FAILED: patch "[PATCH] tracing: Set the trace clock before registering the histogram" failed to apply to 6.1-stable tree
Subsystems (2)
[email protected]
maintainerThe patch below does not apply to the 6.1-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.1.y
git checkout FETCH_HEAD
git cherry-pick -x 6ede78d0563a2a3ae3e46f9c07cedb5d79645429
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '2026091627-stylized-awry-e55f@gregkh' --subject-prefix 'PATCH 6.1.y' 'HEAD^..'
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 6ede78d0563a2a3ae3e46f9c07cedb5d79645429 Mon Sep 17 00:00:00 2001
From: Donggeun Yoo <[email protected]>
Date: Mon, 7 Sep 2026 18:14:15 +0900
Subject: [PATCH] tracing: Set the trace clock before registering the histogram
trigger
hist_register_trigger() puts the trigger on the global named_triggers list in cmd_ops->init(), and only then sets the trace clock:
if (data->cmd_ops->init) {
ret = data->cmd_ops->init(data);
if (ret < 0)
goto out;
}
if (hist_data->enable_timestamps) {
ret = tracing_set_clock(file->tr, hist_data->attrs->clock);
if (ret) {
hist_err(tr, HIST_ERR_SET_CLOCK_FAIL, errpos(clock));
goto out;
}The clock string is not checked anywhere before that call, so a named trigger using common_timestamp with an unknown clock fails after it has already become findable. event_hist_trigger_parse() then frees it without taking it off the list, and the next lookup by name reads the freed object:
~# cd /sys/kernel/tracing/events/sched/sched_switch
~# echo 'hist:name=foo:keys=common_pid:ts=common_timestamp:clock=bogus' > trigger
bash: echo: write error: Invalid argument
~# echo 'hist:name=foo:keys=common_pid' > trigger
BUG: KASAN: slab-use-after-free in find_named_trigger+0xac/0xc0 Read of size 8 at addr ffff88800915d760 by task init/1 find_named_trigger+0xac/0xc0 hist_register_trigger+0xc1/0x900 event_hist_trigger_parse+0x3146/0x6af0 event_trigger_write+0xce/0x160 Freed by task 63: kfree+0x154/0x420 trigger_kthread_fn+0xfd/0x160
Set the clock before the trigger is registered, so that nothing which can fail runs after it is published, the way commit 6f86bdeab633 ("tracing: Fix bad hist from corrupting named_triggers list") moved the registration below the rest of the setup.
tracing_set_filter_buffering() is reference counted, so the init failure path has to drop the reference that the clock block now takes first.
kernel/trace/trace_events_hist.c +9 -6
@@ -6631,12 +6631,6 @@ static int hist_register_trigger(char *glob, data->cmd_ops = cmd_ops; } -if (data->cmd_ops->init) { - ret = data->cmd_ops->init (data); -if (ret <0 ) - goto out; - } -if (hist_data->enable_timestamps) {char *clock = hist_data->attrs->clock;
@@ -6649,6 +6643,15 @@ static int hist_register_trigger(char *glob,tracing_set_filter_buffering (file->tr, true); } +if (data->cmd_ops->init) { + ret = data->cmd_ops->init (data); +if (ret <0 ) { +if (hist_data->enable_timestamps) +tracing_set_filter_buffering (file->tr, false); + goto out; + } + } +if (named_data) {remove_hist_vars (hist_data);destroy_hist_data (hist_data);
Sasha Levin
maintainerPATCH 1/3 tracing: Constify struct event_trigger_ops
From: Christophe JAILLET <[email protected]>
[ Upstream commit 502d2e71a89fa706843fa9277f4d6de1947072c8 ]
'event_trigger_ops mwifiex_if_ops' are not modified in these drivers.
Constifying these structures moves some data to a read-only section, so increase overall security, especially when the structure holds some function pointers.
