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strcpy() is deprecated; use memcpy() instead.
Link: https://lore.kernel.org/all/20250820214717.778243-3-thorsten.blum@linux.dev/
Link: https://github.com/KSPP/linux/issues/88
Signed-off-by: Thorsten Blum <thorsten.blum@linux.dev>
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
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rcu_read_lock() is not needed in fprobe_entry, but rcu_dereference_check()
is used in rhltable_lookup(), which causes suspicious RCU usage warning:
WARNING: suspicious RCU usage
6.17.0-rc1-00001-gdfe0d675df82 #1 Tainted: G S
-----------------------------
include/linux/rhashtable.h:602 suspicious rcu_dereference_check() usage!
......
stack backtrace:
CPU: 1 UID: 0 PID: 4652 Comm: ftracetest Tainted: G S
Tainted: [S]=CPU_OUT_OF_SPEC, [I]=FIRMWARE_WORKAROUND
Hardware name: Dell Inc. OptiPlex 7040/0Y7WYT, BIOS 1.1.1 10/07/2015
Call Trace:
<TASK>
dump_stack_lvl+0x7c/0x90
lockdep_rcu_suspicious+0x14f/0x1c0
__rhashtable_lookup+0x1e0/0x260
? __pfx_kernel_clone+0x10/0x10
fprobe_entry+0x9a/0x450
? __lock_acquire+0x6b0/0xca0
? find_held_lock+0x2b/0x80
? __pfx_fprobe_entry+0x10/0x10
? __pfx_kernel_clone+0x10/0x10
? lock_acquire+0x14c/0x2d0
? __might_fault+0x74/0xc0
function_graph_enter_regs+0x2a0/0x550
? __do_sys_clone+0xb5/0x100
? __pfx_function_graph_enter_regs+0x10/0x10
? _copy_to_user+0x58/0x70
? __pfx_kernel_clone+0x10/0x10
? __x64_sys_rt_sigprocmask+0x114/0x180
? __pfx___x64_sys_rt_sigprocmask+0x10/0x10
? __pfx_kernel_clone+0x10/0x10
ftrace_graph_func+0x87/0xb0
As we discussed in [1], fix this by using guard(rcu)() in fprobe_entry()
to protect the rhltable_lookup() and rhl_for_each_entry_rcu() with
rcu_read_lock and suppress this warning.
Link: https://lore.kernel.org/all/20250904062729.151931-1-dongml2@chinatelecom.cn/
Link: https://lore.kernel.org/all/20250829021436.19982-1-dongml2@chinatelecom.cn/ [1]
Reported-by: kernel test robot <oliver.sang@intel.com>
Closes: https://lore.kernel.org/oe-lkp/202508281655.54c87330-lkp@intel.com
Fixes: dfe0d675df82 ("tracing: fprobe: use rhltable for fprobe_ip_table")
Signed-off-by: Menglong Dong <dongml2@chinatelecom.cn>
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
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Since traceprobe_parse_context is reusable among a probe arguments,
it is more efficient to allocate it outside of the loop for parsing
probe argument as kprobe and fprobe events do.
Link: https://lore.kernel.org/all/175509541393.193596.16330324746701582114.stgit@devnote2/
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
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Use __free() to cleanup ugly gotos in __trace_uprobe_create().
Link: https://lore.kernel.org/all/175509540482.193596.6541098946023873304.stgit@devnote2/
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
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Use __free(trace_event_probe_cleanup) to remove unneeded gotos and
cleanup the last part of trace_eprobe_parse_filter().
Link: https://lore.kernel.org/all/175509539571.193596.4674012182718751429.stgit@devnote2/
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
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Use __free() for trace_probe_log_clear() to cleanup error log interface.
Link: https://lore.kernel.org/all/175509538609.193596.16646724647358218778.stgit@devnote2/
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
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For now, all the kernel functions who are hooked by the fprobe will be
added to the hash table "fprobe_ip_table". The key of it is the function
address, and the value of it is "struct fprobe_hlist_node".
