From: Zekun Shen <bruceshenzk@gmail.com>
To: unlisted-recipients:; (no To-header on input)
Cc: Zekun Shen <bruceshenzk@gmail.com>,
Jay Cliburn <jcliburn@gmail.com>,
Chris Snook <chris.snook@gmail.com>,
"David S. Miller" <davem@davemloft.net>,
Jakub Kicinski <kuba@kernel.org>,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH v2] net: alx: fix race condition in alx_remove
Date: Mon, 15 Jun 2020 11:50:29 -0400 [thread overview]
Message-ID: <20200615155029.21002-1-bruceshenzk@gmail.com> (raw)
In-Reply-To: <20200614165912.25622-1-bruceshenzk@gmail.com>
There is a race condition exist during termination. The path is
alx_stop and then alx_remove. An alx_schedule_link_check could be called
before alx_stop by interrupt handler and invoke alx_link_check later.
Alx_stop frees the napis, and alx_remove cancels any pending works.
If any of the work is scheduled before termination and invoked before
alx_remove, a null-ptr-deref occurs because both expect alx->napis[i].
This patch fix the race condition by moving cancel_work_sync functions
before alx_free_napis inside alx_stop. Because interrupt handler can call
alx_schedule_link_check again, alx_free_irq is moved before
cancel_work_sync calls too.
Signed-off-by: Zekun Shen <bruceshenzk@gmail.com>
---
Changes in v2:
- move alx_free_irq before cancel_work_sync calls
- prevent another interrupt to cause race condition
drivers/net/ethernet/atheros/alx/main.c | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)
diff --git a/drivers/net/ethernet/atheros/alx/main.c b/drivers/net/ethernet/atheros/alx/main.c
index b9b4edb91..9b7f1af5f 100644
--- a/drivers/net/ethernet/atheros/alx/main.c
+++ b/drivers/net/ethernet/atheros/alx/main.c
@@ -1249,8 +1249,12 @@ static int __alx_open(struct alx_priv *alx, bool resume)
static void __alx_stop(struct alx_priv *alx)
{
- alx_halt(alx);
alx_free_irq(alx);
+
+ cancel_work_sync(&alx->link_check_wk);
+ cancel_work_sync(&alx->reset_wk);
+
+ alx_halt(alx);
alx_free_rings(alx);
alx_free_napis(alx);
}
@@ -1855,9 +1859,6 @@ static void alx_remove(struct pci_dev *pdev)
struct alx_priv *alx = pci_get_drvdata(pdev);
struct alx_hw *hw = &alx->hw;
- cancel_work_sync(&alx->link_check_wk);
- cancel_work_sync(&alx->reset_wk);
-
/* restore permanent mac address */
alx_set_macaddr(hw, hw->perm_addr);
--
2.17.1
next prev parent reply other threads:[~2020-06-15 15:51 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-14 16:59 [PATCH] net: alx: fix race condition in alx_remove Zekun Shen
2020-06-15 15:50 ` Zekun Shen [this message]
2020-06-15 20:20 ` [PATCH v2] " David Miller
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