Add the filter option to the event probe. This is useful if user wants
to derive a new event based on the condition of the original event.
E.g.
echo 'e:egroup/stat_runtime_4core sched/sched_stat_runtime \
runtime=$runtime:u32 if cpu < 4' >> ../dynamic_events
Then it can filter the events only on first 4 cores.
Note that the fields used for 'if' must be the fields in the original
events, not eprobe events.
Link: https://lkml.kernel.org/r/165932114513.2850673.2592206685744598080.stgit@devnote2
Cc: Tzvetomir Stoyanov <[email protected]>
Cc: Ingo Molnar <[email protected]>
Signed-off-by: Masami Hiramatsu (Google) <[email protected]>
Signed-off-by: Steven Rostedt (Google) <[email protected]>
Since the check_user_trigger() is called outside of RCU
read lock, this list_for_each_entry_rcu() caused a suspicious
RCU usage warning.
# echo hist:keys=pid > events/sched/sched_stat_runtime/trigger
# cat events/sched/sched_stat_runtime/trigger
[ 43.167032]
[ 43.167418] =============================
[ 43.167992] WARNING: suspicious RCU usage
[ 43.168567] 5.19.0-rc5-00029-g19ebe4651abf #59 Not tainted
[ 43.169283] -----------------------------
[ 43.169863] kernel/trace/trace_events_trigger.c:145 RCU-list traversed in non-reader section!!
...
However, this file->triggers list is safe when it is accessed
under event_mutex is held.
To fix this warning, adds a lockdep_is_held check to the
list_for_each_entry_rcu().
Link: https://lkml.kernel.org/r/166226474977.223837.1992182913048377113.stgit@devnote2
Cc: [email protected]
Fixes: 7491e2c442 ("tracing: Add a probe that attaches to trace events")
Signed-off-by: Masami Hiramatsu (Google) <[email protected]>
Signed-off-by: Steven Rostedt (Google) <[email protected]>
The commit 208003254c32 ("selftests/kprobe: Do not test for GRP/
without event failures") removed a syntax which is no more cause
a syntax error (NO_EVENT_NAME error with GRP/).
However, there are another case (NO_EVENT_NAME error without GRP/)
which causes a same error. This adds a test for that case.
Link: https://lkml.kernel.org/r/165812790993.1377963.9762767354560397298.stgit@devnote2
Signed-off-by: Masami Hiramatsu (Google) <[email protected]>
Signed-off-by: Steven Rostedt (Google) <[email protected]>
There is a small chance that get_kretprobe(ri) returns NULL in
kretprobe_dispatcher() when another CPU unregisters the kretprobe
right after __kretprobe_trampoline_handler().
To avoid this issue, kretprobe_dispatcher() checks the get_kretprobe()
return value again. And if it is NULL, it returns soon because that
kretprobe is under unregistering process.
This issue has been introduced when the kretprobe is decoupled
from the struct kretprobe_instance by commit d741bf41d7
("kprobes: Remove kretprobe hash"). Before that commit, the
struct kretprob_instance::rp directly points the kretprobe
and it is never be NULL.
Link: https://lkml.kernel.org/r/165366693881.797669.16926184644089588731.stgit@devnote2
Reported-by: Yonghong Song <[email protected]>
Fixes: d741bf41d7 ("kprobes: Remove kretprobe hash")
Cc: Peter Zijlstra <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: bpf <[email protected]>
Cc: Kernel Team <[email protected]>
Cc: [email protected]
Signed-off-by: Masami Hiramatsu (Google) <[email protected]>
Acked-by: Jiri Olsa <[email protected]>
Signed-off-by: Steven Rostedt (Google) <[email protected]>
Since the rethook_recycle() will involve the call_rcu() for reclaiming
the rethook_instance, the rethook must be set up at the RCU available
context (non idle). This rethook_recycle() in the rethook trampoline
handler is inevitable, thus the RCU available check must be done before
setting the rethook trampoline.
This adds a rcu_is_watching() check in the rethook_try_get() so that
it will return NULL if it is called when !rcu_is_watching().
