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authorLinus Torvalds <torvalds@linux-foundation.org>2023-05-18 18:04:45 +0200
committerLinus Torvalds <torvalds@linux-foundation.org>2023-05-18 18:04:45 +0200
commit2d1bcbc6cd703e64caf8df314e3669b4786e008a (patch)
tree7b728415795eb0c5f0f807e1f18db5d26d4dd338 /kernel
parentMerge tag 'net-6.4-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/netd... (diff)
parentrethook, fprobe: do not trace rethook related functions (diff)
downloadlinux-2d1bcbc6cd703e64caf8df314e3669b4786e008a.tar.xz
linux-2d1bcbc6cd703e64caf8df314e3669b4786e008a.zip
Merge tag 'probes-fixes-v6.4-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace
Pull probes fixes from Masami Hiramatsu: - Initialize 'ret' local variables on fprobe_handler() to fix the smatch warning. With this, fprobe function exit handler is not working randomly. - Fix to use preempt_enable/disable_notrace for rethook handler to prevent recursive call of fprobe exit handler (which is based on rethook) - Fix recursive call issue on fprobe_kprobe_handler() - Fix to detect recursive call on fprobe_exit_handler() - Fix to make all arch-dependent rethook code notrace (the arch-independent code is already notrace)" * tag 'probes-fixes-v6.4-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: rethook, fprobe: do not trace rethook related functions fprobe: add recursion detection in fprobe_exit_handler fprobe: make fprobe_kprobe_handler recursion free rethook: use preempt_{disable, enable}_notrace in rethook_trampoline_handler tracing: fprobe: Initialize ret valiable to fix smatch error
Diffstat (limited to 'kernel')
-rw-r--r--kernel/trace/fprobe.c73
-rw-r--r--kernel/trace/rethook.c4
2 files changed, 60 insertions, 17 deletions
diff --git a/kernel/trace/fprobe.c b/kernel/trace/fprobe.c
index 9abb3905bc8e..18d36842faf5 100644
--- a/kernel/trace/fprobe.c
+++ b/kernel/trace/fprobe.c
@@ -17,36 +17,30 @@
struct fprobe_rethook_node {
struct rethook_node node;
unsigned long entry_ip;
+ unsigned long entry_parent_ip;
char data[];
};
-static void fprobe_handler(unsigned long ip, unsigned long parent_ip,
- struct ftrace_ops *ops, struct ftrace_regs *fregs)
+static inline void __fprobe_handler(unsigned long ip, unsigned long parent_ip,
+ struct ftrace_ops *ops, struct ftrace_regs *fregs)
{
struct fprobe_rethook_node *fpr;
struct rethook_node *rh = NULL;
struct fprobe *fp;
void *entry_data = NULL;
- int bit, ret;
+ int ret = 0;
fp = container_of(ops, struct fprobe, ops);
- if (fprobe_disabled(fp))
- return;
-
- bit = ftrace_test_recursion_trylock(ip, parent_ip);
- if (bit < 0) {
- fp->nmissed++;
- return;
- }
if (fp->exit_handler) {
rh = rethook_try_get(fp->rethook);
if (!rh) {
fp->nmissed++;
- goto out;
+ return;
}
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;
}
@@ -61,23 +55,60 @@ static void fprobe_handler(unsigned long ip, unsigned long parent_ip,
else
rethook_hook(rh, ftrace_get_regs(fregs), true);
}
-out:
+}
+
+static void fprobe_handler(unsigned long ip, unsigned long parent_ip,
+ struct ftrace_ops *ops, struct ftrace_regs *fregs)
+{
+ struct fprobe *fp;
+ int bit;
+
+ fp = container_of(ops, struct fprobe, ops);
+ if (fprobe_disabled(fp))
+ return;
+
+ /* recursion detection has to go before any traceable function and
+ * all functions before this point should be marked as notrace
+ */
+ bit = ftrace_test_recursion_trylock(ip, parent_ip);
+ if (bit < 0) {
+ fp->nmissed++;
+ return;
+ }
+ __fprobe_handler(ip, parent_ip, ops, fregs);
ftrace_test_recursion_unlock(bit);
+
}
NOKPROBE_SYMBOL(fprobe_handler);
static void fprobe_kprobe_handler(unsigned long ip, unsigned long parent_ip,
struct ftrace_ops *ops, struct ftrace_regs *fregs)
{
- struct fprobe *fp = container_of(ops, struct fprobe, ops);
+ struct fprobe *fp;
+ int bit;
+
+ fp = container_of(ops, struct fprobe, ops);
+ if (fprobe_disabled(fp))
+ return;
+
+ /* recursion detection has to go before any traceable function and
+ * all functions called before this point should be marked as notrace
+ */
+ bit = ftrace_test_recursion_trylock(ip, parent_ip);
+ if (bit < 0) {
+ fp->nmissed++;
+ return;
+ }
if (unlikely(kprobe_running())) {
fp->nmissed++;
return;
}
+
kprobe_busy_begin();
- fprobe_handler(ip, parent_ip, ops, fregs);
+ __fprobe_handler(ip, parent_ip, ops, fregs);
kprobe_busy_end();
+ ftrace_test_recursion_unlock(bit);
}
static void fprobe_exit_handler(struct rethook_node *rh, void *data,
@@ -85,14 +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);
diff --git a/kernel/trace/rethook.c b/kernel/trace/rethook.c
index 32c3dfdb4d6a..60f6cb2b486b 100644
--- a/kernel/trace/rethook.c
+++ b/kernel/trace/rethook.c
@@ -288,7 +288,7 @@ unsigned long rethook_trampoline_handler(struct pt_regs *regs,
* These loops must be protected from rethook_free_rcu() because those
* are accessing 'rhn->rethook'.
*/
- preempt_disable();
+ preempt_disable_notrace();
/*
* Run the handler on the shadow stack. Do not unlink the list here because
@@ -321,7 +321,7 @@ unsigned long rethook_trampoline_handler(struct pt_regs *regs,
first = first->next;
rethook_recycle(rhn);
}
- preempt_enable();
+ preempt_enable_notrace();
return correct_ret_addr;
}