The budget of the hash table is FPROBE_IP_TABLE_SIZE, which is 256. And
this means the overhead of the hash table lookup will grow linearly if
the count of the functions in the fprobe more than 256. When we try to
hook all the kernel functions, the overhead will be huge.
Therefore, replace the hash table with rhltable to reduce the overhead.
Link: https://lore.kernel.org/all/20250819031825.55653-1-dongml2@chinatelecom.cn/
Signed-off-by: Menglong Dong <dongml2@chinatelecom.cn>
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
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The persistent ring buffer from a previous boot has to be careful printing
events as the print formats of random events can have pointers to strings
and such that are not available.
Ftrace static events (like the function tracer event) are stable and are
printed normally.
System call event formats are also stable. Allow them to be printed
normally as well:
Instead of:
<...>-1 [005] ...1. 57.240405: sys_enter_waitid: __syscall_nr=0xf7 (247) which=0x1 (1) upid=0x499 (1177) infop=0x7ffd5294d690 (140725988939408) options=0x5 (5) ru=0x0 (0)
<...>-1 [005] ...1. 57.240433: sys_exit_waitid: __syscall_nr=0xf7 (247) ret=0x0 (0)
<...>-1 [005] ...1. 57.240437: sys_enter_rt_sigprocmask: __syscall_nr=0xe (14) how=0x2 (2) nset=0x7ffd5294d7c0 (140725988939712) oset=0x0 (0) sigsetsize=0x8 (8)
<...>-1 [005] ...1. 57.240438: sys_exit_rt_sigprocmask: __syscall_nr=0xe (14) ret=0x0 (0)
<...>-1 [005] ...1. 57.240442: sys_enter_close: __syscall_nr=0x3 (3) fd=0x4 (4)
<...>-1 [005] ...1. 57.240463: sys_exit_close: __syscall_nr=0x3 (3) ret=0x0 (0)
<...>-1 [005] ...1. 57.240485: sys_enter_openat: __syscall_nr=0x101 (257) dfd=0xffffffffffdfff9c (-2097252) filename=(0xffff8b81639ca01c) flags=0x80000 (524288) mode=0x0 (0) __filename_val=/run/systemd/reboot-param
<...>-1 [005] ...1. 57.240555: sys_exit_openat: __syscall_nr=0x101 (257) ret=0xffffffffffdffffe (-2097154)
<...>-1 [005] ...1. 57.240571: sys_enter_openat: __syscall_nr=0x101 (257) dfd=0xffffffffffdfff9c (-2097252) filename=(0xffff8b81639ca01c) flags=0x80000 (524288) mode=0x0 (0) __filename_val=/run/systemd/reboot-param
<...>-1 [005] ...1. 57.240620: sys_exit_openat: __syscall_nr=0x101 (257) ret=0xffffffffffdffffe (-2097154)
<...>-1 [005] ...1. 57.240629: sys_enter_writev: __syscall_nr=0x14 (20) fd=0x3 (3) vec=0x7ffd5294ce50 (140725988937296) vlen=0x7 (7)
<...>-1 [005] ...1. 57.242281: sys_exit_writev: __syscall_nr=0x14 (20) ret=0x24 (36)
<...>-1 [005] ...1. 57.242286: sys_enter_reboot: __syscall_nr=0xa9 (169) magic1=0xfee1dead (4276215469) magic2=0x28121969 (672274793) cmd=0x1234567 (19088743) arg=0x0 (0)
Have:
<...>-1 [000] ...1. 91.446011: sys_waitid(which: 1, upid: 0x4d2, infop: 0x7ffdccdadfd0, options: 5, ru: 0)
<...>-1 [000] ...1. 91.446042: sys_waitid -> 0x0
<...>-1 [000] ...1. 91.446045: sys_rt_sigprocmask(how: 2, nset: 0x7ffdccdae100, oset: 0, sigsetsize: 8)
<...>-1 [000] ...1. 91.446047: sys_rt_sigprocmask -> 0x0
<...>-1 [000] ...1. 91.446051: sys_close(fd: 4)
<...>-1 [000] ...1. 91.446073: sys_close -> 0x0
<...>-1 [000] ...1. 91.446095: sys_openat(dfd: 18446744073709551516, filename: 139732544945794 "/run/systemd/reboot-param", flags: O_RDONLY|O_CLOEXEC)
<...>-1 [000] ...1. 91.446165: sys_openat -> 0xfffffffffffffffe
<...>-1 [000] ...1. 91.446182: sys_openat(dfd: 18446744073709551516, filename: 139732544945794 "/run/systemd/reboot-param", flags: O_RDONLY|O_CLOEXEC)
<...>-1 [000] ...1. 91.446233: sys_openat -> 0xfffffffffffffffe
<...>-1 [000] ...1. 91.446242: sys_writev(fd: 3, vec: 0x7ffdccdad790, vlen: 7)
<...>-1 [000] ...1. 91.447877: sys_writev -> 0x24
