mirror of
https://github.com/freebsd/freebsd-src
synced 2024-09-22 17:54:52 +00:00
- Remove the lock(9) protecting the kernel linker system.
- Added a mutex, kld_mtx, to protect the kernel_linker system. Note that while ``classes'' is global (to that file), it is only read only after SI_SUB_KLD, SI_ORDER_ANY. - Add a SYSINIT to flip a flag that disallows class registration after SI_SUB_KLD, SI_ORDER_ANY. Idea for ``classes'' read only by: jake Reviewed by: jake
This commit is contained in:
Andrew R. Reiter
parent
3370c5bfd7
commit
2eb7b21b00
Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=98452
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@ -68,22 +68,27 @@ MALLOC_DEFINE(M_LINKER, "linker", "kernel linker");
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linker_file_t linker_kernel_file;
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static struct lock lock; /* lock for the file list */
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static struct mtx kld_mtx; /* kernel linker mutex */
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static linker_class_list_t classes;
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static linker_file_list_t linker_files;
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static int next_file_id = 1;
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static int linker_no_more_classes = 0;
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#define LINKER_GET_NEXT_FILE_ID(a) do { \
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linker_file_t lftmp; \
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\
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retry: \
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mtx_lock(&kld_mtx); \
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TAILQ_FOREACH(lftmp, &linker_files, link) { \
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if (next_file_id == lftmp->id) { \
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next_file_id++; \
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mtx_unlock(&kld_mtx); \
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goto retry; \
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} \
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} \
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(a) = next_file_id; \
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mtx_unlock(&kld_mtx); /* Hold for safe read of id variable */ \
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} while(0)
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@ -115,17 +120,32 @@ static void
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linker_init(void *arg)
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{
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lockinit(&lock, PVM, "klink", 0, 0);
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mtx_init(&kld_mtx, "kernel linker", NULL, MTX_DEF);
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TAILQ_INIT(&classes);
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TAILQ_INIT(&linker_files);
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}
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SYSINIT(linker, SI_SUB_KLD, SI_ORDER_FIRST, linker_init, 0)
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static void
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linker_stop_class_add(void *arg)
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{
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linker_no_more_classes = 1;
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}
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SYSINIT(linker_class, SI_SUB_KLD, SI_ORDER_ANY, linker_stop_class_add, NULL)
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int
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linker_add_class(linker_class_t lc)
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{
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/*
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* We disallow any class registration passt SI_ORDER_ANY
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* of SI_SUB_KLD.
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*/
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if (linker_no_more_classes == 1)
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return (EPERM);
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kobj_class_compile((kobj_class_t) lc);
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TAILQ_INSERT_TAIL(&classes, lc, link);
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return (0);
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@ -315,6 +335,12 @@ linker_load_file(const char *filename, linker_file_t *result)
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}
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lf = NULL;
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foundfile = 0;
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/*
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* We do not need to protect (lock) classes here because there is
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* no class registration past startup (SI_SUB_KLD, SI_ORDER_ANY)
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* and there is no class deregistration mechanism at this time.
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*/
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TAILQ_FOREACH(lc, &classes, link) {
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KLD_DPF(FILE, ("linker_load_file: trying to load %s\n",
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filename));
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@ -374,14 +400,14 @@ linker_find_file_by_name(const char *filename)
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goto out;
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sprintf(koname, "%s.ko", filename);
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lockmgr(&lock, LK_SHARED, 0, curthread);
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mtx_lock(&kld_mtx);
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TAILQ_FOREACH(lf, &linker_files, link) {
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if (strcmp(lf->filename, koname) == 0)
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break;
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if (strcmp(lf->filename, filename) == 0)
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break;
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}
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lockmgr(&lock, LK_RELEASE, 0, curthread);
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mtx_unlock(&kld_mtx);
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out:
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if (koname)
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free(koname, M_LINKER);
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@ -393,11 +419,11 @@ linker_find_file_by_id(int fileid)
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{
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linker_file_t lf = 0;
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lockmgr(&lock, LK_SHARED, 0, curthread);
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mtx_lock(&kld_mtx);
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TAILQ_FOREACH(lf, &linker_files, link)
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if (lf->id == fileid)
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break;
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lockmgr(&lock, LK_RELEASE, 0, curthread);
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mtx_unlock(&kld_mtx);
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return (lf);
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}
