From: Duoming Zhou <duoming@zju.edu.cn>
To: linux-hams@vger.kernel.org
Cc: ralf@linux-mips.org, davem@davemloft.net, edumazet@google.com,
kuba@kernel.org, pabeni@redhat.com, netdev@vger.kernel.org,
linux-kernel@vger.kernel.org, Duoming Zhou <duoming@zju.edu.cn>
Subject: [PATCH net] netrom: fix sleep in atomic context bugs in timer handlers
Date: Sat, 23 Jul 2022 11:56:46 +0800 [thread overview]
Message-ID: <20220723035646.29857-1-duoming@zju.edu.cn> (raw)
There are sleep in atomic context bugs in timer handlers of netrom
such as nr_t1timer_expiry(), nr_t2timer_expiry(), nr_heartbeat_expiry(),
nr_idletimer_expiry() and so on.
The root cause is kmemdup() with GFP_KERNEL parameter that may sleep
could be called by different timer handlers which is in interrupt context.
One of the call paths that could trigger bug is shown below:
(interrupt context)
nr_heartbeat_expiry
nr_write_internal
nr_transmit_buffer
nr_route_frame
nr_add_node
kmemdup(..,GFP_KERNEL) //may sleep
This patch changes gfp_t parameter of kmemdup in nr_add_node()
from GFP_KERNEL to GFP_ATOMIC in order to prevent sleep in atomic
context bugs.
Fixes: eafff86d3bd8 ("[NETROM]: Use kmemdup")
Signed-off-by: Duoming Zhou <duoming@zju.edu.cn>
---
net/netrom/nr_route.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/net/netrom/nr_route.c b/net/netrom/nr_route.c
index baea3cbd76c..1ddcf13de6a 100644
--- a/net/netrom/nr_route.c
+++ b/net/netrom/nr_route.c
@@ -163,7 +163,7 @@ static int __must_check nr_add_node(ax25_address *nr, const char *mnemonic,
if (ax25_digi != NULL && ax25_digi->ndigi > 0) {
nr_neigh->digipeat = kmemdup(ax25_digi,
sizeof(*ax25_digi),
- GFP_KERNEL);
+ GFP_ATOMIC);
if (nr_neigh->digipeat == NULL) {
kfree(nr_neigh);
if (nr_node)
--
2.17.1
next reply other threads:[~2022-07-23 3:56 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-07-23 3:56 Duoming Zhou [this message]
2022-07-26 2:49 ` [PATCH net] netrom: fix sleep in atomic context bugs in timer handlers Jakub Kicinski
2022-07-26 3:20 ` duoming
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