<...>-1 [000] ...1. 91.447883: sys_reboot(magic1: 0xfee1dead, magic2: 0x28121969, cmd: 0x1234567, arg: 0)
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Takaya Saeki <takayas@google.com>
Cc: Tom Zanussi <zanussi@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ian Rogers <irogers@google.com>
Cc: Douglas Raillard <douglas.raillard@arm.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Link: https://lore.kernel.org/20251028231149.097404581@kernel.org
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
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When the "fields" option is enabled, it prints each trace event field
based on its type. But a dynamic array and a dynamic string can both have
a "char *" type. Printing it as a string can cause escape characters to be
printed and mess up the output of the trace.
For dynamic strings, test if there are any non-printable characters, and
if so, print both the string with the non printable characters as '.', and
the print the hex value of the array.
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Takaya Saeki <takayas@google.com>
Cc: Tom Zanussi <zanussi@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ian Rogers <irogers@google.com>
Cc: Douglas Raillard <douglas.raillard@arm.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Link: https://lore.kernel.org/20251028231148.929243047@kernel.org
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
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Add some logic to give the openat system call trace event a bit more human
readable information:
syscalls:sys_enter_openat: dfd: 0xffffff9c, filename: 0x7f0053dc121c "/etc/ld.so.cache", flags: O_RDONLY|O_CLOEXEC, mode: 0000
The above is output from "perf script" and now shows the flags used by the
openat system call.
Since the output from tracing is in the kernel, it can also remove the
mode field when not used (when flags does not contain O_CREATE|O_TMPFILE)
touch-1185 [002] ...1. 1291.690154: sys_openat(dfd: 4294967196, filename: 139785545139344 "/usr/lib/locale/locale-archive", flags: O_RDONLY|O_CLOEXEC)
touch-1185 [002] ...1. 1291.690504: sys_openat(dfd: 18446744073709551516, filename: 140733603151330 "/tmp/x", flags: O_WRONLY|O_CREAT|O_NOCTTY|O_NONBLOCK, mode: 0666)
As system calls have a fixed ABI, their trace events can be extended. This
currently only updates the openat system call, but others may be extended
in the future.
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Takaya Saeki <takayas@google.com>
Cc: Tom Zanussi <zanussi@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ian Rogers <irogers@google.com>
Cc: Douglas Raillard <douglas.raillard@arm.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Link: https://lore.kernel.org/20251028231148.763161484@kernel.org
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
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When displaying the contents of the user space data passed to the kernel,
instead of just showing the array values, also print any printable
content.
Instead of just:
bash-1113 [003] ..... 3433.290654: sys_write(fd: 2, buf: 0x555a8deeddb0 (72:6f:6f:74:40:64:65:62:69:61:6e:2d:78:38:36:2d:36:34:3a:7e:23:20), count: 0x16)
Display:
bash-1113 [003] ..... 3433.290654: sys_write(fd: 2, buf: 0x555a8deeddb0 (72:6f:6f:74:40:64:65:62:69:61:6e:2d:78:38:36:2d:36:34:3a:7e:23:20) "root@debian-x86-64:~# ", count: 0x16)
This only affects tracing and does not affect perf, as this only updates
the output from the kernel. The output from perf is via user space. This
may change by an update to libtraceevent that will then update perf to
have this as well.
