,[^;]*/\1)/' $a > /tmp/test-file; mv /tmp/test-file $a; done I then searched for __assign_str() that did not end with ';' as those were multi line assignments that the sed script above would fail to catch. Note, the same updates will need to be done for: __assign_str_len() __assign_rel_str() __assign_rel_str_len() I tested this with both an allmodconfig and an allyesconfig (build only for both). [1] https://lore.kernel.org/linux-trace-kernel/20240222211442.634192653@goodmis.org/ Link: https://lore.kernel.org/linux-trace-kernel/20240516133454.681ba6a0@rorschach.local.home Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Julia Lawall <Julia.Lawall@inria.fr> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org> Acked-by: Jani Nikula <jani.nikula@intel.com> Acked-by: Christian König <christian.koenig@amd.com> for the amdgpu parts. Acked-by: Thomas Hellström <thomas.hellstrom@linux.intel.com> #for Acked-by: Rafael J. Wysocki <rafael@kernel.org> # for thermal Acked-by: Takashi Iwai <tiwai@suse.de> Acked-by: Darrick J. Wong <djwong@kernel.org> # xfs Tested-by: Guenter Roeck <linux@roeck-us.net>
2024-05-16 13:34:54 -04:00
__assign_str(devname);
devres: Enable trace events In some cases the printf() mechanism is too heavy and can't be used. For example, when debugging a race condition involving devres API. When CONFIG_DEBUG_DEVRES is enabled I can't reproduce an issue, and otherwise it's quite visible with a useful information being collected. Enable trace events for devres part of the driver core. Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Link: https://lore.kernel.org/r/20210517122946.53161-4-andriy.shevchenko@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-05-17 15:29:46 +03:00
__entry->op = op;
__entry->node = node;
devres: Fix page faults when tracing devres from unloaded modules The devres ftrace event logs the name of the devres node, which is often a function name (e.g., "devm_work_drop") stringified by macros like devm_add_action. Currently, ftrace stores this name as a string literal address, which can become invalid when the module containing the string is unloaded. This results in page faults when ftrace tries to access the name. This behavior is problematic because the devres ftrace event is designed to trace resource management throughout a device driver's lifecycle, including during module unload. The event should be available even after the module is unloaded to properly diagnose resource issues. Fix the issue by copying the devres node name into the ftrace ring buffer using __assign_str(), instead of storing just the address. This ensures that ftrace can always access the name, even if the module is unloaded. This change increases the memory usage for each of the ftrace entry by 12-16 bytes assuming the average devres node name is 20 bytes long, depending on the size of const char *. Note that this change does not affect anything unless all of following conditions are met. - CONFIG_DEBUG_DEVRES is enabled - ftrace tracing is enabled - The devres event is enabled in ftrace tracing Fixes: 09705dcb63d2 ("devres: Enable trace events") Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Keita Morisaki <keyz@google.com> Link: https://lore.kernel.org/r/20240928125005.714781-1-keyz@google.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-09-28 20:50:05 +08:00
__assign_str(name);
devres: Enable trace events In some cases the printf() mechanism is too heavy and can't be used. For example, when debugging a race condition involving devres API. When CONFIG_DEBUG_DEVRES is enabled I can't reproduce an issue, and otherwise it's quite visible with a useful information being collected. Enable trace events for devres part of the driver core. Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Link: https://lore.kernel.org/r/20210517122946.53161-4-andriy.shevchenko@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-05-17 15:29:46 +03:00
__entry->size = size;
),
TP_printk("%s %3s %p %s (%zu bytes)", __get_str(devname),
devres: Fix page faults when tracing devres from unloaded modules The devres ftrace event logs the name of the devres node, which is often a function name (e.g., "devm_work_drop") stringified by macros like devm_add_action. Currently, ftrace stores this name as a string literal address, which can become invalid when the module containing the string is unloaded. This results in page faults when ftrace tries to access the name. This behavior is problematic because the devres ftrace event is designed to trace resource management throughout a device driver's lifecycle, including during module unload. The event should be available even after the module is unloaded to properly diagnose resource issues. Fix the issue by copying the devres node name into the ftrace ring buffer using __assign_str(), instead of storing just the address. This ensures that ftrace can always access the name, even if the module is unloaded. This change increases the memory usage for each of the ftrace entry by 12-16 bytes assuming the average devres node name is 20 bytes long, depending on the size of const char *. Note that this change does not affect anything unless all of following conditions are met. - CONFIG_DEBUG_DEVRES is enabled - ftrace tracing is enabled - The devres event is enabled in ftrace tracing Fixes: 09705dcb63d2 ("devres: Enable trace events") Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Keita Morisaki <keyz@google.com> Link: https://lore.kernel.org/r/20240928125005.714781-1-keyz@google.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-09-28 20:50:05 +08:00
__entry->op, __entry->node, __get_str(name), __entry->size)
devres: Enable trace events In some cases the printf() mechanism is too heavy and can't be used. For example, when debugging a race condition involving devres API. When CONFIG_DEBUG_DEVRES is enabled I can't reproduce an issue, and otherwise it's quite visible with a useful information being collected. Enable trace events for devres part of the driver core. Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Link: https://lore.kernel.org/r/20210517122946.53161-4-andriy.shevchenko@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-05-17 15:29:46 +03:00
);
DEFINE_EVENT(devres, devres_log,
TP_PROTO(struct device *dev, const char *op, void *node, const char *name, size_t size),
TP_ARGS(dev, op, node, name, size)
);
#endif /* __DEV_TRACE_H */
/* this part has to be here */
#undef TRACE_INCLUDE_PATH
#define TRACE_INCLUDE_PATH .
#undef TRACE_INCLUDE_FILE
#define TRACE_INCLUDE_FILE trace
#include <trace/define_trace.h>
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