From: Changbin Du <[email protected]>
I found there are some problems in the tracing parser when I investiage the root
cause of issues mentioned in below patch.
https://patchwork.kernel.org/patch/10132953/
This serials can fix them.
v3: Polish commit msg from Steven Rostedt.
v2:
- Drop 1 old patch and add a new one.
- Stop parsing when '\0' found.
Changbin Du (3):
tracing: detect the string termination character when parsing user
input string
tracing: clear parser->idx if parser gets nothing
tracing: make sure the parsed string always terminates with '\0'
kernel/trace/ftrace.c | 2 --
kernel/trace/trace.c | 14 +++++++-------
kernel/trace/trace_events.c | 2 --
3 files changed, 7 insertions(+), 11 deletions(-)
--
2.7.4
From: Changbin Du <[email protected]>
User space can pass in a C nul character '\0' along with its input. The
function trace_get_user() will try to process it as a normal character,
and that will fail to parse.
open("/sys/kernel/debug/tracing//set_ftrace_pid", O_WRONLY|O_TRUNC) = 3
write(3, " \0", 2) = -1 EINVAL (Invalid argument)
while parse can handle spaces, so below works.
$ echo "" > set_ftrace_pid
$ echo " " > set_ftrace_pid
$ echo -n " " > set_ftrace_pid
Have the parser stop on '\0' and cease any further parsing. Only process
the characters up to the nul '\0' character and do not process it.
Cc: Steven Rostedt <[email protected]>
Signed-off-by: Changbin Du <[email protected]>
---
v3: Polish commit msg from Steven Rostedt.
v2: Stop parsing when '\0' found.
---
kernel/trace/trace.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 2a8d8a2..144d08e 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -1237,7 +1237,7 @@ int trace_get_user(struct trace_parser *parser, const char __user *ubuf,
}
/* only spaces were written */
- if (isspace(ch)) {
+ if (isspace(ch) || !ch) {
*ppos += read;
ret = read;
goto out;
@@ -1247,7 +1247,7 @@ int trace_get_user(struct trace_parser *parser, const char __user *ubuf,
}
/* read the non-space input */
- while (cnt && !isspace(ch)) {
+ while (cnt && !isspace(ch) && ch) {
if (parser->idx < parser->size - 1)
parser->buffer[parser->idx++] = ch;
else {
@@ -1262,7 +1262,7 @@ int trace_get_user(struct trace_parser *parser, const char __user *ubuf,
}
/* We either got finished input or we have to wait for another call. */
- if (isspace(ch)) {
+ if (isspace(ch) || !ch) {
parser->buffer[parser->idx] = 0;
parser->cont = false;
} else if (parser->idx < parser->size - 1) {
--
2.7.4
From: Changbin Du <[email protected]>
Always mark the parsed string with a terminated '\0' even parser expects
another input to be parsed. Thus the users needn't append '0' before
using parsed string if new input is not given.
Signed-off-by: Changbin Du <[email protected]>
---
kernel/trace/ftrace.c | 2 --
kernel/trace/trace.c | 4 ++--
kernel/trace/trace_events.c | 2 --
3 files changed, 2 insertions(+), 6 deletions(-)
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index ccdf366..3addb82 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -5010,7 +5010,6 @@ int ftrace_regex_release(struct inode *inode, struct file *file)
parser = &iter->parser;
if (trace_parser_loaded(parser)) {
- parser->buffer[parser->idx] = 0;
ftrace_match_records(iter->hash, parser->buffer, parser->idx);
}
@@ -5324,7 +5323,6 @@ ftrace_graph_release(struct inode *inode, struct file *file)
parser = &fgd->parser;
if (trace_parser_loaded((parser))) {
- parser->buffer[parser->idx] = 0;
ret = ftrace_graph_set_hash(fgd->new_hash,
parser->buffer);
}
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index b44926e..8f7fea2 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -530,8 +530,6 @@ int trace_pid_write(struct trace_pid_list *filtered_pids,
ubuf += ret;
cnt -= ret;
- parser.buffer[parser.idx] = 0;
-
ret = -EINVAL;
if (kstrtoul(parser.buffer, 0, &val))
break;
@@ -1268,6 +1266,8 @@ int trace_get_user(struct trace_parser *parser, const char __user *ubuf,
} else if (parser->idx < parser->size - 1) {
parser->cont = true;
parser->buffer[parser->idx++] = ch;
+ /* Make sure the parsed string always terminates with '\0'. */
+ parser->buffer[parser->idx] = 0;
} else {
ret = -EINVAL;
goto out;
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index ec0f9aa..7f8027c 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -885,8 +885,6 @@ ftrace_event_write(struct file *file, const char __user *ubuf,
if (*parser.buffer == '!')
set = 0;
- parser.buffer[parser.idx] = 0;
-
ret = ftrace_set_clr_event(tr, parser.buffer + !set, set);
if (ret)
goto out_put;
--
2.7.4
From: Changbin Du <[email protected]>
If only spaces was got in that cycle, we should clear parser->idx to make
trace_parser_loaded() return false.