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Takaya Saeki <takayas@google.com>
Cc: Tom Zanussi <zanussi@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ian Rogers <irogers@google.com>
Cc: Douglas Raillard <douglas.raillard@arm.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Link: https://lore.kernel.org/20251028231148.429422865@kernel.org
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
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When a system call that can copy user space addresses into the ring
buffer, it can copy up to 511 bytes of data. This can waste precious ring
buffer space if the user isn't interested in the output. Add a new file
"syscall_user_buf_size" that gets initialized to a new config
CONFIG_SYSCALL_BUF_SIZE_DEFAULT that defaults to 63.
The config also is used to limit how much perf can read from user space.
Also lower the max down to 165, as this isn't to record everything that a
system call may be passing through to the kernel. 165 is more than enough.
The reason for 165 is because adding one for the nul terminating byte, as
well as possibly needing to append the "..." string turns it into 170
bytes. As this needs to save up to 3 arguments and 3 * 170 is 510 which
fits nicely in 512 bytes (a power of 2).
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Takaya Saeki <takayas@google.com>
Cc: Tom Zanussi <zanussi@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ian Rogers <irogers@google.com>
Cc: Douglas Raillard <douglas.raillard@arm.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Link: https://lore.kernel.org/20251028231148.260068913@kernel.org
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
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Allow more than one field of a syscall trace event to read user space.
Build on top of the user_mask by allowing more than one bit to be set that
corresponds to the @args array of the syscall metadata. For each argument
in the @args array that is to be read, it will have a dynamic array/string
field associated to it.
Note that multiple fields to be read from user space is not supported if
the user_arg_size field is set in the syscall metada. That field can only
be used if only one field is being read from user space as that field is a
number representing the size field of the syscall event that holds the
size of the data to read from user space. It becomes ambiguous if the
system call reads more than one field. Currently this is not an issue.
If a syscall event happens to enable two events to read user space and
sets the user_arg_size field, it will trigger a warning at boot and the
user_arg_size field will be cleared.
The per CPU buffer that is used to read the user space addresses is now
broken up into 3 sections, each of 168 bytes. The reason for 168 is that
it is the biggest portion of 512 bytes divided by 3 that is 8 byte aligned.
The max amount copied into the ring buffer from user space is now only 128
bytes, which is plenty. When reading user space, it still reads 167
(168-1) bytes and uses the remaining to know if it should append the extra
"..." to the end or not.
This will allow the event to look like this:
sys_renameat2(olddfd: 0xffffff9c, oldname: 0x7ffe02facdff "/tmp/x", newdfd: 0xffffff9c, newname: 0x7ffe02face06 "/tmp/y", flags: 1)
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Takaya Saeki <takayas@google.com>
Cc: Tom Zanussi <zanussi@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ian Rogers <irogers@google.com>
Cc: Douglas Raillard <douglas.raillard@arm.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Link: https://lore.kernel.org/20251028231148.095789277@kernel.org
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
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Some of the system calls that read a fixed length of memory from the user
space address are not arrays but strings. Take a bit away from the nb_args
field in the syscall meta data to use as a flag to denote that the system
call's user_arg_size is being used as a string. The nb_args should never
be more than 6, so 7 bits is plenty to hold that number. When the
user_arg_is_str flag that, when set, will display the data array from the
user space address as a string and not an array.
This will allow the output to look like this:
sys_sethostname(name: 0x5584310eb2a0 "debian", len: 6)
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Takaya Saeki <takayas@google.com>
Cc: Tom Zanussi <zanussi@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ian Rogers <irogers@google.com>
Cc: Douglas Raillard <douglas.raillard@arm.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Link: https://lore.kernel.org/20251028231147.930550359@kernel.org
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
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For system call events that have a length field, add a "user_arg_size"
parameter to the system call meta data that denotes the index of the args
array that holds the size of arg that the user_mask field has a bit set
for.
The "user_mask" has a bit set that denotes the arg that points to an array
in the user space address space and if a system call event has the
user_mask field set and the user_arg_size set, it will then record the
content of that address into the trace event, up to the size defined by
SYSCALL_FAULT_BUF_SZ - 1.
