================================================================== 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 ffff88811e74c730 by task v4l_id/13219 CPU: 0 UID: 0 PID: 13219 Comm: v4l_id Not tainted 6.14.0-rc6-syzkaller-ged492c95f13a #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:408 [inline] print_report+0xc3/0x670 mm/kasan/report.c:521 kasan_report+0xd9/0x110 mm/kasan/report.c:634 v4l2_fh_init+0x27d/0x2c0 drivers/media/v4l2-core/v4l2-fh.c:25 v4l2_fh_open+0x83/0xc0 drivers/media/v4l2-core/v4l2-fh.c:63 em28xx_v4l2_open+0x250/0x7e0 drivers/media/usb/em28xx/em28xx-video.c:2153 v4l2_open+0x222/0x490 drivers/media/v4l2-core/v4l2-dev.c:429 chrdev_open+0x237/0x6a0 fs/char_dev.c:414 do_dentry_open+0x6cb/0x1390 fs/open.c:956 vfs_open+0x82/0x3f0 fs/open.c:1086 do_open fs/namei.c:3830 [inline] path_openat+0x1e88/0x2d80 fs/namei.c:3989 do_filp_open+0x20c/0x470 fs/namei.c:4016 do_sys_openat2+0x17a/0x1e0 fs/open.c:1428 do_sys_open fs/open.c:1443 [inline] __do_sys_openat fs/open.c:1459 [inline] __se_sys_openat fs/open.c:1454 [inline] __x64_sys_openat+0x175/0x210 fs/open.c:1454 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f6e14e369a4 Code: 24 20 48 8d 44 24 30 48 89 44 24 28 64 8b 04 25 18 00 00 00 85 c0 75 2c 44 89 e2 48 89 ee bf 9c ff ff ff b8 01 01 00 00 0f 05 <48> 3d 00 f0 ff ff 76 60 48 8b 15 55 a4 0d 00 f7 d8 64 89 02 48 83 RSP: 002b:00007ffe7b05ca60 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007ffe7b05cc78 RCX: 00007f6e14e369a4 RDX: 0000000000000000 RSI: 00007ffe7b05cf22 RDI: 00000000ffffff9c RBP: 00007ffe7b05cf22 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffe7b05cc90 R14: 000055a0cde79670 R15: 00007f6e15285a80 Allocated by task 6641: kasan_save_stack+0x33/0x60 mm/kasan/common.c:47 kasan_save_track+0x14/0x30 mm/kasan/common.c:68 poison_kmalloc_redzone mm/kasan/common.c:377 [inline] __kasan_kmalloc+0x8f/0xa0 mm/kasan/common.c:394 kmalloc_noprof include/linux/slab.h:901 [inline] kzalloc_noprof include/linux/slab.h:1037 [inline] em28xx_v4l2_init+0x114/0x4050 drivers/media/usb/em28xx/em28xx-video.c:2532 em28xx_init_extension+0x137/0x200 drivers/media/usb/em28xx/em28xx-core.c:1117 request_module_async+0x61/0x70 drivers/media/usb/em28xx/em28xx-cards.c:3457 process_one_work+0x9c5/0x1ba0 kernel/workqueue.c:3238 process_scheduled_works kernel/workqueue.c:3319 [inline] worker_thread+0x6c8/0xf00 kernel/workqueue.c:3400 kthread+0x3af/0x750 kernel/kthread.c:464 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 Freed by task 6641: kasan_save_stack+0x33/0x60 mm/kasan/common.c:47 kasan_save_track+0x14/0x30 mm/kasan/common.c:68 kasan_save_free_info+0x3b/0x60 mm/kasan/generic.c:576 poison_slab_object mm/kasan/common.c:247 [inline] __kasan_slab_free+0x37/0x50 mm/kasan/common.c:264 kasan_slab_free include/linux/kasan.h:233 [inline] slab_free_hook mm/slub.c:2353 [inline] slab_free mm/slub.c:4609 [inline] kfree+0x294/0x480 mm/slub.c:4757 em28xx_free_v4l2 drivers/media/usb/em28xx/em28xx-video.c:2118 [inline] kref_put include/linux/kref.h:65 [inline] em28xx_v4l2_init+0x22a4/0x4050 drivers/media/usb/em28xx/em28xx-video.c:2901 em28xx_init_extension+0x137/0x200 drivers/media/usb/em28xx/em28xx-core.c:1117 request_module_async+0x61/0x70 drivers/media/usb/em28xx/em28xx-cards.c:3457 process_one_work+0x9c5/0x1ba0 kernel/workqueue.c:3238 process_scheduled_works kernel/workqueue.c:3319 [inline] worker_thread+0x6c8/0xf00 kernel/workqueue.c:3400 kthread+0x3af/0x750 kernel/kthread.c:464 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 The buggy address belongs to the object at ffff88811e74c000 which belongs to the cache kmalloc-8k of size 