Messages in this thread | | | Date | Fri, 7 Mar 2003 09:12:31 -0800 | From | Bob Miller <> | Subject | Re: Patch/resubmit linux-2.5.63-bk4 try_module_get simplification |
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The patch below was included by Linus around 2/14/03.
On Fri, Mar 07, 2003 at 05:34:18PM +1100, Rusty Russell wrote: > Three other requests, if I may. > > It'd be nice to have a comment for the two smp_mb() eg. /* Must increment > before checking state */ and vice-versa above the one in module.c. Secondly > probably nicer to just rename the modlist_lock to module_lock and use that, > and thirdly merge with the racefix patch below if Linus hasn't already > taken it. > > > Name: Fix two module races > Author: Bob Miller, Rusty Russell > Status: Trivial > > D: Bob Miller points out that the try_module_get in use_module() can, > D: of course, fail. Secondly, there is a race between setting the module > D: live, and a simultaneous removal of it. > > diff -urpN --exclude TAGS -X /home/rusty/devel/kernel/kernel-patches/current-dontdiff --minimal linux-2.5.62-bk6/kernel/module.c working-2.5.62-bk6-modraces/kernel/module.c > --- linux-2.5.62-bk6/kernel/module.c 2003-02-18 11:18:57.000000000 +1100 > +++ working-2.5.62-bk6-modraces/kernel/module.c 2003-02-24 13:42:44.000000000 +1100 > @@ -173,16 +173,19 @@ static int use_module(struct module *a, > struct module_use *use; > if (b == NULL || already_uses(a, b)) return 1; > > + if (!strong_try_module_get(b)) > + return 0; > + > DEBUGP("Allocating new usage for %s.\n", a->name); > use = kmalloc(sizeof(*use), GFP_ATOMIC); > if (!use) { > printk("%s: out of memory loading\n", a->name); > + module_put(b); > return 0; > } > > use->module_which_uses = a; > list_add(&use->list, &b->modules_which_use_me); > - try_module_get(b); /* Can't fail */ > return 1; > } > > @@ -1456,10 +1459,12 @@ sys_init_module(void *umod, > } > > /* Now it's a first class citizen! */ > + down(&module_mutex); > mod->state = MODULE_STATE_LIVE; > module_free(mod, mod->module_init); > mod->module_init = NULL; > mod->init_size = 0; > + up(&module_mutex); > > return 0; > } >
-- Bob Miller Email: rem@osdl.org Open Source Development Lab Phone: 503.626.2455 Ext. 17 - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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