linux-stable/include/trace/stages/stage5_get_offsets.h

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/* SPDX-License-Identifier: GPL-2.0 */
/* Stage 5 definitions for creating trace events */
/*
* remember the offset of each array from the beginning of the event.
*/
#undef __entry
#define __entry entry
tracing: Add __string_src() helper to help compilers not to get confused The __string() helper macro of the TRACE_EVENT() macro is used to determine how much of the ring buffer needs to be allocated to fit the given source string. Some trace events have a string that is dependent on another variable that could be NULL, and in those cases the string is passed in to be NULL. The __string() macro can handle being passed in a NULL pointer for which it will turn it into "(null)". It does that with: strlen((src) ? (const char *)(src) : "(null)") + 1 But if src itself has the same conditional type it can confuse the compiler. That is: __string(r ? dev(r)->name : NULL) Would turn into: strlen((r ? dev(r)->name : NULL) ? (r ? dev(r)->name : NULL) : "(null)" + 1 For which the compiler thinks that NULL is being passed to strlen() and gives this kind of warning: ./include/trace/stages/stage5_get_offsets.h:50:21: warning: argument 1 null where non-null expected [-Wnonnull] 50 | strlen((src) ? (const char *)(src) : "(null)") + 1) Instead, create a static inline function that takes the src string and will return the string if it is not NULL and will return "(null)" if it is. This will then make the strlen() line: strlen(__string_src(src)) + 1 Where the compiler can see that strlen() will not end up with NULL and does not warn about it. Note that this depends on commit 51270d573a8d ("tracing/net_sched: Fix tracepoints that save qdisc_dev() as a string") being applied, as passing the qdisc_dev() into __string_src() will give an error. Link: https://lore.kernel.org/all/ZfNmfCmgCs4Nc+EH@aschofie-mobl2/ Link: https://lore.kernel.org/linux-trace-kernel/20240314232754.345cea82@rorschach.local.home Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Reported-by: Alison Schofield <alison.schofield@intel.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-03-15 03:27:54 +00:00
#ifndef __STAGE5_STRING_SRC_H
#define __STAGE5_STRING_SRC_H
static inline const char *__string_src(const char *str)
{
if (!str)
return EVENT_NULL_STR;
return str;
}
#endif /* __STAGE5_STRING_SRC_H */
/*
* Fields should never declare an array: i.e. __field(int, arr[5])
* If they do, it will cause issues in parsing and possibly corrupt the
* events. To prevent that from happening, test the sizeof() a fictitious
* type called "struct _test_no_array_##item" which will fail if "item"
* contains array elements (like "arr[5]").
*
* If you hit this, use __array(int, arr, 5) instead.
*/
#undef __field
#define __field(type, item) \
{ (void)sizeof(struct _test_no_array_##item *); }
#undef __field_ext
#define __field_ext(type, item, filter_type) \
{ (void)sizeof(struct _test_no_array_##item *); }
#undef __field_struct
#define __field_struct(type, item) \
{ (void)sizeof(struct _test_no_array_##item *); }
#undef __field_struct_ext
#define __field_struct_ext(type, item, filter_type) \
{ (void)sizeof(struct _test_no_array_##item *); }
#undef __array
#define __array(type, item, len)
#undef __dynamic_array
#define __dynamic_array(type, item, len) \
__item_length = (len) * sizeof(type); \
__data_offsets->item = __data_size + \
offsetof(typeof(*entry), __data); \
__data_offsets->item |= __item_length << 16; \
__data_size += __item_length;
#undef __string
#define __string(item, src) __dynamic_array(char, item, \
