Re: LOOKS GOOD: Possible regression in drm/i915 driver: memleak
From: Mirsad Goran Todorovac
Date: Wed Dec 21 2022 - 19:12:43 EST
On 20. 12. 2022. 20:34, Mirsad Todorovac wrote:
On 12/20/22 16:52, Tvrtko Ursulin wrote:
On 20/12/2022 15:22, srinivas pandruvada wrote:
+Added DRM mailing list and maintainers
On Tue, 2022-12-20 at 15:33 +0100, Mirsad Todorovac wrote:
Hi all,
I have been unsuccessful to find any particular Intel i915 maintainer
emails, so my best bet is to post here, as you will must assuredly
already know them.
For future reference you can use ${kernel_dir}/scripts/get_maintainer.pl -f ...
The problem is a kernel memory leak that is repeatedly occurring
triggered during the execution of Chrome browser under the latest
6.1.0+
kernel of this morning and Almalinux 8.6 on a Lenovo desktop box
with Intel(R) Core(TM) i5-8400 CPU @ 2.80GHz CPU.
The build is with KMEMLEAK, KASAN and MGLRU turned on during the
build,
on a vanilla mainline kernel from Mr. Torvalds' tree.
The leaks look like this one:
unreferenced object 0xffff888131754880 (size 64):
comm "chrome", pid 13058, jiffies 4298568878 (age 3708.084s)
hex dump (first 32 bytes):
01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
................
00 00 00 00 00 00 00 00 00 80 1e 3e 83 88 ff ff
...........>....
backtrace:
[<ffffffff9e9b5542>] slab_post_alloc_hook+0xb2/0x340
[<ffffffff9e9bbf5f>] __kmem_cache_alloc_node+0x1bf/0x2c0
[<ffffffff9e8f767a>] kmalloc_trace+0x2a/0xb0
[<ffffffffc08dfde5>] drm_vma_node_allow+0x45/0x150 [drm]
[<ffffffffc0b33315>] __assign_mmap_offset_handle+0x615/0x820
[i915]
[<ffffffffc0b34057>] i915_gem_mmap_offset_ioctl+0x77/0x110
[i915]
[<ffffffffc08bc5e1>] drm_ioctl_kernel+0x181/0x280 [drm]
[<ffffffffc08bc9cd>] drm_ioctl+0x2dd/0x6a0 [drm]
[<ffffffff9ea54744>] __x64_sys_ioctl+0xc4/0x100
[<ffffffff9fbc0178>] do_syscall_64+0x58/0x80
[<ffffffff9fc000aa>] entry_SYSCALL_64_after_hwframe+0x72/0xdc
The complete list of leaks in attachment, but they seem similar or
the same.
Please find attached lshw and kernel build config file.
I will probably check the same parms on my laptop at home, which is
also
Lenovo, but a different hw config and Ubuntu 22.10.
Could you try the below patch?
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_mman.c b/drivers/gpu/drm/i915/gem/i915_gem_mman.c
index c3ea243d414d..0b07534c203a 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_mman.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_mman.c
@@ -679,9 +679,10 @@ mmap_offset_attach(struct drm_i915_gem_object *obj,
insert:
mmo = insert_mmo(obj, mmo);
GEM_BUG_ON(lookup_mmo(obj, mmap_type) != mmo);
-out:
+
if (file)
drm_vma_node_allow(&mmo->vma_node, file);
+out:
return mmo;
err:
Maybe it is not the best fix but curious to know if it will make the leak go away.
Hi,
After 27 minutes uptime with the patched kernel it looks promising.
It is much longer than it took for the buggy kernel to leak slabs.
Here is the output:
[root@pc-mtodorov marvin]# echo scan > /sys/kernel/debug/kmemleak
[root@pc-mtodorov marvin]# cat !$
cat /sys/kernel/debug/kmemleak
unreferenced object 0xffff888105028d80 (size 16):
comm "kworker/u12:5", pid 359, jiffies 4294902898 (age 1620.144s)
hex dump (first 16 bytes):
6d 65 6d 73 74 69 63 6b 30 00 00 00 00 00 00 00 memstick0.......
backtrace:
[<ffffffffb6bb5542>] slab_post_alloc_hook+0xb2/0x340
[<ffffffffb6bbbf5f>] __kmem_cache_alloc_node+0x1bf/0x2c0
[<ffffffffb6af8175>] __kmalloc_node_track_caller+0x55/0x160
[<ffffffffb6ae34a6>] kstrdup+0x36/0x60
[<ffffffffb6ae3508>] kstrdup_const+0x28/0x30
[<ffffffffb70d0757>] kvasprintf_const+0x97/0xd0
[<ffffffffb7c9cdf4>] kobject_set_name_vargs+0x34/0xc0
[<ffffffffb750289b>] dev_set_name+0x9b/0xd0
[<ffffffffc12d9201>] memstick_check+0x181/0x639 [memstick]
[<ffffffffb676e1d6>] process_one_work+0x4e6/0x7e0
[<ffffffffb676e556>] worker_thread+0x76/0x770
[<ffffffffb677b468>] kthread+0x168/0x1a0
[<ffffffffb6604c99>] ret_from_fork+0x29/0x50
[root@pc-mtodorov marvin]# w
20:27:35 up 27 min, 2 users, load average: 0.83, 1.15, 1.19
USER TTY FROM LOGIN@ IDLE JCPU PCPU WHAT
marvin tty2 tty2 20:01 27:10 10:12 2.09s /opt/google/chrome/chrome --type=utility --utility-sub-type=audio.m
marvin pts/1 - 20:01 0.00s 2:00 0.38s sudo bash
[root@pc-mtodorov marvin]# uname -rms
Linux 6.1.0-b6bb9676f216-mglru-kmemlk-kasan+ x86_64
[root@pc-mtodorov marvin]#
As I hear no reply from Tvrtko, and there is already 1d5h uptime with no leaks (but
the kworker with memstick_check nag I couldn't bisect on the only box that reproduced it,
because something in hw was not supported in pre 4.16 kernels on the Lenovo V530S-07ICB.
Or I am doing something wrong.)
However, now I can find the memstick maintainers thanks to Tvrtko's hint.
If you no longer require my service, I would close this on my behalf.
I hope I did not cause too much trouble. The knowledgeable knew that this was not a security
risk, but only a bug. (30 leaks of 64 bytes each were hardly to exhaust memory in any realistic
time.)
However, having some experience with software development, I always preferred bugs reported
and fixed rather than concealed and lying in wait (or worse, found first by a motivated
adversary.) Forgive me this rant, I do not live from writing kernel drivers, this is just a
pet project as of time being ...
Thanks,
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
The European Union