Proxmox-Port/linux-loongson
1
0
Fork 0
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson synced 2025-08-27 06:50:37 +00:00
Code Issues Actions Packages Projects Releases Wiki Activity

tracing: tprobe-events: Fix leakage of module refcount

Browse Source 
When enabling the tracepoint at loading module, the target module
refcount is incremented by find_tracepoint_in_module(). But it is
unnecessary because the module is not unloaded while processing
module loading callbacks.
Moreover, the refcount is not decremented in that function.
To be clear the module refcount handling, move the try_module_get()
callsite to trace_fprobe_create_internal(), where it is actually
required.

Link: https://lore.kernel.org/all/174182761071.83274.18334217580449925882.stgit@devnote2/

Fixes: 57a7e6de9e ("tracing/fprobe: Support raw tracepoints on future loaded modules")
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Cc: stable@vger.kernel.org
This commit is contained in:
Masami Hiramatsu (Google) 2025-03-13 10:00:10 +09:00
parent 0a8bb688aa
commit ac91052f0a
1 changed files with 8 additions and 13 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

21
kernel/trace/trace_fprobe.c
View File

@ -920,13 +920,8 @@ static void __find_tracepoint_module_cb(struct tracepoint *tp, struct module *mo
if (!data->tpoint && !strcmp(data->tp_name, tp->name)) {
data->tpoint = tp;
if (!data->mod) {
if (!data->mod)
data->mod = mod;
if (!try_module_get(data->mod)) {
data->tpoint = NULL;
data->mod = NULL;
}
}
}
}
@ -938,13 +933,7 @@ static void __find_tracepoint_cb(struct tracepoint *tp, void *priv)
data->tpoint = tp;
}
/*
* Find a tracepoint from kernel and module. If the tracepoint is in a module,
* this increments the module refcount to prevent unloading until the
* trace_fprobe is registered to the list. After registering the trace_fprobe
* on the trace_fprobe list, the module refcount is decremented because
* tracepoint_probe_module_cb will handle it.
*/
/* Find a tracepoint from kernel and module. */
static struct tracepoint *find_tracepoint(const char *tp_name,
struct module **tp_mod)
{
@ -973,6 +962,7 @@ static void reenable_trace_fprobe(struct trace_fprobe *tf)
}
}
/* Find a tracepoint from specified module. */
static struct tracepoint *find_tracepoint_in_module(struct module *mod,
const char *tp_name)
{
@ -1179,6 +1169,11 @@ static int trace_fprobe_create_internal(int argc, const char *argv[],
if (is_tracepoint) {
ctx->flags |= TPARG_FL_TPOINT;
tpoint = find_tracepoint(symbol, &tp_mod);
/* lock module until register this tprobe. */
if (tp_mod && !try_module_get(tp_mod)) {
tpoint = NULL;
tp_mod = NULL;
}
if (tpoint) {
ctx->funcname = kallsyms_lookup(
(unsigned long)tpoint->probestub,