This allows the output to look like:
sys_write(fd: 0xa, buf: 0x5646978d13c0 (01:00:05:00:00:00:00:00:01:87:55:89:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00), count: 0x20)
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Takaya Saeki <takayas@google.com>
Cc: Tom Zanussi <zanussi@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ian Rogers <irogers@google.com>
Cc: Douglas Raillard <douglas.raillard@arm.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Link: https://lore.kernel.org/20251028231147.763528474@kernel.org
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
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Allow some of the system call events to read user space buffers. Instead
of just showing the pointer into user space, allow perf events to also
record the content of those pointers. For example:
# perf record -e syscalls:sys_enter_openat ls /usr/bin
[..]
# perf script
ls 1024 [005] 52.902721: syscalls:sys_enter_openat: dfd: 0xffffff9c, filename: 0x7fc1dbae321c "/etc/ld.so.cache", flags: 0x00080000, mode: 0x00000000
ls 1024 [005] 52.902899: syscalls:sys_enter_openat: dfd: 0xffffff9c, filename: 0x7fc1dbaae140 "/lib/x86_64-linux-gnu/libselinux.so.1", flags: 0x00080000, mode: 0x00000000
ls 1024 [005] 52.903471: syscalls:sys_enter_openat: dfd: 0xffffff9c, filename: 0x7fc1dbaae690 "/lib/x86_64-linux-gnu/libcap.so.2", flags: 0x00080000, mode: 0x00000000
ls 1024 [005] 52.903946: syscalls:sys_enter_openat: dfd: 0xffffff9c, filename: 0x7fc1dbaaebe0 "/lib/x86_64-linux-gnu/libc.so.6", flags: 0x00080000, mode: 0x00000000
ls 1024 [005] 52.904629: syscalls:sys_enter_openat: dfd: 0xffffff9c, filename: 0x7fc1dbaaf110 "/lib/x86_64-linux-gnu/libpcre2-8.so.0", flags: 0x00080000, mode: 0x00000000
ls 1024 [005] 52.906985: syscalls:sys_enter_openat: dfd: 0xffffffffffffff9c, filename: 0x7fc1dba92904 "/proc/filesystems", flags: 0x00080000, mode: 0x00000000
ls 1024 [005] 52.907323: syscalls:sys_enter_openat: dfd: 0xffffff9c, filename: 0x7fc1dba19490 "/usr/lib/locale/locale-archive", flags: 0x00080000, mode: 0x00000000
ls 1024 [005] 52.907746: syscalls:sys_enter_openat: dfd: 0xffffff9c, filename: 0x556fb888dcd0 "/usr/bin", flags: 0x00090800, mode: 0x00000000
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Takaya Saeki <takayas@google.com>
Cc: Tom Zanussi <zanussi@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ian Rogers <irogers@google.com>
Cc: Douglas Raillard <douglas.raillard@arm.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Link: https://lore.kernel.org/20251028231147.593925979@kernel.org
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
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|
Use guard(mutex)(&syscall_trace_lock) for perf_sysenter_enable() and
perf_sysenter_disable() as well as for the perf_sysexit_enable() and
perf_sysexit_disable(). This will make it easier to update these functions
with other code that has early exit handling.
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Takaya Saeki <takayas@google.com>
Cc: Tom Zanussi <zanussi@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ian Rogers <irogers@google.com>
Cc: Douglas Raillard <douglas.raillard@arm.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Link: https://lore.kernel.org/20251028231147.429583335@kernel.org
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
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As of commit 654ced4a1377 ("tracing: Introduce tracepoint_is_faultable()")
system call trace events allow faulting in user space memory. Have some of
the system call trace events take advantage of this.
Use the trace_user_fault_read() logic to read the user space buffer from
user space and instead of just saving the pointer to the buffer in the
system call event, also save the string that is passed in.
The syscall event has its nb_args shorten from an int to a short (where
even u8 is plenty big enough) and the freed two bytes are used for
"user_mask". The new "user_mask" field is used to store the index of the
"args" field array that has the address to read from user space. This
value is set to 0 if the system call event does not need to read user
space for a field. This mask can be used to know if the event may fault or
not. Only one bit set in user_mask is supported at this time.