tracing: Add __string_src() helper to help compilers not to get confused The __string() helper macro of the TRACE_EVENT() macro is used to determine how much of the ring buffer needs to be allocated to fit the given source string. Some trace events have a string that is dependent on another variable that could be NULL, and in those cases the string is passed in to be NULL. The __string() macro can handle being passed in a NULL pointer for which it will turn it into "(null)". It does that with: strlen((src) ? (const char *)(src) : "(null)") + 1 But if src itself has the same conditional type it can confuse the compiler. That is: __string(r ? dev(r)->name : NULL) Would turn into: strlen((r ? dev(r)->name : NULL) ? (r ? dev(r)->name : NULL) : "(null)" + 1 For which the compiler thinks that NULL is being passed to strlen() and gives this kind of warning: ./include/trace/stages/stage5_get_offsets.h:50:21: warning: argument 1 null where non-null expected [-Wnonnull] 50 | strlen((src) ? (const char *)(src) : "(null)") + 1) Instead, create a static inline function that takes the src string and will return the string if it is not NULL and will return "(null)" if it is. This will then make the strlen() line: strlen(__string_src(src)) + 1 Where the compiler can see that strlen() will not end up with NULL and does not warn about it. Note that this depends on commit 51270d573a8d ("tracing/net_sched: Fix tracepoints that save qdisc_dev() as a string") being applied, as passing the qdisc_dev() into __string_src() will give an error. Link: https://lore.kernel.org/all/ZfNmfCmgCs4Nc+EH@aschofie-mobl2/ Link: https://lore.kernel.org/linux-trace-kernel/20240314232754.345cea82@rorschach.local.home Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Reported-by: Alison Schofield <alison.schofield@intel.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-03-15 03:27:54 +00:00
strlen(__string_src(src)) + 1) \
__data_offsets->item##_ptr_ = src;
#undef __string_len
#define __string_len(item, src, len) __dynamic_array(char, item, (len) + 1)\
__data_offsets->item##_ptr_ = src;
tracing/events: Add __vstring() and __assign_vstr() helper macros There's several places that open code the following logic: TP_STRUCT__entry(__dynamic_array(char, msg, MSG_MAX)), TP_fast_assign(vsnprintf(__get_str(msg), MSG_MAX, vaf->fmt, *vaf->va);) To load a string created by variable array va_list. The main issue with this approach is that "MSG_MAX" usage in the __dynamic_array() portion. That actually just reserves the MSG_MAX in the event, and even wastes space because there's dynamic meta data also saved in the event to denote the offset and size of the dynamic array. It would have been better to just use a static __array() field. Instead, create __vstring() and __assign_vstr() that work like __string and __assign_str() but instead of taking a destination string to copy, take a format string and a va_list pointer and fill in the values. It uses the helper: #define __trace_event_vstr_len(fmt, va) \ ({ \ va_list __ap; \ int __ret; \ \ va_copy(__ap, *(va)); \ __ret = vsnprintf(NULL, 0, fmt, __ap) + 1; \ va_end(__ap); \ \ min(__ret, TRACE_EVENT_STR_MAX); \ }) To figure out the length to store the string. It may be slightly slower as it needs to run the vsnprintf() twice, but it now saves space on the ring buffer. Link: https://lkml.kernel.org/r/20220705224749.053570613@goodmis.org Cc: Dennis Dalessandro <dennis.dalessandro@cornelisnetworks.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Leon Romanovsky <leon@kernel.org> Cc: Kalle Valo <kvalo@kernel.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Eric Dumazet <edumazet@google.com> Cc: Jakub Kicinski <kuba@kernel.org> Cc: Paolo Abeni <pabeni@redhat.com> Cc: Arend van Spriel <aspriel@gmail.com> Cc: Franky Lin <franky.lin@broadcom.com> Cc: Hante Meuleman <hante.meuleman@broadcom.com> Cc: Gregory Greenman <gregory.greenman@intel.com> Cc: Peter Chen <peter.chen@kernel.