syzbot

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BUG: KASAN: use-after-free in v4l2_fh_init+0x279/0x2c0 drivers/media/v4l2-core/v4l2-fh.c:25
Read of size 8 at addr ffff88803fae88b8 by task v4l_id/8601

CPU: 1 PID: 8601 Comm: v4l_id Not tainted 5.14.0-rc3-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:105
 print_address_description.constprop.0.cold+0x6c/0x2d6 mm/kasan/report.c:233
 __kasan_report mm/kasan/report.c:419 [inline]
 kasan_report.cold+0x83/0xdf mm/kasan/report.c:436
 v4l2_fh_init+0x279/0x2c0 drivers/media/v4l2-core/v4l2-fh.c:25
 v4l2_fh_open+0x88/0xc0 drivers/media/v4l2-core/v4l2-fh.c:63
 em28xx_v4l2_open+0x11c/0x570 drivers/media/usb/em28xx/em28xx-video.c:2163
 v4l2_open+0x21c/0x3f0 drivers/media/v4l2-core/v4l2-dev.c:427
 chrdev_open+0x266/0x770 fs/char_dev.c:414
 do_dentry_open+0x4c8/0x11d0 fs/open.c:826
 do_open fs/namei.c:3374 [inline]
 path_openat+0x1c23/0x27f0 fs/namei.c:3507
 do_filp_open+0x1aa/0x400 fs/namei.c:3534
 do_sys_openat2+0x16d/0x420 fs/open.c:1204
 do_sys_open fs/open.c:1220 [inline]
 __do_sys_open fs/open.c:1228 [inline]
 __se_sys_open fs/open.c:1224 [inline]
 __x64_sys_open+0x119/0x1c0 fs/open.c:1224
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7f3821706840
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:00007ffe30e806c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000002
RAX: ffffffffffffffda RBX: 00007ffe30e80838 RCX: 00007f3821706840
RDX: 00007f38216f2ea0 RSI: 0000000000000000 RDI: 00007ffe30e81f1e
RBP: 0000000000000003 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000002 R11: 0000000000000246 R12: 00005578438148d0
R13: 00007ffe30e80830 R14: 0000000000000000 R15: 0000000000000000

Allocated by task 8478:
 kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38
 kasan_set_track mm/kasan/common.c:46 [inline]
 set_alloc_info mm/kasan/common.c:434 [inline]
 ____kasan_kmalloc mm/kasan/common.c:513 [inline]
 ____kasan_kmalloc mm/kasan/common.c:472 [inline]
 __kasan_kmalloc+0x98/0xc0 mm/kasan/common.c:522
 kasan_kmalloc include/linux/kasan.h:264 [inline]
 kmem_cache_alloc_trace+0x1e4/0x480 mm/slab.c:3575
 kmalloc include/linux/slab.h:591 [inline]
 kzalloc include/linux/slab.h:721 [inline]
 em28xx_v4l2_init drivers/media/usb/em28xx/em28xx-video.c:2542 [inline]
 em28xx_v4l2_init.cold+0x93/0x329d drivers/media/usb/em28xx/em28xx-video.c:2520
 em28xx_init_extension+0x12f/0x1f0 drivers/media/usb/em28xx/em28xx-core.c:1126
 request_module_async+0x5d/0x70 drivers/media/usb/em28xx/em28xx-cards.c:3410
 process_one_work+0x98d/0x1630 kernel/workqueue.c:2276
 worker_thread+0x658/0x11f0 kernel/workqueue.c:2422
 kthread+0x3e5/0x4d0 kernel/kthread.c:319
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295

Freed by task 8478:
 kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38
 kasan_set_track+0x1c/0x30 mm/kasan/common.c:46
 kasan_set_free_info+0x20/0x30 mm/kasan/generic.c:360
 ____kasan_slab_free mm/kasan/common.c:366 [inline]
 ____kasan_slab_free mm/kasan/common.c:328 [inline]
 __kasan_slab_free+0xcd/0x100 mm/kasan/common.c:374
 kasan_slab_free include/linux/kasan.h:230 [inline]
 __cache_free mm/slab.c:3445 [inline]
 kfree+0x106/0x2c0 mm/slab.c:3803
 kref_put.isra.0+0x6f/0xa0 include/linux/kref.h:65
 em28xx_v4l2_init drivers/media/usb/em28xx/em28xx-video.c:2911 [inline]
 em28xx_v4l2_init.cold+0x263/0x329d drivers/media/usb/em28xx/em28xx-video.c:2520
 em28xx_init_extension+0x12f/0x1f0 drivers/media/usb/em28xx/em28xx-core.c:1126
 request_module_async+0x5d/0x70 drivers/media/usb/em28xx/em28xx-cards.c:3410
 process_one_work+0x98d/0x1630 kernel/workqueue.c:2276
 worker_thread+0x658/0x11f0 kernel/workqueue.c:2422
 kthread+0x3e5/0x4d0 kernel/kthread.c:319
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295

