syzbot


KASAN: slab-use-after-free Read in snd_usbmidi_error_timer

Status: moderation: reported on 2025/05/08 03:01
Subsystems: sound
[Documentation on labels]
Reported-by: syzbot+cfd5b2e2404f7fd3eeb4@syzkaller.appspotmail.com
First crash: 13d, last: 7d11h

Sample crash report:
==================================================================
BUG: KASAN: slab-use-after-free in snd_usbmidi_error_timer+0x602/0x660 sound/usb/midi.c:352
Read of size 1 at addr ffff888030e30d43 by task syz.1.91/6238

CPU: 0 UID: 0 PID: 6238 Comm: syz.1.91 Not tainted 6.15.0-rc5-syzkaller-00136-g9c69f8884904 #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/29/2025
Call Trace:
 <IRQ>
 dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:408 [inline]
 print_report+0xb4/0x290 mm/kasan/report.c:521
 kasan_report+0x118/0x150 mm/kasan/report.c:634
 snd_usbmidi_error_timer+0x602/0x660 sound/usb/midi.c:352
 call_timer_fn+0x17b/0x5f0 kernel/time/timer.c:1789
 expire_timers kernel/time/timer.c:1840 [inline]
 __run_timers kernel/time/timer.c:2414 [inline]
 __run_timer_base+0x61a/0x860 kernel/time/timer.c:2426
 run_timer_base kernel/time/timer.c:2435 [inline]
 run_timer_softirq+0xb7/0x180 kernel/time/timer.c:2445
 handle_softirqs+0x283/0x870 kernel/softirq.c:579
 __do_softirq kernel/softirq.c:613 [inline]
 invoke_softirq kernel/softirq.c:453 [inline]
 __irq_exit_rcu+0xca/0x1f0 kernel/softirq.c:680
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:696
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1049 [inline]
 sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1049
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:160 [inline]
RIP: 0010:_raw_spin_unlock_irq+0x29/0x50 kernel/locking/spinlock.c:202
Code: 90 f3 0f 1e fa 53 48 89 fb 48 83 c7 18 48 8b 74 24 08 e8 9a b2 4c f6 48 89 df e8 c2 49 4d f6 e8 7d d1 75 f6 fb bf 01 00 00 00 <e8> d2 53 3f f6 65 8b 05 1b 85 20 07 85 c0 74 07 5b c3 cc cc cc cc
RSP: 0018:ffffc9000574fa70 EFLAGS: 00000282
RAX: 06b14195e906d400 RBX: ffff88814d4a0638 RCX: 06b14195e906d400
RDX: 0000000000000000 RSI: ffffffff8d73731e RDI: 0000000000000001
RBP: ffffc9000574fc30 R08: ffffffff8f7da777 R09: 1ffffffff1efb4ee
R10: dffffc0000000000 R11: fffffbfff1efb4ef R12: 0000000000000000
R13: 000000000000d79f R14: dffffc0000000000 R15: ffff888033a39a00
 spin_unlock_irq include/linux/spinlock.h:401 [inline]
 snd_rawmidi_write+0x58e/0xbd0 sound/core/rawmidi.c:1628
 do_loop_readv_writev include/linux/uio.h:-1 [inline]
 vfs_writev+0x4a2/0x9a0 fs/read_write.c:1057
 do_writev+0x14d/0x2d0 fs/read_write.c:1101
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xf6/0x210 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f03fb78e969
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f03fc687038 EFLAGS: 00000246 ORIG_RAX: 0000000000000014
RAX: ffffffffffffffda RBX: 00007f03fb9b5fa0 RCX: 00007f03fb78e969
RDX: 0000000000000002 RSI: 0000200000000840 RDI: 0000000000000004
RBP: 00007f03fb810ab1 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f03fb9b5fa0 R15: 00007ffee96f5c68
 </TASK>

