- 20 Mar, 2022 1 commit
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Steven Rostedt (Google) authored
When an enum is used in the visible parts of a trace event that is exported to user space, the user space applications like perf and trace-cmd do not have a way to know what the value of the enum is. To solve this, at boot up (or module load) the printk formats are modified to replace the enum with their numeric value in the string output. Array fields of the event are defined by [<nr-elements>] in the type portion of the format file so that the user space parsers can correctly parse the array into the appropriate size chunks. But in some trace events, an enum is used in defining the size of the array, which once again breaks the parsing of user space tooling. This was solved the same way as the print formats were, but it modified the type strings of the trace event. This caused crashes in some architectures because, as supposed to the print string, is a const string value. This was not detected on x86, as it appears that const strings are still writable (at least in boot up), but other architectures this is not the case, and writing to a const string will cause a kernel fault. To fix this, use kstrdup() to copy the type before modifying it. If the trace event is for the core kernel there's no need to free it because the string will be in use for the life of the machine being on line. For modules, create a link list to store all the strings being allocated for modules and when the module is removed, free them. Link: https://lore.kernel.org/all/yt9dr1706b4i.fsf@linux.ibm.com/ Link: https://lkml.kernel.org/r/20220318153432.3984b871@gandalf.local.homeTested-by:
Marc Zyngier <maz@kernel.org> Tested-by:
Sven Schnelle <svens@linux.ibm.com> Reported-by:
Steven Rostedt (Google) <rostedt@goodmis.org>
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- 15 Mar, 2022 1 commit
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Beau Belgrave authored
Tracefs by default is locked down heavily. System operators can open up some files, such as user_events to a broader set of users. These users do not have access within tracefs beyond just the user_event files. Due to this restriction the trace_add_event_call/remove calls will silently fail since the caller does not have permissions to create directories. To fix this trace_add_event_call/remove calls will be issued with override creds of the global root UID. Creds are reverted immediately afterward. Link: https://lkml.kernel.org/r/20220308222807.2040-1-beaub@linux.microsoft.comSigned-off-by:
Beau Belgrave <beaub@linux.microsoft.com> Signed-off-by:
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- 11 Mar, 2022 8 commits
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Steven Rostedt (Google) authored
kzalloc virtual addresses do not work with SetPageReserved, use the actual page virtual addresses instead via alloc_pages. The issue is reported when booting with user_events and DEBUG_VM_PGFLAGS=y. Also make the number of events based on the ORDER. Link: https://lore.kernel.org/all/CADYN=9+xY5Vku3Ws5E9S60SM5dCFfeGeRBkmDFbcxX0ZMoFing@mail.gmail.com/ Link: https://lore.kernel.org/all/20220311223028.1865-1-beaub@linux.microsoft.com/ Cc: Beau Belgrave <beaub@linux.microsoft.com> Reported-by:
Anders Roxell <anders.roxell@linaro.org> Signed-off-by:
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Steven Rostedt (Google) authored
Add ftrace_boot_snapshot kernel parameter that will take a snapshot at the end of boot up just before switching over to user space (it happens during the kernel freeing of init memory). This is useful when there's interesting data that can be collected from kernel start up, but gets overridden by user space start up code. With this option, the ring buffer content from the boot up traces gets saved in the snapshot at the end of boot up. This trace can be read from: /sys/kernel/tracing/snapshot Signed-off-by: -
Steven Rostedt (Google) authored
The macro TRACE_DEFINE_ENUM is used to convert enums in the kernel to their actual value when they are exported to user space via the trace event format file. Currently only the enums in the "print fmt" (TP_printk in the TRACE_EVENT macro) have the enums converted. But the enums can be used to denote array size: field:unsigned int fc_ineligible_rc[EXT4_FC_REASON_MAX]; offset:12; size:36; signed:0; The EXT4_FC_REASON_MAX has no meaning to userspace but it needs to know that information to know how to parse the array. Have the array indexes also be parsed as well. Link: https://lore.kernel.org/all/cover.1646922487.git.riteshh@linux.ibm.com/Reported-by:Ritesh Harjani <riteshh@linux.ibm.com> Tested-by:
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Tom Zanussi authored
0-day reported the strncpy error below: ../kernel/trace/trace_events_synth.c: In function 'last_cmd_set': ../kernel/trace/trace_events_synth.c:65:9: warning: 'strncpy' specified bound depends on the length o\ f the source argument [-Wstringop-truncation] 65 | strncpy(last_cmd, str, strlen(str) + 1); | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ../kernel/trace/trace_events_synth.c:65:32: note: length computed here 65 | strncpy(last_cmd, str, strlen(str) + 1); | ^~~~~~~~~~~ There's no reason to use strncpy here, in fact there's no reason to do anything but a simple kstrdup() (note we don't even need to check for failure since last_cmod is expected to be either the last cmd string or NULL, and the containing function is a void return). Link: https://lkml.kernel.org/r/77deca8cbfd226981b3f1eab203967381e9b5bd9.camel@kernel.org Fixes: 27c888da ("tracing: Remove size restriction on synthetic event cmd error logging") Reported-by:kernel test robot <lkp@intel.com> Signed-off-by:
Tom Zanussi <zanussi@kernel.org> Signed-off-by:
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Beau Belgrave authored
Find user_events always while under the event_mutex and before leaving the lock, add a ref count to the user_event. This ensures that all paths under the event_mutex that check the ref counts will be synchronized. The ioctl add/delete paths are protected by the reg_mutex. However, dyn_event is only protected by the event_mutex. The dyn_event delete path cannot acquire reg_mutex, since that could cause a deadlock between the ioctl delete case acquiring event_mutex after acquiring the reg_mutex. Link: https://lkml.kernel.org/r/20220310001141.1660-1-beaub@linux.microsoft.comSigned-off-by:
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Steven Rostedt (Google) authored
To make it really easy to add custom events from modules, add a TRACE_CUSTOM_EVENT() macro that acts just like the TRACE_EVENT() macro, but creates a custom event to an already existing tracepoint. The trace_custom_sched.[ch] has been updated to use this new macro to show how simple it is. Link: https://lkml.kernel.org/r/20220303220625.738622494@goodmis.org Cc: Ingo Molnar <mingo@kernel.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Joel Fernandes <joel@joelfernandes.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Tom Zanussi <zanussi@kernel.org> Signed-off-by:
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Steven Rostedt (Google) authored
In an effort to add custom event macros that can be used to create your own custom events based on existing tracepoints, move the defines of the special macros used in TRACE_EVENT() into their own files such that they can be reused for TRACE_CUSTOM_EVENT(). Link: https://lkml.kernel.org/r/20220303220625.553406495@goodmis.org Cc: Ingo Molnar <mingo@kernel.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Joel Fernandes <joel@joelfernandes.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Tom Zanussi <zanussi@kernel.org> Signed-off-by:
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Steven Rostedt (Google) authored
Add sample code to show how to create custom trace events in the tracefs directory that can be enabled and modified like any event in tracefs (including triggers, histograms, synthetic events and event probes). The example is creating a custom sched_switch and a sched_waking to limit what is recorded: If the custom sched switch only records the prev_prio, next_prio and next_pid, it can bring the size from 64 bytes per event, down to just 16 bytes! If sched_waking only records the prio and pid of the woken event, it will bring the size down from 36 bytes to 12 bytes per event. This will allow for a much smaller footprint into the ring buffer and keep more events from dropping. Link: https://lkml.kernel.org/r/20220303220625.369226746@goodmis.org Cc: Ingo Molnar <mingo@kernel.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Tom Zanussi <zanussi@kernel.org> Suggested-by:
Joel Fernandes <joel@joelfernandes.org> Signed-off-by:
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- 10 Mar, 2022 3 commits
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Steven Rostedt (Google) authored