Fixes: 54ecbe6f1e ("rethook: Add a generic return hook")
Signed-off-by: Masami Hiramatsu (Google) <[email protected]>
Signed-off-by: Daniel Borkmann <[email protected]>
Acked-by: Steven Rostedt (Google) <[email protected]>
Acked-by: Jiri Olsa <[email protected]>
Link: https://lore.kernel.org/bpf/165461827269.280167.7379263615545598958.stgit@devnote2
Max Filippov reported:
When building kernel with CONFIG_KRETPROBES=n kernel/kprobes.c
compilation fails with the following messages:
kernel/kprobes.c: In function ‘recycle_rp_inst’:
kernel/kprobes.c:1273:32: error: implicit declaration of function
‘get_kretprobe’
kernel/kprobes.c: In function ‘kprobe_flush_task’:
kernel/kprobes.c:1299:35: error: ‘struct task_struct’ has no member
named ‘kretprobe_instances’
This came from the commit d741bf41d7 ("kprobes: Remove
kretprobe hash") which introduced get_kretprobe() and
kretprobe_instances member in task_struct when CONFIG_KRETPROBES=y,
but did not make recycle_rp_inst() and kprobe_flush_task()
depending on CONFIG_KRETPORBES.
Since those functions are only used for kretprobe, move those
functions into #ifdef CONFIG_KRETPROBE area.
Link: https://lkml.kernel.org/r/165163539094.74407.3838114721073251225.stgit@devnote2
Reported-by: Max Filippov <[email protected]>
Fixes: d741bf41d7 ("kprobes: Remove kretprobe hash")
Cc: "Naveen N . Rao" <[email protected]>
Cc: Anil S Keshavamurthy <[email protected]>
Cc: "David S . Miller" <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: [email protected]
Signed-off-by: Masami Hiramatsu <[email protected]>
Tested-by: Max Filippov <[email protected]>
Signed-off-by: Steven Rostedt (Google) <[email protected]>
This allows kernel developer to embed a default bootconfig file in
the kernel instead of embedding it in the initrd. This will be good
for who are using the kernel without initrd, or who needs a default
bootconfigs.
This needs to set two kconfigs: CONFIG_BOOT_CONFIG_EMBED=y and set
the file path to CONFIG_BOOT_CONFIG_EMBED_FILE.
Note that you still need 'bootconfig' command line option to load the
embedded bootconfig. Also if you boot using an initrd with a different
bootconfig, the kernel will use the bootconfig in the initrd, instead
of the default bootconfig.
Link: https://lkml.kernel.org/r/164921227943.1090670.14035119557571329218.stgit@devnote2
Cc: Padmanabha Srinivasaiah <[email protected]>
Cc: Jonathan Corbet <[email protected]>
Cc: Randy Dunlap <[email protected]>
Cc: Nick Desaulniers <[email protected]>
Cc: Sami Tolvanen <[email protected]>
Cc: Nathan Chancellor <[email protected]>
Cc: Masahiro Yamada <[email protected]>
Cc: Linux Kbuild mailing list <[email protected]>
Signed-off-by: Masami Hiramatsu <[email protected]>
Signed-off-by: Steven Rostedt (Google) <[email protected]>
Use rethook for kretprobe function return hooking if the arch sets
CONFIG_HAVE_RETHOOK=y. In this case, CONFIG_KRETPROBE_ON_RETHOOK is
set to 'y' automatically, and the kretprobe internal data fields
switches to use rethook. If not, it continues to use kretprobe
specific function return hooks.
Suggested-by: Peter Zijlstra <[email protected]>
Signed-off-by: Masami Hiramatsu <[email protected]>
Signed-off-by: Alexei Starovoitov <[email protected]>
Link: https://lore.kernel.org/bpf/164826162556.2455864.12255833167233452047.stgit@devnote2
Introduce FPROBE_FL_KPROBE_SHARED flag for sharing fprobe callback with
kprobes safely from the viewpoint of recursion.
Since the recursion safety of the fprobe (and ftrace) is a bit different
from the kprobes, this may cause an issue if user wants to run the same
code from the fprobe and the kprobes.
The kprobes has per-cpu 'current_kprobe' variable which protects the
kprobe handler from recursion in any case. On the other hand, the fprobe
uses only ftrace_test_recursion_trylock(), which will allow interrupt
context calls another (or same) fprobe during the fprobe user handler is
running.
This is not a matter in cases if the common callback shared among the
kprobes and the fprobe has its own recursion detection, or it can handle
the recursion in the different contexts (normal/interrupt/NMI.)
But if it relies on the 'current_kprobe' recursion lock, it has to check
kprobe_running() and use kprobe_busy_*() APIs.
Fprobe has FPROBE_FL_KPROBE_SHARED flag to do this. If your common callback
code will be shared with kprobes, please set FPROBE_FL_KPROBE_SHARED
*before* registering the fprobe, like;
fprobe.flags = FPROBE_FL_KPROBE_SHARED;
register_fprobe(&fprobe, "func*", NULL);
This will protect your common callback from the nested call.
