From accf74fff36315a31dc7319dae2927af06e9296f Mon Sep 17 00:00:00 2001 From: Mauro Carvalho Chehab Date: Mon, 16 Aug 2010 18:34:37 -0300 Subject: [PATCH] i7core_edac: don't use a freed mci struct This is a nasty bug. Since kobject count will be reduced by zero by edac_mc_del_mc(), and this triggers the kobj release method, the mci memory will be freed automatically. So, all we have left is ctl_name, as shown by enabling debug: [ 80.822186] EDAC DEBUG: in drivers/edac/edac_mc_sysfs.c, line at 1020: edac_remove_sysfs_mci_device() remove_link [ 80.832590] EDAC DEBUG: in drivers/edac/edac_mc_sysfs.c, line at 1024: edac_remove_sysfs_mci_device() remove_mci_instance [ 80.843776] EDAC DEBUG: in drivers/edac/edac_mc_sysfs.c, line at 640: edac_mci_control_release() mci instance idx=0 releasing [ 80.855163] EDAC MC: Removed device 0 for i7core_edac.c i7 core #0: DEV 0000:3f:03.0 [ 80.862936] EDAC DEBUG: in drivers/edac/i7core_edac.c, line at 2089: (null): free structs [ 80.871134] EDAC DEBUG: in drivers/edac/edac_mc.c, line at 238: edac_mc_free() [ 80.878379] EDAC DEBUG: in drivers/edac/edac_mc_sysfs.c, line at 726: edac_mc_unregister_sysfs_main_kobj() [ 80.888043] EDAC DEBUG: in drivers/edac/i7core_edac.c, line at 1232: drivers/edac/i7core_edac.c: i7core_put_devices() Also, kfree(mci) shouldn't happen at the kobj.release, as it happens when edac_remove_sysfs_mci_device() is called, but the logic is: edac_remove_sysfs_mci_device(mci); edac_printk(KERN_INFO, EDAC_MC, "Removed device %d for %s %s: DEV %s\n", mci->mc_idx, mci->mod_name, mci->ctl_name, edac_dev_name(mci)); So, as the edac_printk() needs the mci struct, this generates an OOPS. Signed-off-by: Mauro Carvalho Chehab --- drivers/edac/edac_mc.c | 3 +++ drivers/edac/edac_mc_sysfs.c | 3 --- drivers/edac/i7core_edac.c | 3 +-- 3 files changed, 4 insertions(+), 5 deletions(-) diff --git a/drivers/edac/edac_mc.c b/drivers/edac/edac_mc.c index 889ce7566b56..ba6586a69ccc 100644 --- a/drivers/edac/edac_mc.c +++ b/drivers/edac/edac_mc.c @@ -238,6 +238,9 @@ void edac_mc_free(struct mem_ctl_info *mci) debugf1("%s()\n", __func__); edac_mc_unregister_sysfs_main_kobj(mci); + + /* free the mci instance memory here */ + kfree(mci); } EXPORT_SYMBOL_GPL(edac_mc_free); diff --git a/drivers/edac/edac_mc_sysfs.c b/drivers/edac/edac_mc_sysfs.c index ddd765253630..2905dc103393 100644 --- a/drivers/edac/edac_mc_sysfs.c +++ b/drivers/edac/edac_mc_sysfs.c @@ -630,9 +630,6 @@ static void edac_mci_control_release(struct kobject *kobj) /* decrement the module ref count */ module_put(mci->owner); - - /* free the mci instance memory here */ - kfree(mci); } static struct kobj_type ktype_mci = { diff --git a/drivers/edac/i7core_edac.c b/drivers/edac/i7core_edac.c index b0559973c66f..8e789a2e35d6 100644 --- a/drivers/edac/i7core_edac.c +++ b/drivers/edac/i7core_edac.c @@ -2085,8 +2085,7 @@ static void __devexit i7core_remove(struct pci_dev *pdev) /* Remove MC sysfs nodes */ edac_mc_del_mc(&i7core_dev->pdev[0]->dev); - /* Free data */ - debugf1("%s: free structs\n"); + debugf1("%s: free mci struct\n", mci->ctl_name); kfree(mci->ctl_name); edac_mc_free(mci);