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authorÍñigo Huguet2022-07-13 11:21:16 +0200
committerPaolo Abeni2022-07-14 12:46:56 +0200
commitada74c5539eba06cf8b47d068f92e0b3963a9a6e (patch)
treee703f51c128ceba2a041987ea40ef725ff09580a
parentcc91b09b9ef8f8a9f29b4fdff5f65ab5700872e2 (diff)
sfc: fix kernel panic when creating VF
When creating VFs a kernel panic can happen when calling to efx_ef10_try_update_nic_stats_vf. When releasing a DMA coherent buffer, sometimes, I don't know in what specific circumstances, it has to unmap memory with vunmap. It is disallowed to do that in IRQ context or with BH disabled. Otherwise, we hit this line in vunmap, causing the crash: BUG_ON(in_interrupt()); This patch reenables BH to release the buffer. Log messages when the bug is hit: kernel BUG at mm/vmalloc.c:2727! invalid opcode: 0000 [#1] PREEMPT SMP NOPTI CPU: 6 PID: 1462 Comm: NetworkManager Kdump: loaded Tainted: G I --------- --- 5.14.0-119.el9.x86_64 #1 Hardware name: Dell Inc. PowerEdge R740/06WXJT, BIOS 2.8.2 08/27/2020 RIP: 0010:vunmap+0x2e/0x30 ...skip... Call Trace: __iommu_dma_free+0x96/0x100 efx_nic_free_buffer+0x2b/0x40 [sfc] efx_ef10_try_update_nic_stats_vf+0x14a/0x1c0 [sfc] efx_ef10_update_stats_vf+0x18/0x40 [sfc] efx_start_all+0x15e/0x1d0 [sfc] efx_net_open+0x5a/0xe0 [sfc] __dev_open+0xe7/0x1a0 __dev_change_flags+0x1d7/0x240 dev_change_flags+0x21/0x60 ...skip... Fixes: d778819609a2 ("sfc: DMA the VF stats only when requested") Reported-by: Ma Yuying <yuma@redhat.com> Signed-off-by: Íñigo Huguet <ihuguet@redhat.com> Acked-by: Edward Cree <ecree.xilinx@gmail.com> Link: https://lore.kernel.org/r/20220713092116.21238-1-ihuguet@redhat.com Signed-off-by: Paolo Abeni <pabeni@redhat.com>
-rw-r--r--drivers/net/ethernet/sfc/ef10.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/drivers/net/ethernet/sfc/ef10.c b/drivers/net/ethernet/sfc/ef10.c
index 186cb28c03bd..8b62ce21aff3 100644
--- a/drivers/net/ethernet/sfc/ef10.c
+++ b/drivers/net/ethernet/sfc/ef10.c
@@ -1932,7 +1932,10 @@ static int efx_ef10_try_update_nic_stats_vf(struct efx_nic *efx)
efx_update_sw_stats(efx, stats);
out:
+ /* releasing a DMA coherent buffer with BH disabled can panic */
+ spin_unlock_bh(&efx->stats_lock);
efx_nic_free_buffer(efx, &stats_buf);
+ spin_lock_bh(&efx->stats_lock);
return rc;
}