From: trix@redhat.com
To: jpoimboe@redhat.com, jikos@kernel.org, mbenes@suse.cz,
pmladek@suse.com, joe.lawrence@redhat.com, nathan@kernel.org,
ndesaulniers@google.com
Cc: live-patching@vger.kernel.org, linux-kernel@vger.kernel.org,
llvm@lists.linux.dev, Tom Rix <trix@redhat.com>
Subject: [PATCH v2] livepatch: Reorder to use before freeing a pointer
Date: Sat, 19 Mar 2022 18:51:43 -0700 [thread overview]
Message-ID: <20220320015143.2208591-1-trix@redhat.com> (raw)
From: Tom Rix <trix@redhat.com>
Clang static analysis reports this issue
livepatch-shadow-fix1.c:113:2: warning: Use of
memory after it is freed
pr_info("%s: dummy @ %p, prevented leak @ %p\n",
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
The pointer is freed in the previous statement.
Reorder the pr_info to report before the free.
Similar issue in livepatch-shadow-fix2.c
Signed-off-by: Tom Rix <trix@redhat.com>
---
v2: Fix similar issue in livepatch-shadow-fix2.c
samples/livepatch/livepatch-shadow-fix1.c | 2 +-
samples/livepatch/livepatch-shadow-fix2.c | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/samples/livepatch/livepatch-shadow-fix1.c b/samples/livepatch/livepatch-shadow-fix1.c
index 918ce17b43fda..6701641bf12d4 100644
--- a/samples/livepatch/livepatch-shadow-fix1.c
+++ b/samples/livepatch/livepatch-shadow-fix1.c
@@ -109,9 +109,9 @@ static void livepatch_fix1_dummy_leak_dtor(void *obj, void *shadow_data)
void *d = obj;
int **shadow_leak = shadow_data;
- kfree(*shadow_leak);
pr_info("%s: dummy @ %p, prevented leak @ %p\n",
__func__, d, *shadow_leak);
+ kfree(*shadow_leak);
}
static void livepatch_fix1_dummy_free(struct dummy *d)
diff --git a/samples/livepatch/livepatch-shadow-fix2.c b/samples/livepatch/livepatch-shadow-fix2.c
index 29fe5cd420472..361046a4f10cf 100644
--- a/samples/livepatch/livepatch-shadow-fix2.c
+++ b/samples/livepatch/livepatch-shadow-fix2.c
@@ -61,9 +61,9 @@ static void livepatch_fix2_dummy_leak_dtor(void *obj, void *shadow_data)
void *d = obj;
int **shadow_leak = shadow_data;
- kfree(*shadow_leak);
pr_info("%s: dummy @ %p, prevented leak @ %p\n",
__func__, d, *shadow_leak);
+ kfree(*shadow_leak);
}
static void livepatch_fix2_dummy_free(struct dummy *d)
--
2.26.3
next reply other threads:[~2022-03-20 1:52 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-03-20 1:51 trix [this message]
2022-03-21 13:24 ` Petr Mladek
2022-03-21 13:39 ` Joe Lawrence
2022-03-21 14:05 ` Tom Rix
2022-03-23 3:21 ` David Vernet
2022-03-23 15:53 ` Petr Mladek
2022-03-23 16:17 ` Tom Rix
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