Signed-off-by: Masami Hiramatsu <[email protected]>
Signed-off-by: Steven Rostedt (Google) <[email protected]>
Tested-by: Steven Rostedt (Google) <[email protected]>
Signed-off-by: Alexei Starovoitov <[email protected]>
Link: https://lore.kernel.org/bpf/164735293127.1084943.15687374237275817599.stgit@devnote2
Add a sample program for the fprobe. The sample_fprobe puts a fprobe on
kernel_clone() by default. This dump stack and some called address info
at the function entry and exit.
The sample_fprobe.ko gets 2 parameters.
- symbol: you can specify the comma separated symbols or wildcard symbol
pattern (in this case you can not use comma)
- stackdump: a bool value to enable or disable stack dump in the fprobe
handler.
Signed-off-by: Masami Hiramatsu <[email protected]>
Signed-off-by: Steven Rostedt (Google) <[email protected]>
Tested-by: Steven Rostedt (Google) <[email protected]>
Signed-off-by: Alexei Starovoitov <[email protected]>
Link: https://lore.kernel.org/bpf/164735291987.1084943.4449670993752806840.stgit@devnote2
Add a return hook framework which hooks the function return. Most of the
logic came from the kretprobe, but this is independent from kretprobe.
Note that this is expected to be used with other function entry hooking
feature, like ftrace, fprobe, adn kprobes. Eventually this will replace
the kretprobe (e.g. kprobe + rethook = kretprobe), but at this moment,
this is just an additional hook.
Signed-off-by: Masami Hiramatsu <[email protected]>
Signed-off-by: Steven Rostedt (Google) <[email protected]>
Tested-by: Steven Rostedt (Google) <[email protected]>
Signed-off-by: Alexei Starovoitov <[email protected]>
Link: https://lore.kernel.org/bpf/164735285066.1084943.9259661137330166643.stgit@devnote2
The fprobe is a wrapper API for ftrace function tracer.
Unlike kprobes, this probes only supports the function entry, but this
can probe multiple functions by one fprobe. The usage is similar, user
will set their callback to fprobe::entry_handler and call
register_fprobe*() with probed functions.
There are 3 registration interfaces,
- register_fprobe() takes filtering patterns of the functin names.
- register_fprobe_ips() takes an array of ftrace-location addresses.
- register_fprobe_syms() takes an array of function names.
The registered fprobes can be unregistered with unregister_fprobe().
e.g.
struct fprobe fp = { .entry_handler = user_handler };
const char *targets[] = { "func1", "func2", "func3"};
...
ret = register_fprobe_syms(&fp, targets, ARRAY_SIZE(targets));
...
unregister_fprobe(&fp);
Signed-off-by: Masami Hiramatsu <[email protected]>
Signed-off-by: Steven Rostedt (Google) <[email protected]>
Tested-by: Steven Rostedt (Google) <[email protected]>
Signed-off-by: Alexei Starovoitov <[email protected]>
Link: https://lore.kernel.org/bpf/164735283857.1084943.1154436951479395551.stgit@devnote2
Since -Warray-bounds checks the destination size from the type of given
pointer, __assign_rel_str() macro gets warned because it passes the
pointer to the 'u32' field instead of 'trace_event_raw_*' data structure.
Pass the data address calculated from the 'trace_event_raw_*' instead of
'u32' __rel_loc field.
Link: https://lkml.kernel.org/r/[email protected]
Cc: Stephen Rothwell <[email protected]>
Cc: Kees Cook <[email protected]>
Signed-off-by: Masami Hiramatsu <[email protected]>
[ This did not fix the warning, but is still a nice clean up ]
Signed-off-by: Steven Rostedt (Google) <[email protected]>
Add '__rel_loc' new dynamic data location attribute which encodes
the data location from the next to the field itself.
The '__data_loc' is used for encoding the dynamic data location on
the trace event record. But '__data_loc' is not useful if the writer
doesn't know the event header (e.g. user event), because it records
the dynamic data offset from the entry of the record, not the field
itself.
This new '__rel_loc' attribute encodes the data location relatively
from the next of the field. For example, when there is a record like
below (the number in the parentheses is the size of fields)
|header(N)|common(M)|fields(K)|__data_loc(4)|fields(L)|data(G)|
In this case, '__data_loc' field will be
__data_loc = (G << 16) | (N+M+K+4+L)
If '__rel_loc' is used, this will be
|header(N)|common(M)|fields(K)|__rel_loc(4)|fields(L)|data(G)|
where
__rel_loc = (G << 16) | (L)
This case shows L bytes after the '__rel_loc' attribute field,
if there is no fields after the __rel_loc field, L must be 0.
