On Fri, May 12, 2023 at 11:33:31PM +0200, Mirsad Goran Todorovac wrote: > Hi, > > On 5/9/23 04:59, Greg Kroah-Hartman wrote: > > On Tue, May 09, 2023 at 01:51:35AM +0200, Mirsad Goran Todorovac wrote: > > > > > > > > > On 08. 05. 2023. 16:01, Greg Kroah-Hartman wrote: > > > > On Mon, May 08, 2023 at 08:51:55AM +0200, Greg Kroah-Hartman wrote: > > > > > On Mon, May 08, 2023 at 08:30:07AM +0200, Mirsad Goran Todorovac wrote: > > > > > > Hi, > > > > > > > > > > > > There seems to be a kernel memory leak in the USB keyboard driver. > > > > > > > > > > > > The leaked memory allocs are 96 and 512 bytes. > > > > > > > > > > > > The platform is Ubuntu 22.04 LTS on a assembled AMD Ryzen 9 with X670E PG > > > > > > Lightning mobo, > > > > > > and Genius SlimStar i220 GK-080012 keyboard. > > > > > > > > > > > > (Logitech M100 HID mouse is not affected by the bug.) > > > > > > > > > > > > BIOS is: > > > > > > > > > > > > *-firmware > > > > > > description: BIOS > > > > > > vendor: American Megatrends International, LLC. > > > > > > physical id: 0 > > > > > > version: 1.21 > > > > > > date: 04/26/2023 > > > > > > size: 64KiB > > > > > > > > > > > > The kernel is 6.3.0-torvalds-<id>-13466-gfc4354c6e5c2. > > > > > > > > > > > > The keyboard is recognised as Chicony: > > > > > > > > > > > > *-usb > > > > > > description: Keyboard > > > > > > product: CHICONY USB Keyboard > > > > > > vendor: CHICONY > > > > > > physical id: 2 > > > > > > bus info: usb@5:2 > > > > > > logical name: input35 > > > > > > logical name: /dev/input/event4 > > > > > > logical name: input35::capslock > > > > > > logical name: input35::numlock > > > > > > logical name: input35::scrolllock > > > > > > logical name: input36 > > > > > > logical name: /dev/input/event5 > > > > > > logical name: input37 > > > > > > logical name: /dev/input/event6 > > > > > > logical name: input38 > > > > > > logical name: /dev/input/event8 > > > > > > version: 2.30 > > > > > > capabilities: usb-2.00 usb > > > > > > configuration: driver=usbhid maxpower=100mA > > > > > > speed=1Mbit/s > > > > > > > > > > > > The bug is easily reproduced by unplugging the USB keyboard, waiting about a > > > > > > couple of seconds, > > > > > > and then reconnect and scan for memory leaks twice. > > > > > > > > > > > > The kmemleak log is as follows [edited privacy info]: > > > > > > > > > > > > root@hostname:/home/username# cat /sys/kernel/debug/kmemleak > > > > > > unreferenced object 0xffff8dd020037c00 (size 96): > > > > > > comm "systemd-udevd", pid 435, jiffies 4294892550 (age 8909.356s) > > > > > > hex dump (first 32 bytes): > > > > > > 5d 8e 4e b9 ff ff ff ff 00 00 00 00 00 00 00 00 ].N............. > > > > > > 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ > > > > > > backtrace: > > > > > > [<ffffffffb81a74be>] __kmem_cache_alloc_node+0x22e/0x2b0 > > > > > > [<ffffffffb8127b6e>] kmalloc_trace+0x2e/0xa0 > > > > > > [<ffffffffb87543d9>] class_create+0x29/0x80 > > > > > > [<ffffffffb8880d24>] usb_register_dev+0x1d4/0x2e0 > > > > > > > > > > As the call to class_create() in this path is now gone in 6.4-rc1, can > > > > > you retry that release to see if this is still there or not? > > > > > > > > No, wait, it's still there, I was looking at a development branch of > > > > mine that isn't sent upstream