* [PATCH] net-sysfs: add check for netdevice being present to speed_show
@ 2022-02-17 1:55 Suresh Kumar
2022-02-18 11:10 ` patchwork-bot+netdevbpf
0 siblings, 1 reply; 2+ messages in thread
From: Suresh Kumar @ 2022-02-17 1:55 UTC (permalink / raw)
To: davem, kuba, netdev, linux-kernel; +Cc: suresh kumar
From: suresh kumar <suresh2514@gmail.com>
When bringing down the netdevice or system shutdown, a panic can be
triggered while accessing the sysfs path because the device is already
removed.
[ 755.549084] mlx5_core 0000:12:00.1: Shutdown was called
[ 756.404455] mlx5_core 0000:12:00.0: Shutdown was called
...
[ 757.937260] BUG: unable to handle kernel NULL pointer dereference at (null)
[ 758.031397] IP: [<ffffffff8ee11acb>] dma_pool_alloc+0x1ab/0x280
crash> bt
...
PID: 12649 TASK: ffff8924108f2100 CPU: 1 COMMAND: "amsd"
...
#9 [ffff89240e1a38b0] page_fault at ffffffff8f38c778
[exception RIP: dma_pool_alloc+0x1ab]
RIP: ffffffff8ee11acb RSP: ffff89240e1a3968 RFLAGS: 00010046
RAX: 0000000000000246 RBX: ffff89243d874100 RCX: 0000000000001000
RDX: 0000000000000000 RSI: 0000000000000246 RDI: ffff89243d874090
RBP: ffff89240e1a39c0 R8: 000000000001f080 R9: ffff8905ffc03c00
R10: ffffffffc04680d4 R11: ffffffff8edde9fd R12: 00000000000080d0
R13: ffff89243d874090 R14: ffff89243d874080 R15: 0000000000000000
ORIG_RAX: ffffffffffffffff CS: 0010 SS: 0018
#10 [ffff89240e1a39c8] mlx5_alloc_cmd_msg at ffffffffc04680f3 [mlx5_core]
#11 [ffff89240e1a3a18] cmd_exec at ffffffffc046ad62 [mlx5_core]
#12 [ffff89240e1a3ab8] mlx5_cmd_exec at ffffffffc046b4fb [mlx5_core]
#13 [ffff89240e1a3ae8] mlx5_core_access_reg at ffffffffc0475434 [mlx5_core]
#14 [ffff89240e1a3b40] mlx5e_get_fec_caps at ffffffffc04a7348 [mlx5_core]
#15 [ffff89240e1a3bb0] get_fec_supported_advertised at ffffffffc04992bf [mlx5_core]
#16 [ffff89240e1a3c08] mlx5e_get_link_ksettings at ffffffffc049ab36 [mlx5_core]
#17 [ffff89240e1a3ce8] __ethtool_get_link_ksettings at ffffffff8f25db46
#18 [ffff89240e1a3d48] speed_show at ffffffff8f277208
#19 [ffff89240e1a3dd8] dev_attr_show at ffffffff8f0b70e3
#20 [ffff89240e1a3df8] sysfs_kf_seq_show at ffffffff8eedbedf
#21 [ffff89240e1a3e18] kernfs_seq_show at ffffffff8eeda596
#22 [ffff89240e1a3e28] seq_read at ffffffff8ee76d10
#23 [ffff89240e1a3e98] kernfs_fop_read at ffffffff8eedaef5
#24 [ffff89240e1a3ed8] vfs_read at ffffffff8ee4e3ff
#25 [ffff89240e1a3f08] sys_read at ffffffff8ee4f27f
#26 [ffff89240e1a3f50] system_call_fastpath at ffffffff8f395f92
crash> net_device.state ffff89443b0c0000
state = 0x5 (__LINK_STATE_START| __LINK_STATE_NOCARRIER)
To prevent this scenario, we also make sure that the netdevice is present.
Signed-off-by: suresh kumar <suresh2514@gmail.com>
---
net/core/net-sysfs.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c
index 53ea262ecafd..fbddf966206b 100644
--- a/net/core/net-sysfs.c
+++ b/net/core/net-sysfs.c
@@ -213,7 +213,7 @@ static ssize_t speed_show(struct device *dev,
if (!rtnl_trylock())
return restart_syscall();
- if (netif_running(netdev)) {
+ if (netif_running(netdev) && netif_device_present(netdev)) {
struct ethtool_link_ksettings cmd;
if (!__ethtool_get_link_ksettings(netdev, &cmd))
--
2.27.0
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] net-sysfs: add check for netdevice being present to speed_show
2022-02-17 1:55 [PATCH] net-sysfs: add check for netdevice being present to speed_show Suresh Kumar
@ 2022-02-18 11:10 ` patchwork-bot+netdevbpf
0 siblings, 0 replies; 2+ messages in thread
From: patchwork-bot+netdevbpf @ 2022-02-18 11:10 UTC (permalink / raw)
To: Suresh Kumar; +Cc: davem, kuba, netdev, linux-kernel, suresh2514
Hello:
This patch was applied to netdev/net.git (master)
by David S. Miller <davem@davemloft.net>:
On Thu, 17 Feb 2022 07:25:18 +0530 you wrote:
> From: suresh kumar <suresh2514@gmail.com>
>
> When bringing down the netdevice or system shutdown, a panic can be
> triggered while accessing the sysfs path because the device is already
> removed.
>
> [ 755.549084] mlx5_core 0000:12:00.1: Shutdown was called
> [ 756.404455] mlx5_core 0000:12:00.0: Shutdown was called
> ...
> [ 757.937260] BUG: unable to handle kernel NULL pointer dereference at (null)
> [ 758.031397] IP: [<ffffffff8ee11acb>] dma_pool_alloc+0x1ab/0x280
>
> [...]
Here is the summary with links:
- net-sysfs: add check for netdevice being present to speed_show
https://git.kernel.org/netdev/net/c/4224cfd7fb65
You are awesome, thank you!
--
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html
^ permalink raw reply [flat|nested] 2+ messages in thread
end of thread, other threads:[~2022-02-18 11:10 UTC | newest]
Thread overview: 2+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2022-02-17 1:55 [PATCH] net-sysfs: add check for netdevice being present to speed_show Suresh Kumar
2022-02-18 11:10 ` patchwork-bot+netdevbpf
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).