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Subject[PATCH AUTOSEL 4.14 09/37] media: au0828: cannot kfree dev before usb disconnect
Date
From: Brad Love <brad@nextdimension.cc>

[ Upstream commit 4add7104919f9e94e0db03e234caeadbfcc02ea9 ]

If au0828_analog_register fails, the dev is kfree'd and then flow
jumps to done, which can call au0828_usb_disconnect. Since all USB
error codes are negative, au0828_usb_disconnect will be called. The
problem is au0828_usb_disconnect uses dev, if dev is NULL then there
is immediate oops encountered.

[ 7.454307] au0828: au0828_usb_probe() au0282_dev_register failed to register on V4L2
[ 7.454323] BUG: unable to handle kernel NULL pointer dereference at 0000000000000050
[ 7.454421] PGD 0 P4D 0
[ 7.454457] Oops: 0002 [#1] SMP PTI
[ 7.454500] CPU: 1 PID: 262 Comm: systemd-udevd Tainted: P O 4.18.3 #1
[ 7.454584] Hardware name: Google Panther/Panther, BIOS MattDevo 04/27/2015
[ 7.454670] RIP: 0010:_raw_spin_lock_irqsave+0x2c/0x50
[ 7.454725] Code: 44 00 00 55 48 89 e5 41 54 53 48 89 fb 9c 58 0f 1f 44 00 00 49 89 c4 fa 66 0f 1f 44 00 00 e8 db 23 1b ff 31 c0 ba 01 00 00 00 <f0> 0f b1 13 85 c0 75 08 4c 89 e0 5b 41 5c 5d c3 89 c6 48 89 df e8
[ 7.455004] RSP: 0018:ffff9130f53ef988 EFLAGS: 00010046
[ 7.455063] RAX: 0000000000000000 RBX: 0000000000000050 RCX: 0000000000000000
[ 7.455139] RDX: 0000000000000001 RSI: 0000000000000003 RDI: 0000000000000050
[ 7.455216] RBP: ffff9130f53ef998 R08: 0000000000000018 R09: 0000000000000090
[ 7.455292] R10: ffffed4cc53cb000 R11: ffffed4cc53cb108 R12: 0000000000000082
[ 7.455369] R13: ffff9130cf2c6188 R14: 0000000000000000 R15: 0000000000000018
[ 7.455447] FS: 00007f2ff8514cc0(0000) GS:ffff9130fcb00000(0000) knlGS:0000000000000000
[ 7.455535] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 7.455597] CR2: 0000000000000050 CR3: 00000001753f0002 CR4: 00000000000606a0
[ 7.455675] Call Trace:
[ 7.455713] __wake_up_common_lock+0x65/0xc0
[ 7.455764] __wake_up+0x13/0x20
[ 7.455808] ir_lirc_unregister+0x57/0xe0 [rc_core]
[ 7.455865] rc_unregister_device+0xa0/0xc0 [rc_core]
[ 7.455935] au0828_rc_unregister+0x25/0x40 [au0828]
[ 7.455999] au0828_usb_disconnect+0x33/0x80 [au0828]
[ 7.456064] au0828_usb_probe.cold.16+0x8d/0x2aa [au0828]
[ 7.456130] usb_probe_interface+0xf1/0x300
[ 7.456184] driver_probe_device+0x2e3/0x460
[ 7.456235] __driver_attach+0xe4/0x110
[ 7.456282] ? driver_probe_device+0x460/0x460
[ 7.456335] bus_for_each_dev+0x74/0xb0
[ 7.456385] ? kmem_cache_alloc_trace+0x15d/0x1d0
[ 7.456441] driver_attach+0x1e/0x20
[ 7.456485] bus_add_driver+0x159/0x230
[ 7.456532] driver_register+0x70/0xc0
[ 7.456578] usb_register_driver+0x7f/0x140
[ 7.456626] ? 0xffffffffc0474000
[ 7.456674] au0828_init+0xbc/0x1000 [au0828]
[ 7.456725] do_one_initcall+0x4a/0x1c9
[ 7.456771] ? _cond_resched+0x19/0x30
[ 7.456817] ? kmem_cache_alloc_trace+0x15d/0x1d0
[ 7.456873] do_init_module+0x60/0x210
[ 7.456918] load_module+0x221b/0x2710
[ 7.456966] ? vfs_read+0xf5/0x120
[ 7.457010] __do_sys_finit_module+0xbd/0x120
[ 7.457061] ? __do_sys_finit_module+0xbd/0x120
[ 7.457115] __x64_sys_finit_module+0x1a/0x20
[ 7.457166] do_syscall_64+0x5b/0x110
[ 7.457210] entry_SYSCALL_64_after_hwframe+0x49/0xbe

Signed-off-by: Brad Love <brad@nextdimension.cc>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/media/usb/au0828/au0828-core.c | 1 -
1 file changed, 1 deletion(-)

diff --git a/drivers/media/usb/au0828/au0828-core.c b/drivers/media/usb/au0828/au0828-core.c
index cd363a2100d4..257ae0d8cfe2 100644
--- a/drivers/media/usb/au0828/au0828-core.c
+++ b/drivers/media/usb/au0828/au0828-core.c
@@ -629,7 +629,6 @@ static int au0828_usb_probe(struct usb_interface *interface,
pr_err("%s() au0282_dev_register failed to register on V4L2\n",
__func__);
mutex_unlock(&dev->lock);
- kfree(dev);
goto done;
}

--
2.19.1
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