When an unqualified kprobe target exists in both vmlinux and a loaded
module, number_of_same_symbols() returns a count greater than 1,
causing kprobe attachment to fail with -EADDRNOTAVAIL even though the
vmlinux symbol is unambiguous.
When no module qualifier is given and the symbol is found in vmlinux,
return the vmlinux-only count without scanning loaded modules. This
preserves the existing behavior for all other cases:
- Symbol only in a module: vmlinux count is 0, falls through to module
scan as before.
- Symbol qualified with MOD:SYM: mod != NULL, unchanged path.
- Symbol ambiguous within vmlinux itself: count > 1 is returned as-is.
Fixes: 926fe783c8a6 ("tracing/kprobes: Fix symbol counting logic by looking at
modules as well")
Fixes: 9d8616034f16 ("tracing/kprobes: Add symbol counting check when module
loads")
Suggested-by: Ihor Solodrai <[email protected]>
Acked-by: Jiri Olsa <[email protected]>
Acked-by: Ihor Solodrai <[email protected]>
Signed-off-by: Andrey Grodzovsky <[email protected]>
---
kernel/trace/trace_kprobe.c | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index a5dbb72528e0..058724c41c46 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -765,6 +765,14 @@ static unsigned int number_of_same_symbols(const char
*mod, const char *func_nam
if (!mod)
kallsyms_on_each_match_symbol(count_symbols, func_name,
&ctx.count);
+ /*
+ * If the symbol is found in vmlinux, use vmlinux resolution only.
+ * This prevents module symbols from shadowing vmlinux symbols
+ * and causing -EADDRNOTAVAIL for unqualified kprobe targets.
+ */
+ if (!mod && ctx.count > 0)
+ return ctx.count;
+
module_kallsyms_on_each_symbol(mod, count_mod_symbols, &ctx);
return ctx.count;
--
2.34.1