On a x86_64, with allmodconfig, as an example:
Before:
======
text data bss dec hex filename
31368 9024 6200 46592 b600 kernel/trace/trace_events_trigger.o
After:
=====
text data bss dec hex filename
31752 8608 6200 46560 b5e0 kernel/trace/trace_events_trigger.o
Stable-dep-of: 6ede78d0563a ("tracing: Set the trace clock before registering the histogram trigger")
--- kernel/trace/trace.h | 4 +-- kernel/trace/trace_eprobe.c | 6 ++--- kernel/trace/trace_events_hist.c | 20 +++++++-------- kernel/trace/trace_events_trigger.c | 38 ++++++++++++++--------------- 4 files changed, 34 insertions(+), 34 deletions(-)
kernel/trace/trace.h +2 -2
@@ -1557,7 +1557,7 @@ struct event_trigger_data {unsigned long count;int ref;int flags; -struct event_trigger_ops *ops; +const struct event_trigger_ops *ops;struct event_command *cmd_ops;struct event_filter __rcu *filter;char *filter_str;
@@ -1800,7 +1800,7 @@ struct event_command {int (*set_filter)(char *filter_str,struct event_trigger_data *data,struct trace_event_file *file); -struct event_trigger_ops *(*get_trigger_ops)(char *cmd,char *param); +const struct event_trigger_ops *(*get_trigger_ops)(char *cmd,char *param); };/**
kernel/trace/trace_eprobe.c +3 -3
@@ -574,7 +574,7 @@ static void eprobe_trigger_func(struct event_trigger_data *data,__eprobe_trace_func (edata, rec); } -static struct event_trigger_ops eprobe_trigger_ops = { +static const struct event_trigger_ops eprobe_trigger_ops = { .trigger = eprobe_trigger_func, .print = eprobe_trigger_print, .init = eprobe_trigger_init,
@@ -603,8 +603,8 @@ static void eprobe_trigger_unreg_func(char *glob, } -static struct event_trigger_ops *eprobe_trigger_get_ops (char *cmd, -char *param) +static const struct event_trigger_ops *eprobe_trigger_get_ops (char *cmd, +char *param) {return &eprobe_trigger_ops; }
kernel/trace/trace_events_hist.c +10 -10
@@ -6020,7 +6020,7 @@ static void event_hist_trigger_free(struct event_trigger_data *data) } } -static struct event_trigger_ops event_hist_trigger_ops = { +static const struct event_trigger_ops event_hist_trigger_ops = { .trigger = event_hist_trigger, .print = event_hist_trigger_print, .init = event_hist_trigger_init,
@@ -6052,15 +6052,15 @@ static void event_hist_trigger_named_free(struct event_trigger_data *data) } } -static struct event_trigger_ops event_hist_trigger_named_ops = { +static const struct event_trigger_ops event_hist_trigger_named_ops = { .trigger = event_hist_trigger, .print = event_hist_trigger_print, .init = event_hist_trigger_named_init, .free = event_hist_trigger_named_free, }; -static struct event_trigger_ops *event_hist_get_trigger_ops (char *cmd, -char *param) +static const struct event_trigger_ops *event_hist_get_trigger_ops (char *cmd, +char *param) {return &event_hist_trigger_ops; }
@@ -6657,38 +6657,38 @@ hist_enable_count_trigger(struct event_trigger_data *data,hist_enable_trigger (data, buffer, rec, event); } -static struct event_trigger_ops hist_enable_trigger_ops = { +static const struct event_trigger_ops hist_enable_trigger_ops = { .trigger = hist_enable_trigger, .print = event_enable_trigger_print, .init = event_trigger_init, .free = event_enable_trigger_free, }; -static struct event_trigger_ops hist_enable_count_trigger_ops = { +static const struct event_trigger_ops hist_enable_count_trigger_ops = { .trigger = hist_enable_count_trigger, .print = event_enable_trigger_print, .init = event_trigger_init, .free = event_enable_trigger_free, }; -static struct event_trigger_ops hist_disable_trigger_ops = { +static const struct event_trigger_ops hist_disable_trigger_ops = { .trigger = hist_enable_trigger, .print = event_enable_trigger_print, .init = event_trigger_init, .free = event_enable_trigger_free, }; -static struct event_trigger_ops hist_disable_count_trigger_ops = { +static const struct event_trigger_ops hist_disable_count_trigger_ops = { .trigger = hist_enable_count_trigger, .print = event_enable_trigger_print, .init = event_trigger_init, .free = event_enable_trigger_free, }; -static struct event_trigger_ops * +static const struct event_trigger_ops *hist_enable_get_trigger_ops (char *cmd,char *param) { -struct event_trigger_ops *ops; +const struct event_trigger_ops *ops;bool enable; enable = (strcmp (cmd,ENABLE_HIST_STR ) ==0 );
kernel/trace/trace_events_trigger.c +19 -19
@@ -831,7 +831,7 @@ struct event_trigger_data *trigger_data_alloc(struct event_command *cmd_ops, void *private_data) {struct event_trigger_data *trigger_data; -struct event_trigger_ops *trigger_ops; +const struct event_trigger_ops *trigger_ops; trigger_ops = cmd_ops->get_trigger_ops (cmd, param);
@@ -1360,38 +1360,38 @@ traceoff_trigger_print(struct seq_file *m, struct event_trigger_data *data) data->filter_str); } -static struct event_trigger_ops traceon_trigger_ops = { +static const struct event_trigger_ops traceon_trigger_ops = { .trigger = traceon_trigger, .print = traceon_trigger_print, .init = event_trigger_init, .free = event_trigger_free, }; -static struct event_trigger_ops traceon_count_trigger_ops = { +static const struct event_trigger_ops traceon_count_trigger_ops = { .trigger = traceon_count_trigger, .print = traceon_trigger_print, .init = event_trigger_init, .free = event_trigger_free, }; -static struct event_trigger_ops traceoff_trigger_ops = { +static const struct event_trigger_ops traceoff_trigger_ops = { .trigger = traceoff_trigger, .print = traceoff_trigger_print, .init = event_trigger_init, .free = event_trigger_free, }; -static struct event_trigger_ops traceoff_count_trigger_ops = { +static const struct event_trigger_ops traceoff_count_trigger_ops = { .trigger = traceoff_count_trigger, .print = traceoff_trigger_print, .init = event_trigger_init, .free = event_trigger_free, }; -static struct event_trigger_ops * +static const struct event_trigger_ops *onoff_get_trigger_ops (char *cmd,char *param) { -struct event_trigger_ops *ops; +const struct event_trigger_ops *ops;/* we register both traceon and traceoff to this callback */ if (strcmp (cmd,"traceon" ) ==0 )
@@ -1473,21 +1473,21 @@ snapshot_trigger_print(struct seq_file *m, struct event_trigger_data *data) data->filter_str); } -static struct event_trigger_ops snapshot_trigger_ops = { +static const struct event_trigger_ops snapshot_trigger_ops = { .trigger = snapshot_trigger, .print = snapshot_trigger_print, .init = event_trigger_init, .free = event_trigger_free, }; -static struct event_trigger_ops snapshot_count_trigger_ops = { +static const struct event_trigger_ops snapshot_count_trigger_ops = { .trigger = snapshot_count_trigger, .print = snapshot_trigger_print, .init = event_trigger_init, .free = event_trigger_free, }; -static struct event_trigger_ops * +static const struct event_trigger_ops *snapshot_get_trigger_ops (char *cmd,char *param) {return param ? &snapshot_count_trigger_ops : &snapshot_trigger_ops;
@@ -1568,21 +1568,21 @@ stacktrace_trigger_print(struct seq_file *m, struct event_trigger_data *data) data->filter_str); } -static struct event_trigger_ops stacktrace_trigger_ops = { +static const struct event_trigger_ops stacktrace_trigger_ops = { .trigger = stacktrace_trigger, .print = stacktrace_trigger_print, .init = event_trigger_init, .free = event_trigger_free, }; -static struct event_trigger_ops stacktrace_count_trigger_ops = { +static const struct event_trigger_ops stacktrace_count_trigger_ops = { .trigger = stacktrace_count_trigger, .print = stacktrace_trigger_print, .init = event_trigger_init, .free = event_trigger_free, }; -static struct event_trigger_ops * +static const struct event_trigger_ops *stacktrace_get_trigger_ops (char *cmd,char *param) {return param ? &stacktrace_count_trigger_ops : &stacktrace_trigger_ops;
