Hi,

We observed an issue "KASAN: use-after-free Read in snd_pcm_plug_read_transfer".

Unfortunately, we have not found a reproducer for the crash. We will inform you if we have any update on this crash.

Detailed crash information is attached below.

Best regards, Dae R. Jeong

----- - Kernel version: 6.0-rc7

- Crash report: ================================================================== BUG: KASAN: use-after-free in snd_pcm_plug_read_transfer+0x2e6/0x4e0 sound/core/oss/pcm_plugin.c:653 Read of size 8 at addr ffff88801fb82e60 by task syz-executor.0/3194

CPU: 2 PID: 3194 Comm: syz-executor.0 Not tainted 6.0.0-rc7-00167-g92162e4a9862 #2 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014 Call Trace: <TASK> __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x1cf/0x2b7 lib/dump_stack.c:106 print_address_description+0x21/0x470 mm/kasan/report.c:317 print_report+0x108/0x1f0 mm/kasan/report.c:433 kasan_report+0xe5/0x110 mm/kasan/report.c:495 snd_pcm_plug_read_transfer+0x2e6/0x4e0 sound/core/oss/pcm_plugin.c:653 snd_pcm_oss_read2 sound/core/oss/pcm_oss.c:1493 [inline] snd_pcm_oss_read1+0x7a0/0x1130 sound/core/oss/pcm_oss.c:1531 vfs_read+0x31e/0xd30 fs/read_write.c:468 ksys_read+0x182/0x2c0 fs/read_write.c:607 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x4e/0xa0 arch/x86/entry/common.c:82 entry_SYSCALL_64_after_hwframe+0x63/0xcd RIP: 0033:0x4725fd Code: 02 b8 ff ff ff ff c3 66 0f 1f 44 00 00 f3 0f 1e fa 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 bc ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f3e600f5be8 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 RAX: ffffffffffffffda RBX: 0000000000582928 RCX: 00000000004725fd RDX: 0000000000000016 RSI: 0000000020000140 RDI: 0000000000000007 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000582930 R13: 0000000000582934 R14: 00007fff5bd8fb10 R15: 00007f3e600f5d80 </TASK>

Allocated by task 3193: kasan_save_stack mm/kasan/common.c:38 [inline] kasan_set_track mm/kasan/common.c:45 [inline] set_alloc_info mm/kasan/common.c:437 [inline] ____kasan_kmalloc+0xcd/0x100 mm/kasan/common.c:516 kasan_kmalloc include/linux/kasan.h:234 [inline] __kmalloc+0x31e/0x490 mm/slub.c:4429 kmalloc include/linux/slab.h:605 [inline] kzalloc include/linux/slab.h:733 [inline] snd_pcm_plugin_build+0x5e/0x560 sound/core/oss/pcm_plugin.c:164 snd_pcm_plugin_build_rate+0x22d/0x720 sound/core/oss/rate.c:324 snd_pcm_plug_format_plugins+0xb5f/0x1b80 sound/core/oss/pcm_plugin.c:478 snd_pcm_oss_change_params_locked+0x2c06/0x4e20 sound/core/oss/pcm_oss.c:986 snd_pcm_oss_change_params sound/core/oss/pcm_oss.c:1116 [inline] snd_pcm_oss_get_active_substream+0x244/0x2b0 sound/core/oss/pcm_oss.c:1133 snd_pcm_oss_get_rate sound/core/oss/pcm_oss.c:1790 [inline] snd_pcm_oss_set_rate sound/core/oss/pcm_oss.c:1782 [inline] snd_pcm_oss_ioctl+0x217b/0x4190 sound/core/oss/pcm_oss.c:2638 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:870 [inline] __se_sys_ioctl+0x110/0x180 fs/ioctl.c:856 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x4e/0xa0 arch/x86/entry/common.c:82 entry_SYSCALL_64_after_hwframe+0x63/0xcd