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@ -411,7 +437,6 @@ linker_make_file(const char *pathname, linker_class_t lc)
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filename = linker_basename(pathname);
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KLD_DPF(FILE, ("linker_make_file: new file, filename=%s\n", filename));
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lockmgr(&lock, LK_EXCLUSIVE, 0, curthread);
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lf = (linker_file_t)kobj_create((kobj_class_t)lc, M_LINKER, M_WAITOK);
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if (lf == NULL)
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goto out;
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@ -424,9 +449,10 @@ linker_make_file(const char *pathname, linker_class_t lc)
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lf->deps = NULL;
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STAILQ_INIT(&lf->common);
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TAILQ_INIT(&lf->modules);
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mtx_lock(&kld_mtx);
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TAILQ_INSERT_TAIL(&linker_files, lf, link);
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mtx_unlock(&kld_mtx);
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out:
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lockmgr(&lock, LK_RELEASE, 0, curthread);
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return (lf);
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}
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@ -445,7 +471,6 @@ linker_file_unload(linker_file_t file)
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return (EPERM);
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KLD_DPF(FILE, ("linker_file_unload: lf->refs=%d\n", file->refs));
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lockmgr(&lock, LK_EXCLUSIVE, 0, curthread);
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if (file->refs == 1) {
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KLD_DPF(FILE, ("linker_file_unload: file is unloading,"
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" informing modules\n"));
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@ -464,7 +489,6 @@ linker_file_unload(linker_file_t file)
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if ((error = module_unload(mod)) != 0) {
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KLD_DPF(FILE, ("linker_file_unload: module %x"
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" vetoes unload\n", mod));
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lockmgr(&lock, LK_RELEASE, 0, curthread);
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goto out;
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} else
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MOD_XLOCK;
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@ -474,7 +498,6 @@ linker_file_unload(linker_file_t file)
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}
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file->refs--;
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if (file->refs > 0) {
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lockmgr(&lock, LK_RELEASE, 0, curthread);
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goto out;
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}
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for (ml = TAILQ_FIRST(&found_modules); ml; ml = nextml) {
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@ -491,8 +514,9 @@ linker_file_unload(linker_file_t file)
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linker_file_sysuninit(file);
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linker_file_unregister_sysctls(file);
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}
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mtx_lock(&kld_mtx);
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TAILQ_REMOVE(&linker_files, file, link);
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lockmgr(&lock, LK_RELEASE, 0, curthread);
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mtx_unlock(&kld_mtx);
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if (file->deps) {
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for (i = 0; i < file->ndeps; i++)
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@ -828,10 +852,12 @@ kldnext(struct thread *td, struct kldnext_args *uap)
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mtx_lock(&Giant);
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if (SCARG(uap, fileid) == 0) {
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mtx_lock(&kld_mtx);
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if (TAILQ_FIRST(&linker_files))
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td->td_retval[0] = TAILQ_FIRST(&linker_files)->id;
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else
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td->td_retval[0] = 0;
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mtx_unlock(&kld_mtx);
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goto out;
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}
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lf = linker_find_file_by_id(SCARG(uap, fileid));
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@ -963,6 +989,7 @@ kldsym(struct thread *td, struct kldsym_args *uap)
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} else
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error = ENOENT;
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} else {
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mtx_lock(&kld_mtx);
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TAILQ_FOREACH(lf, &linker_files, link) {
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if (LINKER_LOOKUP_SYMBOL(lf, symstr, &sym) == 0 &&
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LINKER_SYMBOL_VALUES(lf, sym, &symval) == 0) {
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@ -973,6 +1000,7 @@ kldsym(struct thread *td, struct kldsym_args *uap)
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break;
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}
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}
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mtx_unlock(&kld_mtx);
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if (lf == NULL)
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error = ENOENT;
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}
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@ -1767,12 +1795,16 @@ sysctl_kern_function_list(SYSCTL_HANDLER_ARGS)
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linker_file_t lf;
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int error;
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mtx_lock(&kld_mtx);
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TAILQ_FOREACH(lf, &linker_files, link) {
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error = LINKER_EACH_FUNCTION_NAME(lf,
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sysctl_kern_function_list_iterate, req);
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if (error)
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if (error) {
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mtx_unlock(&kld_mtx);
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return (error);
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}
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}
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mtx_unlock(&kld_mtx);
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return (SYSCTL_OUT(req, "", 1));
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}
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