================================================================== BUG: KASAN: slab-use-after-free in v4l2_fh_init+0x27d/0x2c0 drivers/media/v4l2-core/v4l2-fh.c:25 Read of size 8 at addr ffff8880140ec748 by task v4l_id/8277 CPU: 3 UID: 0 PID: 8277 Comm: v4l_id Not tainted syzkaller #0 PREEMPT(full) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0x156/0x4c9 mm/kasan/report.c:482 kasan_report+0xdf/0x1e0 mm/kasan/report.c:595 v4l2_fh_init+0x27d/0x2c0 drivers/media/v4l2-core/v4l2-fh.c:25 v4l2_fh_open+0x64/0xa0 drivers/media/v4l2-core/v4l2-fh.c:64 em28xx_v4l2_open+0x11e/0x570 drivers/media/usb/em28xx/em28xx-video.c:2153 v4l2_open+0x1d2/0x490 drivers/media/v4l2-core/v4l2-dev.c:433 chrdev_open+0x234/0x6a0 fs/char_dev.c:411 do_dentry_open+0x6d8/0x1660 fs/open.c:949 vfs_open+0x82/0x3f0 fs/open.c:1081 do_open fs/namei.c:4671 [inline] path_openat+0x208c/0x31a0 fs/namei.c:4830 do_file_open+0x20e/0x430 fs/namei.c:4859 do_sys_openat2+0x10d/0x1e0 fs/open.c:1366 do_sys_open fs/open.c:1372 [inline] __do_sys_openat fs/open.c:1388 [inline] __se_sys_openat fs/open.c:1383 [inline] __x64_sys_openat+0x12d/0x210 fs/open.c:1383 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x106/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f76ae0a7407 Code: 48 89 fa 4c 89 df e8 38 aa 00 00 8b 93 08 03 00 00 59 5e 48 83 f8 fc 74 1a 5b c3 0f 1f 84 00 00 00 00 00 48 8b 44 24 10 0f 05 <5b> c3 0f 1f 80 00 00 00 00 83 e2 39 83 fa 08 75 de e8 23 ff ff ff RSP: 002b:00007ffc1eb11e40 EFLAGS: 00000202 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007f76ae760880 RCX: 00007f76ae0a7407 RDX: 0000000000000000 RSI: 00007ffc1eb13f1b RDI: ffffffffffffff9c RBP: 0000000000000002 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000 R13: 00007ffc1eb12090 R14: 00007f76ae865000 R15: 0000563ccea3e4d8 Allocated by task 24: kasan_save_stack+0x30/0x50 mm/kasan/common.c:57 kasan_save_track+0x14/0x30 mm/kasan/common.c:78 poison_kmalloc_redzone mm/kasan/common.c:398 [inline] __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:415 kmalloc_noprof include/linux/slab.h:962 [inline] kzalloc_noprof include/linux/slab.h:1204 [inline] em28xx_v4l2_init.cold+0x94/0x3503 drivers/media/usb/em28xx/em28xx-video.c:2532 em28xx_init_extension+0x13a/0x200 drivers/media/usb/em28xx/em28xx-core.c:1117 request_module_async+0x61/0x80 drivers/media/usb/em28xx/em28xx-cards.c:3457 process_one_work+0x9d7/0x1920 kernel/workqueue.c:3275 process_scheduled_works kernel/workqueue.c:3358 [inline] worker_thread+0x5da/0xe40 kernel/workqueue.c:3439 kthread+0x370/0x450 kernel/kthread.c:467 ret_from_fork+0x754/0xd80 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Freed by task 24: kasan_save_stack+0x30/0x50 mm/kasan/common.c:57 kasan_save_track+0x14/0x30 mm/kasan/common.c:78 kasan_save_free_info+0x3b/0x70 mm/kasan/generic.c:584 poison_slab_object mm/kasan/common.c:253 [inline] __kasan_slab_free+0x5f/0x80 mm/kasan/common.c:285 kasan_slab_free include/linux/kasan.h:235 [inline] slab_free_hook mm/slub.c:2687 [inline] slab_free mm/slub.c:6124 [inline] kfree+0x1f6/0x6b0 mm/slub.c:6442 kref_put.isra.0+0x56/0x90 include/linux/kref.h:65 em28xx_v4l2_init.cold+0x280/0x3503 drivers/media/usb/em28xx/em28xx-video.c:2901 em28xx_init_extension+0x13a/0x200 drivers/media/usb/em28xx/em28xx-core.c:1117 request_module_async+0x61/0x80 drivers/media/usb/em28xx/em28xx-cards.c:3457 process_one_work+0x9d7/0x1920 kernel/workqueue.c:3275 process_scheduled_works kernel/workqueue.c:3358 [inline] worker_thread+0x5da/0xe40 kernel/workqueue.c:3439 kthread+0x370/0x450 kernel/kthread.c:467 ret_from_fork+0x754/0xd80 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 The buggy address belongs to the object at ffff8880140ec000 which belongs to the cache