[syzbot] [usb?] [sound?] KMSAN: uninit-value in line6_pod_process_message

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 486291a0e624 Merge tag 'drm-fixes-2024-03-30' of https://g..
git tree: upstream
console+strace: https://syzkaller.appspot.com/x/log.txt?x=13ab1129180000
kernel config: https://syzkaller.appspot.com/x/.config?x=e2599baf258ef795
dashboard link: https://syzkaller.appspot.com/bug?extid=7fb05ccf7b3d2f9617b3
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1299932d180000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1101e52d180000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/ea2c2e416c4f/disk-486291a0.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/83fdaf5e5783/vmlinux-486291a0.xz
kernel image: https://storage.googleapis.com/syzbot-assets/1f674430b191/bzImage-486291a0.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+7fb05c...@syzkaller.appspotmail.com

=====================================================
BUG: KMSAN: uninit-value in line6_pod_process_message+0x72f/0x7b0 sound/usb/line6/pod.c:201
line6_pod_process_message+0x72f/0x7b0 sound/usb/line6/pod.c:201
line6_data_received+0x5db/0x7e0 sound/usb/line6/driver.c:317
__usb_hcd_giveback_urb+0x508/0x770 drivers/usb/core/hcd.c:1648
usb_hcd_giveback_urb+0x157/0x720 drivers/usb/core/hcd.c:1732
dummy_timer+0xd93/0x6b10 drivers/usb/gadget/udc/dummy_hcd.c:1987
call_timer_fn+0x49/0x580 kernel/time/timer.c:1793
expire_timers kernel/time/timer.c:1844 [inline]
__run_timers kernel/time/timer.c:2418 [inline]
__run_timer_base+0x84e/0xe90 kernel/time/timer.c:2429
run_timer_base kernel/time/timer.c:2438 [inline]
run_timer_softirq+0x3a/0x70 kernel/time/timer.c:2448
__do_softirq+0x1c0/0x7d7 kernel/softirq.c:554
invoke_softirq kernel/softirq.c:428 [inline]
__irq_exit_rcu kernel/softirq.c:633 [inline]
irq_exit_rcu+0x6a/0x130 kernel/softirq.c:645
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1043 [inline]
sysvec_apic_timer_interrupt+0x83/0x90 arch/x86/kernel/apic/apic.c:1043
asm_sysvec_apic_timer_interrupt+0x1f/0x30 arch/x86/include/asm/idtentry.h:702
native_safe_halt arch/x86/include/asm/irqflags.h:48 [inline]
arch_safe_halt arch/x86/include/asm/irqflags.h:86 [inline]
acpi_safe_halt+0x25/0x30 drivers/acpi/processor_idle.c:112
acpi_idle_do_entry+0x22/0x40 drivers/acpi/processor_idle.c:573
acpi_idle_enter+0xa1/0xc0 drivers/acpi/processor_idle.c:707
cpuidle_enter_state+0xcb/0x250 drivers/cpuidle/cpuidle.c:267
cpuidle_enter+0x7f/0xf0 drivers/cpuidle/cpuidle.c:388
call_cpuidle kernel/sched/idle.c:155 [inline]
cpuidle_idle_call kernel/sched/idle.c:236 [inline]
do_idle+0x551/0x750 kernel/sched/idle.c:332
cpu_startup_entry+0x65/0x80 kernel/sched/idle.c:430
rest_init+0x1e8/0x260 init/main.c:732
start_kernel+0x927/0xa70 init/main.c:1074
x86_64_start_reservations+0x2e/0x30 arch/x86/kernel/head64.c:507
x86_64_start_kernel+0x98/0xa0 arch/x86/kernel/head64.c:488
common_startup_64+0x12c/0x137