Allocated by task 24:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:68
 poison_kmalloc_redzone mm/kasan/common.c:377 [inline]
 __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:394
 kasan_kmalloc include/linux/kasan.h:260 [inline]
 __kmalloc_cache_noprof+0x230/0x3d0 mm/slub.c:4358
 kmalloc_noprof include/linux/slab.h:905 [inline]
 kzalloc_noprof include/linux/slab.h:1039 [inline]
 snd_usbmidi_in_endpoint_create+0x7e/0xa30 sound/usb/midi.c:1342
 snd_usbmidi_create_endpoints_midiman sound/usb/midi.c:2362 [inline]
 __snd_usbmidi_create+0x21bd/0x29d0 sound/usb/midi.c:2645
 snd_usb_midi_v2_create+0x43e1/0x4650 sound/usb/midi2.c:1177
 usb_audio_probe+0xb78/0x1dc0 sound/usb/card.c:886
 usb_probe_interface+0x641/0xbc0 drivers/usb/core/driver.c:396
 call_driver_probe drivers/base/dd.c:-1 [inline]
 really_probe+0x26a/0x9a0 drivers/base/dd.c:657
 __driver_probe_device+0x18c/0x2f0 drivers/base/dd.c:799
 driver_probe_device+0x4f/0x430 drivers/base/dd.c:829
 __device_attach_driver+0x2ce/0x530 drivers/base/dd.c:957
 bus_for_each_drv+0x24e/0x2e0 drivers/base/bus.c:462
 __device_attach+0x2b8/0x400 drivers/base/dd.c:1029
 bus_probe_device+0x185/0x260 drivers/base/bus.c:537
 device_add+0x7b6/0xb50 drivers/base/core.c:3692
 usb_set_configuration+0x1a87/0x20e0 drivers/usb/core/message.c:2210
 usb_generic_driver_probe+0x8d/0x150 drivers/usb/core/generic.c:250
 usb_probe_device+0x1c1/0x390 drivers/usb/core/driver.c:291
 call_driver_probe drivers/base/dd.c:-1 [inline]
 really_probe+0x26a/0x9a0 drivers/base/dd.c:657
 __driver_probe_device+0x18c/0x2f0 drivers/base/dd.c:799
 driver_probe_device+0x4f/0x430 drivers/base/dd.c:829
 __device_attach_driver+0x2ce/0x530 drivers/base/dd.c:957
 bus_for_each_drv+0x24e/0x2e0 drivers/base/bus.c:462
 __device_attach+0x2b8/0x400 drivers/base/dd.c:1029
 bus_probe_device+0x185/0x260 drivers/base/bus.c:537
 device_add+0x7b6/0xb50 drivers/base/core.c:3692
 usb_new_device+0xa39/0x16c0 drivers/usb/core/hub.c:2663
 hub_port_connect drivers/usb/core/hub.c:5531 [inline]
 hub_port_connect_change drivers/usb/core/hub.c:5671 [inline]
 port_event drivers/usb/core/hub.c:5831 [inline]
 hub_event+0x2941/0x4a00 drivers/usb/core/hub.c:5913
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0xadb/0x17a0 kernel/workqueue.c:3319
 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3400
 kthread+0x70e/0x8a0 kernel/kthread.c:464
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Freed by task 24:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:68
 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:576
 poison_slab_object mm/kasan/common.c:247 [inline]
 __kasan_slab_free+0x62/0x70 mm/kasan/common.c:264
 kasan_slab_free include/linux/kasan.h:233 [inline]
 slab_free_hook mm/slub.c:2380 [inline]
 slab_free mm/slub.c:4642 [inline]
 kfree+0x193/0x440 mm/slub.c:4841
 snd_usbmidi_free sound/usb/midi.c:1530 [inline]
 snd_usbmidi_rawmidi_free+0xae/0x150 sound/usb/midi.c:1590
 snd_rawmidi_free+0x3bc/0x410 sound/core/rawmidi.c:1934
 snd_rawmidi_dev_free+0x38/0x50 sound/core/rawmidi.c:1945
 __snd_device_free+0x1d2/0x2e0 sound/core/device.c:76
 snd_device_free_all+0xcf/0x180 sound/core/device.c:233
 snd_card_do_free sound/core/init.c:587 [inline]
 release_card_device+0x75/0x1b0 sound/core/init.c:153
 device_release+0x99/0x1c0 drivers/base/core.c:-1
 kobject_cleanup lib/kobject.c:689 [inline]
 kobject_release lib/kobject.c:720 [inline]
 kref_put include/linux/kref.h:65 [inline]
 kobject_put+0x228/0x480 lib/kobject.c:737
 snd_card_free_when_closed sound/core/init.c:618 [inline]
 snd_card_free+0x110/0x190 sound/core/init.c:650
 usb_audio_probe+0x18ea/0x1dc0 sound/usb/card.c:940
 usb_probe_interface+0x641/0xbc0 drivers/usb/core/driver.c:396
 call_driver_probe drivers/base/dd.c:-1 [inline]
 really_probe+0x26a/0x9a0 drivers/base/dd.c:657
 __driver_probe_device+0x18c/0x2f0 drivers/base/dd.c:799
 driver_probe_device+0x4f/0x430 drivers/base/dd.c:829
 __device_attach_driver+0x2ce/0x530 drivers/base/dd.c:957
 bus_for_each_drv+0x24e/0x2e0 drivers/base/bus.c:462
 __device_attach+0x2b8/0x400 drivers/base/dd.c:1029
 bus_probe_device+0x185/0x260 drivers/base/bus.c:537
 device_add+0x7b6/0xb50 drivers/base/core.c:3692
 usb_set_configuration+0x1a87/0x20e0 drivers/usb/core/message.c:2210
 usb_generic_driver_probe+0x8d/0x150 drivers/usb/core/generic.c:250
 usb_probe_device+0x1c1/0x390 drivers/usb/core/driver.c:291
 call_driver_probe drivers/base/dd.c:-1 [inline]
 really_probe+0x26a/0x9a0 drivers/base/dd.c:657
 __driver_probe_device+0x18c/0x2f0 drivers/base/dd.c:799
 driver_probe_device+0x4f/0x430 drivers/base/dd.c:829
 __device_attach_driver+0x2ce/0x530 drivers/base/dd.c:957
 bus_for_each_drv+0x24e/0x2e0 drivers/base/bus.c:462
 __device_attach+0x2b8/0x400 drivers/base/dd.c:1029
 bus_probe_device+0x185/0x260 drivers/base/bus.c:537
 device_add+0x7b6/0xb50 drivers/base/core.c:3692
 usb_new_device+0xa39/0x16c0 drivers/usb/core/hub.c:2663
 hub_port_connect drivers/usb/core/hub.c:5531 [inline]
 hub_port_connect_change drivers/usb/core/hub.c:5671 [inline]
 port_event drivers/usb/core/hub.c:5831 [inline]
 hub_event+0x2941/0x4a00 drivers/usb/core/hub.c:5913
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0xadb/0x17a0 kernel/workqueue.c:3319
 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3400
 kthread+0x70e/0x8a0 kernel/kthread.c:464
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

