On 3/28/23 13:28, Greg Kroah-Hartman wrote:
On Tue, Mar 28, 2023 at 01:13:33PM +0200, Mirsad Todorovac wrote:
Hi all,
Here is another kernel memory leak report, just as I thought we have done with
them by the xhci patch by Mathias.
The memory leaks were caught on an AlmaLinux 8.7 (CentOS) fork system, running
on a Lenovo desktop box (see lshw.txt) and the newest Linux kernel 6.3-rc4 commit
g3a93e40326c8 with Mathias' patch for a xhci systemd-devd triggered leak.
See: <20230327095019.1017159-1-mathias.nyman@xxxxxxxxxxxxxxx> on LKML.
This leak is also systemd-devd triggered, except for the memstick_check() leaks
which I was unable to bisect due to the box not booting older kernels (work in
progress).
unreferenced object 0xffff88ad12392710 (size 96):
comm "systemd-udevd", pid 735, jiffies 4294896759 (age 2257.568s)
hex dump (first 32 bytes):
53 65 72 69 61 6c 50 6f 72 74 31 41 64 64 72 65 SerialPort1Addre
73 73 2c 33 46 38 2f 49 52 51 34 3b 5b 4f 70 74 ss,3F8/IRQ4;[Opt
backtrace:
[<ffffffffae8fb26c>] slab_post_alloc_hook+0x8c/0x3e0
[<ffffffffae902b49>] __kmem_cache_alloc_node+0x1d9/0x2a0
[<ffffffffae8773c9>] __kmalloc_node_track_caller+0x59/0x180
[<ffffffffae866a1a>] kstrdup+0x3a/0x70
[<ffffffffc0d839aa>] tlmi_extract_output_string.isra.0+0x2a/0x60 [think_lmi]
[<ffffffffc0d83b64>] tlmi_setting.constprop.4+0x54/0x90 [think_lmi]
[<ffffffffc0d842b1>] tlmi_probe+0x591/0xba0 [think_lmi]
[<ffffffffc051dc53>] wmi_dev_probe+0x163/0x230 [wmi]
Why aren't you looking at the wmi.c driver? That should be where the
issue is, not the driver core, right?
thanks,
greg k-h
Hi, Mr. Greg,
Thanks for the quick reply.
I have added CC: for additional developers per drivers/platform/x86/wmi.c,
however, this seems to me like hieroglyphs. There is nothing obvious, but
I had not noticed it with v6.3-rc3?
Maybe, there seems to be something off:
949 static int wmi_dev_probe(struct device *dev)
950 {
951 struct wmi_block *wblock = dev_to_wblock(dev);
952 struct wmi_driver *wdriver = drv_to_wdrv(dev->driver);
953 int ret = 0;
954 char *buf;
955
956 if (ACPI_FAILURE(wmi_method_enable(wblock, true)))
957 dev_warn(dev, "failed to enable device -- probing anyway\n");
958
959 if (wdriver->probe) {
960 ret = wdriver->probe(dev_to_wdev(dev),
961 find_guid_context(wblock, wdriver));
962 if (ret != 0)
963 goto probe_failure;
964 }
965
966 /* driver wants a character device made */
967 if (wdriver->filter_callback) {
968 /* check that required buffer size declared by driver or MOF */
969 if (!wblock->req_buf_size) {
970 dev_err(&wblock->dev.dev,
971 "Required buffer size not set\n");
972 ret = -EINVAL;
973 goto probe_failure;
974 }
975
976 wblock->handler_data = kmalloc(wblock->req_buf_size,
977 GFP_KERNEL);
978 if (!wblock->handler_data) {
979 ret = -ENOMEM;
980 goto probe_failure;
981 }
982
983 buf = kasprintf(GFP_KERNEL, "wmi/%s", wdriver->driver.name);
984 if (!buf) {
985 ret = -ENOMEM;
986 goto probe_string_failure;
987 }
988 wblock->char_dev.minor = MISC_DYNAMIC_MINOR;
989 wblock->char_dev.name = buf;
990 wblock->char_dev.fops = &wmi_fops;
991 wblock->char_dev.mode = 0444;
992 ret = misc_register(&wblock->char_dev);
993 if (ret) {
994 dev_warn(dev, "failed to register char dev: %d\n", ret);
995 ret = -ENOMEM;
996 goto probe_misc_failure;
997 }
998 }
999
1000 set_bit(WMI_PROBED, &wblock->flags);
1001 return 0;
1002
1003 probe_misc_failure:
1004 kfree(buf);
1005 probe_string_failure:
1006 kfree(wblock->handler_data);
1007 probe_failure:
1008 if (ACPI_FAILURE(wmi_method_enable(wblock, false)))
1009 dev_warn(dev, "failed to disable device\n");
char *buf is passed to kfree(buf) uninitialised if wdriver->filter_callback
is not set.
It seems like a logical error per se, but I don't believe this is the cause
of the leak?
Thank you again.
Best regards,
Mirsad
--
Mirsad Goran Todorovac
Sistem inženjer
Grafički fakultet | Akademija likovnih umjetnosti
Sveučilište u Zagrebu
System engineer
Faculty of Graphic Arts | Academy of Fine Arts
University of Zagreb, Republic of Croatia
"What’s this thing suddenly coming towards me very fast? Very very fast.
... I wonder if it will be friends with me?"