Signed-off-by: Changbin Du <[email protected]>
---
kernel/trace/trace.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 144d08e..b44926e 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -1236,14 +1236,14 @@ int trace_get_user(struct trace_parser *parser, const char __user *ubuf,
cnt--;
}
+ parser->idx = 0;
+
/* only spaces were written */
if (isspace(ch) || !ch) {
*ppos += read;
ret = read;
goto out;
}
-
- parser->idx = 0;
}
/* read the non-space input */
--
2.7.4
On Tue, 16 Jan 2018 17:02:27 +0800
[email protected] wrote:
> From: Changbin Du <[email protected]>
>
> I found there are some problems in the tracing parser when I investiage the root
> cause of issues mentioned in below patch.
> https://patchwork.kernel.org/patch/10132953/
I pulled in your patches and tweaked the change logs of the other two
patches as well. You can see my temporary git tree here, but it may
rebase.
git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace.git
ftrace/core
-- Steve
On Tue, Jan 16, 2018 at 05:02:27PM +0800, [email protected] wrote:
> From: Changbin Du <[email protected]>
>
> I found there are some problems in the tracing parser when I investiage the root
> cause of issues mentioned in below patch.
> https://patchwork.kernel.org/patch/10132953/
>
> This serials can fix them.
>
> v3: Polish commit msg from Steven Rostedt.
> v2:
> - Drop 1 old patch and add a new one.
> - Stop parsing when '\0' found.
>
> Changbin Du (3):
> tracing: detect the string termination character when parsing user
> input string
> tracing: clear parser->idx if parser gets nothing
> tracing: make sure the parsed string always terminates with '\0'
Acked-by: Namhyung Kim <[email protected]>
Thanks,
Namhyung
>
> kernel/trace/ftrace.c | 2 --
> kernel/trace/trace.c | 14 +++++++-------
> kernel/trace/trace_events.c | 2 --
> 3 files changed, 7 insertions(+), 11 deletions(-)
>
> --
> 2.7.4
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-perf-users" in
> the body of a message to [email protected]
> More majordomo info at http://vger.kernel.org/majordomo-info.html
On Tue, Jan 16, 2018 at 12:42:26PM -0500, Steven Rostedt wrote:
> On Tue, 16 Jan 2018 17:02:27 +0800
> [email protected] wrote:
>
> > From: Changbin Du <[email protected]>
> >
> > I found there are some problems in the tracing parser when I investiage the root
> > cause of issues mentioned in below patch.
> > https://patchwork.kernel.org/patch/10132953/
>
> I pulled in your patches and tweaked the change logs of the other two
> patches as well. You can see my temporary git tree here, but it may
> rebase.
>
> git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace.git
>
> ftrace/core
>
> -- Steve
Got it. Thank you!
Hi Olsa, so the perf patch 'perf ftrace: Fix the buffer size in__write_tracing_file'
is still needed. I will resend you at appropriate time.
--
Thanks,
Changbin Du
Hello,
On Wed, Jan 17, 2018 at 12:54:34PM +0800, Du, Changbin wrote:
> On Tue, Jan 16, 2018 at 12:42:26PM -0500, Steven Rostedt wrote:
> > On Tue, 16 Jan 2018 17:02:27 +0800
> > [email protected] wrote:
> >
> > > From: Changbin Du <[email protected]>
> > >
> > > I found there are some problems in the tracing parser when I investiage the root
> > > cause of issues mentioned in below patch.
> > > https://patchwork.kernel.org/patch/10132953/
> >
> > I pulled in your patches and tweaked the change logs of the other two
> > patches as well. You can see my temporary git tree here, but it may
> > rebase.
> >
> > git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace.git
> >
> > ftrace/core
> >
> > -- Steve
> Got it. Thank you!
>
> Hi Olsa, so the perf patch 'perf ftrace: Fix the buffer size in__write_tracing_file'
> is still needed. I will resend you at appropriate time.
But it will work on the future kernels only, right? For tools to be
compatible with old kernels, you'd better writing a whitespace after
the function name IMHO.
Thanks,
Namhyung
On Wed, Jan 17, 2018 at 02:45:24PM +0900, Namhyung Kim wrote:
> Hello,
>
> On Wed, Jan 17, 2018 at 12:54:34PM +0800, Du, Changbin wrote:
> > On Tue, Jan 16, 2018 at 12:42:26PM -0500, Steven Rostedt wrote:
> > > On Tue, 16 Jan 2018 17:02:27 +0800
> > > [email protected] wrote:
> > >
> > > > From: Changbin Du <[email protected]>
> > > >
> > > > I found there are some problems in the tracing parser when I investiage the root
> > > > cause of issues mentioned in below patch.
> > > > https://patchwork.kernel.org/patch/10132953/
> > >
> > > I pulled in your patches and tweaked the change logs of the other two
> > > patches as well. You can see my temporary git tree here, but it may
> > > rebase.
> > >
> > > git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace.git
> > >
> > > ftrace/core
> > >
> > > -- Steve
> > Got it. Thank you!
> >
> > Hi Olsa, so the perf patch 'perf ftrace: Fix the buffer size in__write_tracing_file'
> > is still needed. I will resend you at appropriate time.
>
> But it will work on the future kernels only, right? For tools to be
> compatible with old kernels, you'd better writing a whitespace after
> the function name IMHO.
>
Yes, it needs to write a space if it doesn't want possible error hidden.
> Thanks,
> Namhyung
--
Thanks,
Changbin Du