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Mathias Nyman <mathias.nyman@intel.com> Cc: Chunfeng Yun <chunfeng.yun@mediatek.com> Cc: Bin Liu <b-liu@ti.com> Cc: Marek Lindner <mareklindner@neomailbox.ch> Cc: Simon Wunderlich <sw@simonwunderlich.de> Cc: Antonio Quartulli <a@unstable.cc> Cc: Sven Eckelmann <sven@narfation.org> Cc: Johannes Berg <johannes@sipsolutions.net> Cc: Jim Cromie <jim.cromie@gmail.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2022-07-05 22:44:54 +00:00
#undef __vstring
#define __vstring(item, fmt, ap) __dynamic_array(char, item, \
__trace_event_vstr_len(fmt, ap))
#undef __rel_dynamic_array
#define __rel_dynamic_array(type, item, len) \
__item_length = (len) * sizeof(type); \
__data_offsets->item = __data_size + \
offsetof(typeof(*entry), __data) - \
offsetof(typeof(*entry), __rel_loc_##item) - \
sizeof(u32); \
__data_offsets->item |= __item_length << 16; \
__data_size += __item_length;
#undef __rel_string
#define __rel_string(item, src) __rel_dynamic_array(char, item, \
tracing: Add __string_src() helper to help compilers not to get confused The __string() helper macro of the TRACE_EVENT() macro is used to determine how much of the ring buffer needs to be allocated to fit the given source string. Some trace events have a string that is dependent on another variable that could be NULL, and in those cases the string is passed in to be NULL. The __string() macro can handle being passed in a NULL pointer for which it will turn it into "(null)". It does that with: strlen((src) ? (const char *)(src) : "(null)") + 1 But if src itself has the same conditional type it can confuse the compiler. That is: __string(r ? dev(r)->name : NULL) Would turn into: strlen((r ? dev(r)->name : NULL) ? (r ? dev(r)->name : NULL) : "(null)" + 1 For which the compiler thinks that NULL is being passed to strlen() and gives this kind of warning: ./include/trace/stages/stage5_get_offsets.h:50:21: warning: argument 1 null where non-null expected [-Wnonnull] 50 | strlen((src) ? (const char *)(src) : "(null)") + 1) Instead, create a static inline function that takes the src string and will return the string if it is not NULL and will return "(null)" if it is. This will then make the strlen() line: strlen(__string_src(src)) + 1 Where the compiler can see that strlen() will not end up with NULL and does not warn about it. Note that this depends on commit 51270d573a8d ("tracing/net_sched: Fix tracepoints that save qdisc_dev() as a string") being applied, as passing the qdisc_dev() into __string_src() will give an error. Link: https://lore.kernel.org/all/ZfNmfCmgCs4Nc+EH@aschofie-mobl2/ Link: https://lore.kernel.org/linux-trace-kernel/20240314232754.345cea82@rorschach.local.home Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Reported-by: Alison Schofield <alison.schofield@intel.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-03-15 03:27:54 +00:00
strlen(__string_src(src)) + 1) \
__data_offsets->item##_ptr_ = src;
#undef __rel_string_len
#define __rel_string_len(item, src, len) __rel_dynamic_array(char, item, (len) + 1)\
__data_offsets->item##_ptr_ = src;
/*
* __bitmask_size_in_bytes_raw is the number of bytes needed to hold
* num_possible_cpus().
*/
#define __bitmask_size_in_bytes_raw(nr_bits) \
(((nr_bits) + 7) / 8)
#define __bitmask_size_in_longs(nr_bits) \
((__bitmask_size_in_bytes_raw(nr_bits) + \
((BITS_PER_LONG / 8) - 1)) / (BITS_PER_LONG / 8))
/*
* __bitmask_size_in_bytes is the number of bytes needed to hold
* num_possible_cpus() padded out to the nearest long. This is what
* is saved in the buffer, just to be consistent.
