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Merge tag 'probes-fixes-v6.17' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

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Pull probe fix from Masami Hiramatsu:

 - Fix race condition in kprobe initialization causing NULL pointer
   dereference. This happens on weak memory model, which does not
   correctly manage the flags access with appropriate memory barriers.
   Use RELEASE-ACQUIRE to fix it.

* tag 'probes-fixes-v6.17' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  tracing: Fix race condition in kprobe initialization causing NULL pointer dereference
This commit is contained in:
Linus Torvalds
2025-10-05 08:16:20 -07:00
parent 6093a688a0 9cf9aa7b0a
commit 2cd14dff16
4 changed files with 28 additions and 14 deletions
Download Patch File Download Diff File Expand all files Collapse all files
kernel/trace/trace_fprobe.c
+6 -4
View File
@@ -522,13 +522,14 @@ static int fentry_dispatcher(struct fprobe *fp, unsigned long entry_ip,
void *entry_data)
{
struct trace_fprobe *tf = container_of(fp, struct trace_fprobe, fp);
unsigned int flags = trace_probe_load_flag(&tf->tp);
int ret = 0;
if (trace_probe_test_flag(&tf->tp, TP_FLAG_TRACE))
if (flags & TP_FLAG_TRACE)
fentry_trace_func(tf, entry_ip, fregs);
#ifdef CONFIG_PERF_EVENTS
if (trace_probe_test_flag(&tf->tp, TP_FLAG_PROFILE))
if (flags & TP_FLAG_PROFILE)
ret = fentry_perf_func(tf, entry_ip, fregs);
#endif
return ret;
@@ -540,11 +541,12 @@ static void fexit_dispatcher(struct fprobe *fp, unsigned long entry_ip,
void *entry_data)
{
struct trace_fprobe *tf = container_of(fp, struct trace_fprobe, fp);
unsigned int flags = trace_probe_load_flag(&tf->tp);
if (trace_probe_test_flag(&tf->tp, TP_FLAG_TRACE))
if (flags & TP_FLAG_TRACE)
fexit_trace_func(tf, entry_ip, ret_ip, fregs, entry_data);
#ifdef CONFIG_PERF_EVENTS
if (trace_probe_test_flag(&tf->tp, TP_FLAG_PROFILE))
if (flags & TP_FLAG_PROFILE)
fexit_perf_func(tf, entry_ip, ret_ip, fregs, entry_data);
#endif
}
kernel/trace/trace_kprobe.c
+7 -4
View File
@@ -1815,14 +1815,15 @@ static int kprobe_register(struct trace_event_call *event,
static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs)
{
struct trace_kprobe *tk = container_of(kp, struct trace_kprobe, rp.kp);
unsigned int flags = trace_probe_load_flag(&tk->tp);
int ret = 0;
raw_cpu_inc(*tk->nhit);
if (trace_probe_test_flag(&tk->tp, TP_FLAG_TRACE))
if (flags & TP_FLAG_TRACE)
kprobe_trace_func(tk, regs);
#ifdef CONFIG_PERF_EVENTS
if (trace_probe_test_flag(&tk->tp, TP_FLAG_PROFILE))
if (flags & TP_FLAG_PROFILE)
ret = kprobe_perf_func(tk, regs);
#endif
return ret;
@@ -1834,6 +1835,7 @@ kretprobe_dispatcher(struct kretprobe_instance *ri, struct pt_regs *regs)
{
struct kretprobe *rp = get_kretprobe(ri);
struct trace_kprobe *tk;
unsigned int flags;
/*
* There is a small chance that get_kretprobe(ri) returns NULL when
@@ -1846,10 +1848,11 @@ kretprobe_dispatcher(struct kretprobe_instance *ri, struct pt_regs *regs)
tk = container_of(rp, struct trace_kprobe, rp);
raw_cpu_inc(*tk->nhit);
if (trace_probe_test_flag(&tk->tp, TP_FLAG_TRACE))
flags = trace_probe_load_flag(&tk->tp);
if (flags & TP_FLAG_TRACE)
kretprobe_trace_func(tk, ri, regs);
#ifdef CONFIG_PERF_EVENTS
if (trace_probe_test_flag(&tk->tp, TP_FLAG_PROFILE))
if (flags & TP_FLAG_PROFILE)
kretprobe_perf_func(tk, ri, regs);
#endif
return 0; /* We don't tweak kernel, so just return 0 */
kernel/trace/trace_probe.h
+7 -2
View File
@@ -271,16 +271,21 @@ struct event_file_link {
struct list_head list;
};
static inline unsigned int trace_probe_load_flag(struct trace_probe *tp)
{
return smp_load_acquire(&tp->event->flags);
}
static inline bool trace_probe_test_flag(struct trace_probe *tp,
unsigned int flag)
{
return !!(tp->event->flags & flag);
return !!(trace_probe_load_flag(tp) & flag);
}
static inline void trace_probe_set_flag(struct trace_probe *tp,
unsigned int flag)
{
tp->event->flags |= flag;
smp_store_release(&tp->event->flags, tp->event->flags | flag);
}
static inline void trace_probe_clear_flag(struct trace_probe *tp,
kernel/trace/trace_uprobe.c
+8 -4
View File
@@ -1547,6 +1547,7 @@ static int uprobe_dispatcher(struct uprobe_consumer *con, struct pt_regs *regs,
struct trace_uprobe *tu;
struct uprobe_dispatch_data udd;
struct uprobe_cpu_buffer *ucb = NULL;
unsigned int flags;
int ret = 0;
tu = container_of(con, struct trace_uprobe, consumer);
@@ -1561,11 +1562,12 @@ static int uprobe_dispatcher(struct uprobe_consumer *con, struct pt_regs *regs,
if (WARN_ON_ONCE(!uprobe_cpu_buffer))
return 0;
if (trace_probe_test_flag(&tu->tp, TP_FLAG_TRACE))
flags = trace_probe_load_flag(&tu->tp);
if (flags & TP_FLAG_TRACE)
ret |= uprobe_trace_func(tu, regs, &ucb);
#ifdef CONFIG_PERF_EVENTS
if (trace_probe_test_flag(&tu->tp, TP_FLAG_PROFILE))
if (flags & TP_FLAG_PROFILE)
ret |= uprobe_perf_func(tu, regs, &ucb);
#endif
uprobe_buffer_put(ucb);
@@ -1579,6 +1581,7 @@ static int uretprobe_dispatcher(struct uprobe_consumer *con,
struct trace_uprobe *tu;
struct uprobe_dispatch_data udd;
struct uprobe_cpu_buffer *ucb = NULL;
unsigned int flags;
tu = container_of(con, struct trace_uprobe, consumer);
@@ -1590,11 +1593,12 @@ static int uretprobe_dispatcher(struct uprobe_consumer *con,
if (WARN_ON_ONCE(!uprobe_cpu_buffer))
return 0;
if (trace_probe_test_flag(&tu->tp, TP_FLAG_TRACE))
flags = trace_probe_load_flag(&tu->tp);
if (flags & TP_FLAG_TRACE)
uretprobe_trace_func(tu, func, regs, &ucb);
#ifdef CONFIG_PERF_EVENTS
if (trace_probe_test_flag(&tu->tp, TP_FLAG_PROFILE))
if (flags & TP_FLAG_PROFILE)
uretprobe_perf_func(tu, func, regs, &ucb);
#endif
uprobe_buffer_put(ucb);