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    Subject[PATCH 5.15 107/201] ixgbe: Add locking to prevent panic when setting sriov_numvfs to zero
    Date
    From: Piotr Skajewski <piotrx.skajewski@intel.com>

    [ Upstream commit 1e53834ce541d4fe271cdcca7703e50be0a44f8a ]

    It is possible to disable VFs while the PF driver is processing requests
    from the VF driver. This can result in a panic.

    BUG: unable to handle kernel paging request at 000000000000106c
    PGD 0 P4D 0
    Oops: 0000 [#1] SMP NOPTI
    CPU: 8 PID: 0 Comm: swapper/8 Kdump: loaded Tainted: G I --------- -
    Hardware name: Dell Inc. PowerEdge R740/06WXJT, BIOS 2.8.2 08/27/2020
    RIP: 0010:ixgbe_msg_task+0x4c8/0x1690 [ixgbe]
    Code: 00 00 48 8d 04 40 48 c1 e0 05 89 7c 24 24 89 fd 48 89 44 24 10 83 ff
    01 0f 84 b8 04 00 00 4c 8b 64 24 10 4d 03 a5 48 22 00 00 <41> 80 7c 24 4c
    00 0f 84 8a 03 00 00 0f b7 c7 83 f8 08 0f 84 8f 0a
    RSP: 0018:ffffb337869f8df8 EFLAGS: 00010002
    RAX: 0000000000001020 RBX: 0000000000000000 RCX: 000000000000002b
    RDX: 0000000000000002 RSI: 0000000000000008 RDI: 0000000000000006
    RBP: 0000000000000006 R08: 0000000000000002 R09: 0000000000029780
    R10: 00006957d8f42832 R11: 0000000000000000 R12: 0000000000001020
    R13: ffff8a00e8978ac0 R14: 000000000000002b R15: ffff8a00e8979c80
    FS: 0000000000000000(0000) GS:ffff8a07dfd00000(0000) knlGS:00000000000000
    CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
    CR2: 000000000000106c CR3: 0000000063e10004 CR4: 00000000007726e0
    DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
    DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
    PKRU: 55555554
    Call Trace:
    <IRQ>
    ? ttwu_do_wakeup+0x19/0x140
    ? try_to_wake_up+0x1cd/0x550
    ? ixgbevf_update_xcast_mode+0x71/0xc0 [ixgbevf]
    ixgbe_msix_other+0x17e/0x310 [ixgbe]
    __handle_irq_event_percpu+0x40/0x180
    handle_irq_event_percpu+0x30/0x80
    handle_irq_event+0x36/0x53
    handle_edge_irq+0x82/0x190
    handle_irq+0x1c/0x30
    do_IRQ+0x49/0xd0
    common_interrupt+0xf/0xf

    This can be eventually be reproduced with the following script:

    while :
    do
    echo 63 > /sys/class/net/<devname>/device/sriov_numvfs
    sleep 1
    echo 0 > /sys/class/net/<devname>/device/sriov_numvfs
    sleep 1
    done

    Add lock when disabling SR-IOV to prevent process VF mailbox communication.

    Fixes: d773d1310625 ("ixgbe: Fix memory leak when SR-IOV VFs are direct assigned")
    Signed-off-by: Piotr Skajewski <piotrx.skajewski@intel.com>
    Tested-by: Marek Szlosek <marek.szlosek@intel.com>
    Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>
    Link: https://lore.kernel.org/r/20220715214456.2968711-1-anthony.l.nguyen@intel.com
    Signed-off-by: Jakub Kicinski <kuba@kernel.org>
    Signed-off-by: Sasha Levin <sashal@kernel.org>
    ---
    drivers/net/ethernet/intel/ixgbe/ixgbe.h | 1 +
    drivers/net/ethernet/intel/ixgbe/ixgbe_main.c | 3 +++
    drivers/net/ethernet/intel/ixgbe/ixgbe_sriov.c | 6 ++++++
    3 files changed, 10 insertions(+)

    diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe.h b/drivers/net/ethernet/intel/ixgbe/ixgbe.h
    index a604552fa634..c375a5d54b40 100644
    --- a/drivers/net/ethernet/intel/ixgbe/ixgbe.h
    +++ b/drivers/net/ethernet/intel/ixgbe/ixgbe.h
    @@ -770,6 +770,7 @@ struct ixgbe_adapter {
    #ifdef CONFIG_IXGBE_IPSEC
    struct ixgbe_ipsec *ipsec;
    #endif /* CONFIG_IXGBE_IPSEC */
    + spinlock_t vfs_lock;
    };

    static inline u8 ixgbe_max_rss_indices(struct ixgbe_adapter *adapter)
    diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
    index 750b02bb2fdc..8cb20af51ecd 100644
    --- a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
    +++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
    @@ -6397,6 +6397,9 @@ static int ixgbe_sw_init(struct ixgbe_adapter *adapter,
    /* n-tuple support exists, always init our spinlock */
    spin_lock_init(&adapter->fdir_perfect_lock);

    + /* init spinlock to avoid concurrency of VF resources */
    + spin_lock_init(&adapter->vfs_lock);
    +
    #ifdef CONFIG_IXGBE_DCB
    ixgbe_init_dcb(adapter);
    #endif
    diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_sriov.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_sriov.c
    index aaebdae8b5ff..0078ae592616 100644
    --- a/drivers/net/ethernet/intel/ixgbe/ixgbe_sriov.c
    +++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_sriov.c
    @@ -204,10 +204,13 @@ void ixgbe_enable_sriov(struct ixgbe_adapter *adapter, unsigned int max_vfs)
    int ixgbe_disable_sriov(struct ixgbe_adapter *adapter)
    {
    unsigned int num_vfs = adapter->num_vfs, vf;
    + unsigned long flags;
    int rss;

    + spin_lock_irqsave(&adapter->vfs_lock, flags);
    /* set num VFs to 0 to prevent access to vfinfo */
    adapter->num_vfs = 0;
    + spin_unlock_irqrestore(&adapter->vfs_lock, flags);

    /* put the reference to all of the vf devices */
    for (vf = 0; vf < num_vfs; ++vf) {
    @@ -1305,8 +1308,10 @@ static void ixgbe_rcv_ack_from_vf(struct ixgbe_adapter *adapter, u32 vf)
    void ixgbe_msg_task(struct ixgbe_adapter *adapter)
    {
    struct ixgbe_hw *hw = &adapter->hw;
    + unsigned long flags;
    u32 vf;

    + spin_lock_irqsave(&adapter->vfs_lock, flags);
    for (vf = 0; vf < adapter->num_vfs; vf++) {
    /* process any reset requests */
    if (!ixgbe_check_for_rst(hw, vf))
    @@ -1320,6 +1325,7 @@ void ixgbe_msg_task(struct ixgbe_adapter *adapter)
    if (!ixgbe_check_for_ack(hw, vf))
    ixgbe_rcv_ack_from_vf(adapter, vf);
    }
    + spin_unlock_irqrestore(&adapter->vfs_lock, flags);
    }

    void ixgbe_disable_tx_rx(struct ixgbe_adapter *adapter)
    --
    2.35.1


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