================================================================== BUG: KASAN: use-after-free in v4l2_open+0x62c/0x670 drivers/media/v4l2-core/v4l2-dev.c:437 Read of size 4 at addr ffff8881befa0968 by task v4l_id/3242 CPU: 0 PID: 3242 Comm: v4l_id Not tainted 5.9.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x107/0x16e lib/dump_stack.c:118 print_address_description.constprop.0+0x1c/0x210 mm/kasan/report.c:383 __kasan_report mm/kasan/report.c:513 [inline] kasan_report.cold+0x37/0x7c mm/kasan/report.c:530 v4l2_open+0x62c/0x670 drivers/media/v4l2-core/v4l2-dev.c:437 chrdev_open+0x266/0x770 fs/char_dev.c:414 do_dentry_open+0x4b4/0x1090 fs/open.c:817 do_open fs/namei.c:3251 [inline] path_openat+0x190d/0x2690 fs/namei.c:3368 do_filp_open+0x17e/0x3c0 fs/namei.c:3395 do_sys_openat2+0x16d/0x420 fs/open.c:1168 do_sys_open fs/open.c:1184 [inline] __do_sys_open fs/open.c:1192 [inline] __se_sys_open fs/open.c:1188 [inline] __x64_sys_open+0x119/0x1c0 fs/open.c:1188 do_syscall_64+0x2d/0x40 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x7f24e191a840 Code: 73 01 c3 48 8b 0d 68 77 20 00 f7 d8 64 89 01 48 83 c8 ff c3 66 0f 1f 44 00 00 83 3d 89 bb 20 00 00 75 10 b8 02 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 31 c3 48 83 ec 08 e8 1e f6 ff ff 48 89 04 24 RSP: 002b:00007ffcf5492218 EFLAGS: 00000246 ORIG_RAX: 0000000000000002 RAX: ffffffffffffffda RBX: 00007ffcf5492388 RCX: 00007f24e191a840 RDX: 00007f24e1906ea0 RSI: 0000000000000000 RDI: 00007ffcf5493f24 RBP: 0000000000000003 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000002 R11: 0000000000000246 R12: 0000561b0484d8d0 R13: 00007ffcf5492380 R14: 0000000000000000 R15: 0000000000000000 Allocated by task 3177: kasan_save_stack+0x1b/0x40 mm/kasan/common.c:48 kasan_set_track mm/kasan/common.c:56 [inline] __kasan_kmalloc.constprop.0+0xc2/0xd0 mm/kasan/common.c:461 kmalloc include/linux/slab.h:554 [inline] kzalloc include/linux/slab.h:666 [inline] kobject_uevent_env+0x236/0x1540 lib/kobject_uevent.c:523 driver_bound+0x1a8/0x300 drivers/base/dd.c:384 really_probe+0x40b/0xde0 drivers/base/dd.c:600 driver_probe_device+0x26b/0x3d0 drivers/base/dd.c:738 __device_attach_driver+0x1d1/0x290 drivers/base/dd.c:844 bus_for_each_drv+0x15f/0x1e0 drivers/base/bus.c:431 __device_attach+0x228/0x4a0 drivers/base/dd.c:912 bus_probe_device+0x1e4/0x290 drivers/base/bus.c:491 device_add+0xb51/0x1c70 drivers/base/core.c:2926 usb_set_configuration+0xf05/0x18a0 drivers/usb/core/message.c:2025 usb_generic_driver_probe+0xba/0xf2 drivers/usb/core/generic.c:240 usb_probe_device+0xd9/0x2c0 drivers/usb/core/driver.c:293 really_probe+0x291/0xde0 drivers/base/dd.c:553 driver_probe_device+0x26b/0x3d0 drivers/base/dd.c:738 __device_attach_driver+0x1d1/0x290 drivers/base/dd.c:844 bus_for_each_drv+0x15f/0x1e0 drivers/base/bus.c:431 __device_attach+0x228/0x4a0 drivers/base/dd.c:912 bus_probe_device+0x1e4/0x290 drivers/base/bus.c:491 device_add+0xb51/0x1c70 drivers/base/core.c:2926 usb_new_device.cold+0x71d/0xfd4 drivers/usb/core/hub.c:2554 hub_port_connect drivers/usb/core/hub.c:5208 [inline] hub_port_connect_change