@@ -1693,28 +1693,28 @@ void event_enable_trigger_free(struct event_trigger_data *data) } } -static struct event_trigger_ops event_enable_trigger_ops = { +static const struct event_trigger_ops event_enable_trigger_ops = { .trigger = event_enable_trigger, .print = event_enable_trigger_print, .init = event_trigger_init, .free = event_enable_trigger_free, }; -static struct event_trigger_ops event_enable_count_trigger_ops = { +static const struct event_trigger_ops event_enable_count_trigger_ops = { .trigger = event_enable_count_trigger, .print = event_enable_trigger_print, .init = event_trigger_init, .free = event_enable_trigger_free, }; -static struct event_trigger_ops event_disable_trigger_ops = { +static const struct event_trigger_ops event_disable_trigger_ops = { .trigger = event_enable_trigger, .print = event_enable_trigger_print, .init = event_trigger_init, .free = event_enable_trigger_free, }; -static struct event_trigger_ops event_disable_count_trigger_ops = { +static const struct event_trigger_ops event_disable_count_trigger_ops = { .trigger = event_enable_count_trigger, .print = event_enable_trigger_print, .init = event_trigger_init,
@@ -1898,10 +1898,10 @@ void event_enable_unregister_trigger(char *glob, data->ops->free (data); } -static struct event_trigger_ops * +static const struct event_trigger_ops *event_enable_get_trigger_ops (char *cmd,char *param) { -struct event_trigger_ops *ops; +const struct event_trigger_ops *ops;bool enable;#ifdef CONFIG_HIST_TRIGGERS
Signature · 1 line
2.53.0
Sasha Levin
maintainerPATCH 2/3 tracing: Merge struct event_trigger_ops into struct event_command
From: Steven Rostedt <[email protected]>
[ Upstream commit b052d70f7c9c156409a70e65c10d83b5650e7e78 ]
Now that there's pretty much a one to one mapping between the struct event_trigger_ops and struct event_command, there's no reason to have two different structures. Merge the function pointers of event_trigger_ops into event_command.
There's one exception in trace_events_hist.c for the event_hist_trigger_named_ops. This has special logic for the init and free function pointers for "named histograms". In this case, allocate the cmd_ops of the event_trigger_data and set it to the proper init and free functions, which are used to initialize and free the event_trigger_data respectively. Have the free function and the init function (on failure) free the cmd_ops of the data element.
[6.6 dependency adaptation]
The stable branch still selects separate counted trigger callbacks through get_trigger_ops(), and lacks the upstream count_func/data_ops_trigger refactoring. Merge the callbacks into event_command while retaining the existing counted callbacks as count_trigger. Select them in the existing trigger dispatch functions using EVENT_TRIGGER_FL_COUNT, preserving the old parameter-based selection and count semantics without adding functions. Remove the obsolete get_trigger_ops callbacks and event_trigger_ops tables, including the eprobe selector left behind by the automatic merge.
For shared named histograms, retain the dependency's per-trigger copy of cmd_ops and its specialized init/free callbacks. Mark the copy as owned by the trigger and release it in trigger_data_free(), instead of adding frees to named init/free. This covers normal teardown and parse error cleanup, including clock validation failure before init after the target is applied.
Keep hist_register_trigger() in the form expected by 6ede78d0563a so that its clock-before-registration change applies directly. The target itself is not included in this dependency.