Uninit was created at:
slab_post_alloc_hook mm/slub.c:3804 [inline]
slab_alloc_node mm/slub.c:3845 [inline]
kmalloc_trace+0x578/0xba0 mm/slub.c:3992
kmalloc include/linux/slab.h:628 [inline]
line6_init_cap_control+0x4f1/0x770 sound/usb/line6/driver.c:700
line6_probe+0xeae/0x1120 sound/usb/line6/driver.c:797
pod_probe+0x79/0x90 sound/usb/line6/pod.c:522
usb_probe_interface+0xd6f/0x1350 drivers/usb/core/driver.c:399
really_probe+0x4db/0xd90 drivers/base/dd.c:656
__driver_probe_device+0x2ab/0x5d0 drivers/base/dd.c:798
driver_probe_device+0x72/0x890 drivers/base/dd.c:828
__device_attach_driver+0x568/0x9e0 drivers/base/dd.c:956
bus_for_each_drv+0x403/0x620 drivers/base/bus.c:457
__device_attach+0x3c1/0x650 drivers/base/dd.c:1028
device_initial_probe+0x32/0x40 drivers/base/dd.c:1077
bus_probe_device+0x3dc/0x5c0 drivers/base/bus.c:532
device_add+0x1475/0x1c90 drivers/base/core.c:3705
usb_set_configuration+0x31c9/0x38d0 drivers/usb/core/message.c:2210
usb_generic_driver_probe+0x109/0x2a0 drivers/usb/core/generic.c:254
usb_probe_device+0x3a7/0x690 drivers/usb/core/driver.c:294
really_probe+0x4db/0xd90 drivers/base/dd.c:656
__driver_probe_device+0x2ab/0x5d0 drivers/base/dd.c:798
driver_probe_device+0x72/0x890 drivers/base/dd.c:828
__device_attach_driver+0x568/0x9e0 drivers/base/dd.c:956
bus_for_each_drv+0x403/0x620 drivers/base/bus.c:457
__device_attach+0x3c1/0x650 drivers/base/dd.c:1028
device_initial_probe+0x32/0x40 drivers/base/dd.c:1077
bus_probe_device+0x3dc/0x5c0 drivers/base/bus.c:532
device_add+0x1475/0x1c90 drivers/base/core.c:3705
usb_new_device+0x15ff/0x2470 drivers/usb/core/hub.c:2643
hub_port_connect drivers/usb/core/hub.c:5512 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5652 [inline]
port_event drivers/usb/core/hub.c:5812 [inline]
hub_event+0x4ff8/0x72d0 drivers/usb/core/hub.c:5894
process_one_work kernel/workqueue.c:3254 [inline]
process_scheduled_works+0xa81/0x1bd0 kernel/workqueue.c:3335
worker_thread+0xea5/0x1560 kernel/workqueue.c:3416
kthread+0x3e2/0x540 kernel/kthread.c:388
ret_from_fork+0x6d/0x90 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:243

CPU: 0 PID: 0 Comm: swapper/0 Not tainted 6.9.0-rc1-syzkaller-00274-g486291a0e624 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
=====================================================


---
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[Edward Adam Davis]

please test uninit-value in line6_pod_process_message

#syz test https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master

diff --git a/sound/usb/line6/driver.c b/sound/usb/line6/driver.c
index b67617b68e50..8fd9d42aa8e2 100644
--- a/sound/usb/line6/driver.c
+++ b/sound/usb/line6/driver.c
@@ -697,7 +697,7 @@ static int line6_init_cap_control(struct usb_line6 *line6)
return -ENOMEM;

if (line6->properties->capabilities & LINE6_CAP_CONTROL_MIDI) {
- line6->buffer_message = kmalloc(LINE6_MIDI_MESSAGE_MAXLEN, GFP_KERNEL);
+ line6->buffer_message = kzalloc(LINE6_MIDI_MESSAGE_MAXLEN, GFP_KERNEL);
if (!line6->buffer_message)
return -ENOMEM;

[syzbot]

Hello,

syzbot has tested the proposed patch and the reproducer did not trigger any issue:

Reported-and-tested-by: syzbot+7fb05c...@syzkaller.appspotmail.com

Tested on:

commit: 026e680b Merge tag 'pwm/for-6.9-rc3-fixes' of git://gi..
git tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
console output: https://syzkaller.appspot.com/x/log.txt?x=15e939b1180000
kernel config: https://syzkaller.appspot.com/x/.config?x=5112b3f484393436

dashboard link: https://syzkaller.appspot.com/bug?extid=7fb05ccf7b3d2f9617b3
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

patch: https://syzkaller.appspot.com/x/patch.diff?x=17da6855180000

Note: testing is done by a robot and is best-effort only.

[Edward Adam Davis]

[Syzbot reported]

[Fix]
Let's clear all the content of the buffer message during alloc.

Reported-and-tested-by: syzbot+7fb05c...@syzkaller.appspotmail.com
Signed-off-by: Edward Adam Davis <ead...@qq.com>
---
sound/usb/line6/driver.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/sound/usb/line6/driver.c b/sound/usb/line6/driver.c
index b67617b68e50..8fd9d42aa8e2 100644
--- a/sound/usb/line6/driver.c
+++ b/sound/usb/line6/driver.c
@@ -697,7 +697,7 @@ static int line6_init_cap_control(struct usb_line6 *line6)
return -ENOMEM;

if (line6->properties->capabilities & LINE6_CAP_CONTROL_MIDI) {
- line6->buffer_message = kmalloc(LINE6_MIDI_MESSAGE_MAXLEN, GFP_KERNEL);
+ line6->buffer_message = kzalloc(LINE6_MIDI_MESSAGE_MAXLEN, GFP_KERNEL);
if (!line6->buffer_message)
return -ENOMEM;

--
2.43.0

[Takashi Iwai]

A fix already submitted in https://lore.kernel.org/r/20240402063628...@suse.de


thanks,

Takashi