The buggy address belongs to the object at ffff88803fae8000
 which belongs to the cache kmalloc-16k of size 16384
The buggy address is located 2232 bytes inside of
 16384-byte region [ffff88803fae8000, ffff88803faec000)
The buggy address belongs to the page:
page:ffffea0000feba00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x3fae8
head:ffffea0000feba00 order:3 compound_mapcount:0 compound_pincount:0
flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000010200 ffffea0000f4d408 ffff888010841c50 ffff888010840b00
raw: 0000000000000000 ffff88803fae8000 0000000100000001 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 0x2420c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_COMP|__GFP_THISNODE), pid 8478, ts 92658518419, free_ts 82645319032
 prep_new_page mm/page_alloc.c:2436 [inline]
 get_page_from_freelist+0xa72/0x2f80 mm/page_alloc.c:4169
 __alloc_pages+0x1b2/0x500 mm/page_alloc.c:5391
 __alloc_pages_node include/linux/gfp.h:570 [inline]
 kmem_getpages mm/slab.c:1377 [inline]
 cache_grow_begin+0x75/0x460 mm/slab.c:2593
 cache_alloc_refill+0x27f/0x380 mm/slab.c:2965
 ____cache_alloc mm/slab.c:3048 [inline]
 ____cache_alloc mm/slab.c:3031 [inline]
 __do_cache_alloc mm/slab.c:3275 [inline]
 slab_alloc mm/slab.c:3316 [inline]
 kmem_cache_alloc_trace+0x38c/0x480 mm/slab.c:3573
 kmalloc include/linux/slab.h:591 [inline]
 kzalloc include/linux/slab.h:721 [inline]
 em28xx_v4l2_init drivers/media/usb/em28xx/em28xx-video.c:2542 [inline]
 em28xx_v4l2_init.cold+0x93/0x329d drivers/media/usb/em28xx/em28xx-video.c:2520
 em28xx_init_extension+0x12f/0x1f0 drivers/media/usb/em28xx/em28xx-core.c:1126
 request_module_async+0x5d/0x70 drivers/media/usb/em28xx/em28xx-cards.c:3410
 process_one_work+0x98d/0x1630 kernel/workqueue.c:2276
 worker_thread+0x658/0x11f0 kernel/workqueue.c:2422
 kthread+0x3e5/0x4d0 kernel/kthread.c:319
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1346 [inline]
 free_pcp_prepare+0x2c5/0x780 mm/page_alloc.c:1397
 free_unref_page_prepare mm/page_alloc.c:3332 [inline]
 free_unref_page+0x19/0x690 mm/page_alloc.c:3411
 __put_page+0xf9/0x3f0 mm/swap.c:127
 put_page include/linux/mm.h:1246 [inline]
 page_to_skb+0x977/0xc60 drivers/net/virtio_net.c:497
 receive_mergeable drivers/net/virtio_net.c:1031 [inline]
 receive_buf+0x335b/0x6310 drivers/net/virtio_net.c:1141
 virtnet_receive drivers/net/virtio_net.c:1433 [inline]
 virtnet_poll+0x5bf/0x11c0 drivers/net/virtio_net.c:1542
 __napi_poll+0xaf/0x440 net/core/dev.c:7047
 napi_poll net/core/dev.c:7114 [inline]
 net_rx_action+0x801/0xb40 net/core/dev.c:7201
 __do_softirq+0x29b/0x9c2 kernel/softirq.c:558
 invoke_softirq kernel/softirq.c:432 [inline]
 __irq_exit_rcu+0x16e/0x1c0 kernel/softirq.c:636
 irq_exit_rcu+0x5/0x20 kernel/softirq.c:648
 common_interrupt+0xa4/0xd0 arch/x86/kernel/irq.c:240
 asm_common_interrupt+0x1e/0x40 arch/x86/include/asm/idtentry.h:629
 native_safe_halt arch/x86/include/asm/irqflags.h:51 [inline]
 arch_safe_halt arch/x86/include/asm/irqflags.h:89 [inline]
 acpi_safe_halt drivers/acpi/processor_idle.c:109 [inline]
 acpi_idle_do_entry+0x1c6/0x250 drivers/acpi/processor_idle.c:553
 acpi_idle_enter+0x361/0x500 drivers/acpi/processor_idle.c:688
 cpuidle_enter_state+0x1b1/0xc80 drivers/cpuidle/cpuidle.c:237

Memory state around the buggy address:
 ffff88803fae8780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88803fae8800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88803fae8880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                        ^
 ffff88803fae8900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88803fae8980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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