Re: [PATCH v3 2/8] staging: qlge: Initialize devlink health dump framework

[Shung-Hsi Yu]

On Tue, Oct 20, 2020 at 04:57:11PM +0800, Shung-Hsi Yu wrote:
> Hi,
> 
> This patch trigger the following KASAN error inside qlge_init_device().
> 
> [...] general protection fault, probably for non-canonical address 0xdffffc000000004b: 0000 [#1] SMP DEBUG_PAGEALLOC KASAN PTI
> [...] KASAN: null-ptr-deref in range [0x0000000000000258-0x000000000000025f]
> [...] CPU: 0 PID: 438 Comm: systemd-udevd Tainted: G         C  E     5.9.0-kvmsmall+ #7
> [...] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.13.0-48-
> g...ilt.opensuse.org 04/01/2014
> [...] RIP: 0010:qlge_get_8000_flash_params+0x377/0x6e0 [qlge]
> [...] Code: 03 80 3c 02 00 0f 85 57 03 00 00 49 8b af 68 08 00 00 48 b8 00 00 00 00 00 fc ff df 48 8d bd 5f 02 00 00 48 89 fa 48 c1 ea 03 <0f> b6 04 02 48 89 fa 83 e2 07 38 d0 7f 08 84 c0 0f 85 c6 02 00 00
> [...] RSP: 0018:ffffc90000f97788 EFLAGS: 00010207
> [...] RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 0000000000000000
> [...] RDX: 000000000000004b RSI: ffffffffc08cb843 RDI: 000000000000025f
> [...] R10: fffffbfff5f718a0 R11: 0000000000000001 R12: dffffc0000000000
> [...] R13: ffff888111085d40 R14: ffff888111085d40 R15: ffff888111080280
> [...] FS:  00007f315f5db280(0000) GS:ffff8881f5200000(0000) knlGS:0000000000000000
> [...] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [...] CR2: 000055bb25297170 CR3: 0000000110674000 CR4: 00000000000006f0
> [...] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> [...] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> [...] Call Trace:
> [...]  ? qlge_get_8012_flash_params+0x600/0x600 [qlge]
> [...]  ? static_obj+0x8a/0xc0
> [...]  ? lockdep_init_map_waits+0x26a/0x700
> [...]  qlge_init_device+0x425/0x1000 [qlge]
> [...]  ? debug_mutex_init+0x31/0x60
> [...]  qlge_probe+0xfe/0x6c0 [qlge]
> <snip>
> 
> With qlge_get_8000_flash_params+0x377/0x6e0 corresponding to the following:
> 
> 	if (qdev->flash.flash_params_8000.data_type1 == 2)
> 		memcpy(mac_addr,
> 		       qdev->flash.flash_params_8000.mac_addr1,
> 		       qdev->ndev->addr_len); // <---- Here

This is because qdev->ndev == 0.

The reason is that before qlge_get_8000_flash_params() get called qdev is memset-ed inside qlge_init_device().

static int qlge_init_device(struct pci_dev *pdev, struct qlge_adapter *qdev,
				    int cards_found)
	{
	struct net_device *ndev = qdev->ndev;
	int err = 0;

	memset((void *)qdev, 0, sizeof(*qdev));

	// ...

	// qlge_get_8000_flash_params() get's called
	err = qdev->nic_ops->get_flash(qdev);

	// ...
	}