The ndev was accessed on shutdown without a check if it actually exists.
This triggered the crash pasted below. This patch simply adds a check
before using ndev.
BUG: kernel NULL pointer dereference, address: 0000000000000300
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 0 P4D 0
Oops: 0000 [#1] SMP
CPU: 0 PID: 1 Comm: systemd-shutdow Not tainted 6.5.0-rc2_for_upstream_min_debug_2023_07_17_15_05 #1
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014
RIP: 0010:mlx5v_shutdown+0xe/0x50 [mlx5_vdpa]
RSP: 0018:ffff8881003bfdc0 EFLAGS: 00010286
RAX: ffff888103befba0 RBX: ffff888109d28008 RCX: 0000000000000017
RDX: 0000000000000001 RSI: 0000000000000212 RDI: ffff888109d28000
RBP: 0000000000000000 R08: 0000000d3a3a3882 R09: 0000000000000001
R10: 0000000000000000 R11: 0000000000000000 R12: ffff888109d28000
R13: ffff888109d28080 R14: 00000000fee1dead R15: 0000000000000000
FS: 00007f4969e0be40(0000) GS:ffff88852c800000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000300 CR3: 00000001051cd006 CR4: 0000000000370eb0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
? __die+0x20/0x60
? page_fault_oops+0x14c/0x3c0
? exc_page_fault+0x75/0x140
? asm_exc_page_fault+0x22/0x30
? mlx5v_shutdown+0xe/0x50 [mlx5_vdpa]
device_shutdown+0x13e/0x1e0
kernel_restart+0x36/0x90
__do_sys_reboot+0x141/0x210
? vfs_writev+0xcd/0x140
? handle_mm_fault+0x161/0x260
? do_writev+0x6b/0x110
do_syscall_64+0x3d/0x90
entry_SYSCALL_64_after_hwframe+0x46/0xb0
RIP: 0033:0x7f496990fb56
RSP: 002b:00007fffc7bdde88 EFLAGS: 00000206 ORIG_RAX: 00000000000000a9
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f496990fb56
RDX: 0000000001234567 RSI: 0000000028121969 RDI: fffffffffee1dead
RBP: 00007fffc7bde1d0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000
R13: 00007fffc7bddf10 R14: 0000000000000000 R15: 00007fffc7bde2b8
</TASK>
CR2: 0000000000000300
---[ end trace 0000000000000000 ]---
Fixes: bc9a2b3e686e ("vdpa/mlx5: Support interrupt bypassing")
Signed-off-by: Dragos Tatulea <dtatulea@xxxxxxxxxx>
---
drivers/vdpa/mlx5/net/mlx5_vnet.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.c b/drivers/vdpa/mlx5/net/mlx5_vnet.c
index 9138ef2fb2c8..e2e7ebd71798 100644
--- a/drivers/vdpa/mlx5/net/mlx5_vnet.c
+++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c
@@ -3556,7 +3556,8 @@ static void mlx5v_shutdown(struct auxiliary_device *auxdev)
mgtdev = auxiliary_get_drvdata(auxdev);
ndev = mgtdev->ndev;
- free_irqs(ndev);
+ if (ndev)
+ free_irqs(ndev);
}
static const struct auxiliary_device_id mlx5v_id_table[] = {
--
2.41.0
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