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BUG: KASAN: slab-use-after-free in dvb_frontend_release+0x374/0x414 drivers/media/dvb-core/dvb_frontend.c:2916
Read of size 4 at addr ffff0000cba3903c by task syz.3.447/6733

CPU: 0 UID: 0 PID: 6733 Comm: syz.3.447 Not tainted syzkaller #0 PREEMPT 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/02/2026
Call trace:
 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:499 (C)
 __dump_stack+0x30/0x40 lib/dump_stack.c:94
 dump_stack_lvl+0xd8/0x12c lib/dump_stack.c:120
 print_address_description+0xb0/0x238 mm/kasan/report.c:378
 print_report+0x68/0x84 mm/kasan/report.c:482
 kasan_report+0x8c/0xc4 mm/kasan/report.c:595
 __asan_report_load4_noabort+0x20/0x2c mm/kasan/report_generic.c:380
 dvb_frontend_release+0x374/0x414 drivers/media/dvb-core/dvb_frontend.c:2916
 __fput+0x338/0x74c fs/file_table.c:512
 ____fput+0x20/0x30 fs/file_table.c:540
 task_work_run+0x1cc/0x25c kernel/task_work.c:233
 get_signal+0xf30/0x1094 kernel/signal.c:2810
 arch_do_signal_or_restart+0x288/0x444c arch/arm64/kernel/signal.c:1665
 __exit_to_user_mode_loop kernel/entry/common.c:66 [inline]
 exit_to_user_mode_loop+0x70/0x17c kernel/entry/common.c:101
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline]
 arm64_syscall_exit_to_user_mode arch/arm64/kernel/entry-common.c:88 [inline]
 el0_svc+0x18c/0x260 arch/arm64/kernel/entry-common.c:737
 el0t_64_sync_handler+0x48/0x148 arch/arm64/kernel/entry-common.c:755
 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:594

Allocated by task 1:
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x40/0x78 mm/kasan/common.c:78
 kasan_save_alloc_info+0x44/0x54 mm/kasan/generic.c:570
 poison_kmalloc_redzone mm/kasan/common.c:398 [inline]
 __kasan_kmalloc+0x9c/0xb4 mm/kasan/common.c:415
 kasan_kmalloc include/linux/kasan.h:263 [inline]
 __kmalloc_cache_noprof+0x2e8/0x5ec mm/slub.c:5515
 _kmalloc_noprof include/linux/slab.h:969 [inline]
 _kzalloc_noprof include/linux/slab.h:1290 [inline]
 dvb_register_device+0x1a4/0x16e0 drivers/media/dvb-core/dvbdev.c:472
 dvb_register_frontend+0x474/0x6d0 drivers/media/dvb-core/dvb_frontend.c:3051
 vidtv_bridge_dvb_init drivers/media/test-drivers/vidtv/vidtv_bridge.c:438 [inline]
 vidtv_bridge_probe+0x5a4/0xa58 drivers/media/test-drivers/vidtv/vidtv_bridge.c:510
 platform_probe+0x100/0x1a4 drivers/base/platform.c:1439
 call_driver_probe drivers/base/dd.c:-1 [inline]
 really_probe+0x29c/0x800 drivers/base/dd.c:706
 __driver_probe_device+0x1e0/0x350 drivers/base/dd.c:868
 driver_probe_device+0x6c/0x19c drivers/base/dd.c:898
 __driver_attach+0x168/0x384 drivers/base/dd.c:1292
 bus_for_each_dev+0x128/0x1b4 drivers/base/bus.c:383
 driver_attach+0x50/0x60 drivers/base/dd.c:1310
 bus_add_driver+0x208/0x500 drivers/base/bus.c:763
 driver_register+0x220/0x310 drivers/base/driver.c:174
 __platform_driver_register+0x90/0xa4 drivers/base/platform.c:927
 vidtv_bridge_init+0x4c/0x74 drivers/media/test-drivers/vidtv/vidtv_bridge.c:602
 do_one_initcall+0x274/0xc38 init/main.c:1347
 do_initcall_level+0x12c/0x1c4 init/main.c:1409
 do_initcalls+0x70/0xd0 init/main.c:1425
 do_basic_setup+0x7c/0x90 init/main.c:1445
 kernel_init_freeable+0x268/0x3a8 init/main.c:1658
 kernel_init+0x24/0x1dc init/main.c:1548
 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:842

Freed by task 6733:
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x40/0x78 mm/kasan/common.c:78
 kasan_save_free_info+0x58/0x70 mm/kasan/generic.c:584
 poison_slab_object mm/kasan/common.c:253 [inline]
 __kasan_slab_free+0x74/0xa4 mm/kasan/common.c:285
 kasan_slab_free include/linux/kasan.h:235 [inline]
 slab_free_hook mm/slub.c:2705 [inline]
 slab_free mm/slub.c:6405 [inline]
 kfree+0x188/0x690 mm/slub.c:6720
 dvb_free_device drivers/media/dvb-core/dvbdev.c:616 [inline]
 kref_put include/linux/kref.h:65 [inline]
 dvb_device_put+0x64/0xd0 drivers/media/dvb-core/dvbdev.c:629
 dvb_generic_release+0xec/0x158 drivers/media/dvb-core/dvbdev.c:169
 dvb_frontend_release+0x114/0x414 drivers/media/dvb-core/dvb_frontend.c:2914
 __fput+0x338/0x74c fs/file_table.c:512
 ____fput+0x20/0x30 fs/file_table.c:540
 task_work_run+0x1cc/0x25c kernel/task_work.c:233
 get_signal+0xf30/0x1094 kernel/signal.c:2810
 arch_do_signal_or_restart+0x288/0x444c arch/arm64/kernel/signal.c:1665
 __exit_to_user_mode_loop kernel/entry/common.c:66 [inline]
 exit_to_user_mode_loop+0x70/0x17c kernel/entry/common.c:101
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline]
 arm64_syscall_exit_to_user_mode arch/arm64/kernel/entry-common.c:88 [inline]
 el0_svc+0x18c/0x260 arch/arm64/kernel/entry-common.c:737
 el0t_64_sync_handler+0x48/0x148 arch/arm64/kernel/entry-common.c:755
 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:594

The buggy address belongs to the object at ffff0000cba39000
 which belongs to the cache kmalloc-256 of size 256
The buggy address is located 60 bytes inside of
 freed 256-byte region [ffff0000cba39000, ffff0000cba39100)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff0000cba38c00 pfn:0x10ba38
head: order:1 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0x5ffc00000000240(workingset|head|node=0|zone=2|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 05ffc00000000240 ffff0000c0001b40 fffffdffc3e5a610 fffffdffc3e5a190
raw: ffff0000cba38c00 000000080010000f 00000000f5000000 0000000000000000
head: 05ffc00000000240 ffff0000c0001b40 fffffdffc3e5a610 fffffdffc3e5a190
head: ffff0000cba38c00 000000080010000f 00000000f5000000 0000000000000000
head: 05ffc00000000001 fffffdffc32e8e01 00000000ffffffff 00000000ffffffff
head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000002
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff0000cba38f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff0000cba38f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff0000cba39000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                        ^
 ffff0000cba39080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff0000cba39100: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
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