[PATCH AUTOSEL 6.0 18/18] fbdev: smscufx: fix error handling code in ufx_usb_probe

Sasha Levin
2022-12-24T01:34:52Z

From: Dongliang Mu <dzm91@hust.edu.cn>

[ Upstream commit b76449ee75e21acfe9fa4c653d8598f191ed7d68 ]

The current error handling code in ufx_usb_probe have many unmatching
issues, e.g., missing ufx_free_usb_list, destroy_modedb label should
only include framebuffer_release, fb_dealloc_cmap only matches
fb_alloc_cmap.

My local syzkaller reports a memory leak bug:

memory leak in ufx_usb_probe

BUG: memory leak
unreferenced object 0xffff88802f879580 (size 128):
comm "kworker/0:7", pid 17416, jiffies 4295067474 (age 46.710s)
hex dump (first 32 bytes):
80 21 7c 2e 80 88 ff ff 18 d0 d0 0c 80 88 ff ff .!|.............
00 d0 d0 0c 80 88 ff ff e0 ff ff ff 0f 00 00 00 ................
backtrace:
[<ffffffff814c99a0>] kmalloc_trace+0x20/0x90 mm/slab_common.c:1045
[<ffffffff824d219c>] kmalloc include/linux/slab.h:553 [inline]
[<ffffffff824d219c>] kzalloc include/linux/slab.h:689 [inline]
[<ffffffff824d219c>] ufx_alloc_urb_list drivers/video/fbdev/smscufx.c:1873 [inline]
[<ffffffff824d219c>] ufx_usb_probe+0x11c/0x15a0 drivers/video/fbdev/smscufx.c:1655
[<ffffffff82d17927>] usb_probe_interface+0x177/0x370 drivers/usb/core/driver.c:396
[<ffffffff82712f0d>] call_driver_probe drivers/base/dd.c:560 [inline]
[<ffffffff82712f0d>] really_probe+0x12d/0x390 drivers/base/dd.c:639
[<ffffffff8271322f>] __driver_probe_device+0xbf/0x140 drivers/base/dd.c:778
[<ffffffff827132da>] driver_probe_device+0x2a/0x120 drivers/base/dd.c:808
[<ffffffff82713c27>] __device_attach_driver+0xf7/0x150 drivers/base/dd.c:936
[<ffffffff82710137>] bus_for_each_drv+0xb7/0x100 drivers/base/bus.c:427
[<ffffffff827136b5>] __device_attach+0x105/0x2d0 drivers/base/dd.c:1008
[<ffffffff82711d36>] bus_probe_device+0xc6/0xe0 drivers/base/bus.c:487
[<ffffffff8270e242>] device_add+0x642/0xdc0 drivers/base/core.c:3517
[<ffffffff82d14d5f>] usb_set_configuration+0x8ef/0xb80 drivers/usb/core/message.c:2170
[<ffffffff82d2576c>] usb_generic_driver_probe+0x8c/0xc0 drivers/usb/core/generic.c:238
[<ffffffff82d16ffc>] usb_probe_device+0x5c/0x140 drivers/usb/core/driver.c:293
[<ffffffff82712f0d>] call_driver_probe drivers/base/dd.c:560 [inline]
[<ffffffff82712f0d>] really_probe+0x12d/0x390 drivers/base/dd.c:639
[<ffffffff8271322f>] __driver_probe_device+0xbf/0x140 drivers/base/dd.c:778

Fix this bug by rewriting the error handling code in ufx_usb_probe.