Stable-dep-of: 6ede78d0563a ("tracing: Set the trace clock before registering the histogram trigger")
--- kernel/trace/trace.h | 120 ++++++--------- kernel/trace/trace_eprobe.c | 19 +-- kernel/trace/trace_events_hist.c | 117 +++++--------- kernel/trace/trace_events_trigger.c | 230 ++++++++-------------------- 4 files changed, 157 insertions(+), 329 deletions(-)
kernel/trace/trace.h +51 -69
@@ -1551,13 +1551,14 @@ extern void clear_event_triggers(struct trace_array *tr);enum {EVENT_TRIGGER_FL_PROBE =BIT (0 ), +EVENT_TRIGGER_FL_COUNT =BIT (1 ), +EVENT_TRIGGER_FL_CMD_ALLOC =BIT (2 ), };struct event_trigger_data {unsigned long count;int ref;int flags; -const struct event_trigger_ops *ops;struct event_command *cmd_ops;struct event_filter __rcu *filter;char *filter_str;
@@ -1644,64 +1645,6 @@ extern void event_trigger_unregister(struct event_command *cmd_ops,extern void event_file_get (struct trace_event_file *file);extern void event_file_put (struct trace_event_file *file); -/** -* struct event_trigger_ops - callbacks for trace event triggers -* -* The methods in this structure provide per-event trigger hooks for -* various trigger operations. -* -* The @init and @free methods are used during trigger setup and -* teardown, typically called from an event_command's @parse() -* function implementation. -* -* The @print method is used to print the trigger spec. -* -* The @trigger method is the function that actually implements the -* trigger and is called in the context of the triggering event -* whenever that event occurs. -* -* All the methods below, except for @init() and @free(), must be -* implemented. -* -* @trigger: The trigger 'probe' function called when the triggering -* event occurs. The data passed into this callback is the data -* that was supplied to the event_command @reg() function that -* registered the trigger (see struct event_command) along with -* the trace record, rec. -* -* @init: An optional initialization function called for the trigger -* when the trigger is registered (via the event_command reg() -* function). This can be used to perform per-trigger -* initialization such as incrementing a per-trigger reference -* count, for instance. This is usually implemented by the -* generic utility function @event_trigger_init() (see -* trace_event_triggers.c). -* -* @free: An optional de-initialization function called for the -* trigger when the trigger is unregistered (via the -* event_command @reg() function). This can be used to perform -* per-trigger de-initialization such as decrementing a -* per-trigger reference count and freeing corresponding trigger -* data, for instance. This is usually implemented by the -* generic utility function @event_trigger_free() (see -* trace_event_triggers.c). -* -* @print: The callback function invoked to have the trigger print -* itself. This is usually implemented by a wrapper function -* that calls the generic utility function @event_trigger_print() -* (see trace_event_triggers.c). -*/ -struct event_trigger_ops { -void (*trigger)(struct event_trigger_data *data, -struct trace_buffer *buffer, -void *rec, -struct ring_buffer_event *rbe); -int (*init)(struct event_trigger_data *data); -void (*free)(struct event_trigger_data *data); -int (*print)(struct seq_file *m, -struct event_trigger_data *data); -}; -/** * struct event_command - callbacks and data members for event commands *
@@ -1751,7 +1694,7 @@ struct event_trigger_ops {* * @reg: Adds the trigger to the list of triggers associated with the * event, and enables the event trigger itself, after -* initializing it (via the event_trigger_ops @init() function). +* initializing it (via the event_command @init() function). * This is also where commands can use the @trigger_type value to * make the decision as to whether or not multiple instances of * the trigger should be allowed. This is usually implemented by