Allow custom events to be added to the events directory in the tracefs file system. For example, a module could be installed that attaches to an event and wants to be enabled and disabled via the tracefs file system. It would use trace_add_event_call() to add the event to the tracefs directory, and trace_remove_event_call() to remove it. Make both those functions EXPORT_SYMBOL_GPL(). Link: https://lkml.kernel.org/r/20220303220625.186988045@goodmis.org Cc: Ingo Molnar <mingo@kernel.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Joel Fernandes <joel@joelfernandes.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Tom Zanussi <zanussi@kernel.org> Signed-off-by:
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Steven Rostedt (Google) authored
Using strnlen(dest, str, n) is confusing, as the size of dest must be strlen(dest) + n + 1. Even more confusing, using sizeof(string constant) gives you strlen(string constant) + 1 and not just strlen(). These two together made using strncat() with a constant string a bit off in the calculations as we have: len = sizeof(HIST_PREFIX) + strlen(str) + 1; kfree(last_cmd); last_cmd = kzalloc(len, GFP_KERNEL); strcpy(last_cmd, HIST_PREFIX); len -= sizeof(HIST_PREFIX) + 1; strncat(last_cmd, str, len); The above works if we s/sizeof/strlen/ with HIST_PREFIX (which is defined as "hist:", but because sizeof(HIST_PREFIX) is equal to strlen(HIST_PREFIX) + 1, we can drop the +1 in the code. But at least comment that we are doing so. Link: https://lore.kernel.org/all/202203082112.Iu7tvFl4-lkp@intel.com/ Fixes: 9f8e5aee ("tracing: Fix allocation of last_cmd in last_cmd_set()") Reported-by:
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Beau Belgrave authored
Ensure name is initialized by default to NULL to prevent possible edge cases that could lead to it being left uninitialized. Add an explicit check for NULL name to ensure edge boundaries. Link: https://lore.kernel.org/bpf/20220224105334.GA2248@kili/ Link: https://lore.kernel.org/linux-trace-devel/20220224181637.2129-1-beaub@linux.microsoft.comSigned-off-by:
Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by:
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- 24 Feb, 2022 1 commit
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Steven Rostedt (Google) authored
The strncat() used in last_cmd_set() includes the nul byte of length of the string being copied in, when it should only hold the size of the string being copied (not the nul byte). Change it to subtract the length of the allocated space and the nul byte to pass that into the strncat(). Also, assign "len" instead of initializing it to zero and its first update is to do a "+=". Link: https://lore.kernel.org/all/202202140628.fj6e4w4v-lkp@intel.com/Reported-by:
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- 11 Feb, 2022 16 commits
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Beau Belgrave authored
Add a documentation file about user_events with example code, etc. explaining how it may be used. Link: https://lkml.kernel.org/r/20220118204326.2169-13-beaub@linux.microsoft.comAcked-by:
Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by:
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Beau Belgrave authored
Add sample code for user_events typical usage to show how to register and monitor status, as well as to write out data. Link: https://lkml.kernel.org/r/20220118204326.2169-12-beaub@linux.microsoft.comAcked-by:
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Beau Belgrave authored
Tests to ensure validator boundary cases are working correctly within close and far bounds. Ensures __data_loc and __rel_loc strings are null terminated and within range. Ensures min size checks work as expected. Link: https://lkml.kernel.org/r/20220118204326.2169-11-beaub@linux.microsoft.comAcked-by:
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Beau Belgrave authored
Tests perf can be attached to and written out correctly. Ensures attach updates status bits in user programs. Link: https://lkml.kernel.org/r/20220118204326.2169-10-beaub@linux.microsoft.comAcked-by:
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Beau Belgrave authored
Tests matching deletes, creation of basic and complex types. Ensures common patterns work correctly when interacting with dynamic_events file. Link: https://lkml.kernel.org/r/20220118204326.2169-9-beaub@linux.microsoft.comAcked-by:
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Beau Belgrave authored
Tests basic functionality of registering/deregistering, status and writing data out via ftrace mechanisms within user_events. Link: https://lkml.kernel.org/r/20220118204326.2169-8-beaub@linux.microsoft.comAcked-by:
