From: Robert Richter rrichter@marvell.com
[ Upstream commit 29a0c843973bc385918158c6976e4dbe891df969 ]
The function should return NULL in case no device is found, but it always returns the last checked mc device from the list even if the index did not match. Fix that.
I did some analysis why this did not raise any issues for about 3 years and the reason is that edac_mc_find() is mostly used to search for existing devices. Thus, the bug is not triggered.
[ bp: Drop the if (mci->mc_idx > idx) test in favor of readability. ]
Fixes: c73e8833bec5 ("EDAC, mc: Fix locking around mc_devices list") Signed-off-by: Robert Richter rrichter@marvell.com Signed-off-by: Borislav Petkov bp@suse.de Cc: "linux-edac@vger.kernel.org" linux-edac@vger.kernel.org Cc: James Morse james.morse@arm.com Cc: Mauro Carvalho Chehab mchehab@kernel.org Link: https://lkml.kernel.org/r/20190514104838.15065-1-rrichter@marvell.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/edac/edac_mc.c | 12 ++++-------- 1 file changed, 4 insertions(+), 8 deletions(-)
diff --git a/drivers/edac/edac_mc.c b/drivers/edac/edac_mc.c index f59511bd99261..fd440b35d76ed 100644 --- a/drivers/edac/edac_mc.c +++ b/drivers/edac/edac_mc.c @@ -681,22 +681,18 @@ static int del_mc_from_global_list(struct mem_ctl_info *mci)
struct mem_ctl_info *edac_mc_find(int idx) { - struct mem_ctl_info *mci = NULL; + struct mem_ctl_info *mci; struct list_head *item;
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) { - goto unlock; - } - break; - } + if (mci->mc_idx == idx) + goto unlock; }
+ mci = NULL; unlock: mutex_unlock(&mem_ctls_mutex); return mci;