@@ -1760,7 +1703,7 @@ struct event_trigger_ops {* * @unreg: Removes the trigger from the list of triggers associated * with the event, and disables the event trigger itself, after -* initializing it (via the event_trigger_ops @free() function). +* initializing it (via the event_command @free() function). * This is usually implemented by the generic utility function * @unregister_trigger() (see trace_event_triggers.c). *
@@ -1774,12 +1717,40 @@ struct event_trigger_ops {* ignored. This is usually implemented by the generic utility * function @set_trigger_filter() (see trace_event_triggers.c). * -* @get_trigger_ops: The callback function invoked to retrieve the -* event_trigger_ops implementation associated with the command. -* This callback function allows a single event_command to -* support multiple trigger implementations via different sets of -* event_trigger_ops, depending on the value of the @param -* string. +* All the methods below, except for @count_trigger(), @init() and +* @free(), must be implemented. +* +* @trigger: The trigger 'probe' function called when the triggering +* event occurs. The data passed into this callback is the data +* that was supplied to the event_command @reg() function that +* registered the trigger (see struct event_command) along with +* the trace record, rec. +* +* @count_trigger: If defined and a numeric parameter is passed to the +* trigger, this function is called instead of @trigger. It handles +* the count and invokes the trigger when appropriate. +* +* @init: An optional initialization function called for the trigger +* when the trigger is registered (via the event_command reg() +* function). This can be used to perform per-trigger +* initialization such as incrementing a per-trigger reference +* count, for instance. This is usually implemented by the +* generic utility function @event_trigger_init() (see +* trace_event_triggers.c). +* +* @free: An optional de-initialization function called for the +* trigger when the trigger is unregistered (via the +* event_command @reg() function). This can be used to perform +* per-trigger de-initialization such as decrementing a +* per-trigger reference count and freeing corresponding trigger +* data, for instance. This is usually implemented by the +* generic utility function @event_trigger_free() (see +* trace_event_triggers.c). +* +* @print: The callback function invoked to have the trigger print +* itself. This is usually implemented by a wrapper function +* that calls the generic utility function @event_trigger_print() +* (see trace_event_triggers.c). */ struct event_command {struct list_head list;
@@ -1800,7 +1771,18 @@ struct event_command {int (*set_filter)(char *filter_str,struct event_trigger_data *data,struct trace_event_file *file); -const struct event_trigger_ops *(*get_trigger_ops)(char *cmd,char *param); +void (*trigger)(struct event_trigger_data *data, +struct trace_buffer *buffer, +void *rec, +struct ring_buffer_event *rbe); +void (*count_trigger)(struct event_trigger_data *data, +struct trace_buffer *buffer, +void *rec, +struct ring_buffer_event *rbe); +int (*init)(struct event_trigger_data *data); +void (*free)(struct event_trigger_data *data); +int (*print)(struct seq_file *m, +struct event_trigger_data *data); };/**
@@ -1821,7 +1803,7 @@ struct event_command {* either committed or discarded. At that point, if any commands * have deferred their triggers, those commands are finally * invoked following the close of the current event. In other -* words, if the event_trigger_ops @func() probe implementation +* words, if the event_command @func() probe implementation * itself logs to the trace buffer, this flag should be set, * otherwise it can be left unspecified. *
kernel/trace/trace_eprobe.c +4 -15
@@ -574,13 +574,6 @@ static void eprobe_trigger_func(struct event_trigger_data *data,__eprobe_trace_func (edata, rec); } -static const struct event_trigger_ops eprobe_trigger_ops = { - .trigger = eprobe_trigger_func, - .print = eprobe_trigger_print, - .init = eprobe_trigger_init, - .free = eprobe_trigger_free, -}; - static int eprobe_trigger_cmd_parse(struct event_command *cmd_ops, struct trace_event_file *file, char *glob, char *cmd,