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Beau Belgrave authored
Add validation to ensure data is at or greater than the min size for the fields of the event. If a dynamic array is used and is a type of char, ensure null termination of the array exists. Link: https://lkml.kernel.org/r/20220118204326.2169-7-beaub@linux.microsoft.comAcked-by:
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Beau Belgrave authored
Pass iterator through to probes to allow copying data directly to the probe buffers instead of taking multiple copies. Enables eBPF user and raw iterator types out to programs for no-copy scenarios. Link: https://lkml.kernel.org/r/20220118204326.2169-6-beaub@linux.microsoft.comAcked-by:
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Beau Belgrave authored
Adds support to write out user_event data to perf_probe/perf files as well as to any attached eBPF program. Link: https://lkml.kernel.org/r/20220118204326.2169-5-beaub@linux.microsoft.comAcked-by:
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Beau Belgrave authored
Ensures that when dynamic events requests a match with arguments that they match what is in the user_event. Link: https://lkml.kernel.org/r/20220118204326.2169-4-beaub@linux.microsoft.comAcked-by:
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Beau Belgrave authored
Addes print_fmt format generation for basic types that are supported for user processes. Only supports sizes that are the same on 32 and 64 bit. Link: https://lkml.kernel.org/r/20220118204326.2169-3-beaub@linux.microsoft.comAcked-by:
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Beau Belgrave authored
Minimal support for interacting with dynamic events, trace_event and ftrace. Core outline of flow between user process, ioctl and trace_event APIs. User mode processes that wish to use trace events to get data into ftrace, perf, eBPF, etc are limited to uprobes today. The user events features enables an ABI for user mode processes to create and write to trace events that are isolated from kernel level trace events. This enables a faster path for tracing from user mode data as well as opens managed code to participate in trace events, where stub locations are dynamic. User processes often want to trace only when it's useful. To enable this a set of pages are mapped into the user process space that indicate the current state of the user events that have been registered. User processes can check if their event is hooked to a trace/probe, and if it is, emit the event data out via the write() syscall. Two new files are introduced into tracefs to accomplish this: user_events_status - This file is mmap'd into participating user mode processes to indicate event status. user_events_data - This file is opened and register/delete ioctl's are issued to create/open/delete trace events that can be used for tracing. The typical scenario is on process start to mmap user_events_status. Processes then register the events they plan to use via the REG ioctl. The ioctl reads and updates the passed in user_reg struct. The status_index of the struct is used to know the byte in the status page to check for that event. The write_index of the struct is used to describe that event when writing out to the fd that was used for the ioctl call. The data must always include this index first when writing out data for an event. Data can be written either by write() or by writev(). For example, in memory: int index; char data[]; Psuedo code example of typical usage: struct user_reg reg; int page_fd = open("user_events_status", O_RDWR); char *page_data = mmap(NULL, PAGE_SIZE, PROT_READ, MAP_SHARED, page_fd, 0); close(page_fd); int data_fd = open("user_events_data", O_RDWR); reg.size = sizeof(reg); reg.name_args = (__u64)"test"; ioctl(data_fd, DIAG_IOCSREG, ®); int status_id = reg.status_index; int write_id = reg.write_index; struct iovec io[2]; io[0].iov_base = &write_id; io[0].iov_len = sizeof(write_id); io[1].iov_base = payload; io[1].iov_len = sizeof(payload); if (page_data[status_id]) writev(data_fd, io, 2); User events are also exposed via the dynamic_events tracefs file for both create and delete. Current status is exposed via the user_events_status tracefs file. Simple example to register a user event via dynamic_events: echo u:test >> dynamic_events cat dynamic_events u:test If an event is hooked to a probe, the probe hooked shows up: echo 1 > events/user_events/test/enable cat user_events_status 1:test # Used by ftrace Active: 1 Busy: 1 Max: 