The buggy address belongs to the object at ffff888030e30c00
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 323 bytes inside of
 freed 512-byte region [ffff888030e30c00, ffff888030e30e00)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x30e30
head: order:2 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000040 ffff88801a041c80 dead000000000100 dead000000000122
raw: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000
head: 00fff00000000040 ffff88801a041c80 dead000000000100 dead000000000122
head: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000
head: 00fff00000000002 ffffea0000c38c01 00000000ffffffff 00000000ffffffff
head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000004
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 2, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5203, tgid 5203 (udevadm), ts 37086191681, free_ts 37071696474
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x1d8/0x230 mm/page_alloc.c:1718
 prep_new_page mm/page_alloc.c:1726 [inline]
 get_page_from_freelist+0x21c7/0x22a0 mm/page_alloc.c:3688
 __alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:4970
 alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2301
 alloc_slab_page mm/slub.c:2450 [inline]
 allocate_slab+0x8a/0x3b0 mm/slub.c:2618
 new_slab mm/slub.c:2672 [inline]
 ___slab_alloc+0xbfc/0x1480 mm/slub.c:3858
 __slab_alloc mm/slub.c:3948 [inline]
 __slab_alloc_node mm/slub.c:4023 [inline]
 slab_alloc_node mm/slub.c:4184 [inline]
 __kmalloc_cache_noprof+0x296/0x3d0 mm/slub.c:4353
 kmalloc_noprof include/linux/slab.h:905 [inline]
 kzalloc_noprof include/linux/slab.h:1039 [inline]
 kernfs_fop_open+0x397/0xca0 fs/kernfs/file.c:623
 do_dentry_open+0xdf0/0x1970 fs/open.c:956
 vfs_open+0x3b/0x340 fs/open.c:1086
 do_open fs/namei.c:3880 [inline]
 path_openat+0x2ee5/0x3830 fs/namei.c:4039
 do_filp_open+0x1fa/0x410 fs/namei.c:4066
 do_sys_openat2+0x121/0x1c0 fs/open.c:1429
 do_sys_open fs/open.c:1444 [inline]
 __do_sys_openat fs/open.c:1460 [inline]
 __se_sys_openat fs/open.c:1455 [inline]
 __x64_sys_openat+0x138/0x170 fs/open.c:1455
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xf6/0x210 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
page last free pid 5194 tgid 5194 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1262 [inline]
 __free_frozen_pages+0xb05/0xcd0 mm/page_alloc.c:2725
 discard_slab mm/slub.c:2716 [inline]
 __put_partials+0x161/0x1c0 mm/slub.c:3185
 put_cpu_partial+0x17c/0x250 mm/slub.c:3260
 __slab_free+0x2f7/0x400 mm/slub.c:4512
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x9a/0x140 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286
 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:329
 kasan_slab_alloc include/linux/kasan.h:250 [inline]
 slab_post_alloc_hook mm/slub.c:4147 [inline]
 slab_alloc_node mm/slub.c:4196 [inline]
 __kmalloc_cache_noprof+0x1be/0x3d0 mm/slub.c:4353
 kmalloc_noprof include/linux/slab.h:905 [inline]
 kzalloc_noprof include/linux/slab.h:1039 [inline]
 kernfs_fop_open+0x397/0xca0 fs/kernfs/file.c:623
 do_dentry_open+0xdf0/0x1970 fs/open.c:956
 vfs_open+0x3b/0x340 fs/open.c:1086
 do_open fs/namei.c:3880 [inline]
 path_openat+0x2ee5/0x3830 fs/namei.c:4039
 do_filp_open+0x1fa/0x410 fs/namei.c:4066
 do_sys_openat2+0x121/0x1c0 fs/open.c:1429
 do_sys_open fs/open.c:1444 [inline]
 __do_sys_openat fs/open.c:1460 [inline]
 __se_sys_openat fs/open.c:1455 [inline]
 __x64_sys_openat+0x138/0x170 fs/open.c:1455
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xf6/0x210 arch/x86/entry/syscall_64.c:94

