From c16fd4130dc692a901b2f91d0aeac8931b4111f2 Mon Sep 17 00:00:00 2001 From: Xiang Zheng Date: Tue, 5 Nov 2019 21:49:56 +0800 Subject: [PATCH] pci: lock the pci_cfg_wait queue for the consistency of data hulk inclusion category: bugfix bugzilla: 24273 CVE: NA ----------------------- Commit "7ea7e98fd8d0" suggests that the "pci_lock" is sufficient, and all the callers of pci_wait_cfg() are wrapped with the "pci_lock". However, since the commit "cdcb33f98244" merged, the accesses to the pci_cfg_wait queue are not safe anymore. A "pci_lock" is insufficient and we need to hold an additional queue lock while read/write the wait queue. So let's use the add_wait_queue()/remove_wait_queue() instead of __add_wait_queue()/__remove_wait_queue(). Also move the wait queue functionality around the "schecdule()" function to avoid reintroduce the deadlock addressed by "cdcb33f98244". Signed-off-by: Xiang Zheng Cc: Heyi Guo Cc: Biaoxiang Ye Reviewed-by: Hanjun Guo Signed-off-by: Yang Yingliang --- drivers/pci/access.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/pci/access.c b/drivers/pci/access.c index a3ad2fe185b9..c5204892289b 100644 --- a/drivers/pci/access.c +++ b/drivers/pci/access.c @@ -207,14 +207,14 @@ static noinline void pci_wait_cfg(struct pci_dev *dev) { DECLARE_WAITQUEUE(wait, current); - __add_wait_queue(&pci_cfg_wait, &wait); do { set_current_state(TASK_UNINTERRUPTIBLE); raw_spin_unlock_irq(&pci_lock); + add_wait_queue(&pci_cfg_wait, &wait); schedule(); + remove_wait_queue(&pci_cfg_wait, &wait); raw_spin_lock_irq(&pci_lock); } while (dev->block_cfg_access); - __remove_wait_queue(&pci_cfg_wait, &wait); } /* Returns 0 on success, negative values indicate error. */ -- GitLab