This allows the output to look like this:
sys_access(filename: 0x7f8c55368470 "/etc/ld.so.preload", mode: 4)
sys_execve(filename: 0x564ebcf5a6b8 "/usr/bin/emacs", argv: 0x7fff357c0300, envp: 0x564ebc4a4820)
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Takaya Saeki <takayas@google.com>
Cc: Tom Zanussi <zanussi@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ian Rogers <irogers@google.com>
Cc: Douglas Raillard <douglas.raillard@arm.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Link: https://lore.kernel.org/20251028231147.261867956@kernel.org
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
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The write to the trace_marker file is a critical section where it cannot
take locks nor allocate memory. To read from user space, it allocates a per
CPU buffer when the trace_marker file is opened, and then when the write
system call is performed, it uses the following method to read from user
space:
preempt_disable();
buffer = per_cpu_ptr(cpu_buffers, cpu);
do {
cnt = nr_context_switches_cpu();
migrate_disable();
preempt_enable();
ret = copy_from_user(buffer, ptr, len);
preempt_disable();
migrate_enable();
} while (!ret && cnt != nr_context_switches_cpu());
if (!ret)
ring_buffer_write(buffer);
preempt_enable();
It records the number of context switches for the current CPU, enables
preemption, copies from user space, disable preemption and then checks if
the number of context switches changed. If it did not, then the buffer is
valid, otherwise the buffer may have been corrupted and the read from user
space must be tried again.
The system call trace events are now faultable and have the same
restrictions as the trace_marker write. For system calls to read the user
space buffer (for example to read the file of the openat system call), it
needs the same logic. Instead of copying the code over to the system call
trace events, make the code generic to allow the system call trace events to
use the same code. The following API is added internally to the tracing sub
system (these are only exposed within the tracing subsystem and not to be
used outside of it):
trace_user_fault_init() - initializes a trace_user_buf_info descriptor
that will allocate the per CPU buffers to copy from user space into.
trace_user_fault_destroy() - used to free the allocations made by
trace_user_fault_init().
trace_user_fault_get() - update the ref count of the info descriptor to
allow more than one user to use the same descriptor.
trace_user_fault_put() - decrement the ref count.
trace_user_fault_read() - performs the above action to read user space
into the per CPU buffer. The preempt_disable() is expected before
calling this function and preemption must remain disabled while the
buffer returned is in use.
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Takaya Saeki <takayas@google.com>
Cc: Tom Zanussi <zanussi@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ian Rogers <irogers@google.com>
Cc: Douglas Raillard <douglas.raillard@arm.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Link: https://lore.kernel.org/20251028231147.096570057@kernel.org
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
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The ftrace blktrace path allocates buffers and writes trace events but
was using the wrong recording function. After
commit 4d8bc7bd4f73 ("blktrace: move ftrace blk_io_tracer to blk_io_trace2"),
the ftrace interface was moved to use blk_io_trace2 format, but
__blk_add_trace() still called record_blktrace_event() which writes in
blk_io_trace (v1) format.
This causes critical data corruption:
- blk_io_trace (v1) has 32-bit 'action' field at offset 28
- blk_io_trace2 (v2) has 32-bit 'pid' at offset 28 and 64-bit 'action'
at offset 32
- When record_blktrace_event() writes to a v2 buffer:
* Writing pid (offset 32 in v1) corrupts the v2 action field
* Writing action (offset 28 in v1) corrupts the v2 pid field
* The 64-bit action is truncated to 32-bit via lower_32_bits()
Fix by:
1. Adding version switch to select correct format (v1 vs v2)
2. Calling appropriate recording function based on version
3. Defaulting to v2 for ftrace (as intended by commit 4d8bc7bd4f73)
4. Adding WARN_ONCE for unexpected version values
Without this patch :-
linux-block (for-next) # sh reproduce_blktrace_bug.sh
dd-14242 [033] d..1. 3903.022308: Unknown action 36a2
dd-14242 [033] d..1. 3903.022333: Unknown action 36a2
dd-14242 [033] d..1. 3903.022365: Unknown action 36a2
dd-14242 [033] d..1. 3903.022366: Unknown action 36a2
dd-14242 [033] d..1. 3903.022369: Unknown action 36a2
The action field is corrupted because:
- ftrace allocated blk_io_trace2 buffer (64 bytes)
- But called record_blktrace_event() (writes v1, 48 bytes)
- Field offsets don't match, causing corruption
The hex value shown 0x30e3 is actually a PID, not an action code!
