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authorAlexey Dobriyan <adobriyan@gmail.com>2008-03-10 11:43:53 -0700
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2008-03-10 18:01:20 -0700
commite24e2e64c468c8060bb7173abecdf11d00ed5751 (patch)
treeb03faa2fd187a207d0a2e78af75a787a66ab21fe
parent6c5db22d280302c33dafb309c25bf2841fb99c37 (diff)
modules: warn about suspicious return values from module's ->init() hook
Return value convention of module's init functions is 0/-E. Sometimes, e.g. during forward-porting mistakes happen and buggy module created, where result of comparison "workqueue != NULL" is propagated all the way up to sys_init_module. What happens is that some other module created workqueue in question, our module created it again and module was successfully loaded. Or it could be some other bug. Let's make such mistakes much more visible. In retrospective, such messages would noticeably shorten some of my head-scratching sessions. Note, that dump_stack() is just a way to get attention from user. Sample message: sys_init_module: 'foo'->init suspiciously returned 1, it should follow 0/-E convention sys_init_module: loading module anyway... Pid: 4223, comm: modprobe Not tainted 2.6.24-25f666300625d894ebe04bac2b4b3aadb907c861 #5 Call Trace: [<ffffffff80254b05>] sys_init_module+0xe5/0x1d0 [<ffffffff8020b39b>] system_call_after_swapgs+0x7b/0x80 Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--kernel/module.c8
1 files changed, 8 insertions, 0 deletions
diff --git a/kernel/module.c b/kernel/module.c
index 68d05d2f4d8a..5d437bffd8dc 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -2178,6 +2178,14 @@ sys_init_module(void __user *umod,
wake_up(&module_wq);
return ret;
}
+ if (ret > 0) {
+ printk(KERN_WARNING "%s: '%s'->init suspiciously returned %d, "
+ "it should follow 0/-E convention\n"
+ KERN_WARNING "%s: loading module anyway...\n",
+ __func__, mod->name, ret,
+ __func__);
+ dump_stack();
+ }
/* Now it's a first class citizen! Wake up anyone waiting for it. */
mod->state = MODULE_STATE_LIVE;

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