This is relatively easy (and no need to consider the kernel header
change) when the event data fields are composed by user who doesn't
know header and common fields.
Link: https://lkml.kernel.org/r/163757341258.510314.4214431827833229956.stgit@devnote2
Cc: Beau Belgrave <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Tom Zanussi <[email protected]>
Signed-off-by: Masami Hiramatsu <[email protected]>
Signed-off-by: Steven Rostedt (VMware) <[email protected]>
The 'kprobe::data_size' is unsigned, thus it can not be negative. But if
user sets it enough big number (e.g. (size_t)-8), the result of 'data_size
+ sizeof(struct kretprobe_instance)' becomes smaller than sizeof(struct
kretprobe_instance) or zero. In result, the kretprobe_instance are
allocated without enough memory, and kretprobe accesses outside of
allocated memory.
To avoid this issue, introduce a max limitation of the
kretprobe::data_size. 4KB per instance should be OK.
Link: https://lkml.kernel.org/r/163836995040.432120.10322772773821182925.stgit@devnote2
Cc: [email protected]
Fixes: f47cd9b553 ("kprobes: kretprobe user entry-handler")
Reported-by: zhangyue <[email protected]>
Signed-off-by: Masami Hiramatsu <[email protected]>
Signed-off-by: Steven Rostedt (VMware) <[email protected]>
Do not copy the fixed-size char array field of the events over
the field size. The histogram treats char array as a string and
there are 2 types of char array in the event, fixed-size and
dynamic string. The dynamic string (__data_loc) field must be
null terminated, but the fixed-size char array field may not
be null terminated (not a string, but just a data).
In that case, histogram can copy the data after the field.
This uses the original field size for fixed-size char array
field to restrict the histogram not to access over the original
field size.
Link: https://lkml.kernel.org/r/163673292822.195747.3696966210526410250.stgit@devnote2
Fixes: 02205a6752 (tracing: Add support for 'field variables')
Signed-off-by: Masami Hiramatsu <[email protected]>
Signed-off-by: Steven Rostedt (VMware) <[email protected]>
Stop tracing while reading the trace file by default, to prevent
the test results while checking it and to avoid taking a long time
to check the result.
If there is any testcase which wants to test the tracing while reading
the trace file, please override this setting inside the test case.
This also recovers the pause-on-trace when clean it up.
Link: https://lkml.kernel.org/r/163529053143.690749.15365238954175942026.stgit@devnote2
Signed-off-by: Masami Hiramatsu <[email protected]>
Signed-off-by: Steven Rostedt (VMware) <[email protected]>
Add a test case for stacktrace from kretprobe handler and
nested kretprobe handlers.
This test checks both of stack trace inside kretprobe handler
and stack trace from pt_regs. Those stack trace must include
actual function return address instead of kretprobe trampoline.
The nested kretprobe stacktrace test checks whether the unwinder
can correctly unwind the call frame on the stack which has been
modified by the kretprobe.
Since the stacktrace on kretprobe is correctly fixed only on x86,
this introduces a meta kconfig ARCH_CORRECT_STACKTRACE_ON_KRETPROBE
which tells user that the stacktrace on kretprobe is correct or not.
The test results will be shown like below;
TAP version 14
1..1
# Subtest: kprobes_test
1..6
ok 1 - test_kprobe
ok 2 - test_kprobes
ok 3 - test_kretprobe
ok 4 - test_kretprobes
ok 5 - test_stacktrace_on_kretprobe
ok 6 - test_stacktrace_on_nested_kretprobe
# kprobes_test: pass:6 fail:0 skip:0 total:6
# Totals: pass:6 fail:0 skip:0 total:6
ok 1 - kprobes_test
Link: https://lkml.kernel.org/r/163516211244.604541.18350507860972214415.stgit@devnote2
Signed-off-by: Masami Hiramatsu <[email protected]>
Signed-off-by: Steven Rostedt (VMware) <[email protected]>
Since the kretprobe replaces the function return address with
the kretprobe_trampoline on the stack, arm unwinder shows it
instead of the correct return address.
This finds the correct return address from the per-task
kretprobe_instances list and verify it is in between the
caller fp and callee fp.
Note that this supports both GCC and clang if CONFIG_FRAME_POINTER=y
and CONFIG_ARM_UNWIND=n. For the ARM unwinder, this is still
not working correctly.
