6.6-stable review patch. If anyone has any objections, please let me know.
------------------
From: Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx>
commit 8c427cc2fa73684ea140999e121b7b6c1c717632 upstream.
Fix to show a parse error for bad type (non-string) for $comm/$COMM and
immediate-string. With this fix, error_log file shows appropriate error
message as below.
/sys/kernel/tracing # echo 'p vfs_read $comm:u32' >> kprobe_events
sh: write error: Invalid argument
/sys/kernel/tracing # echo 'p vfs_read \"hoge":u32' >> kprobe_events
sh: write error: Invalid argument
/sys/kernel/tracing # cat error_log
[ 30.144183] trace_kprobe: error: $comm and immediate-string only accepts string type
Command: p vfs_read $comm:u32
^
[ 62.618500] trace_kprobe: error: $comm and immediate-string only accepts string type
Command: p vfs_read \"hoge":u32
^
Link: https://lore.kernel.org/all/170602215411.215583.2238016352271091852.stgit@devnote2/
Fixes: 3dd1f7f24f8c ("tracing: probeevent: Fix to make the type of $comm string")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
kernel/trace/trace_probe.c | 7 +++++--
kernel/trace/trace_probe.h | 3 ++-
2 files changed, 7 insertions(+), 3 deletions(-)
--- a/kernel/trace/trace_probe.c
+++ b/kernel/trace/trace_probe.c
@@ -1159,9 +1159,12 @@ static int traceprobe_parse_probe_arg_bo
if (!(ctx->flags & TPARG_FL_TEVENT) &&
(strcmp(arg, "$comm") == 0 || strcmp(arg, "$COMM") == 0 ||
strncmp(arg, "\\\"", 2) == 0)) {
- /* The type of $comm must be "string", and not an array. */
- if (parg->count || (t && strcmp(t, "string")))
+ /* The type of $comm must be "string", and not an array type. */
+ if (parg->count || (t && strcmp(t, "string"))) {
+ trace_probe_log_err(ctx->offset + (t ? (t - arg) : 0),
+ NEED_STRING_TYPE);
goto out;
+ }
parg->type = find_fetch_type("string", ctx->flags);
} else
parg->type = find_fetch_type(t, ctx->flags);
--- a/kernel/trace/trace_probe.h
+++ b/kernel/trace/trace_probe.h
@@ -515,7 +515,8 @@ extern int traceprobe_define_arg_fields(
C(BAD_HYPHEN, "Failed to parse single hyphen. Forgot '>'?"), \
C(NO_BTF_FIELD, "This field is not found."), \
C(BAD_BTF_TID, "Failed to get BTF type info."),\
- C(BAD_TYPE4STR, "This type does not fit for string."),
+ C(BAD_TYPE4STR, "This type does not fit for string."),\
+ C(NEED_STRING_TYPE, "$comm and immediate-string only accepts string type"),
#undef C
#define C(a, b) TP_ERR_##a
