4.4-stable review patch. If anyone has any objections, please let me know.
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From: Lorenzo Bianconi lorenzo.bianconi@redhat.com
[ Upstream commit 8e1da73acded4751a93d4166458a7e640f37d26c ]
Add napi_disable routine in gro_cells_destroy since starting from commit c42858eaf492 ("gro_cells: remove spinlock protecting receive queues") gro_cell_poll and gro_cells_destroy can run concurrently on napi_skbs list producing a kernel Oops if the tunnel interface is removed while gro_cell_poll is running. The following Oops has been triggered removing a vxlan device while the interface is receiving traffic
[ 5628.948853] BUG: unable to handle kernel NULL pointer dereference at 0000000000000008 [ 5628.949981] PGD 0 P4D 0 [ 5628.950308] Oops: 0002 [#1] SMP PTI [ 5628.950748] CPU: 0 PID: 9 Comm: ksoftirqd/0 Not tainted 4.20.0-rc6+ #41 [ 5628.952940] RIP: 0010:gro_cell_poll+0x49/0x80 [ 5628.955615] RSP: 0018:ffffc9000004fdd8 EFLAGS: 00010202 [ 5628.956250] RAX: 0000000000000000 RBX: ffffe8ffffc08150 RCX: 0000000000000000 [ 5628.957102] RDX: 0000000000000000 RSI: ffff88802356bf00 RDI: ffffe8ffffc08150 [ 5628.957940] RBP: 0000000000000026 R08: 0000000000000000 R09: 0000000000000000 [ 5628.958803] R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000040 [ 5628.959661] R13: ffffe8ffffc08100 R14: 0000000000000000 R15: 0000000000000040 [ 5628.960682] FS: 0000000000000000(0000) GS:ffff88803ea00000(0000) knlGS:0000000000000000 [ 5628.961616] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 5628.962359] CR2: 0000000000000008 CR3: 000000000221c000 CR4: 00000000000006b0 [ 5628.963188] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 5628.964034] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 5628.964871] Call Trace: [ 5628.965179] net_rx_action+0xf0/0x380 [ 5628.965637] __do_softirq+0xc7/0x431 [ 5628.966510] run_ksoftirqd+0x24/0x30 [ 5628.966957] smpboot_thread_fn+0xc5/0x160 [ 5628.967436] kthread+0x113/0x130 [ 5628.968283] ret_from_fork+0x3a/0x50 [ 5628.968721] Modules linked in: [ 5628.969099] CR2: 0000000000000008 [ 5628.969510] ---[ end trace 9d9dedc7181661fe ]--- [ 5628.970073] RIP: 0010:gro_cell_poll+0x49/0x80 [ 5628.972965] RSP: 0018:ffffc9000004fdd8 EFLAGS: 00010202 [ 5628.973611] RAX: 0000000000000000 RBX: ffffe8ffffc08150 RCX: 0000000000000000 [ 5628.974504] RDX: 0000000000000000 RSI: ffff88802356bf00 RDI: ffffe8ffffc08150 [ 5628.975462] RBP: 0000000000000026 R08: 0000000000000000 R09: 0000000000000000 [ 5628.976413] R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000040 [ 5628.977375] R13: ffffe8ffffc08100 R14: 0000000000000000 R15: 0000000000000040 [ 5628.978296] FS: 0000000000000000(0000) GS:ffff88803ea00000(0000) knlGS:0000000000000000 [ 5628.979327] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 5628.980044] CR2: 0000000000000008 CR3: 000000000221c000 CR4: 00000000000006b0 [ 5628.980929] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 5628.981736] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 5628.982409] Kernel panic - not syncing: Fatal exception in interrupt [ 5628.983307] Kernel Offset: disabled
Fixes: c42858eaf492 ("gro_cells: remove spinlock protecting receive queues") Signed-off-by: Lorenzo Bianconi lorenzo.bianconi@redhat.com Acked-by: Eric Dumazet edumazet@google.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- include/net/gro_cells.h | 1 + 1 file changed, 1 insertion(+)
--- a/include/net/gro_cells.h +++ b/include/net/gro_cells.h @@ -84,6 +84,7 @@ static inline void gro_cells_destroy(str for_each_possible_cpu(i) { struct gro_cell *cell = per_cpu_ptr(gcells->cells, i);
+ napi_disable(&cell->napi); netif_napi_del(&cell->napi); __skb_queue_purge(&cell->napi_skbs); }