From c73e8833bec5a8ed4f55db0ca964cc1e998656df Mon Sep 17 00:00:00 2001 From: Borislav Petkov Date: Mon, 14 Nov 2016 13:26:11 +0100 Subject: [PATCH] EDAC, mc: Fix locking around mc_devices list When accessing the mc_devices list of memory controller descriptors, we need to hold mem_ctls_mutex. This was not always the case, fix that. Make all external callers call a version which grabs the mutex since the last is local to edac_mc.c. Reported-by: Yazen Ghannam Signed-off-by: Borislav Petkov --- drivers/edac/edac_mc.c | 49 ++++++++++++++++++++++++++---------------- 1 file changed, 31 insertions(+), 18 deletions(-) diff --git a/drivers/edac/edac_mc.c b/drivers/edac/edac_mc.c index c3ee3ad98a63..d2ea9c4f1824 100644 --- a/drivers/edac/edac_mc.c +++ b/drivers/edac/edac_mc.c @@ -482,15 +482,8 @@ void edac_mc_free(struct mem_ctl_info *mci) } EXPORT_SYMBOL_GPL(edac_mc_free); - -/** - * find_mci_by_dev - * - * scan list of controllers looking for the one that manages - * the 'dev' device - * @dev: pointer to a struct device related with the MCI - */ -struct mem_ctl_info *find_mci_by_dev(struct device *dev) +/* Caller must hold mem_ctls_mutex */ +static struct mem_ctl_info *__find_mci_by_dev(struct device *dev) { struct mem_ctl_info *mci; struct list_head *item; @@ -506,6 +499,24 @@ struct mem_ctl_info *find_mci_by_dev(struct device *dev) return NULL; } + +/** + * find_mci_by_dev + * + * scan list of controllers looking for the one that manages + * the 'dev' device + * @dev: pointer to a struct device related with the MCI + */ +struct mem_ctl_info *find_mci_by_dev(struct device *dev) +{ + struct mem_ctl_info *ret; + + mutex_lock(&mem_ctls_mutex); + ret = __find_mci_by_dev(dev); + mutex_unlock(&mem_ctls_mutex); + + return ret; +} EXPORT_SYMBOL_GPL(find_mci_by_dev); /* @@ -588,7 +599,7 @@ static int add_mc_to_global_list(struct mem_ctl_info *mci) insert_before = &mc_devices; - p = find_mci_by_dev(mci->pdev); + p = __find_mci_by_dev(mci->pdev); if (unlikely(p != NULL)) goto fail0; @@ -640,26 +651,28 @@ static int del_mc_from_global_list(struct mem_ctl_info *mci) * * If found, return a pointer to the structure. * Else return NULL. - * - * Caller must hold mem_ctls_mutex. */ struct mem_ctl_info *edac_mc_find(int idx) { + struct mem_ctl_info *mci = NULL; struct list_head *item; - struct mem_ctl_info *mci; + + mutex_lock(&mem_ctls_mutex); list_for_each(item, &mc_devices) { mci = list_entry(item, struct mem_ctl_info, link); if (mci->mc_idx >= idx) { - if (mci->mc_idx == idx) - return mci; - + if (mci->mc_idx == idx) { + goto unlock; + } break; } } - return NULL; +unlock: + mutex_unlock(&mem_ctls_mutex); + return mci; } EXPORT_SYMBOL(edac_mc_find); @@ -779,7 +792,7 @@ struct mem_ctl_info *edac_mc_del_mc(struct device *dev) mutex_lock(&mem_ctls_mutex); /* find the requested mci struct in the global list */ - mci = find_mci_by_dev(dev); + mci = __find_mci_by_dev(dev); if (mci == NULL) { mutex_unlock(&mem_ctls_mutex); return NULL;