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authorZe Gao <zegao2021@gmail.com>2023-05-17 11:45:08 +0800
committerMasami Hiramatsu (Google) <mhiramat@kernel.org>2023-05-18 07:08:01 +0900
commit2752741080f84f9b2fc93fa92735315d10a415bf (patch)
tree56511a45fad7d44e6147ceffb87052ffe1f85ecc /kernel
parent3cc4e2c5fbae84e5033723fb7e350bc6c164e3a2 (diff)
fprobe: add recursion detection in fprobe_exit_handler
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. Link: https://lore.kernel.org/all/20230517034510.15639-4-zegao@tencent.com/ 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> Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/trace/fprobe.c14
1 files changed, 14 insertions, 0 deletions
diff --git a/kernel/trace/fprobe.c b/kernel/trace/fprobe.c
index 7a692c02f787..18d36842faf5 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 parent_ip,
}
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);