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From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	stable@vger.kernel.org, suresh kumar <suresh2514@gmail.com>,
	"David S. Miller" <davem@davemloft.net>,
	Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.9 10/20] net-sysfs: add check for netdevice being present to speed_show
Date: Mon, 14 Mar 2022 12:34:11 +0100	[thread overview]
Message-ID: <20220314112730.805998272@linuxfoundation.org> (raw)
In-Reply-To: <20220314112730.388955049@linuxfoundation.org>

From: suresh kumar <suresh2514@gmail.com>

[ Upstream commit 4224cfd7fb6523f7a9d1c8bb91bb5df1e38eb624 ]

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>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 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 3fb5d8ecc849..e42df58b8876 100644
--- a/net/core/net-sysfs.c
+++ b/net/core/net-sysfs.c
@@ -198,7 +198,7 @@ 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))
-- 
2.34.1




  parent reply	other threads:[~2022-03-14 11:34 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-03-14 11:34 [PATCH 4.9 00/20] 4.9.307-rc1 review Greg Kroah-Hartman
2022-03-14 11:34 ` [PATCH 4.9 01/20] net: qlogic: check the return value of dma_alloc_coherent() in qed_vf_hw_prepare() Greg Kroah-Hartman
2022-03-14 11:34 ` [PATCH 4.9 02/20] qed: return status of qed_iov_get_link Greg Kroah-Hartman
2022-03-14 11:34 ` [PATCH 4.9 03/20] ethernet: Fix error handling in xemaclite_of_probe Greg Kroah-Hartman
2022-03-14 11:34 ` [PATCH 4.9 04/20] net: ethernet: lpc_eth: Handle error for clk_enable Greg Kroah-Hartman
2022-03-14 11:34 ` [PATCH 4.9 05/20] ax25: Fix NULL pointer dereference in ax25_kill_by_device Greg Kroah-Hartman
2022-03-14 11:34 ` [PATCH 4.9 06/20] net/mlx5: Fix size field in bufferx_reg struct Greg Kroah-Hartman
2022-03-14 11:34 ` [PATCH 4.9 07/20] NFC: port100: fix use-after-free in port100_send_complete Greg Kroah-Hartman
2022-03-14 11:34 ` [PATCH 4.9 08/20] gpio: ts4900: Do not set DAT and OE together Greg Kroah-Hartman
2022-03-14 11:34 ` [PATCH 4.9 09/20] sctp: fix kernel-infoleak for SCTP sockets Greg Kroah-Hartman
2022-03-14 11:34 ` Greg Kroah-Hartman [this message]
2022-03-14 11:34 ` [PATCH 4.9 11/20] Revert "xen-netback: Check for hotplug-status existence before watching" Greg Kroah-Hartman
2022-03-14 11:34 ` [PATCH 4.9 12/20] tracing: Ensure trace buffer is at least 4096 bytes large Greg Kroah-Hartman
2022-03-14 11:34 ` [PATCH 4.9 13/20] selftests/memfd: clean up mapping in mfd_fail_write Greg Kroah-Hartman
2022-03-14 11:34 ` [PATCH 4.9 14/20] ARM: Spectre-BHB: provide empty stub for non-config Greg Kroah-Hartman
2022-03-14 11:34 ` [PATCH 4.9 15/20] staging: gdm724x: fix use after free in gdm_lte_rx() Greg Kroah-Hartman
2022-03-14 11:34 ` [PATCH 4.9 16/20] KVM: arm64: Reset PMC_EL0 to avoid a panic() on systems with no PMU Greg Kroah-Hartman
2022-03-14 11:34 ` [PATCH 4.9 17/20] batman-adv: Request iflink once in batadv-on-batadv check Greg Kroah-Hartman
2022-03-14 11:34 ` [PATCH 4.9 18/20] batman-adv: Dont expect inter-netns unique iflink indices Greg Kroah-Hartman
2022-03-14 11:34 ` [PATCH 4.9 19/20] ARM: fix Thumb2 regression with Spectre BHB Greg Kroah-Hartman
2022-03-14 11:34 ` [PATCH 4.9 20/20] btrfs: unlock newly allocated extent buffer after error Greg Kroah-Hartman

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