Freed by task 3195: kasan_save_stack mm/kasan/common.c:38 [inline] kasan_set_track+0x3d/0x60 mm/kasan/common.c:45 kasan_set_free_info+0x1f/0x40 mm/kasan/generic.c:370 ____kasan_slab_free+0x134/0x1c0 mm/kasan/common.c:367 kasan_slab_free include/linux/kasan.h:200 [inline] slab_free_hook mm/slub.c:1759 [inline] slab_free_freelist_hook+0x278/0x370 mm/slub.c:1785 slab_free mm/slub.c:3539 [inline] kfree+0x108/0x460 mm/slub.c:4567 snd_pcm_plugin_free+0xd1/0xe0 sound/core/oss/pcm_plugin.c:199 snd_pcm_oss_plugin_clear sound/core/oss/pcm_oss.c:547 [inline] snd_pcm_oss_release_buffers sound/core/oss/pcm_oss.c:852 [inline] snd_pcm_oss_change_params_locked+0x11d9/0x4e20 sound/core/oss/pcm_oss.c:1096 snd_pcm_oss_change_params sound/core/oss/pcm_oss.c:1116 [inline] snd_pcm_oss_make_ready sound/core/oss/pcm_oss.c:1175 [inline] snd_pcm_oss_set_trigger+0x45f/0xf70 sound/core/oss/pcm_oss.c:2092 snd_pcm_oss_poll+0x810/0xab0 sound/core/oss/pcm_oss.c:2878 vfs_poll include/linux/poll.h:88 [inline] p9_fd_poll net/9p/trans_fd.c:233 [inline] p9_conn_create+0x52f/0x700 net/9p/trans_fd.c:598 p9_fd_create+0x3e0/0x4c0 net/9p/trans_fd.c:1077 p9_client_create+0x916/0x11d0 net/9p/client.c:966 v9fs_session_init+0x223/0x1cf0 fs/9p/v9fs.c:408 v9fs_mount+0xdd/0xe90 fs/9p/vfs_super.c:126 legacy_get_tree+0x135/0x1f0 fs/fs_context.c:610 vfs_get_tree+0xa5/0x310 fs/super.c:1530 do_new_mount fs/namespace.c:3040 [inline] path_mount+0x1b37/0x3090 fs/namespace.c:3370 do_mount fs/namespace.c:3383 [inline] __do_sys_mount fs/namespace.c:3591 [inline] __se_sys_mount+0x313/0x3d0 fs/namespace.c:3568 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x4e/0xa0 arch/x86/entry/common.c:82 entry_SYSCALL_64_after_hwframe+0x63/0xcd

Last potentially related work creation: kasan_save_stack+0x2b/0x50 mm/kasan/common.c:38 __kasan_record_aux_stack+0xac/0xc0 mm/kasan/generic.c:348 insert_work+0x54/0x400 kernel/workqueue.c:1358 __queue_work+0xa95/0xe00 kernel/workqueue.c:1517 queue_work_on+0x12c/0x210 kernel/workqueue.c:1545 queue_work include/linux/workqueue.h:503 [inline] call_usermodehelper_exec+0x298/0x4b0 kernel/umh.c:435 kobject_uevent_env+0x1571/0x1990 lib/kobject_uevent.c:618 kobject_synth_uevent+0x3ed/0x980 lib/kobject_uevent.c:208 uevent_store+0x20/0x60 drivers/base/core.c:2509 kernfs_fop_write_iter+0x450/0x600 fs/kernfs/file.c:354 call_write_iter include/linux/fs.h:2187 [inline] new_sync_write fs/read_write.c:491 [inline] vfs_write+0x848/0xd90 fs/read_write.c:578 ksys_write+0x182/0x2c0 fs/read_write.c:631 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x4e/0xa0 arch/x86/entry/common.c:82 entry_SYSCALL_64_after_hwframe+0x63/0xcd