Signed-off-by: Masami Hiramatsu <[email protected]>
Signed-off-by: Steven Rostedt (VMware) <[email protected]>
Currently kretprobe on ARM just fills r0-r11 of pt_regs, but
that is not enough for the stacktrace. Moreover, from the user
kretprobe handler, stacktrace needs a frame pointer on the
__kretprobe_trampoline.
This adds a frame pointer on __kretprobe_trampoline for both gcc
and clang case. Those have different frame pointer so we need
different but similar stack on pt_regs.
Gcc makes the frame pointer (fp) to point the 'pc' address of
the {fp, ip (=sp), lr, pc}, this means {r11, r13, r14, r15}.
Thus if we save the r11 (fp) on pt_regs->r12, we can make this
set on the end of pt_regs.
On the other hand, Clang makes the frame pointer to point the
'fp' address of {fp, lr} on stack. Since the next to the
pt_regs->lr is pt_regs->sp, I reused the pair of pt_regs->fp
and pt_regs->ip.
So this stores the 'lr' on pt_regs->ip and make the fp to point
pt_regs->fp.
For both cases, saves __kretprobe_trampoline address to
pt_regs->lr, so that the stack tracer can identify this frame
pointer has been made by the __kretprobe_trampoline.
Note that if the CONFIG_FRAME_POINTER is not set, this keeps
fp as is.
Signed-off-by: Masami Hiramatsu <[email protected]>
Reviewed-by: Nick Desaulniers <[email protected]>
Signed-off-by: Steven Rostedt (VMware) <[email protected]>
Currently the stacktrace on clang compiled arm kernel uses the 'lr'
register to find the first frame address from pt_regs. However, that
is wrong after calling another function, because the 'lr' register
is used by 'bl' instruction and never be recovered.
As same as gcc arm kernel, directly use the frame pointer (r11) of
the pt_regs to find the first frame address.
Note that this fixes kretprobe stacktrace issue only with
CONFIG_UNWINDER_FRAME_POINTER=y. For the CONFIG_UNWINDER_ARM,
we need another fix.
Signed-off-by: Masami Hiramatsu <[email protected]>
Reviewed-by: Nick Desaulniers <[email protected]>
Signed-off-by: Steven Rostedt (VMware) <[email protected]>
Since the kretprobe replaces the function return address with
the kretprobe_trampoline on the stack, stack unwinder shows it
instead of the correct return address.
This checks whether the next return address is the
__kretprobe_trampoline(), and if so, try to find the correct
return address from the kretprobe instance list. For this purpose
this adds 'kr_cur' loop cursor to memorize the current kretprobe
instance.
With this fix, now arm64 can enable
CONFIG_ARCH_CORRECT_STACKTRACE_ON_KRETPROBE, and pass the
kprobe self tests.
Signed-off-by: Masami Hiramatsu <[email protected]>
Acked-by: Will Deacon <[email protected]>
Signed-off-by: Steven Rostedt (VMware) <[email protected]>
Make a frame pointer (make the x29 register points the
address of pt_regs->regs[29]) on __kretprobe_trampoline.
This frame pointer will be used by the stacktracer when it is
called from the kretprobe handlers. In this case, the stack
tracer will unwind stack to trampoline_probe_handler() and
find the next frame pointer in the stack frame of the
__kretprobe_trampoline().
Signed-off-by: Masami Hiramatsu <[email protected]>
Acked-by: Will Deacon <[email protected]>
Signed-off-by: Steven Rostedt (VMware) <[email protected]>
Record the frame pointer instead of stack address with kretprobe
instance as the identifier on the instance list.
Since arm64 always enable CONFIG_FRAME_POINTER, we can use the
actual frame pointer (x29).
This will allow the stacktrace code to find the original return
address from the FP alone.
Signed-off-by: Masami Hiramatsu <[email protected]>
Acked-by: Will Deacon <[email protected]>
Acked-by: Mark Rutland <[email protected]>
Signed-off-by: Steven Rostedt (VMware) <[email protected]>
Compile kretprobe related stacktrace entry recovery code and
unwind_state::kr_cur field only when CONFIG_KRETPROBES=y.
Signed-off-by: Masami Hiramatsu <[email protected]>
Signed-off-by: Steven Rostedt (VMware) <[email protected]>
In x86, the fake return address on the stack saved by
__kretprobe_trampoline() will be replaced with the real return
address after returning from trampoline_handler(). Before fixing
the return address, the real return address can be found in the
'current->kretprobe_instances'.
However, since there is a window between updating the
'current->kretprobe_instances' and fixing the address on the stack,
if an interrupt happens at that timing and the interrupt handler
does stacktrace, it may fail to unwind because it can not get
the correct return address from 'current->kretprobe_instances'.