Memory state around the buggy address:
 ffff888030e30c00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888030e30c80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888030e30d00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                           ^
 ffff888030e30d80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888030e30e00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================
----------------
Code disassembly (best guess):
   0:	90                   	nop
   1:	f3 0f 1e fa          	endbr64
   5:	53                   	push   %rbx
   6:	48 89 fb             	mov    %rdi,%rbx
   9:	48 83 c7 18          	add    $0x18,%rdi
   d:	48 8b 74 24 08       	mov    0x8(%rsp),%rsi
  12:	e8 9a b2 4c f6       	call   0xf64cb2b1
  17:	48 89 df             	mov    %rbx,%rdi
  1a:	e8 c2 49 4d f6       	call   0xf64d49e1
  1f:	e8 7d d1 75 f6       	call   0xf675d1a1
  24:	fb                   	sti
  25:	bf 01 00 00 00       	mov    $0x1,%edi
* 2a:	e8 d2 53 3f f6       	call   0xf63f5401 <-- trapping instruction
  2f:	65 8b 05 1b 85 20 07 	mov    %gs:0x720851b(%rip),%eax        # 0x7208551
  36:	85 c0                	test   %eax,%eax
  38:	74 07                	je     0x41
  3a:	5b                   	pop    %rbx
  3b:	c3                   	ret
  3c:	cc                   	int3
  3d:	cc                   	int3
  3e:	cc                   	int3
  3f:	cc                   	int3

Crashes (3):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/05/09 18:11 upstream 9c69f8884904 bb813bcc .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root KASAN: slab-use-after-free Read in snd_usbmidi_error_timer
2025/05/08 11:47 upstream 707df3375124 dbf35fa1 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root KASAN: slab-use-after-free Read in snd_usbmidi_error_timer
2025/05/04 02:52 upstream 2a239ffbebb5 b0714e37 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce KASAN: slab-use-after-free Read in snd_usbmidi_error_timer
* Struck through repros no longer work on HEAD.