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authorKonstantin Khorenko <khorenko@virtuozzo.com>2019-11-13 12:29:50 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2019-12-17 20:40:02 +0100
commit4faf1cc3dbbd85e49787f4ff3ffa21257c2256bb (patch)
treebdc1e262d9f11159676dea71f23e7d3bdacc6d7d /kernel
parentcb9e778a29b803402ef7451451063d11f583c598 (diff)
kernel/module.c: wakeup processes in module_wq on module unload
[ Upstream commit 5d603311615f612320bb77bd2a82553ef1ced5b7 ] Fix the race between load and unload a kernel module. sys_delete_module() try_stop_module() mod->state = _GOING add_unformed_module() old = find_module_all() (old->state == _GOING => wait_event_interruptible()) During pre-condition finished_loading() rets 0 schedule() (never gets waken up later) free_module() mod->state = _UNFORMED list_del_rcu(&mod->list) (dels mod from "modules" list) return The race above leads to modprobe hanging forever on loading a module. Error paths on loading module call wake_up_all(&module_wq) after freeing module, so let's do the same on straight module unload. Fixes: 6e6de3dee51a ("kernel/module.c: Only return -EEXIST for modules that have finished loading") Reviewed-by: Prarit Bhargava <prarit@redhat.com> Signed-off-by: Konstantin Khorenko <khorenko@virtuozzo.com> Signed-off-by: Jessica Yu <jeyu@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/module.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/kernel/module.c b/kernel/module.c
index 468567591241..feb1e0fbc3e8 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -1020,6 +1020,8 @@ SYSCALL_DEFINE2(delete_module, const char __user *, name_user,
strlcpy(last_unloaded_module, mod->name, sizeof(last_unloaded_module));
free_module(mod);
+ /* someone could wait for the module in add_unformed_module() */
+ wake_up_all(&module_wq);
return 0;
out:
mutex_unlock(&module_mutex);