Second to last potentially related work creation: kasan_save_stack+0x2b/0x50 mm/kasan/common.c:38 __kasan_record_aux_stack+0xac/0xc0 mm/kasan/generic.c:348 insert_work+0x54/0x400 kernel/workqueue.c:1358 __queue_work+0xa95/0xe00 kernel/workqueue.c:1517 queue_work_on+0x12c/0x210 kernel/workqueue.c:1545 queue_work include/linux/workqueue.h:503 [inline] call_usermodehelper_exec+0x298/0x4b0 kernel/umh.c:435 kobject_uevent_env+0x1571/0x1990 lib/kobject_uevent.c:618 device_add+0x1339/0x1b60 drivers/base/core.c:3498 usb_new_device+0xd9d/0x1bb0 drivers/usb/core/hub.c:2573 hub_port_connect+0x1243/0x2dd0 drivers/usb/core/hub.c:5353 hub_port_connect_change+0x696/0xd40 drivers/usb/core/hub.c:5497 port_event+0xaca/0x12b0 drivers/usb/core/hub.c:5653 hub_event+0x511/0xed0 drivers/usb/core/hub.c:5735 process_one_work+0x83f/0x11a0 kernel/workqueue.c:2289 worker_thread+0xa6c/0x1290 kernel/workqueue.c:2436 kthread+0x28a/0x320 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306

The buggy address belongs to the object at ffff88801fb82e00 which belongs to the cache kmalloc-192 of size 192 The buggy address is located 96 bytes inside of 192-byte region [ffff88801fb82e00, ffff88801fb82ec0)

The buggy address belongs to the physical page: page:ffffea00007ee080 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1fb82 flags: 0xfff00000000200(slab|node=0|zone=1|lastcpupid=0x7ff) raw: 00fff00000000200 ffffea0000503380 dead000000000002 ffff888013442a00 raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 0, migratetype Unmovable, gfp_mask 0x12c00(GFP_NOIO|__GFP_NOWARN|__GFP_NORETRY), pid 949, tgid 949 (kworker/0:2), ts 20844494854, free_ts 20409160136 prep_new_page mm/page_alloc.c:2532 [inline] get_page_from_freelist+0x800/0xc10 mm/page_alloc.c:4283 __alloc_pages+0x2f0/0x650 mm/page_alloc.c:5549 alloc_slab_page mm/slub.c:1829 [inline] allocate_slab+0x1eb/0xc00 mm/slub.c:1974 new_slab mm/slub.c:2034 [inline] ___slab_alloc+0x581/0xff0 mm/slub.c:3036 __slab_alloc mm/slub.c:3123 [inline] slab_alloc_node mm/slub.c:3214 [inline] slab_alloc mm/slub.c:3256 [inline] __kmalloc+0x3cb/0x490 mm/slub.c:4425 kmalloc include/linux/slab.h:605 [inline] usb_alloc_urb+0x38/0x180 drivers/usb/core/urb.c:74 usb_internal_control_msg drivers/usb/core/message.c:95 [inline] usb_control_msg+0x1bd/0x590 drivers/usb/core/message.c:153 get_port_status drivers/usb/core/hub.c:581 [inline] hub_ext_port_status+0x12d/0x780 drivers/usb/core/hub.c:598 usb_hub_port_status drivers/usb/core/hub.c:620 [inline] hub_activate+0x917/0x2060 drivers/usb/core/hub.c:1130 process_one_work+0x83f/0x11a0 kernel/workqueue.c:2289 worker_thread+0xa6c/0x1290 kernel/workqueue.c:2436 kthread+0x28a/0x320 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306 page last free stack trace: reset_page_owner include/linux/page_owner.h:24 [inline] free_pages_prepare mm/page_alloc.c:1449 [inline] free_pcp_prepare+0x76d/0x890 mm/page_alloc.c:1499 free_unref_page_prepare mm/page_alloc.c:3380 [inline] free_unref_page+0x8a/0x880 mm/page_alloc.c:3476 __tlb_remove_table arch/x86/include/asm/tlb.h:34 [inline] __tlb_remove_table_free mm/mmu_gather.c:114 [inline] tlb_remove_table_rcu+0x9b/0x120 mm/mmu_gather.c:169 rcu_do_batch kernel/rcu/tree.c:2245 [inline] rcu_core+0x9bb/0x1680 kernel/rcu/tree.c:2505 __do_softirq+0x372/0x783 kernel/softirq.c:571

Memory state around the buggy address: ffff88801fb82d00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88801fb82d80: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc

ffff88801fb82e00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb

^ ffff88801fb82e80: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc ffff88801fb82f00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================