@@ -603,12 +596,6 @@ static void eprobe_trigger_unreg_func(char *glob, } -static const struct event_trigger_ops *eprobe_trigger_get_ops (char *cmd, -char *param) -{ -return &eprobe_trigger_ops; -} -static struct event_command event_trigger_cmd = { .name ="eprobe" , .trigger_type =ETT_EVENT_EPROBE ,
@@ -617,8 +604,11 @@ static struct event_command event_trigger_cmd = { .reg = eprobe_trigger_reg_func, .unreg = eprobe_trigger_unreg_func, .unreg_all = NULL, - .get_trigger_ops = eprobe_trigger_get_ops, .set_filter = NULL, + .trigger = eprobe_trigger_func, + .print = eprobe_trigger_print, + .init = eprobe_trigger_init, + .free = eprobe_trigger_free, }; static struct event_trigger_data *
@@ -638,7 +628,6 @@ new_eprobe_trigger(struct trace_eprobe *ep, struct trace_event_file *file) trigger->flags =EVENT_TRIGGER_FL_PROBE ; trigger->count =-1 ; - trigger->ops = &eprobe_trigger_ops;/* * EVENT PROBE triggers are not registered as commands with
kernel/trace/trace_events_hist.c +37 -80
196 lines not on this page · raw message
kernel/trace/trace_events_trigger.c +65 -165
394 lines not on this page · raw message
Signature · 1 line
2.53.0
Sasha Levin
maintainerPATCH 3/3 tracing: Set the trace clock before registering the histogram trigger
In reply to Sasha LevinFrom: Donggeun Yoo <[email protected]>
[ Upstream commit 6ede78d0563a2a3ae3e46f9c07cedb5d79645429 ]
hist_register_trigger() puts the trigger on the global named_triggers list in cmd_ops->init(), and only then sets the trace clock:
if (data->cmd_ops->init) {
ret = data->cmd_ops->init(data);
if (ret < 0)
goto out;
}
if (hist_data->enable_timestamps) {
ret = tracing_set_clock(file->tr, hist_data->attrs->clock);
if (ret) {
hist_err(tr, HIST_ERR_SET_CLOCK_FAIL, errpos(clock));
goto out;
}The clock string is not checked anywhere before that call, so a named trigger using common_timestamp with an unknown clock fails after it has already become findable. event_hist_trigger_parse() then frees it without taking it off the list, and the next lookup by name reads the freed object:
~# cd /sys/kernel/tracing/events/sched/sched_switch
~# echo 'hist:name=foo:keys=common_pid:ts=common_timestamp:clock=bogus' > trigger
bash: echo: write error: Invalid argument
~# echo 'hist:name=foo:keys=common_pid' > trigger
BUG: KASAN: slab-use-after-free in find_named_trigger+0xac/0xc0 Read of size 8 at addr ffff88800915d760 by task init/1 find_named_trigger+0xac/0xc0 hist_register_trigger+0xc1/0x900 event_hist_trigger_parse+0x3146/0x6af0 event_trigger_write+0xce/0x160 Freed by task 63: kfree+0x154/0x420 trigger_kthread_fn+0xfd/0x160
Set the clock before the trigger is registered, so that nothing which can fail runs after it is published, the way commit 6f86bdeab633 ("tracing: Fix bad hist from corrupting named_triggers list") moved the registration below the rest of the setup.
tracing_set_filter_buffering() is reference counted, so the init failure path has to drop the reference that the clock block now takes first.
--- kernel/trace/trace_events_hist.c | 15 +++++++++------ 1 file changed, 9 insertions(+), 6 deletions(-)
kernel/trace/trace_events_hist.c +9 -6
@@ -6255,12 +6255,6 @@ static int hist_register_trigger(char *glob, data->cmd_ops = cmd_ops; } -if (data->cmd_ops->init) { - ret = data->cmd_ops->init (data); -if (ret <0 ) - goto out; - } -if (hist_data->enable_timestamps) {char *clock = hist_data->attrs->clock;
@@ -6273,6 +6267,15 @@ static int hist_register_trigger(char *glob,tracing_set_filter_buffering (file->tr, true); } +if (data->cmd_ops->init) { + ret = data->cmd_ops->init (data); +if (ret <0 ) { +if (hist_data->enable_timestamps) +tracing_set_filter_buffering (file->tr, false); + goto out; + } + } +if (named_data) {remove_hist_vars (hist_data);destroy_hist_data (hist_data);
Signature · 1 line
2.53.0