drivers/usb/core/hub.c:5348 [inline] port_event drivers/usb/core/hub.c:5494 [inline] hub_event+0x2361/0x4390 drivers/usb/core/hub.c:5576 process_one_work+0x94c/0x15f0 kernel/workqueue.c:2269 worker_thread+0x64c/0x1120 kernel/workqueue.c:2415 kthread+0x392/0x470 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294 Freed by task 3177: kasan_save_stack+0x1b/0x40 mm/kasan/common.c:48 kasan_set_track+0x1c/0x30 mm/kasan/common.c:56 kasan_set_free_info+0x1b/0x30 mm/kasan/generic.c:355 __kasan_slab_free+0xf3/0x130 mm/kasan/common.c:422 slab_free_hook mm/slub.c:1544 [inline] slab_free_freelist_hook+0x5d/0x150 mm/slub.c:1577 slab_free mm/slub.c:3138 [inline] kfree+0xbe/0x470 mm/slub.c:4119 kobject_uevent_env+0x2af/0x1540 lib/kobject_uevent.c:625 driver_bound+0x1a8/0x300 drivers/base/dd.c:384 really_probe+0x40b/0xde0 drivers/base/dd.c:600 driver_probe_device+0x26b/0x3d0 drivers/base/dd.c:738 __device_attach_driver+0x1d1/0x290 drivers/base/dd.c:844 bus_for_each_drv+0x15f/0x1e0 drivers/base/bus.c:431 __device_attach+0x228/0x4a0 drivers/base/dd.c:912 bus_probe_device+0x1e4/0x290 drivers/base/bus.c:491 device_add+0xb51/0x1c70 drivers/base/core.c:2926 usb_set_configuration+0xf05/0x18a0 drivers/usb/core/message.c:2025 usb_generic_driver_probe+0xba/0xf2 drivers/usb/core/generic.c:240 usb_probe_device+0xd9/0x2c0 drivers/usb/core/driver.c:293 really_probe+0x291/0xde0 drivers/base/dd.c:553 driver_probe_device+0x26b/0x3d0 drivers/base/dd.c:738 __device_attach_driver+0x1d1/0x290 drivers/base/dd.c:844 bus_for_each_drv+0x15f/0x1e0 drivers/base/bus.c:431 __device_attach+0x228/0x4a0 drivers/base/dd.c:912 bus_probe_device+0x1e4/0x290 drivers/base/bus.c:491 device_add+0xb51/0x1c70 drivers/base/core.c:2926 usb_new_device.cold+0x71d/0xfd4 drivers/usb/core/hub.c:2554 hub_port_connect drivers/usb/core/hub.c:5208 [inline] hub_port_connect_change drivers/usb/core/hub.c:5348 [inline] port_event drivers/usb/core/hub.c:5494 [inline] hub_event+0x2361/0x4390 drivers/usb/core/hub.c:5576 process_one_work+0x94c/0x15f0 kernel/workqueue.c:2269 worker_thread+0x64c/0x1120 kernel/workqueue.c:2415 kthread+0x392/0x470 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294 The buggy address belongs to the object at ffff8881befa0000 which belongs to the cache kmalloc-4k of size 4096 The buggy address is located 2408 bytes inside of 4096-byte region [ffff8881befa0000, ffff8881befa1000) The buggy address belongs to the page: page:00000000ee59a58b refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1befa0 head:00000000ee59a58b order:3 compound_mapcount:0 compound_pincount:0 flags: 0x200000000010200(slab|head) raw: 0200000000010200 dead000000000100 dead000000000122 ffff8881da042140 raw: 0000000000000000 0000000000040004 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8881befa0800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8881befa0880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8881befa0900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8881befa0980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8881befa0a00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================