*/
#define __bitmask_size_in_bytes(nr_bits) \
(__bitmask_size_in_longs(nr_bits) * (BITS_PER_LONG / 8))
#undef __bitmask
#define __bitmask(item, nr_bits) __dynamic_array(unsigned long, item, \
__bitmask_size_in_longs(nr_bits))
#undef __cpumask
#define __cpumask(item) __bitmask(item, nr_cpumask_bits)
#undef __rel_bitmask
#define __rel_bitmask(item, nr_bits) __rel_dynamic_array(unsigned long, item, \
__bitmask_size_in_longs(nr_bits))
Tracing updates for 5.18: - New user_events interface. User space can register an event with the kernel describing the format of the event. Then it will receive a byte in a page mapping that it can check against. A privileged task can then enable that event like any other event, which will change the mapped byte to true, telling the user space application to start writing the event to the tracing buffer. - Add new "ftrace_boot_snapshot" kernel command line parameter. When set, the tracing buffer will be saved in the snapshot buffer at boot up when the kernel hands things over to user space. This will keep the traces that happened at boot up available even if user space boot up has tracing as well. - Have TRACE_EVENT_ENUM() also update trace event field type descriptions. Thus if a static array defines its size with an enum, the user space trace event parsers can still know how to parse that array. - Add new TRACE_CUSTOM_EVENT() macro. This acts the same as the TRACE_EVENT() macro, but will attach to an existing tracepoint. This will make one tracepoint be able to trace different content and not be stuck at only what the original TRACE_EVENT() macro exports. - Fixes to tracing error logging. - Better saving of cmdlines to PIDs when tracing (use the wakeup events for mapping). -----BEGIN PGP SIGNATURE----- iIoEABYIADIWIQRRSw7ePDh/lE+zeZMp5XQQmuv6qgUCYjiO3RQccm9zdGVkdEBn b29kbWlzLm9yZwAKCRAp5XQQmuv6qhQzAQDtek5p80p/zkMGymm14wSH6qq0NdgN Kv7fTBwEewUa0gD/UCOVLw4Oj+JtHQhCa3sCGZopmRv0BT1+4UQANqosKQY= =Au08 -----END PGP SIGNATURE----- Merge tag 'trace-v5.18' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace Pull tracing updates from Steven Rostedt: - New user_events interface. User space can register an event with the kernel describing the format of the event. Then it will receive a byte in a page mapping that it can check against. A privileged task can then enable that event like any other event, which will change the mapped byte to true, telling the user space application to start writing the event to the tracing buffer. - Add new "ftrace_boot_snapshot" kernel command line parameter. When set, the tracing buffer will be saved in the snapshot buffer at boot up when the kernel hands things over to user space. This will keep the traces that happened at boot up available even if user space boot up has tracing as well. - Have TRACE_EVENT_ENUM() also update trace event field type descriptions. Thus if a static array defines its size with an enum, the user space trace event parsers can still know how to parse that array. - Add new TRACE_CUSTOM_EVENT() macro. This acts the same as the TRACE_EVENT() macro, but will attach to an existing tracepoint. This will make one tracepoint be able to trace different content and not be stuck at only what the original TRACE_EVENT() macro exports. - Fixes to tracing error logging. - Better saving of cmdlines to PIDs when tracing (use the wakeup events for mapping). * tag 'trace-v5.18' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (30 commits) tracing: Have type enum modifications copy the strings user_events: Add trace event call as root for low permission cases tracing/user_events: Use alloc_pages instead of kzalloc() for register pages tracing: Add snapshot at end of kernel boot up tracing: Have TRACE_DEFINE_ENUM affect trace event types as well tracing: Fix strncpy warning in trace_events_synth.c user_events: Prevent dyn_event delete racing with ioctl add/delete tracing: Add TRACE_CUSTOM_EVENT() macro tracing: Move the defines to create TRACE_EVENTS into their own files tracing: Add sample code for custom trace events tracing: Allow custom events to be added to the tracefs directory tracing: Fix last_cmd_set() string management in histogram code user_events: Fix potential uninitialized pointer while parsing field tracing: Fix allocation of last_cmd in last_cmd_set() user_events: Add documentation file user_events: Add sample code for typical usage user_events: Add self-test for validator boundaries user_events: Add self-test for perf_event integration user_events: Add self-test for dynamic_events integration user_events: Add self-test for ftrace integration ...