yet. And syzbot just reported the same > > > > thing: > > > > https://lore.kernel.org/r/00000000000058d15f05fb264013@xxxxxxxxxx > > > > > > > > So something's wrong here, let me dig into it tomorrow when I get a > > > > chance... > > > > > > If this could help, here is the bisect of the bug (I could not discern what > > > could possibly be wrong): > > > > > > user@host:~/linux/kernel/linux_torvalds$ git bisect log > > > git bisect start > > > # bad: [ac9a78681b921877518763ba0e89202254349d1b] Linux 6.4-rc1 > > > git bisect bad ac9a78681b921877518763ba0e89202254349d1b > > > # good: [c9c3395d5e3dcc6daee66c6908354d47bf98cb0c] Linux 6.2 > > > git bisect good c9c3395d5e3dcc6daee66c6908354d47bf98cb0c > > > # good: [85496c9b3bf8dbe15e2433d3a0197954d323cadc] Merge branch > > > 'net-remove-some-rcu_bh-cruft' > > > git bisect good 85496c9b3bf8dbe15e2433d3a0197954d323cadc > > > # good: [b68ee1c6131c540a62ecd443be89c406401df091] Merge tag 'scsi-misc' of > > > git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi > > > git bisect good b68ee1c6131c540a62ecd443be89c406401df091 > > > # bad: [888d3c9f7f3ae44101a3fd76528d3dd6f96e9fd0] Merge tag 'sysctl-6.4-rc1' > > > of git://git.kernel.org/pub/scm/linux/kernel/git/mcgrof/linux > > > git bisect bad 888d3c9f7f3ae44101a3fd76528d3dd6f96e9fd0 > > > # good: [34b62f186db9614e55d021f8c58d22fc44c57911] Merge tag > > > 'pci-v6.4-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/pci/pci > > > git bisect good 34b62f186db9614e55d021f8c58d22fc44c57911 > > > # good: [34da76dca4673ab1819830b4924bb5b436325b26] Merge tag > > > 'for-linus-2023042601' of > > > git://git.kernel.org/pub/scm/linux/kernel/git/hid/hid > > > git bisect good 34da76dca4673ab1819830b4924bb5b436325b26 > > > # good: [97b2ff294381d05e59294a931c4db55276470cb5] Merge tag > > > 'staging-6.4-rc1' of > > > git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging > > > git bisect good 97b2ff294381d05e59294a931c4db55276470cb5 > > > # good: [2025b2ca8004c04861903d076c67a73a0ec6dfca] mcb-lpc: Reallocate > > > memory region to avoid memory overlapping > > > git bisect good 2025b2ca8004c04861903d076c67a73a0ec6dfca > > > # bad: [d06f5a3f7140921ada47d49574ae6fa4de5e2a89] cdx: fix build failure due > > > to sysfs 'bus_type' argument needing to be const > > > git bisect bad d06f5a3f7140921ada47d49574ae6fa4de5e2a89 > > > # good: [dcfbb67e48a2becfce7990386e985b9c45098ee5] driver core: class: use > > > lock_class_key already present in struct subsys_private > > > git bisect good dcfbb67e48a2becfce7990386e985b9c45098ee5 > > > # bad: [6f14c02220c791d5c46b0f965b9340c58f3d503d] driver core: create > > > class_is_registered() > > > git bisect bad 6f14c02220c791d5c46b0f965b9340c58f3d503d > > > # good: [2f9e87f5a2941b259336c7ea6c5a1499ede4554a] driver core: Add a > > > comment to set_primary_fwnode() on nullifying > > > git bisect good 2f9e87f5a2941b259336c7ea6c5a1499ede4554a > > > # bad: [02fe26f25325b547b7a31a65deb0326c04bb5174] firmware_loader: Add debug > > > message with checksum for FW file > > > git bisect bad 02fe26f25325b547b7a31a65deb0326c04bb5174 > > > # good: [884f8ce42ccec9d0bf11d8bf9f111e5961ca1c82] driver core: class: > > > implement class_get/put without the private pointer. > > > git bisect good 884f8ce42ccec9d0bf11d8bf9f111e5961ca1c82 > > > # bad: [3f84aa5ec052dba960baca4ab8a352d43d47028e] base: soc: populate > > > machine name in soc_device_register if empty > > > git bisect bad 3f84aa5ec052dba960baca4ab8a352d43d47028e > > > # bad: [7b884b7f24b42fa25e92ed724ad82f137610afaf] driver core: class.c: > > > convert to only use class_to_subsys > > > git bisect bad 7b884b7f24b42fa25e92ed724ad82f137610afaf > > > # first bad commit: [7b884b7f24b42fa25e92ed724ad82f137610afaf] driver core: > > > class.c: convert to only use class_to_subsys > > > user@host:~/linux/kernel/linux_torvalds$ > > > > This helps a lot, thanks. I got the reference counting wrong somewhere > > in here, I thought I tested this better, odd it shows up now... > > > > I'll try to work on it this week. > > I have figured out that the leak occurs on keyboard unplugging only, one > or two leaks (maybe a race condition?). > > Please NOTE that the number of leaks is now odd: > > root@defiant:/home/marvin# cat /sys/kernel/debug/kmemleak | grep comm > comm "systemd-udevd", pid 330, jiffies 4294892588 (age 715.772s) > comm "systemd-udevd", pid 330, jiffies 4294892588 (age 715.772s) > comm "kworker/6:0", pid 54, jiffies 4294907989 (age 654.224s) > comm "kworker/6:0", pid 54, jiffies 4294907989 (age 654.272s) > comm "kworker/6:3", pid 3046, jiffies 4294935362 (age 544.780s) > comm "kworker/6:0", pid 54, jiffies 4294964122 (age 429.740s) > comm "kworker/6:0", pid 54, jiffies 4294964122 (age 429.784s) > root@defiant:/home/marvin# > > At one time unplugging keyboard generated only one leak, but only at one > time. As it requires manually unplugging keyboard, I didn't seem to find a > way to automate it, but it doesn't seem to require root access. > > BTW, I've seen in syzbot output that kmemleak output has debug source file > names and line numbers. I couldn't make that work with the dbg .deb. > > I will do some more homework, but this was a rough week. I made up a patch based on code inspection alone, as I couldn't reproduce this locally at all: https://lore.kernel.org/r/2023051628-thumb-boaster-5680@gregkh and it seemed to pass syzbot's tests. I've included it here below, can you test it as well? Hm, I only tested with a USB mouse unplug/plug cycle, maybe the issue is a keyboard? thanks, greg k-h ------------- diff --git a/drivers/base/class.c b/drivers/base/class.c index ac1808d1a2e8..9b44edc8416f 100644 --- a/drivers/base/class.c +++ b/drivers/base/class.c @@ -320,6 +322,7 @@ void class_dev_iter_init(struct class_dev_iter *iter, const struct class *class, start_knode = &start->p->knode_class; klist_iter_init_node(&sp->klist_devices, &iter->ki, start_knode); iter->type = type; + iter->sp = sp; } EXPORT_SYMBOL_GPL(class_dev_iter_init); @@ -361,6 +364,7 @@ EXPORT_SYMBOL_GPL(class_dev_iter_next); void class_dev_iter_exit(struct class_dev_iter *iter) { klist_iter_exit(&iter->ki); + subsys_put(iter->sp); } EXPORT_SYMBOL_GPL(class_dev_iter_exit); diff --git a/include/linux/device/class.h b/include/linux/device/class.h index 9deeaeb457bb..abf3d3bfb6fe 100644 --- a/include/linux/device/class.h +++ b/include/linux/device/class.h @@ -74,6 +74,7 @@ struct class { struct class_dev_iter { struct klist_iter ki; const struct device_type *type; + struct subsys_private *sp; }; int __must_check class_register(const struct class *class);
