================================================================== 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 ffff888020f10740 by task v4l_id/5570 CPU: 1 PID: 5570 Comm: v4l_id Not tainted 6.9.0-rc3-syzkaller-00344-g8f2c057754b2 #0 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:114 print_address_description mm/kasan/report.c:377 [inline] print_report+0xc3/0x620 mm/kasan/report.c:488 kasan_report+0xd9/0x110 mm/kasan/report.c:601 v4l2_fh_init+0x27d/0x2c0 drivers/media/v4l2-core/v4l2-fh.c:25 v4l2_fh_open+0x89/0xc0 drivers/media/v4l2-core/v4l2-fh.c:63 em28xx_v4l2_open+0x250/0x7e0 drivers/media/usb/em28xx/em28xx-video.c:2155 v4l2_open+0x228/0x490 drivers/media/v4l2-core/v4l2-dev.c:427 chrdev_open+0x26d/0x6f0 fs/char_dev.c:414 do_dentry_open+0x8da/0x18c0 fs/open.c:955 do_open fs/namei.c:3642 [inline] path_openat+0x1dfb/0x2990 fs/namei.c:3799 do_filp_open+0x1dc/0x430 fs/namei.c:3826 do_sys_openat2+0x17a/0x1e0 fs/open.c:1406 do_sys_open fs/open.c:1421 [inline] __do_sys_openat fs/open.c:1437 [inline] __se_sys_openat fs/open.c:1432 [inline] __x64_sys_openat+0x175/0x210 fs/open.c:1432 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcf/0x260 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fabc7d7d9a4 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:00007ffce614a5b0 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007ffce614a7c8 RCX: 00007fabc7d7d9a4 RDX: 0000000000000000 RSI: 00007ffce614bf21 RDI: 00000000ffffff9c RBP: 00007ffce614bf21 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffce614a7e0 R14: 000055b2f13b3670 R15: 00007fabc7f40a80 Allocated by task 5493: 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:370 [inline] __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:387 kmalloc include/linux/slab.h:628 [inline] kzalloc include/linux/slab.h:749 [inline] em28xx_v4l2_init+0x114/0x4070 drivers/media/usb/em28xx/em28xx-video.c:2534 em28xx_init_extension+0x137/0x200 drivers/media/usb/em28xx/em28xx-core.c:1116 request_module_async+0x61/0x70 drivers/media/usb/em28xx/em28xx-cards.c:3405 process_one_work+0x9a9/0x1ac0 kernel/workqueue.c:3254 process_scheduled_works kernel/workqueue.c:3335 [inline] worker_thread+0x6c8/0xf70 kernel/workqueue.c:3416 kthread+0x2c1/0x3a0 kernel/kthread.c:388 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 Freed by task 5493: 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:579 poison_slab_object mm/kasan/common.c:240 [inline] __kasan_slab_free+0x11d/0x1a0 mm/kasan/common.c:256 kasan_slab_free include/linux/kasan.h:184 [inline] slab_free_hook mm/slub.c:2106 [inline] slab_free mm/slub.c:4280 [inline] kfree+0x129/0x390 mm/slub.c:4390 em28xx_free_v4l2 drivers/media/usb/em28xx/em28xx-video.c:2120 [inline] kref_put include/linux/kref.h:65 [inline] em28xx_v4l2_init+0x22a9/0x4070 drivers/media/usb/em28xx/em28xx-video.c:2903 em28xx_init_extension+0x137/0x200 drivers/media/usb/em28xx/em28xx-core.c:1116 request_module_async+0x61/0x70 drivers/media/usb/em28xx/em28xx-cards.c:3405 process_one_work+0x9a9/0x1ac0 kernel/workqueue.c:3254 process_scheduled_works kernel/workqueue.c:3335 [inline] worker_thread+0x6c8/0xf70 kernel/workqueue.c:3416 kthread+0x2c1/0x3a0 kernel/kthread.c:388 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 The buggy address belongs to the object at ffff888020f10000 which belongs to the cache kmalloc-8k of size 8192 The buggy address is located 1856 bytes inside of freed 8192-byte region [ffff888020f10000, ffff888020f12000) The buggy address belongs to the physical page: page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x20f10 head: order:3 entire_mapcount:0 nr_pages_mapped:0 pincount:0 flags: 0xfff80000000840(slab|head|node=0|zone=1|lastcpupid=0xfff) page_type: 0xffffffff() raw: 00fff80000000840 ffff888015043180 dead000000000100 dead000000000122 raw: 0000000000000000 0000000080020002 00000001ffffffff 0000000000000000 head: 00fff80000000840 ffff888015043180 dead000000000100 dead000000000122 head: 0000000000000000 0000000080020002 00000001ffffffff 0000000000000000 head: 00fff80000000003 ffffea000083c401 ffffea000083c448 00000000ffffffff head: 0000000800000000 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 1, tgid 1 (swapper/0), ts 11508590801, free_ts 0 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x2d4/0x350 mm/page_alloc.c:1534 prep_new_page mm/page_alloc.c:1541 [inline] get_page_from_freelist+0xa28/0x3780 mm/page_alloc.c:3317 __alloc_pages+0x22b/0x2460 mm/page_alloc.c:4575 __alloc_pages_node include/linux/gfp.h:238 [inline] alloc_pages_node include/linux/gfp.h:261 [inline] alloc_slab_page mm/slub.c:2175 [inline] allocate_slab mm/slub.c:2338 [inline] new_slab+0xcc/0x3a0 mm/slub.c:2391 ___slab_alloc+0x66d/0x1790 mm/slub.c:3525 __slab_alloc.constprop.0+0x56/0xb0 mm/slub.c:3610 __slab_alloc_node mm/slub.c:3663 [inline] slab_alloc_node mm/slub.c:3835 [inline] __do_kmalloc_node mm/slub.c:3965 [inline] __kmalloc+0x3b4/0x440 mm/slub.c:3979 kmalloc_array include/linux/slab.h:665 [inline] fb_show_logo_line drivers/video/fbdev/core/fb_logo.c:313 [inline] fb_show_logo+0x10e5/0x2410 drivers/video/fbdev/core/fb_logo.c:502 fbcon_switch+0xf32/0x12f0 drivers/video/fbdev/core/fbcon.c:2175 redraw_screen+0x2bf/0x760 drivers/tty/vt/vt.c:957 con2fb_init_display drivers/video/fbdev/core/fbcon.c:806 [inline] set_con2fb_map+0x796/0x1060 drivers/video/fbdev/core/fbcon.c:865 do_fb_registered drivers/video/fbdev/core/fbcon.c:2972 [inline] fbcon_fb_registered+0x21d/0x670 drivers/video/fbdev/core/fbcon.c:2988 do_register_framebuffer drivers/video/fbdev/core/fbmem.c:449 [inline] register_framebuffer+0x485/0x840 drivers/video/fbdev/core/fbmem.c:515 __drm_fb_helper_initial_config_and_unlock+0xd82/0x1650 drivers/gpu/drm/drm_fb_helper.c:1871 drm_fb_helper_initial_config drivers/gpu/drm/drm_fb_helper.c:1936 [inline] drm_fb_helper_initial_config+0x44/0x60 drivers/gpu/drm/drm_fb_helper.c:1928 drm_fbdev_generic_client_hotplug+0x1a6/0x280 drivers/gpu/drm/drm_fbdev_generic.c:279 page_owner free stack trace missing Memory state around the buggy address: ffff888020f10600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888020f10680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff888020f10700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888020f10780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888020f10800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================