8192 The buggy address is located 1840 bytes inside of freed 8192-byte region [ffff88811e74c000, ffff88811e74e000) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x11e748 head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 flags: 0x200000000000040(head|node=0|zone=2) page_type: f5(slab) raw: 0200000000000040 ffff888100042280 ffffea0004541600 dead000000000002 raw: 0000000000000000 0000000000020002 00000000f5000000 0000000000000000 head: 0200000000000040 ffff888100042280 ffffea0004541600 dead000000000002 head: 0000000000000000 0000000000020002 00000000f5000000 0000000000000000 head: 0200000000000003 ffffea000479d201 ffffffffffffffff 0000000000000000 head: 0000000000000008 0000000000000000 00000000ffffffff 0000000000000000 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 25, tgid 25 (kworker/1:0), ts 471756199207, free_ts 471314361040 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x181/0x1b0 mm/page_alloc.c:1551 prep_new_page mm/page_alloc.c:1559 [inline] get_page_from_freelist+0xe76/0x2b90 mm/page_alloc.c:3477 __alloc_frozen_pages_noprof+0x21c/0x2290 mm/page_alloc.c:4740 alloc_pages_mpol+0xe7/0x410 mm/mempolicy.c:2270 alloc_slab_page mm/slub.c:2423 [inline] allocate_slab mm/slub.c:2587 [inline] new_slab+0x23d/0x330 mm/slub.c:2640 ___slab_alloc+0xc41/0x1670 mm/slub.c:3826 __slab_alloc.constprop.0+0x56/0xb0 mm/slub.c:3916 __slab_alloc_node mm/slub.c:3991 [inline] slab_alloc_node mm/slub.c:4152 [inline] __do_kmalloc_node mm/slub.c:4293 [inline] __kmalloc_noprof+0x154/0x4d0 mm/slub.c:4306 kmalloc_noprof include/linux/slab.h:905 [inline] hcd_buffer_alloc+0x1f5/0x290 drivers/usb/core/buffer.c:134 usb_alloc_coherent+0x5f/0xa0 drivers/usb/core/usb.c:1001 usb_allocate_stream_buffers+0x1aa/0x300 drivers/media/usb/dvb-usb/usb-urb.c:121 usb_bulk_urb_init drivers/media/usb/dvb-usb/usb-urb.c:142 [inline] usb_urb_init+0x777/0x1130 drivers/media/usb/dvb-usb/usb-urb.c:229 dvb_usb_adapter_stream_init+0x145/0x3e0 drivers/media/usb/dvb-usb/dvb-usb-urb.c:108 dvb_usb_adapter_init drivers/media/usb/dvb-usb/dvb-usb-init.c:82 [inline] dvb_usb_init drivers/media/usb/dvb-usb/dvb-usb-init.c:186 [inline] dvb_usb_device_init+0x159f/0x20a0 drivers/media/usb/dvb-usb/dvb-usb-init.c:310 cxusb_probe+0x3a7/0x7d0 drivers/media/usb/dvb-usb/cxusb.c:1649 usb_probe_interface+0x300/0x9c0 drivers/usb/core/driver.c:396 page last free pid 5295 tgid 5295 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1127 [inline] free_frozen_pages+0x653/0xde0 mm/page_alloc.c:2660 __put_partials+0x14c/0x170 mm/slub.c:3153 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x4e/0x120 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x195/0x1e0 mm/kasan/quarantine.c:286 __kasan_slab_alloc+0x4e/0x70 mm/kasan/common.c:329 kasan_slab_alloc include/linux/kasan.h:250 [inline] slab_post_alloc_hook mm/slub.c:4115 [inline] slab_alloc_node mm/slub.c:4164 [inline] kmem_cache_alloc_noprof+0x154/0x3b0 mm/slub.c:4171 getname_flags.part.0+0x4c/0x550 fs/namei.c:139 getname_flags include/linux/audit.h:322 [inline] getname fs/namei.c:223 [inline] __do_sys_unlink fs/namei.c:4637 [inline] __se_sys_unlink fs/namei.c:4635 [inline] __x64_sys_unlink+0xb0/0x110 fs/namei.c:4635 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f Memory state around the buggy address: ffff88811e74c600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88811e74c680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff88811e74c700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88811e74c780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88811e74c800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================