linux-block (for-next) #
linux-block (for-next) #
linux-block (for-next) # sh reproduce_blktrace_bug.sh
Trace output looks correct:
dd-2420 [019] d..1. 59.641742: 251,0 Q RS 0 + 8 [dd]
dd-2420 [019] d..1. 59.641775: 251,0 G RS 0 + 8 [dd]
dd-2420 [019] d..1. 59.641784: 251,0 P N [dd]
dd-2420 [019] d..1. 59.641785: 251,0 U N [dd] 1
dd-2420 [019] d..1. 59.641788: 251,0 D RS 0 + 8 [dd]
Fixes: 4d8bc7bd4f73 ("blktrace: move ftrace blk_io_tracer to blk_io_trace2")
Signed-off-by: Chaitanya Kulkarni <ckulkarnilinux@gmail.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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The WARN_ON_ONCE introduced in
commit f9ee38bbf70f ("blktrace: add block trace commands for zone operations")
triggers kernel warnings when zone operations are traced with blktrace
version 1. This can spam the kernel log during normal operation with
zoned block devices when userspace is using the legacy blktrace
protocol.
Currently blktrace implementation drops newly added REQ_OP_ZONE_XXX
when blktrace userspce version is set to 1.
Remove the WARN_ON_ONCE and quietly filter these events. Add a
rate-limited debug message to help diagnose potential issues without
flooding the kernel log. The debug message can be enabled via dynamic
debug when needed for troubleshooting.
This approach is more appropriate as encountering zone operations with
blktrace v1 is an expected condition that should be handled gracefully
rather than warned about, since users may be running older blktrace
userspace tools that only support version 1 of the protocol.
With this patch :-
linux-block (for-next) # git log -1
commit c8966006a0971d2b4bf94c0426eb7e4407c6853f (HEAD -> for-next)
Author: Chaitanya Kulkarni <ckulkarnilinux@gmail.com>
Date: Mon Oct 27 19:26:53 2025 -0700
blktrace: use debug print to report dropped events
linux-block (for-next) # cdblktests
blktests (master) # ./check blktrace
blktrace/001 (blktrace zone management command tracing) [passed]
runtime 3.805s ... 3.889s
blktests (master) # dmesg -c
blktests (master) # echo "file kernel/trace/blktrace.c +p" > /sys/kernel/debug/dynamic_debug/control
blktests (master) # ./check blktrace
blktrace/001 (blktrace zone management command tracing) [passed]
runtime 3.889s ... 3.881s
blktests (master) # dmesg -c
[ 77.826237] blktrace: blktrace v1 cannot trace zone operation 0x1000190001
[ 77.826260] blktrace: blktrace v1 cannot trace zone operation 0x1000190004
[ 77.826282] blktrace: blktrace v1 cannot trace zone operation 0x1001490007
[ 77.826288] blktrace: blktrace v1 cannot trace zone operation 0x1001890008
[ 77.826343] blktrace: blktrace v1 cannot trace zone operation 0x1000190001
[ 77.826347] blktrace: blktrace v1 cannot trace zone operation 0x1000190004
[ 77.826350] blktrace: blktrace v1 cannot trace zone operation 0x1001490007
[ 77.826354] blktrace: blktrace v1 cannot trace zone operation 0x1001890008
[ 77.826373] blktrace: blktrace v1 cannot trace zone operation 0x1000190001
[ 77.826377] blktrace: blktrace v1 cannot trace zone operation 0x1000190004
blktests (master) # echo "file kernel/trace/blktrace.c -p" > /sys/kernel/debug/dynamic_debug/control
blktests (master) # ./check blktrace
blktrace/001 (blktrace zone management command tracing) [passed]
runtime 3.881s ... 3.824s
blktests (master) # dmesg -c
blktests (master) #
Reported-by: syzbot+153e64c0aa875d7e4c37@syzkaller.appspotmail.com
Fixes: f9ee38bbf70f ("blktrace: add block trace commands for zone operations")
Signed-off-by: Chaitanya Kulkarni <ckulkarnilinux@gmail.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Dynptr currently caps size and offset at 24 bits, which isn’t sufficient
for file-backed use cases; even 32 bits can be limiting. Refactor dynptr
helpers/kfuncs to use 64-bit size and offset, ensuring consistency
across the APIs.
