Re: [PATCH] pcmcia: i82092: fix a null pointer dereference bug

[Dominik Brodowski <linux@dominikbrodowski.net>]

Applied to pcmcia-next, thanks. Are you aware of the last version where this
driver worked correctly? It seems that this bug has been present there for
ages.

Thanks,
	Dominik


Am Tue, Jun 22, 2021 at 07:11:31AM +0000 schrieb Zheyu Ma:
> During the driver loading process, the 'dev' field was not assigned, but
> the 'dev' field was referenced in the subsequent 'i82092aa_set_mem_map'
> function.
> 
> This log reveals it:
> 
> [    3.928168] BUG: kernel NULL pointer dereference, address: 0000000000000010
> [    3.928678] #PF: supervisor read access in kernel mode
> [    3.929054] #PF: error_code(0x0000) - not-present page
> [    3.929428] PGD 0 P4D 0
> [    3.929617] Oops: 0000 [#1] PREEMPT SMP PTI
> [    3.929923] CPU: 3 PID: 4409 Comm: pccardd Not tainted 5.13.0-rc7-next-20210621 #1
> [    3.930468] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.12.0-59-gc9ba5276e321-prebuilt.qemu.org 04/01/2014
> [    3.931277] RIP: 0010:i82092aa_set_mem_map+0x45/0x2c0
> [    3.931649] Code: 28 65 48 8b 04 25 28 00 00 00 48 89 45 d0 31 c0 e8 f0 44 8f fd 49 8b 84 24 28 09 00 00 48 8b 53 18 48 8d 75 c0 45 8b 6c 24 f0 <48> 8b 78 10 e8 92 05 2f fe 44 0f b6 33 41 80 fe 04 0f 87 16 02 00
> [    3.932973] RSP: 0000:ffffc9000a6bfdb8 EFLAGS: 00010293
> [    3.933351] RAX: 0000000000000000 RBX: ffffc9000a6bfe30 RCX: 0000000000000000
> [    3.933859] RDX: ffffc9000a6bfe50 RSI: ffffc9000a6bfdc8 RDI: ffffffff88457bb0
> [    3.934370] RBP: ffffc9000a6bfe08 R08: 0000000000000001 R09: 0000000000000001
> [    3.934876] R10: 0000000000000001 R11: 0000000000000000 R12: ffffffff88457bb0
> [    3.935385] R13: 0000000000000000 R14: ffffffff839f7b80 R15: ffffffff88457bb0
> [    3.935891] FS:  0000000000000000(0000) GS:ffff88817aa00000(0000) knlGS:0000000000000000
> [    3.936467] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [    3.936877] CR2: 0000000000000010 CR3: 0000000006c32000 CR4: 00000000000006e0
> [    3.937391] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> [    3.937896] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> [    3.938082] Call Trace:
> [    3.938082]  ? pcmcia_parse_uevents+0xa0/0xa0
> [    3.938082]  i82092aa_init+0xb8/0xf0
> [    3.938082]  pccardd+0x64/0x590
> [    3.938082]  ? __kthread_parkme+0xba/0xe0
> [    3.938082]  ? pcmcia_parse_uevents+0xa0/0xa0
> [    3.938082]  kthread+0x19a/0x1e0
> [    3.938082]  ? set_kthread_struct+0x60/0x60
> [    3.938082]  ret_from_fork+0x1f/0x30
> [    3.938082] Modules linked in:
> [    3.938082] Dumping ftrace buffer:
> [    3.938082]    (ftrace buffer empty)
> [    3.938082] CR2: 0000000000000010
> [    3.938082] ---[ end trace f4f9ca1497f3c8b2 ]---
> [    3.938082] RIP: 0010:i82092aa_set_mem_map+0x45/0x2c0
> [    3.938082] Code: 28 65 48 8b 04 25 28 00 00 00 48 89 45 d0 31 c0 e8 f0 44 8f fd 49 8b 84 24 28 09 00 00 48 8b 53 18 48 8d 75 c0 45 8b 6c 24 f0 <48> 8b 78 10 e8 92 05 2f fe 44 0f b6 33 41 80 fe 04 0f 87 16 02 00
> [    3.938082] RSP: 0000:ffffc9000a6bfdb8 EFLAGS: 00010293
> [    3.938082] RAX: 0000000000000000 RBX: ffffc9000a6bfe30 RCX: 0000000000000000
> [    3.938082] RDX: ffffc9000a6bfe50 RSI: ffffc9000a6bfdc8 RDI: ffffffff88457bb0
> [    3.938082] RBP: ffffc9000a6bfe08 R08: 0000000000000001 R09: 0000000000000001
> [    3.938082] R10: 0000000000000001 R11: 0000000000000000 R12: ffffffff88457bb0
> [    3.938082] R13: 0000000000000000 R14: ffffffff839f7b80 R15: ffffffff88457bb0
> [    3.938082] FS:  0000000000000000(0000) GS:ffff88817aa00000(0000) knlGS:0000000000000000
>     3.938082] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [    3.938082] CR2: 0000000000000010 CR3: 0000000006c32000 CR4: 00000000000006e0
> [    3.938082] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> [    3.938082] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> [    3.938082] Kernel panic - not syncing: Fatal exception
> [    3.938082] Dumping ftrace buffer:
> [    3.938082]    (ftrace buffer empty)
> [    3.938082] Kernel Offset: disabled
> [    3.938082] Rebooting in 1 seconds..
> 
> Signed-off-by: Zheyu Ma <zheyuma97@gmail.com>
> ---
>  drivers/pcmcia/i82092.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/pcmcia/i82092.c b/drivers/pcmcia/i82092.c
> index 85887d885b5f..192c9049d654 100644
> --- a/drivers/pcmcia/i82092.c
> +++ b/drivers/pcmcia/i82092.c
> @@ -112,6 +112,7 @@ static int i82092aa_pci_probe(struct pci_dev *dev,
>  	for (i = 0; i < socket_count; i++) {
>  		sockets[i].card_state = 1; /* 1 = present but empty */
>  		sockets[i].io_base = pci_resource_start(dev, 0);
> +		sockets[i].dev = dev;
>  		sockets[i].socket.features |= SS_CAP_PCCARD;
>  		sockets[i].socket.map_size = 0x1000;
>  		sockets[i].socket.irq_mask = 0;
> -- 
> 2.17.6
>