kmalloc-8k of size 8192 The buggy address is located 1864 bytes inside of freed 8192-byte region [ffff8880140ec000, ffff8880140ee000) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff8880140e8000 pfn:0x140e8 head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 flags: 0xfff00000000240(workingset|head|node=0|zone=1|lastcpupid=0x7ff) page_type: f5(slab) raw: 00fff00000000240 ffff88801b843180 ffffea00004de010 ffffea000099c610 raw: ffff8880140e8000 0000000000020001 00000000f5000000 0000000000000000 head: 00fff00000000240 ffff88801b843180 ffffea00004de010 ffffea000099c610 head: ffff8880140e8000 0000000000020001 00000000f5000000 0000000000000000 head: 00fff00000000003 ffffea0000503a01 00000000ffffffff 00000000ffffffff head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000008 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 6075, tgid 6073 (syz.3.16), ts 74886507381, free_ts 70158527814 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x153/0x170 mm/page_alloc.c:1888 prep_new_page mm/page_alloc.c:1896 [inline] get_page_from_freelist+0x111d/0x3140 mm/page_alloc.c:3961 __alloc_frozen_pages_noprof+0x27c/0x2ba0 mm/page_alloc.c:5249 alloc_slab_page mm/slub.c:3255 [inline] allocate_slab mm/slub.c:3444 [inline] new_slab+0xa6/0x6d0 mm/slub.c:3502 refill_objects+0x26b/0x400 mm/slub.c:7134 refill_sheaf mm/slub.c:2804 [inline] alloc_full_sheaf mm/slub.c:2825 [inline] __pcs_replace_empty_main+0x19f/0x600 mm/slub.c:4588 alloc_from_pcs mm/slub.c:4681 [inline] slab_alloc_node mm/slub.c:4815 [inline] __do_kmalloc_node mm/slub.c:5218 [inline] __kmalloc_noprof+0x688/0x850 mm/slub.c:5231 kmalloc_noprof include/linux/slab.h:966 [inline] kmalloc_array_noprof include/linux/slab.h:1113 [inline] snd_pcm_plugin_build+0x434/0x650 sound/core/oss/pcm_plugin.c:181 snd_pcm_plugin_build_route+0x1b3/0x2d0 sound/core/oss/route.c:103 snd_pcm_plug_format_plugins+0xc15/0x1430 sound/core/oss/pcm_plugin.c:525 snd_pcm_oss_change_params_locked+0x2e3c/0x39f0 sound/core/oss/pcm_oss.c:977 snd_pcm_oss_change_params sound/core/oss/pcm_oss.c:1108 [inline] snd_pcm_oss_get_active_substream+0x175/0x1d0 sound/core/oss/pcm_oss.c:1125 snd_pcm_oss_get_channels sound/core/oss/pcm_oss.c:1819 [inline] snd_pcm_oss_set_channels+0x23a/0x370 sound/core/oss/pcm_oss.c:1811 snd_pcm_oss_ioctl+0x206f/0x3720 sound/core/oss/pcm_oss.c:2663 __do_compat_sys_ioctl fs/ioctl.c:695 [inline] __se_compat_sys_ioctl fs/ioctl.c:638 [inline] __ia32_compat_sys_ioctl+0x2cf/0x360 fs/ioctl.c:638 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline] __do_fast_syscall_32+0xe3/0x8c0 arch/x86/entry/syscall_32.c:307 page last free pid 108 tgid 108 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] __free_pages_prepare mm/page_alloc.c:1432 [inline] free_unref_folios+0xac6/0x1760 mm/page_alloc.c:3039 shrink_folio_list+0x46d5/0x6060 mm/vmscan.c:1532 evict_folios+0x7fa/0x1e90 mm/vmscan.c:4708 try_to_shrink_lruvec+0x57e/0x990 mm/vmscan.c:4871 shrink_one+0x307/0x7f0 mm/vmscan.c:4916 shrink_many mm/vmscan.c:4979 [inline] lru_gen_shrink_node mm/vmscan.c:5057 [inline] shrink_node+0x274f/0x3ee0 mm/vmscan.c:6037 kswapd_shrink_node mm/vmscan.c:6884 [inline] balance_pgdat+0xbb7/0x1d40 mm/vmscan.c:7060 kswapd+0x556/0xba0 mm/vmscan.c:7333 kthread+0x370/0x450 kernel/kthread.c:467 ret_from_fork+0x754/0xd80 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Memory state around the buggy address: ffff8880140ec600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880140ec680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8880140ec700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8880140ec780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880140ec800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================