This change does not affect internals of xdp, skb or other dynptrs,
which continue to behave as before. Also it does not break binary
compatibility.
The widening enables large-file access support via dynptr, implemented
in the next patches.
Signed-off-by: Mykyta Yatsenko <yatsenko@meta.com>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20251026203853.135105-3-mykyta.yatsenko5@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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Handle the BLKTRACESETUP2 ioctl, requesting an extended version of the
blktrace protocol from user-space.
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Trace zone write plugging operations on block devices.
As tracing of zoned block commands needs the upper 32bit of the widened
64bit action, only add traces to blktrace if user-space has requested
version 2 of the blktrace protocol.
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
|
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Expose ZONE APPEND completions as a block trace completion action to
blktrace.
As tracing of zoned block commands needs the upper 32bit of the widened
64bit action, only add traces to blktrace if user-space has requested
version 2 of the blktrace protocol.
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
|
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Add block trace commands for zone operations. These commands can only be
handled with version 2 of the blktrace protocol. For version 1, warn if a
command that does not fit into the 16 bits reserved for the command in
this version is passed in.
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
|
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Move ftrace's blk_io_tracer to the new blk_io_trace2 infrastructure.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
|
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Move trace_note() to the new blk_io_trace2 infrastructure.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
|
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Differentiate between blk_io_trace and blk_io_trace2 when relaying to
user-space depending on which version has been requested by the blktrace
utility.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
|
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Add definitions for the extended version of the blktrace protocol using a
wider action type to be able to record new actions in the kernel.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Pass struct blk_user_trace_setup2 to blktrace_setup_finalize(). This
prepares for the incoming extension of the blktrace protocol with a 64bit
act_mask.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
|
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Add definitions for a version 2 of the blk_user_trace_setup ioctl. This
new ioctl will enable a different struct layout of the binary data passed
to user-space when using a new version of the blktrace utility requesting
the new struct layout.
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Split do_blk_trace_setup into two functions, this is done to prepare for
an incoming new BLKTRACESETUP2 ioctl(2) which can receive extended
parameters from user-space.
Also move the size verification logic to the callers in preparation for
using a new internal structure later.
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Change the internal use of the action in blktrace to 64bit. Although for
now only the lower 32bits will be used.
With the upcoming version 2 of the blktrace user-space protocol the upper
32bit will also be utilized.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Untangle the if/else sequence setting the trace action in
__blk_add_trace() and turn it into a switch statement for better
extensibility.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Split out the code relaying a blktrace event to user-space using relayfs.
This enables adding a second version supporting a new version of the
protocol.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Factor out the recording of a blktrace event into its own function,
deduplicating the code.
This also enables recording different versions of the blktrace protocol
later on.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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De-duplicate the calculation of the trace length instead of doing the
calculation twice, once for calling trace_buffer_lock_reserve() and once
for calling relay_reserve().
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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There is no page fault without MMU. Compiling the rtapp/pagefault monitor
without CONFIG_MMU fails as page fault tracepoints' definitions are not
available.
Make rtapp/pagefault monitor depends on CONFIG_MMU.
Fixes: 9162620eb604 ("rv: Add rtapp_pagefault monitor")
Signed-off-by: Nam Cao <namcao@linutronix.de>
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202509260455.6Z9Vkty4-lkp@intel.com/
Cc: stable@vger.kernel.org
Reviewed-by: Gabriele Monaco <gmonaco@redhat.com>
Link: https://lore.kernel.org/r/20251002082317.973839-1-namcao@linutronix.de
Signed-off-by: Gabriele Monaco <gmonaco@redhat.com>
|