4096 If an event is not hooked to a probe, no probe status shows up: echo 0 > events/user_events/test/enable cat user_events_status 1:test Active: 1 Busy: 0 Max: 4096 Users can describe the trace event format via the following format: name[:FLAG1[,FLAG2...] [field1[;field2...]] Each field has the following format: type name Example for char array with a size of 20 named msg: echo 'u:detailed char[20] msg' >> dynamic_events cat dynamic_events u:detailed char[20] msg Data offsets are based on the data written out via write() and will be updated to reflect the correct offset in the trace_event fields. For dynamic data it is recommended to use the new __rel_loc data type. This type will be the same as __data_loc, but the offset is relative to this entry. This allows user_events to not worry about what common fields are being inserted before the data. The above format is valid for both the ioctl and the dynamic_events file. Link: https://lkml.kernel.org/r/20220118204326.2169-2-beaub@linux.microsoft.comAcked-by: -
Steven Rostedt (Google) authored
Use the sched_switch function to save both the wakee and the waker comms in the saved cmdlines list when sched_wakeup is done. Signed-off-by: -
Tom Zanussi authored
Currently, synthetic event command error strings are restricted to a length of MAX_FILTER_STR_VAL (256), which is too short for some commands already seen in the wild (with cmd strings longer than that showing up truncated in err_log). Remove the restriction so that no synthetic event command error string is ever truncated. Link: https://lkml.kernel.org/r/0376692396a81d0b795127c66ea92ca5bf60f481.1643399022.git.zanussi@kernel.orgSigned-off-by:
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Tom Zanussi authored
Currently, hist trigger command error strings are restricted to a length of MAX_FILTER_STR_VAL (256), which is too short for some commands already seen in the wild (with cmd strings longer than that showing up truncated in err_log). Remove the restriction so that no hist trigger command error string is ever truncated. Link: https://lkml.kernel.org/r/0f9d46407222eaf6632cd3b417bc50a11f401b71.1643399022.git.zanussi@kernel.orgSigned-off-by:
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Tom Zanussi authored
Currently, tracing_log_err.cmd strings are restricted to a length of MAX_FILTER_STR_VAL (256), which is too short for some commands already seen in the wild (with cmd strings longer than that showing up truncated). Remove the restriction so that no command string is ever truncated. Link: https://lkml.kernel.org/r/ca965f23256b350ebd94b3dc1a319f28e8267f5f.1643319703.git.zanussi@kernel.orgSigned-off-by:
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- 08 Feb, 2022 3 commits
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JaeSang Yoo authored
The kernel parameter "tp_printk_stop_on_boot" starts with "tp_printk" which is the same as another kernel parameter "tp_printk". If "tp_printk" setup is called before the "tp_printk_stop_on_boot", it will override the latter and keep it from being set. This is similar to other kernel parameter issues, such as: Commit 745a600c ("um: console: Ignore console= option") or init/do_mounts.c:45 (setup function of "ro" kernel param) Fix it by checking for a "_" right after the "tp_printk" and if that exists do not process the parameter. Link: https://lkml.kernel.org/r/20220208195421.969326-1-jsyoo5b@gmail.comSigned-off-by:
JaeSang Yoo <jsyoo5b@gmail.com> [ Fixed up change log and added space after if condition ] Signed-off-by:
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Daniel Bristot de Oliveira authored
Add an RTLA entry in the MAINTAINERS file with Steven Rostedt and myself as maintainers. Link: https://lkml.kernel.org/r/50d8870522580905a1c7f3e6fb611a700f632af1.1643994005.git.bristot@kernel.org Cc: Joe Perches <joe@perches.com> Signed-off-by:
Daniel Bristot de Oliveira <bristot@kernel.org> Signed-off-by:
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Daniel Bristot de Oliveira authored
rtla osnoise and timerlat are causing a segmentation fault when running with the --trace option on a kernel that does not support multiple instances. For example: [root@f34 rtla]# rtla osnoise top -t failed to enable the tracer osnoise Could not enable osnoiser tracer for tracing Failed to enable the trace instance Segmentation fault (core dumped) This error happens because the exit code of the tools is trying to destroy the trace instance that failed to be created. Make osnoise_destroy_tool() aware of possible NULL osnoise_tool *, and do not attempt to destroy it. This also simplifies the exit code. Link: https://lkml.kernel.org/r/5660a2b6bf66c2655842360f2d7f6b48db5dba23.1644327249.git.bristot@kernel.orgSuggested-by:
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- 04 Feb, 2022 3 commits
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Daniel Bristot de Oliveira authored
Use capital and change "tracer %s" to "%s tracer". No functional change. Link: https://lkml.kernel.org/r/361697d27431afefa64c67c323564205385c418d.1643990447.git.bristot@kernel.org Fixes: b1696371 ("rtla: Helper functions for rtla") Cc: Daniel Bristot de Oliveira <bristot@kernel.org> Cc: linux-kernel@vger.kernel.org Cc: linux-trace-devel@vger.kernel.org Signed-off-by:
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Daniel Bristot de Oliveira authored
Use gmtime to format the duration time. This avoids problems when the system uses local time different of Pisa's Local Time. Link: https://lkml.kernel.org/r/a2f0a37bc006c2561bb8ecd871cd70532b4a9f2d.1643990447.git.bristot@kernel.org Fixes: b1696371 ("rtla: Helper functions for rtla") Cc: Daniel Bristot de Oliveira <bristot@kernel.org> Cc: linux-kernel@vger.kernel.org Cc: linux-trace-devel@vger.kernel.org Signed-off-by:
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Daniel Bristot de Oliveira authored
To avoid having commits with new version, it is just easier to follow kernel version. Link: https://lkml.kernel.org/r/9c2df0d1de65cea96c7d731fe64781a2bb90c5b3.1643990447.git.bristot@kernel.org Cc: Daniel Bristot de Oliveira <bristot@kernel.org> Cc: linux-kernel@vger.kernel.org Cc: linux-trace-devel@vger.kernel.org Signed-off-by:
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- 28 Jan, 2022 4 commits
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Tom Zanussi authored
tr->n_err_log_entries should only be increased if entry allocation succeeds. Doing it when it fails won't cause any problems other than wasting an entry, but should be fixed anyway. Link: https://lkml.kernel.org/r/cad1ab28f75968db0f466925e7cba5970cec6c29.1643319703.git.zanussi@kernel.org Cc: stable@vger.kernel.org Fixes: 2f754e77 ("tracing: Don't inc err_log entry count if entry allocation fails") Signed-off-by:
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Tom Zanussi authored
During expression parsing, a new expression field is created which should inherit the properties of the operands, such as size and is_signed. is_signed propagation was missing, causing spurious errors with signed operands. Add it in parse_expr() and parse_unary() to fix the problem. Link: https://lkml.kernel.org/r/f4dac08742fd7a0920bf80a73c6c44042f5eaa40.1643319703.git.zanussi@kernel.org Cc: stable@vger.kernel.org Fixes: 100719dc ("tracing: Add simple expression support to hist triggers") Reported-by:
Yordan Karadzhov <ykaradzhov@vmware.com> BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=215513Signed-off-by:
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Tom Zanussi authored
The patch ec5ce098: "tracing: Allow whitespace to surround hist trigger filter" from Jan 15, 2018, leads to the following Smatch static checker warning: kernel/trace/trace_events_hist.c:6199 event_hist_trigger_parse() warn: 'p' can't be NULL. Since p is always checked for a NULL value at the top of loop and nothing in the rest of the loop will set it to NULL, the warning is correct and might as well be 1 to silence the warning. Link: https://lkml.kernel.org/r/a1d4c79766c0cf61e20438dc35244d216633fef6.1643319703.git.zanussi@kernel.org Fixes: ec5ce098 ("tracing: Allow whitespace to surround hist trigger filter") Reported-by:
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Tom Zanussi authored
The recent rename of event_hist_trigger_parse() caused smatch re-evaluation of trace_events_hist.c and as a result an old warning was found: kernel/trace/trace_events_hist.c:6174 event_hist_trigger_parse() error: we previously assumed 'glob' could be null (see line 6166) glob should never be null (and apparently smatch can also figure that out and skip the warning when using the cross-function DB (but which can't be used with a 0day build as it takes too much time to generate)). Nonetheless for clarity, remove the test but add a WARN_ON() in case the code ever changes. Link: https://lkml.kernel.org/r/96925e5c1f116654ada7ea0613d930b1266b5e1c.1643319703.git.zanussi@kernel.org Fixes: f404da6e ("tracing: Add 'last error' error facility for hist triggers") Reported-by:
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