This will eliminate that window by fixing the return address
right before updating 'current->kretprobe_instances'.
Link: https://lkml.kernel.org/r/163163057094.489837.9044470370440745866.stgit@devnote2
Signed-off-by: Masami Hiramatsu <[email protected]>
Tested-by: Andrii Nakryiko <[email protected]>
Signed-off-by: Steven Rostedt (VMware) <[email protected]>
Since the kretprobe replaces the function return address with
the kretprobe_trampoline on the stack, x86 unwinders can not
continue the stack unwinding at that point, or record
kretprobe_trampoline instead of correct return address.
To fix this issue, find the correct return address from task's
kretprobe_instances as like as function-graph tracer does.
With this fix, the unwinder can correctly unwind the stack
from kretprobe event on x86, as below.
<...>-135 [003] ...1 6.722338: r_full_proxy_read_0: (vfs_read+0xab/0x1a0 <- full_proxy_read)
<...>-135 [003] ...1 6.722377: <stack trace>
=> kretprobe_trace_func+0x209/0x2f0
=> kretprobe_dispatcher+0x4a/0x70
=> __kretprobe_trampoline_handler+0xca/0x150
=> trampoline_handler+0x44/0x70
=> kretprobe_trampoline+0x2a/0x50
=> vfs_read+0xab/0x1a0
=> ksys_read+0x5f/0xe0
=> do_syscall_64+0x33/0x40
=> entry_SYSCALL_64_after_hwframe+0x44/0xae
Link: https://lkml.kernel.org/r/163163055130.489837.5161749078833497255.stgit@devnote2
Reported-by: Daniel Xu <[email protected]>
Signed-off-by: Masami Hiramatsu <[email protected]>
Suggested-by: Josh Poimboeuf <[email protected]>
Tested-by: Andrii Nakryiko <[email protected]>
Acked-by: Josh Poimboeuf <[email protected]>
Signed-off-by: Steven Rostedt (VMware) <[email protected]>
Change __kretprobe_trampoline() to push the address of the
__kretprobe_trampoline() as a fake return address at the bottom
of the stack frame. This fake return address will be replaced
with the correct return address in the trampoline_handler().
With this change, the ORC unwinder can check whether the return
address is modified by kretprobes or not.
Link: https://lkml.kernel.org/r/163163054185.489837.14338744048957727386.stgit@devnote2
Signed-off-by: Masami Hiramatsu <[email protected]>
Suggested-by: Josh Poimboeuf <[email protected]>
Tested-by: Andrii Nakryiko <[email protected]>
Acked-by: Josh Poimboeuf <[email protected]>
Signed-off-by: Steven Rostedt (VMware) <[email protected]>
Since the ORC unwinder from pt_regs requires setting up regs->ip
correctly, set the correct return address to the regs->ip before
calling user kretprobe handler.
This allows the kretrprobe handler to trace stack from the
kretprobe's pt_regs by stack_trace_save_regs() (eBPF will do
this), instead of stack tracing from the handler context by
stack_trace_save() (ftrace will do this).
Link: https://lkml.kernel.org/r/163163053237.489837.4272653874525136832.stgit@devnote2
Suggested-by: Josh Poimboeuf <[email protected]>
Signed-off-by: Masami Hiramatsu <[email protected]>
Tested-by: Andrii Nakryiko <[email protected]>
Acked-by: Josh Poimboeuf <[email protected]>
Signed-off-by: Steven Rostedt (VMware) <[email protected]>
Since arm's __kretprobe_trampoline() saves partial 'pt_regs' on the
stack, 'regs->ARM_pc' (instruction pointer) is not accessible from
the kretprobe handler. This means if instruction_pointer_set() is
used from kretprobe handler, it will break the data on the stack.
Make space for instruction pointer (ARM_pc) on the stack in the
__kretprobe_trampoline() for fixing this problem.
Link: https://lkml.kernel.org/r/163163052262.489837.10327621053231461255.stgit@devnote2
Signed-off-by: Masami Hiramatsu <[email protected]>
Signed-off-by: Steven Rostedt (VMware) <[email protected]>
The __kretprobe_trampoline_handler() callback, called from low level
arch kprobes methods, has the 'trampoline_address' parameter, which is
entirely superfluous as it basically just replicates:
dereference_kernel_function_descriptor(kretprobe_trampoline)
In fact we had bugs in arch code where it wasn't replicated correctly.
So remove this superfluous parameter and use kretprobe_trampoline_addr()
instead.
