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Thu, 18 Sep 2025 13:11:47 -0700 (PDT) From: julian-lagattuta To: Luis Chamberlain , Petr Pavlu Cc: Sami Tolvanen , Daniel Gomez , linux-modules@vger.kernel.org, linux-kernel@vger.kernel.org, julian-lagattuta Subject: [PATCH 2/6] module: detect if init crashed and unload Date: Thu, 18 Sep 2025 16:11:08 -0400 Message-ID: <20250918201109.24620-6-julian.lagattuta@gmail.com> X-Mailer: git-send-email 2.45.2 In-Reply-To: <20250918201109.24620-2-julian.lagattuta@gmail.com> References: <20250918201109.24620-2-julian.lagattuta@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Store idempotent and init_pid in struct module. Signed-off-by: julian-lagattuta --- kernel/module/main.c | 36 ++++++++++++++++++++++++++++++++++-- 1 file changed, 34 insertions(+), 2 deletions(-) diff --git a/kernel/module/main.c b/kernel/module/main.c index 413ac6ea3702..2277c53aef2e 100644 --- a/kernel/module/main.c +++ b/kernel/module/main.c @@ -752,6 +752,7 @@ SYSCALL_DEFINE2(delete_module, const char __user *, nam= e_user, char name[MODULE_NAME_LEN]; char buf[MODULE_FLAGS_BUF_SIZE]; int ret, forced =3D 0; + bool did_init_crash __maybe_unused =3D false; =20 if (!capable(CAP_SYS_MODULE) || modules_disabled) return -EPERM; @@ -778,8 +779,11 @@ SYSCALL_DEFINE2(delete_module, const char __user *, na= me_user, } =20 /* Doing init or already dying? */ - if (mod->state !=3D MODULE_STATE_LIVE) { - /* FIXME: if (force), slam module count damn the torpedoes */ + if (mod->state =3D=3D MODULE_STATE_GOING || + (mod->state !=3D MODULE_STATE_LIVE && + !IS_ENABLED(CONFIG_MODULE_FORCE_UNLOAD)) + ) { + if (mod->state =3D=3D MODULE_STATE_GOING) pr_debug("%s already dying\n", mod->name); ret =3D -EBUSY; goto out; @@ -795,6 +799,21 @@ SYSCALL_DEFINE2(delete_module, const char __user *, na= me_user, } } =20 +#ifdef CONFIG_MODULE_FORCE_UNLOAD + if (mod->state =3D=3D MODULE_STATE_COMING) { + struct task_struct *init_process =3D get_pid_task(mod->init_pid, PIDTYPE= _PID); + + /* Did the init process die? */ + if (init_process) { + put_task_struct(init_process); + ret =3D -EBUSY; + goto out; + } else { + did_init_crash =3D true; + } + } +#endif + ret =3D try_stop_module(mod, flags, &forced); if (ret !=3D 0) goto out; @@ -1380,6 +1399,10 @@ static void free_module(struct module *mod) mod->state =3D MODULE_STATE_UNFORMED; mutex_unlock(&module_mutex); =20 +#ifdef CONFIG_MODULE_FORCE_UNLOAD + if (mod->init_pid) + put_pid(mod->init_pid); +#endif /* Arch-specific cleanup. */ module_arch_cleanup(mod); =20 @@ -3044,6 +3067,11 @@ static noinline int do_init_module(struct module *mo= d) ftrace_free_mem(mod, mod->mem[MOD_INIT_TEXT].base, mod->mem[MOD_INIT_TEXT].base + mod->mem[MOD_INIT_TEXT].size); mutex_lock(&module_mutex); +#ifdef CONFIG_MODULE_FORCE_UNLOAD + put_pid(mod->init_pid); + mod->init_pid =3D NULL; + mod->idempotent =3D NULL; +#endif /* Drop initial reference. */ module_put(mod); trim_init_extable(mod); @@ -3474,6 +3502,10 @@ static int load_module(struct load_info *info, const= char __user *uargs, if (codetag_load_module(mod)) goto sysfs_cleanup; =20 +#ifdef CONFIG_MODULE_FORCE_UNLOAD + mod->init_pid =3D get_pid(task_pid(current)); + mod->idempotent =3D info->idempotent; +#endif /* Get rid of temporary copy. */ free_copy(info, flags); =20 --=20 2.45.2