From: "Masami Hiramatsu (Google)" <mhiramat@kernel.org>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Dan Carpenter <dan.carpenter@linaro.org>,
linux-trace-kernel@vger.kernel.org,
LKML <linux-kernel@vger.kernel.org>,
Masami Hiramatsu <mhiramat@kernel.org>
Subject: [PATCH v5 5/5] tracing/probes: Fix to record 0-length data_loc in fetch_store_string*() if fails
Date: Tue, 11 Jul 2023 23:16:07 +0900 [thread overview]
Message-ID: <168908496683.123124.4761206188794205601.stgit@devnote2> (raw)
In-Reply-To: <168908491977.123124.16583481716284477889.stgit@devnote2>
From: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Fix to record 0-length data to data_loc in fetch_store_string*() if it fails
to get the string data.
Currently those expect that the data_loc is updated by store_trace_args() if
it returns the error code. However, that does not work correctly if the
argument is an array of strings. In that case, store_trace_args() only clears
the first entry of the array (which may have no error) and leaves other
entries. So it should be cleared by fetch_store_string*() itself.
Also, 'dyndata' and 'maxlen' in store_trace_args() should be updated
only if it is used (ret > 0 and argument is a dynamic data.)
Fixes: 40b53b771806 ("tracing: probeevent: Add array type support")
Cc: stable@vger.kernel.org
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
---
Changes in v4:
- Simplify the updating data_loc code with set_data_loc().
Changes in v5:
- Move out arg->dynamic check from unlikely() and use likely().
---
kernel/trace/trace_probe_kernel.h | 13 +++++++++----
kernel/trace/trace_probe_tmpl.h | 10 +++-------
kernel/trace/trace_uprobe.c | 3 ++-
3 files changed, 14 insertions(+), 12 deletions(-)
diff --git a/kernel/trace/trace_probe_kernel.h b/kernel/trace/trace_probe_kernel.h
index 6deae2ce34f8..bb723eefd7b7 100644
--- a/kernel/trace/trace_probe_kernel.h
+++ b/kernel/trace/trace_probe_kernel.h
@@ -37,6 +37,13 @@ fetch_store_strlen(unsigned long addr)
return (ret < 0) ? ret : len;
}
+static nokprobe_inline void set_data_loc(int ret, void *dest, void *__dest, void *base)
+{
+ if (ret < 0)
+ ret = 0;
+ *(u32 *)dest = make_data_loc(ret, __dest - base);
+}
+
/*
* Fetch a null-terminated string from user. Caller MUST set *(u32 *)buf
* with max length and relative data location.
@@ -55,8 +62,7 @@ fetch_store_string_user(unsigned long addr, void *dest, void *base)
__dest = get_loc_data(dest, base);
ret = strncpy_from_user_nofault(__dest, uaddr, maxlen);
- if (ret >= 0)
- *(u32 *)dest = make_data_loc(ret, __dest - base);
+ set_data_loc(ret, dest, __dest, base);
return ret;
}
@@ -87,8 +93,7 @@ fetch_store_string(unsigned long addr, void *dest, void *base)
* probing.
*/
ret = strncpy_from_kernel_nofault(__dest, (void *)addr, maxlen);
- if (ret >= 0)
- *(u32 *)dest = make_data_loc(ret, __dest - base);
+ set_data_loc(ret, dest, __dest, base);
return ret;
}
diff --git a/kernel/trace/trace_probe_tmpl.h b/kernel/trace/trace_probe_tmpl.h
index 185da001f4c3..3935b347f874 100644
--- a/kernel/trace/trace_probe_tmpl.h
+++ b/kernel/trace/trace_probe_tmpl.h
@@ -267,13 +267,9 @@ store_trace_args(void *data, struct trace_probe *tp, void *rec,
if (unlikely(arg->dynamic))
*dl = make_data_loc(maxlen, dyndata - base);
ret = process_fetch_insn(arg->code, rec, dl, base);
- if (arg->dynamic) {
- if (unlikely(ret < 0)) {
- *dl = make_data_loc(0, dyndata - base);
- } else {
- dyndata += ret;
- maxlen -= ret;
- }
+ if (arg->dynamic && likely(ret > 0)) {
+ dyndata += ret;
+ maxlen -= ret;
}
}
}
diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c
index 8b92e34ff0c8..7b47e9a2c010 100644
--- a/kernel/trace/trace_uprobe.c
+++ b/kernel/trace/trace_uprobe.c
@@ -170,7 +170,8 @@ fetch_store_string(unsigned long addr, void *dest, void *base)
*/
ret++;
*(u32 *)dest = make_data_loc(ret, (void *)dst - base);
- }
+ } else
+ *(u32 *)dest = make_data_loc(0, (void *)dst - base);
return ret;
}
next prev parent reply other threads:[~2023-07-11 14:16 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-07-11 14:15 [PATCH v5 0/5] tracing/probes: Fix bugs in process_fetch_insn Masami Hiramatsu (Google)
2023-07-11 14:15 ` [PATCH v5 1/5] tracing/probes: Fix to avoid double count of the string length on the array Masami Hiramatsu (Google)
2023-07-11 14:15 ` [PATCH v5 2/5] tracing/probes: Fix not to count error code to total length Masami Hiramatsu (Google)
2023-07-11 14:15 ` [PATCH v5 3/5] tracing/probes: Fix to update dynamic data counter if fetcharg uses it Masami Hiramatsu (Google)
2023-07-13 13:34 ` Steven Rostedt
2023-07-13 14:34 ` Masami Hiramatsu
2023-07-11 14:15 ` [PATCH v5 4/5] Revert "tracing: Add "(fault)" name injection to kernel probes" Masami Hiramatsu (Google)
2023-07-11 16:19 ` Steven Rostedt
2023-07-11 14:16 ` Masami Hiramatsu (Google) [this message]
2023-07-11 16:22 ` [PATCH v5 5/5] tracing/probes: Fix to record 0-length data_loc in fetch_store_string*() if fails Steven Rostedt
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=168908496683.123124.4761206188794205601.stgit@devnote2 \
--to=mhiramat@kernel.org \
--cc=dan.carpenter@linaro.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-trace-kernel@vger.kernel.org \
--cc=rostedt@goodmis.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).