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0755b497cf
This fixes 39d954200bf6 ("fprobe: Skip exit_handler if entry_handler
returns !0"), which causes multiple multi-kprobe tests to fail. Upstream
fix was found at [0].
[0] https://lore.kernel.org/all/168100731160.79534.374827110083836722.stgit@devnote2/#r
Signed-off-by: Daniel Müller <deso@posteo.net>
69 lines
2.3 KiB
Diff
69 lines
2.3 KiB
Diff
From d3484f640bc82cff459beb85a00f7ebab20f0a41 Mon Sep 17 00:00:00 2001
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From: "Masami Hiramatsu (Google)" <mhiramat@kernel.org>
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Date: Sun, 9 Apr 2023 11:28:31 +0900
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Subject: [PATCH] tracing: fprobe: Initialize ret valiable to fix smatch error
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The commit 39d954200bf6 ("fprobe: Skip exit_handler if entry_handler returns
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!0") introduced a hidden dependency of 'ret' local variable in the
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fprobe_handler(), Smatch warns the `ret` can be accessed without
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initialization.
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kernel/trace/fprobe.c:59 fprobe_handler()
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error: uninitialized symbol 'ret'.
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kernel/trace/fprobe.c
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49 fpr->entry_ip = ip;
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50 if (fp->entry_data_size)
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51 entry_data = fpr->data;
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52 }
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53
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54 if (fp->entry_handler)
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55 ret = fp->entry_handler(fp, ip, ftrace_get_regs(fregs), entry_data);
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ret is only initialized if there is an ->entry_handler
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56
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57 /* If entry_handler returns !0, nmissed is not counted. */
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58 if (rh) {
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rh is only true if there is an ->exit_handler. Presumably if you have
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and ->exit_handler that means you also have a ->entry_handler but Smatch
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is not smart enough to figure it out.
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--> 59 if (ret)
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^^^
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Warning here.
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60 rethook_recycle(rh);
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61 else
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62 rethook_hook(rh, ftrace_get_regs(fregs), true);
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63 }
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64 out:
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65 ftrace_test_recursion_unlock(bit);
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66 }
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Reported-by: Dan Carpenter <error27@gmail.com>
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Link: https://lore.kernel.org/all/85429a5c-a4b9-499e-b6c0-cbd313291c49@kili.mountain
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Fixes: 39d954200bf6 ("fprobe: Skip exit_handler if entry_handler returns !0")
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Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
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---
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kernel/trace/fprobe.c | 2 +-
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1 file changed, 1 insertion(+), 1 deletion(-)
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diff --git a/kernel/trace/fprobe.c b/kernel/trace/fprobe.c
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index 9abb3905bc8e..293184227394 100644
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--- a/kernel/trace/fprobe.c
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+++ b/kernel/trace/fprobe.c
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@@ -27,7 +27,7 @@ static void fprobe_handler(unsigned long ip, unsigned long parent_ip,
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struct rethook_node *rh = NULL;
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struct fprobe *fp;
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void *entry_data = NULL;
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- int bit, ret;
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+ int bit, ret = 0;
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fp = container_of(ops, struct fprobe, ops);
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if (fprobe_disabled(fp))
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--
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2.34.1
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