Reported-by: syzkaller <syzkaller@googlegroups.com>
Tested-by: Dongliang Mu <dzm91@hust.edu.cn>
Signed-off-by: Dongliang Mu <dzm91@hust.edu.cn>
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/video/fbdev/smscufx.c | 46 +++++++++++++++++++++++------------
1 file changed, 31 insertions(+), 15 deletions(-)

diff --git a/drivers/video/fbdev/smscufx.c b/drivers/video/fbdev/smscufx.c
index 9343b7a4ac89..2ad6e98ce10d 100644
--- a/drivers/video/fbdev/smscufx.c
+++ b/drivers/video/fbdev/smscufx.c
@@ -1622,7 +1622,7 @@ static int ufx_usb_probe(struct usb_interface *interface,
struct usb_device *usbdev;
struct ufx_data *dev;
struct fb_info *info;
- int retval;
+ int retval = -ENOMEM;
u32 id_rev, fpga_rev;

/* usb initialization */
@@ -1654,15 +1654,17 @@ static int ufx_usb_probe(struct usb_interface *interface,

if (!ufx_alloc_urb_list(dev, WRITES_IN_FLIGHT, MAX_TRANSFER)) {
dev_err(dev->gdev, "ufx_alloc_urb_list failed\n");
- goto e_nomem;
+ goto put_ref;
}

/* We don't register a new USB class. Our client interface is fbdev */

/* allocates framebuffer driver structure, not framebuffer memory */
info = framebuffer_alloc(0, &usbdev->dev);
- if (!info)
- goto e_nomem;
+ if (!info) {
+ dev_err(dev->gdev, "framebuffer_alloc failed\n");
+ goto free_urb_list;
+ }

dev->info = info;
info->par = dev;
@@ -1705,22 +1707,34 @@ static int ufx_usb_probe(struct usb_interface *interface,
check_warn_goto_error(retval, "unable to find common mode for display and adapter");

retval = ufx_reg_set_bits(dev, 0x4000, 0x00000001);
- check_warn_goto_error(retval, "error %d enabling graphics engine", retval);
+ if (retval < 0) {
+ dev_err(dev->gdev, "error %d enabling graphics engine", retval);
+ goto setup_modes;
+ }

/* ready to begin using device */
atomic_set(&dev->usb_active, 1);

dev_dbg(dev->gdev, "checking var");
retval = ufx_ops_check_var(&info->var, info);
- check_warn_goto_error(retval, "error %d ufx_ops_check_var", retval);
+ if (retval < 0) {
+ dev_err(dev->gdev, "error %d ufx_ops_check_var", retval);
+ goto reset_active;
+ }

dev_dbg(dev->gdev, "setting par");
retval = ufx_ops_set_par(info);
- check_warn_goto_error(retval, "error %d ufx_ops_set_par", retval);
+ if (retval < 0) {
+ dev_err(dev->gdev, "error %d ufx_ops_set_par", retval);
+ goto reset_active;
+ }

dev_dbg(dev->gdev, "registering framebuffer");
retval = register_framebuffer(info);
- check_warn_goto_error(retval, "error %d register_framebuffer", retval);
+ if (retval < 0) {
+ dev_err(dev->gdev, "error %d register_framebuffer", retval);
+ goto reset_active;
+ }

dev_info(dev->gdev, "SMSC UDX USB device /dev/fb%d attached. %dx%d resolution."
" Using %dK framebuffer memory\n", info->node,
@@ -1728,21 +1742,23 @@ static int ufx_usb_probe(struct usb_interface *interface,

return 0;

-error:
- fb_dealloc_cmap(&info->cmap);
-destroy_modedb:
+reset_active:
+ atomic_set(&dev->usb_active, 0);
+setup_modes:
fb_destroy_modedb(info->monspecs.modedb);
vfree(info->screen_base);
fb_destroy_modelist(&info->modelist);
+error:
+ fb_dealloc_cmap(&info->cmap);
+destroy_modedb:
framebuffer_release(info);
+free_urb_list:
+ if (dev->urbs.count > 0)
+ ufx_free_urb_list(dev);
put_ref:
kref_put(&dev->kref, ufx_free); /* ref for framebuffer */
kref_put(&dev->kref, ufx_free); /* last ref from kref_init */
return retval;
-
-e_nomem:
- retval = -ENOMEM;
- goto put_ref;
}

static void ufx_usb_disconnect(struct usb_interface *interface)
--
2.35.1