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fprobe: Fix module reference count leak on error in register_fprobe()

In register_fprobe(), get_ips_from_filter() resolves target function addresses and increments module reference counts via try_module_get() for symbols in kernel modules. If get_ips_from_filter() fails on the second pass and returns an error, register_fprobe() returned directly without releasing module references acquired up to that point. Fix this by ensuring the cleanup loop executing module_put() runs even when get_ips_from_filter() returns a negative error. Link: https://lore.kernel.org/all/178528125360.101985.4144133640239273153.stgit@devnote2/

Masami Hiramatsu (Google) committed 3 months ago

Commit 8cf2f401 parent aca0cd11 file · +2 −4Browse files

Unified · Split

kernel/trace/fprobe.c+2−4
@@ -961,10 +961,8 @@ int register_fprobe(struct fprobe *fp, const char *filter, const char *notfilter · 960 unmodified lines
961 return -ENOMEM;961 return -ENOMEM;
962 962
963 ret = get_ips_from_filter(filter, notfilter, addrs, mods, num);963 ret = get_ips_from_filter(filter, notfilter, addrs, mods, num);
964 if (ret < 0)964 if (ret >= 0)
965 return ret;965 ret = register_fprobe_ips(fp, addrs, ret);
966
967 ret = register_fprobe_ips(fp, addrs, ret);
968 966
969 for (int i = 0; i < num; i++) {967 for (int i = 0; i < num; i++) {
970 if (mods[i])968 if (mods[i])