2022-03-23 18:40:25 +00:00
#undef __rel_cpumask
#define __rel_cpumask(item) __rel_bitmask(item, nr_cpumask_bits)
Tracing updates for 5.18: - New user_events interface. User space can register an event with the kernel describing the format of the event. Then it will receive a byte in a page mapping that it can check against. A privileged task can then enable that event like any other event, which will change the mapped byte to true, telling the user space application to start writing the event to the tracing buffer. - Add new "ftrace_boot_snapshot" kernel command line parameter. When set, the tracing buffer will be saved in the snapshot buffer at boot up when the kernel hands things over to user space. This will keep the traces that happened at boot up available even if user space boot up has tracing as well. - Have TRACE_EVENT_ENUM() also update trace event field type descriptions. Thus if a static array defines its size with an enum, the user space trace event parsers can still know how to parse that array. - Add new TRACE_CUSTOM_EVENT() macro. This acts the same as the TRACE_EVENT() macro, but will attach to an existing tracepoint. This will make one tracepoint be able to trace different content and not be stuck at only what the original TRACE_EVENT() macro exports. - Fixes to tracing error logging. - Better saving of cmdlines to PIDs when tracing (use the wakeup events for mapping). -----BEGIN PGP SIGNATURE----- iIoEABYIADIWIQRRSw7ePDh/lE+zeZMp5XQQmuv6qgUCYjiO3RQccm9zdGVkdEBn b29kbWlzLm9yZwAKCRAp5XQQmuv6qhQzAQDtek5p80p/zkMGymm14wSH6qq0NdgN Kv7fTBwEewUa0gD/UCOVLw4Oj+JtHQhCa3sCGZopmRv0BT1+4UQANqosKQY= =Au08 -----END PGP SIGNATURE----- Merge tag 'trace-v5.18' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace Pull tracing updates from Steven Rostedt: - New user_events interface. User space can register an event with the kernel describing the format of the event. Then it will receive a byte in a page mapping that it can check against. A privileged task can then enable that event like any other event, which will change the mapped byte to true, telling the user space application to start writing the event to the tracing buffer. - Add new "ftrace_boot_snapshot" kernel command line parameter. When set, the tracing buffer will be saved in the snapshot buffer at boot up when the kernel hands things over to user space. This will keep the traces that happened at boot up available even if user space boot up has tracing as well. - Have TRACE_EVENT_ENUM() also update trace event field type descriptions. Thus if a static array defines its size with an enum, the user space trace event parsers can still know how to parse that array. - Add new TRACE_CUSTOM_EVENT() macro. This acts the same as the TRACE_EVENT() macro, but will attach to an existing tracepoint. This will make one tracepoint be able to trace different content and not be stuck at only what the original TRACE_EVENT() macro exports. - Fixes to tracing error logging. - Better saving of cmdlines to PIDs when tracing (use the wakeup events for mapping). * tag 'trace-v5.18' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (30 commits) tracing: Have type enum modifications copy the strings user_events: Add trace event call as root for low permission cases tracing/user_events: Use alloc_pages instead of kzalloc() for register pages tracing: Add snapshot at end of kernel boot up tracing: Have TRACE_DEFINE_ENUM affect trace event types as well tracing: Fix strncpy warning in trace_events_synth.c user_events: Prevent dyn_event delete racing with ioctl add/delete tracing: Add TRACE_CUSTOM_EVENT() macro tracing: Move the defines to create TRACE_EVENTS into their own files tracing: Add sample code for custom trace events tracing: Allow custom events to be added to the tracefs directory tracing: Fix last_cmd_set() string management in histogram code user_events: Fix potential uninitialized pointer while parsing field tracing: Fix allocation of last_cmd in last_cmd_set() user_events: Add documentation file user_events: Add sample code for typical usage user_events: Add self-test for validator boundaries user_events: Add self-test for perf_event integration user_events: Add self-test for dynamic_events integration user_events: Add self-test for ftrace integration ...
2022-03-23 18:40:25 +00:00
#undef __sockaddr
#define __sockaddr(field, len) __dynamic_array(u8, field, len)
#undef __rel_sockaddr
#define __rel_sockaddr(field, len) __rel_dynamic_array(u8, field, len)