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[v5,1/5] tracing/probes: Fix to avoid double count of the string length on the array

Message ID 168908492917.123124.15076463491122036025.stgit@devnote2 (mailing list archive)
State Accepted
Commit 66bcf65d6cf0ca6540e2341e88ee7ef02dbdda08
Delegated to: Masami Hiramatsu
Headers show
Series tracing/probes: Fix bugs in process_fetch_insn | expand

Commit Message

Masami Hiramatsu (Google) July 11, 2023, 2:15 p.m. UTC 
From: Masami Hiramatsu (Google) <mhiramat@kernel.org>

If an array is specified with the ustring or symstr, the length of the
strings are accumlated on both of 'ret' and 'total', which means the
length is double counted.
Just set the length to the 'ret' value for avoiding double counting.

Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Closes: https://lore.kernel.org/all/8819b154-2ba1-43c3-98a2-cbde20892023@moroto.mountain/
Fixes: 88903c464321 ("tracing/probe: Add ustring type for user-space string")
Cc: stable@vger.kernel.org
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
 kernel/trace/trace_probe_tmpl.h |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
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Patch

diff --git a/kernel/trace/trace_probe_tmpl.h b/kernel/trace/trace_probe_tmpl.h
index 00707630788d..4735c5cb76fa 100644
--- a/kernel/trace/trace_probe_tmpl.h
+++ b/kernel/trace/trace_probe_tmpl.h
@@ -156,11 +156,11 @@  process_fetch_insn_bottom(struct fetch_insn *code, unsigned long val,
 			code++;
 			goto array;
 		case FETCH_OP_ST_USTRING:
-			ret += fetch_store_strlen_user(val + code->offset);
+			ret = fetch_store_strlen_user(val + code->offset);
 			code++;
 			goto array;
 		case FETCH_OP_ST_SYMSTR:
-			ret += fetch_store_symstrlen(val + code->offset);
+			ret = fetch_store_symstrlen(val + code->offset);
 			code++;
 			goto array;
 		default: