From: Ze Gao <zegao2021@gmail.com>
To: Steven Rostedt <rostedt@goodmis.org>,
Masami Hiramatsu <mhiramat@kernel.org>
Cc: Albert Ou <aou@eecs.berkeley.edu>,
Alexander Gordeev <agordeev@linux.ibm.com>,
Alexei Starovoitov <ast@kernel.org>,
Borislav Petkov <bp@alien8.de>,
Christian Borntraeger <borntraeger@linux.ibm.com>,
Dave Hansen <dave.hansen@linux.intel.com>,
Heiko Carstens <hca@linux.ibm.com>,
"H. Peter Anvin" <hpa@zytor.com>, Ingo Molnar <mingo@redhat.com>,
Palmer Dabbelt <palmer@dabbelt.com>,
Paul Walmsley <paul.walmsley@sifive.com>,
Sven Schnelle <svens@linux.ibm.com>,
Thomas Gleixner <tglx@linutronix.de>,
Vasily Gorbik <gor@linux.ibm.com>,
x86@kernel.org, bpf@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org,
linux-s390@vger.kernel.org, linux-trace-kernel@vger.kernel.org,
Conor Dooley <conor@kernel.org>, Jiri Olsa <jolsa@kernel.org>,
Yonghong Song <yhs@fb.com>, Ze Gao <zegao@tencent.com>,
stable@vger.kernel.org
Subject: [PATCH v3 3/4] fprobe: add recursion detection in fprobe_exit_handler
Date: Wed, 17 May 2023 11:45:08 +0800 [thread overview]
Message-ID: <20230517034510.15639-4-zegao@tencent.com> (raw)
In-Reply-To: <20230517034510.15639-1-zegao@tencent.com>
fprobe_hander and fprobe_kprobe_handler has guarded ftrace recursion
detection but fprobe_exit_handler has not, which possibly introduce
recursive calls if the fprobe exit callback calls any traceable
functions. Checking in fprobe_hander or fprobe_kprobe_handler
is not enough and misses this case.
So add recursion free guard the same way as fprobe_hander. Since
ftrace recursion check does not employ ip(s), so here use entry_ip and
entry_parent_ip the same as fprobe_handler.
Fixes: 5b0ab78998e3 ("fprobe: Add exit_handler support")
Signed-off-by: Ze Gao <zegao@tencent.com>
Cc: stable@vger.kernel.org
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Link: https://lore.kernel.org/linux-trace-kernel/20230516071830.8190-4-zegao@tencent.com
---
kernel/trace/fprobe.c | 14 ++++++++++++++
1 file changed, 14 insertions(+)
diff --git a/kernel/trace/fprobe.c b/kernel/trace/fprobe.c
index 097c740799ba..281b58c7dd14 100644
--- a/kernel/trace/fprobe.c
+++ b/kernel/trace/fprobe.c
@@ -17,6 +17,7 @@
struct fprobe_rethook_node {
struct rethook_node node;
unsigned long entry_ip;
+ unsigned long entry_parent_ip;
char data[];
};
@@ -39,6 +40,7 @@ static inline void __fprobe_handler(unsigned long ip, unsigned long
}
fpr = container_of(rh, struct fprobe_rethook_node, node);
fpr->entry_ip = ip;
+ fpr->entry_parent_ip = parent_ip;
if (fp->entry_data_size)
entry_data = fpr->data;
}
@@ -114,14 +116,26 @@ static void fprobe_exit_handler(struct rethook_node *rh, void *data,
{
struct fprobe *fp = (struct fprobe *)data;
struct fprobe_rethook_node *fpr;
+ int bit;
if (!fp || fprobe_disabled(fp))
return;
fpr = container_of(rh, struct fprobe_rethook_node, node);
+ /*
+ * we need to assure no calls to traceable functions in-between the
+ * end of fprobe_handler and the beginning of fprobe_exit_handler.
+ */
+ bit = ftrace_test_recursion_trylock(fpr->entry_ip, fpr->entry_parent_ip);
+ if (bit < 0) {
+ fp->nmissed++;
+ return;
+ }
+
fp->exit_handler(fp, fpr->entry_ip, regs,
fp->entry_data_size ? (void *)fpr->data : NULL);
+ ftrace_test_recursion_unlock(bit);
}
NOKPROBE_SYMBOL(fprobe_exit_handler);
--
2.40.1
next prev parent reply other threads:[~2023-05-17 3:45 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-05-17 3:45 [PATCH v3 0/3] Make fprobe + rethook immune to recursion Ze Gao
2023-05-17 3:45 ` [PATCH v3 1/4] rethook: use preempt_{disable, enable}_notrace in rethook_trampoline_handler Ze Gao
2023-05-17 11:59 ` Masami Hiramatsu
2023-05-18 2:40 ` Ze Gao
2023-05-17 3:45 ` [PATCH v3 2/4] fprobe: make fprobe_kprobe_handler recursion free Ze Gao
2023-05-17 10:47 ` Jiri Olsa
2023-05-17 11:42 ` Masami Hiramatsu
2023-05-17 12:30 ` Jiri Olsa
2023-05-17 14:27 ` Masami Hiramatsu
2023-05-18 0:16 ` Andrii Nakryiko
2023-05-18 2:49 ` Ze Gao
2023-06-28 7:16 ` Yafang Shao
2023-07-03 6:52 ` Ze Gao
2023-05-17 3:45 ` Ze Gao [this message]
2023-05-17 3:45 ` [PATCH v3 4/4] rethook, fprobe: do not trace rethook related functions Ze Gao
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