Link: https://lkml.kernel.org/r/163163044546.489837.13505751885476015002.stgit@devnote2
Signed-off-by: Masami Hiramatsu <[email protected]>
Tested-by: Andrii Nakryiko <[email protected]>
Signed-off-by: Steven Rostedt (VMware) <[email protected]>
Since get_optimized_kprobe() is only used inside kprobes,
it doesn't need to use 'unsigned long' type for 'addr' parameter.
Make it use 'kprobe_opcode_t *' for the 'addr' parameter and
subsequent call of arch_within_optimized_kprobe() also should use
'kprobe_opcode_t *'.
Note that MAX_OPTIMIZED_LENGTH and RELATIVEJUMP_SIZE are defined
by byte-size, but the size of 'kprobe_opcode_t' depends on the
architecture. Therefore, we must be careful when calculating
addresses using those macros.
Link: https://lkml.kernel.org/r/163163040680.489837.12133032364499833736.stgit@devnote2
Signed-off-by: Masami Hiramatsu <[email protected]>
Signed-off-by: Steven Rostedt (VMware) <[email protected]>
This clean up the error/notification messages in kprobes related code.
Basically this defines 'pr_fmt()' macros for each files and update
the messages which describes
- what happened,
- what is the kernel going to do or not do,
- is the kernel fine,
- what can the user do about it.
Also, if the message is not needed (e.g. the function returns unique
error code, or other error message is already shown.) remove it,
and replace the message with WARN_*() macros if suitable.
Link: https://lkml.kernel.org/r/163163036568.489837.14085396178727185469.stgit@devnote2
Signed-off-by: Masami Hiramatsu <[email protected]>
Signed-off-by: Steven Rostedt (VMware) <[email protected]>
The lib/bootconfig.c file is shared with the 'bootconfig' tooling, and
as a result, the changes incommit 77e02cf57b ("memblock: introduce
saner 'memblock_free_ptr()' interface") need to also be reflected in the
tooling header file.
So define the new memblock_free_ptr() wrapper, and remove unused __pa()
and memblock_free().
Fixes: 77e02cf57b ("memblock: introduce saner 'memblock_free_ptr()' interface")
Signed-off-by: Masami Hiramatsu <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
Rename xbc_node_find_child() to xbc_node_find_subkey() for
clarifying that function returns a key node (no value node).
Since there are xbc_node_for_each_child() (loop on all child
nodes) and xbc_node_for_each_subkey() (loop on only subkey
nodes), this name distinction is necessary to avoid confusing
users.
Link: https://lkml.kernel.org/r/163119459826.161018.11200274779483115300.stgit@devnote2
Signed-off-by: Masami Hiramatsu <[email protected]>
Signed-off-by: Steven Rostedt (VMware) <[email protected]>
Since xbc_node_find_child() doesn't ensure the returned node
is a leaf node (key-value pair or do not have subkeys),
use xbc_node_find_value to ensure the histogram control
parameter is a leaf node in trace_boot_compose_hist_cmd().
Link: https://lkml.kernel.org/r/163119459059.161018.18341288218424528962.stgit@devnote2
Fixes: e66ed86ca6 ("tracing/boot: Add per-event histogram action options")
Signed-off-by: Masami Hiramatsu <[email protected]>
Signed-off-by: Steven Rostedt (VMware) <[email protected]>
trace_boot_hist_add_array() uses the combination of
xbc_node_find_child() and xbc_node_get_child() to get the
child node of the key node. But since it missed to check
the child node is data node or not, user can pass the
subkey node for the array node (anode).
To avoid this issue, check the array node is a data node.
Actually, there is xbc_node_find_value(node, key, vnode),
which ensures the @vnode is a value node, so use it in
trace_boot_hist_add_array() to fix this issue.
Link: https://lkml.kernel.org/r/163119458308.161018.1516455973625940212.stgit@devnote2
Fixes: e66ed86ca6 ("tracing/boot: Add per-event histogram action options")
Signed-off-by: Masami Hiramatsu <[email protected]>
Signed-off-by: Steven Rostedt (VMware) <[email protected]>
Since the commit e5efaeb8a8 ("bootconfig: Support mixing
a value and subkeys under a key") allows to co-exist a value
node and key nodes under a node, xbc_node_for_each_child()
is not only returning key node but also a value node.
In the boot-time tracing using xbc_node_for_each_child() to
iterate the events, groups and instances, but those must be
key nodes. Thus it must use xbc_node_for_each_subkey().
Link: https://lkml.kernel.org/r/163112988361.74896.2267026262061819145.stgit@devnote2
Fixes: e5efaeb8a8 ("bootconfig: Support mixing a value and subkeys under a key")
Signed-off-by: Masami Hiramatsu <[email protected]>
Signed-off-by: Steven Rostedt (VMware) <[email protected]>
Reorder the init parameters from bootconfig and kernel cmdline
so that the kernel cmdline always be the last part of the
parameters as below.
" -- "[bootconfig init params][cmdline init params]
This change will help us to prevent that bootconfig init params
overwrite the init params which user gives in the command line.
Link: https://lkml.kernel.org/r/163077085675.222577.5665176468023636160.stgit@devnote2
Signed-off-by: Masami Hiramatsu <[email protected]>
Signed-off-by: Steven Rostedt (VMware) <[email protected]>
Since kprobe_events and uprobe_events only check whether the
other same-type probe event has the same name or not, if the
user gives the same name of the existing tracepoint event (or
the other type of probe events), it silently fails to create
the tracefs entry (but registered.) as below.
/sys/kernel/tracing # ls events/task/task_rename
enable filter format hist id trigger
/sys/kernel/tracing # echo p:task/task_rename vfs_read >> kprobe_events
[ 113.048508] Could not create tracefs 'task_rename' directory
/sys/kernel/tracing # cat kprobe_events
p:task/task_rename vfs_read
To fix this issue, check whether the existing events have the
same name or not in trace_probe_register_event_call(). If exists,
it rejects to register the new event.
Link: https://lkml.kernel.org/r/162936876189.187130.17558311387542061930.stgit@devnote2
Signed-off-by: Masami Hiramatsu <[email protected]>
Signed-off-by: Steven Rostedt (VMware) <[email protected]>
Since trigger_process_regex() modifies given trigger actions
while parsing, the error message couldn't show what command
was passed to the trigger_process_regex() when it returns
an error.
To fix that, show the backed up trigger action command
instead of parsed buffer.
Link: https://lkml.kernel.org/r/162856126413.203126.9465564928450701424.stgit@devnote2
Signed-off-by: Masami Hiramatsu <[email protected]>
Signed-off-by: Steven Rostedt (VMware) <[email protected]>
Add multiple histograms support for each event. This allows
user to set multiple histograms to an event.
ftrace.[instance.INSTANCE.]event.GROUP.EVENT.hist[.N] {
...
}
The 'N' is a digit started string and it can be omitted
for the default histogram.
For example, multiple hist triggers example in the
Documentation/trace/histogram.rst can be written as below;
ftrace.event.net.netif_receive_skb.hist {
1 {
keys = skbaddr.hex
values = len
filter = len < 0
}
2 {
keys = skbaddr.hex
values = len
filter = len > 4096
}
3 {
keys = skbaddr.hex
values = len
filter = len == 256
}
4 {
keys = skbaddr.hex
values = len
}
5 {
keys = len
values = common_preempt_count
}
}
Link: https://lkml.kernel.org/r/162856125628.203126.15846930277378572120.stgit@devnote2
Signed-off-by: Masami Hiramatsu <[email protected]>
Signed-off-by: Steven Rostedt (VMware) <[email protected]>
Support multiple handlers for per-event histogram in boot-time tracing.
Since the histogram can register multiple same handler-actions with
different parameters, this expands the syntax to support such cases.
With this update, the 'onmax', 'onchange' and 'onmatch' handler subkeys
under per-event histogram option will take a number subkeys optionally
as below. (see [.N])
ftrace.[instance.INSTANCE.]event.GROUP.EVENT.hist {
onmax|onchange[.N] { var = <VAR>; <ACTION> [= <PARAM>] }
onmatch[.N] { event = <EVENT>; <ACTION> [= <PARAM>] }
}
The 'N' must be a digit (or digit started word).
Thus user can add several handler-actions to the histogram,
for example,
ftrace.event.SOMEGROUP.SOMEEVENT.hist {
keys = SOME_ID; lat = common_timestamp.usecs-$ts0
onmatch.1 {
event = GROUP1.STARTEVENT1
trace = latency_event, SOME_ID, $lat
}
onmatch.2 {
event = GROUP2.STARTEVENT2
trace = latency_event, SOME_ID, $lat
}
}
Then, it can trace the elapsed time from GROUP1.STARTEVENT1 to
SOMEGROUP.SOMEEVENT, and from GROUP2.STARTEVENT2 to
SOMEGROUP.SOMEEVENT with SOME_ID key.
Link: https://lkml.kernel.org/r/162856124905.203126.14913731908137885922.stgit@devnote2
Signed-off-by: Masami Hiramatsu <[email protected]>
Signed-off-by: Steven Rostedt (VMware) <[email protected]>
Masami Hiramatsu (Google)